[ { "idx": 1, "title": "Fine-Grained Attribute Level Locking Scheme for Collaborative Scientific Workflow Development", "abstract": "Scientific Workflow Management Systems are being widely used in recent years for data-intensive analysis tasks or domain-specific discoveries. It often becomes challenging for an individual to effectively analyze the large scale scientific data of relatively higher complexity and dimensions, and requires a collaboration of multiple members of different disciplines. Hence, researchers have focused on designing collaborative workflow management systems. However, consistency management in the face of conflicting concurrent operations of the collaborators is a major challenge in such systems. In this paper, we propose a locking scheme (e.g., collaborator gets write access to non-conflicting components of the workflow at a given time) to facilitate consistency management in collaborative scientific workflow management systems. The proposed method allows locking workflow components at a granular level in addition to supporting locks on a targeted part of the collaborative workflow. We conducted several experiments to analyze the performance of the proposed method in comparison to related existing methods. Our studies show that the proposed method can reduce the average waiting time of a collaborator by up to 36.19% in comparison to existing descendent modular level locking techniques for collaborative scientific workflow management systems.", "authors": [ "Mostaeen, Golam", "Roy, Banani", "Roy, Chanchal K.", "Schneider, Kevin A." ], "keywords": [ "" ], "year": "2018", "source": "2018 IEEE INTERNATIONAL CONFERENCE ON SERVICES COMPUTING (IEEE SCC 2018)", "publication_type": "C", "point2d": [ 26.147733688354492, -42.55968475341797 ], "cluster": 5.0 }, { "idx": 4, "title": "CCAligner: a token based large-gap clone detector", "abstract": "Copying code and then pasting with large number of edits is a common activity in software development, and the pasted code is a kind of complicated Type-3 clone. Due to large number of edits, we consider the clone as a large-gap clone. Large-gap clone can reflect the extension of code, such as change and improvement. The existing state-of-the-art clone detectors suffer from several limitations in detecting large-gap clones. In this paper, we propose a tool, CCAligner, using code window that considers e edit distance for matching to detect large-gap clones. In our approach, a novel e-mismatch index is designed and the asymmetric similarity coefficient is used for similarity measure. We thoroughly evaluate CCAligner both for large-gap clone detection, and for general Type-1, Type-2 and Type-3 clone detection. The results show that CCAligner performs better than other competing tools in large-gap clone detection, and has the best execution time for 10MLOC input with good precision and recall in general Type-1 to Type-3 clone detection. Compared with existing state-of-the-art tools, CCAligner is the best performing large-gap clone detection tool, and remains competitive with the best clone detectors in general Type-1, Type-2 and Type-3 clone detection.", "authors": [ "Wang, Pengcheng", "Svajlenko, Jeffrey", "Wu, Yanzhao", "Xu, Yun", "Roy, Chanchal K." ], "keywords": [ "Clone Detection", "Large-gap Clone", "Evaluation" ], "year": "2018", "source": "PROCEEDINGS 2018 IEEE/ACM 40TH INTERNATIONAL CONFERENCE ON SOFTWARE ENGINEERING (ICSE)", "publication_type": "C", "point2d": [ 31.195158004760742, -94.5877914428711 ], "cluster": 5.0 }, { "idx": 10, "title": "The Influence of Shallow Taliks on Permafrost Thaw and Active Layer Dynamics in Subarctic Canada", "abstract": "Measurements of active layer thickness (ALT) are typically taken at the end of summer, a time synonymous with maximum thaw depth. By definition, the active layer is the layer above permafrost that freezes and thaws annually. This study, conducted in peatlands of subarctic Canada, in the zone of thawing discontinuous permafrost, demonstrates that the entire thickness of ground atop permafrost does not always refreeze over winter. In these instances, a talik exists between the permafrost and active layer, and ALT must therefore be measured by the depth of refreeze at the end of winter. As talik thickness increases at the expense of the underlying permafrost, ALT is shown to simultaneously decrease. This suggests that the active layer has a maximum thickness that is controlled by the amount of energy lost from the ground to the atmosphere during winter. The taliks documented in this study are relatively thin (<2m) and exist on forested peat plateaus. The presence of taliks greatly affects the stability of the underlying permafrost. Vertical permafrost thaw was found to be significantly greater in areas with taliks (0.07myear(-1)) than without (0.01myear(-1)). Furthermore, the spatial distribution of areas with taliks increased between 2011 and 2015 from 20% to 48%, a phenomenon likely caused by an anomalously large ground heat flux input in 2012. Rapid talik development and accelerated permafrost thaw indicates that permafrost loss may exhibit a nonlinear response to warming temperatures. Documentation of refreeze depths and talik development is needed across the circumpolar north.", "authors": [ "Connon, Ryan", "Devoie, Elise", "Hayashi, Masaki", "Veness, Tyler", "Quinton, William" ], "keywords": [ "talik", "active layer", "suprapermafrost layer", "permafrost thaw", "peatlands" ], "year": "2018", "source": "JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE", "publication_type": "J", "point2d": [ -29.719820022583008, 43.31584930419922 ], "cluster": 13.0 }, { "idx": 11, "title": "Assessing local adaptation vs. plasticity under different resource conditions in seedlings of a dominant boreal tree species", "abstract": "Under changing climate conditions, understanding local adaptation of plants is crucial to predicting the resilience of ecosystems. We selected black spruce (Picea mariana), the most dominant tree species in the North American boreal forest, in order to evaluate local adaptation vs. plasticity across regions experiencing some of the most extreme climate warming globally. Seeds from three provenances across the latitudinal extent of this species in northwestern Canada were planted in a common garden study in growth chambers. Two levels of two resource conditions were applied (low/high nutrient and ambient/elevated CO2) in a fully factorial design and we measured physiological traits, allocational traits, growth and survival. We found significant differences in height, root length and biomass among populations, with southern populations producing the largest seedlings. However, we did not detect meaningful significant differences among nutrient or CO2 treatments in any traits measured, and there were no consistent population-level differences in physiological traits or allocation patterns. We found that there was greater mortality after simulated winter in the high nutrient treatment, which may reflect an important shift in seedling growth strategies under increased resource availability. Our study provides important insight into how this dominant boreal tree species might respond to the changing climate conditions predicted in this region.", "authors": [ "Sniderhan, Anastasia E.", "McNickle, Gordon G.", "Baltzer, Jennifer L." ], "keywords": [ "Boreal forest", "climate change", "common garden", "functional traits", "resilience", "resource availability" ], "year": "2018", "source": "AOB PLANTS", "publication_type": "J", "point2d": [ -49.0301513671875, 69.28350830078125 ], "cluster": 17.0 }, { "idx": 14, "title": "A Numerical Study of the June 2013 Flood-Producing Extreme Rainstorm over Southern Alberta", "abstract": "A devastating, flood-producing rainstorm occurred over southern Alberta, Canada, from 19 to 22 June 2013. The long-lived, heavy rainfall event was a result of complex interplays between topographic, synoptic, and convective processes that rendered an accurate simulation of this event a challenging task. In this study, the Weather Research and Forecasting (WRF) Model was used to simulate this event and was validated against several observation datasets. Both the timing and location of the model precipitation agree closely with the observations, indicating that the WRF Model is capable of reproducing this type of severe event. Sensitivity tests with different microphysics schemes were conducted and evaluated using equitable threat and bias frequency scores. The WRF double-moment 6-class microphysics scheme (WDM6) generally performed better when compared with other schemes. The application of a conventional convective/stratiform separation algorithm shows that convective activity was dominant during the early stages, then evolved into predominantly stratiform precipitation later in the event. The HYSPLIT back-trajectory analysis and regional water budget assessments using WRF simulation output suggest that the moisture for the precipitation was mainly from recycling antecedent soil moisture through evaporation and evapotranspiration over the Canadian Prairies and the U.S. Great Plains. This analysis also shows that a small fraction of the moisture can be traced back to the northeastern Pacific, and direct uptake from the Gulf of Mexico was not a significant source in this event.", "authors": [ "Li, Yanping", "Szeto, Kit", "Stewart, Ronald E.", "Theriault, Julie M.", "Chen, Liang", "Kochtubajda, Bohdan", "Liu, Anthony", "Boodoo, Sudesh", "Goodson, Ron", "Mooney, Curtis", "Kurkute, Sopan" ], "keywords": [ "" ], "year": "2017", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -43.175716400146484, -22.47624397277832 ], "cluster": 1.0 }, { "idx": 16, "title": "Carbon, water and energy exchange dynamics of a young pine plantation forest during the initial fourteen years of growth", "abstract": "This study presents the energy, water, and carbon (C) flux dynamics of a young afforested temperate white pine (Pines strobus L.) forest in southern Ontario, Canada during the initial fourteen years (2003-2016) of establishment. Energy fluxes, namely, net radiation (Rn), latent heat (LE), and sensible heat (H) flux increased over time, due to canopy development. Annual values of ground heat flux (G) peaked in 2007 and then gradually declined in response to canopy closure. The forest became a consistent C-sink only 5 years after establishment owing in part to low respiratory fluxes from the former agricultural, sandy soils with low residual soil organic matter. Mean annual values of gross ecosystem productivity (GEP), ecosystem respiration (RE), and net ecosystem productivity (NEP) ranged from 494 to 1913, 515 to 1774 and -126 to 216 g Cm-2 year(-1) respectively, over the study period. Annual evapotranspiration (ET) values ranged from 328 to 429 mm year(-1) over the same period. Water use efficiency (WUE) increased with stand age with a mean WUE value of 3.92 g C kg-(1) H2O from 2008 to 2016. Multivariable linear regression analysis conducted using observed data suggested that the overall, C and water dynamics of the stand were primarily driven by radiation and temperature, both of which explained 77%, 48%, 28%, and 76% of the variability in GEP, RE, NEP, and ET, respectively. However, late summer droughts, which were prevalent in the region, reduced NEP. The reduction in NEP was enhanced when summer drought events were accompanied by increased heat such as those in 2005, 2012 and 2016. This study contributes to our understanding of the energy, water and C dynamics of afforested temperate conifer plantations and how these forests may respond to changing climate conditions during the crucial initial stage of their life cycle. Our findings also demonstrate the potential of pine plantation stands to sequester atmospheric CO2 in eastern North America.", "authors": [ "Chan, Felix C. C.", "Arain, M. Altaf", "Khomik, Myroslava", "Brodeur, Jason J.", "Peichl, Matthias", "Restrepo-Coupe, Natalia", "Thorne, Robin", "Beamesderfer, Eric", "McKenzie, Shawn", "Xu, Bing", "Croft, Holly", "Pejam, Mahmoud", "Trant, Janelle", "Kula, Michelle", "Skubel, Rachel" ], "keywords": [ "Carbon", "Water", "Energy balance", "Net ecosystem productivity", "Eddy covariance", "Afforestation", "Temperate forest", "White pine", "CA-TP1" ], "year": "2018", "source": "FOREST ECOLOGY AND MANAGEMENT", "publication_type": "J", "point2d": [ -52.58484649658203, 64.73628997802734 ], "cluster": 17.0 }, { "idx": 17, "title": "Validation of the SMAP freeze/thaw product using categorical triple collocation", "abstract": "The landscape freeze/thaw (FT) state plays an important role in local, regional and global weather and climate, but is difficult to monitor. The Soil Moisture Active Passive (SMAP) satellite mission provides hemispheric estimates of landscape FT state at a spatial resolution of approximately 362 km(2). Previous validation studies of SMAP and other satellite FT products have compared satellite retrievals with point estimates obtained from in situ measurements of air and/or soil temperature. Differences between the two are attributed to errors in the satellite retrieval. However, significant differences can occur between satellite and in-situ estimates solely due to differences in scale between the measurements; these differences can be viewed as 'representativeness errors' in the in-situ product, caused by using a point estimate to represent a large-scale spatial average. Most previous validation studies of landscape FT state have neglected representativeness errors entirely, resulting in conservative estimates of satellite retrieval skill. In this study, we use a variant of triple collocation called 'categorical triple collocation' - a technique that uses model, satellite and in-situ estimates to obtain relative performance rankings of all three products, without neglecting representativeness errors - to validate the SMAP landscape FT product. Performance rankings are obtained for nine sites at northern latitudes. We also investigate differences between using air or soil temperatures to estimate FT state, and between using morning (6 AM) or evening (6 PM) estimates. Overall, at most sites, the SMAP product or in-situ FT measurement is ranked first, and the model FT product is ranked last (although rankings vary across sites). These results suggest SMAP is adding value to model simulations, providing higher-accuracy estimates of landscape FT states compared to models and, in some cases, even in-situ estimates, when representativeness errors are properly accounted for in the validation analysis.", "authors": [ "Lyu, Haobo", "McColl, Kaighin A.", "Li, Xinlu", "Derksen, Chris", "Berg, Aaron", "Black, T. Andrew", "Eusldrchen, Eugenie", "Loranty, Michael", "Pulliainen, Jouni", "Rautiainen, Kimmo", "Rowlandson, Tracy", "Roy, Alexandre", "Royer, Alain", "Langlois, Alexandre", "Stephens, Jilmarie", "Lu, Hui", "Entekhabi, Dara" ], "keywords": [ "SMAP", "Triple collocation", "Validation", "Freeze/thaw" ], "year": "2018", "source": "REMOTE SENSING OF ENVIRONMENT", "publication_type": "J", "point2d": [ -77.4625015258789, 23.69480323791504 ], "cluster": 8.0 }, { "idx": 19, "title": "Capturing agricultural soil freeze/thaw state through remote sensing and ground observations: A soil freeze/thaw validation campaign", "abstract": "A field campaign was conducted October 30th to November 13th, 2015 with the intention of capturing diurnal soil freeze/thaw state at multiple scales using ground measurements and remote sensing measurements. On four of the five sampling days, we observed a significant difference between morning (frozen scenario) and afternoon (thawed scenario) ground-based measurements of the soil relative permittivity. These results were supported by an in situ soil moisture and temperature network (installed at the scale of a spaceborne passive microwave pixel) which indicated surface soil temperatures fell below 0 degrees C for the same four sampling dates. Ground-based radiometers appeared to be highly sensitive to F/T conditions of the very surface of the soil and indicated normalized polarization index (NPR) values that were below the defined freezing values during the morning sampling period on all sampling dates. The Scanning L-band Active Passive (SLAP) instrumentation, flown over the study region, showed very good agreement with the ground-based radiometers, with freezing states observed on all four days that the airborne observations covered the fields with ground-based radiometers. The Soil Moisture Active Passive (SMAP) satellite had morning overpasses on three of the sampling days, and indicated frozen conditions on two of those days. It was found that > 60% of the in situ network had to indicate surface temperatures below 0 degrees C before SMAP indicated freezing conditions. This was also true of the SLAP radiometer measurements. The SMAP, SLAP and ground-based radiometer measurements all indicated freezing conditions when soil temperature sensors installed at 5 cm depth were not frozen.", "authors": [ "Rowlandson, Tracy L.", "Berg, Aaron A.", "Roy, Alexander", "Kim, Edward", "Lara, Renato Pardo", "Powers, Jarrett", "Lewis, Kristin", "Houser, Paul", "McDonald, Kyle", "Toose, Peter", "Wu, Albert", "De Marco, Eugenia", "Derksen, Chris", "Entin, Jared", "Colliander, Andreas", "Xu, Xiaolan", "Mavrovic, Alex" ], "keywords": [ "Freeze/thaw", "Passive microwave", "SLAP", "SMAP", "Impedance probes" ], "year": "2018", "source": "REMOTE SENSING OF ENVIRONMENT", "publication_type": "J", "point2d": [ -74.09223937988281, 24.42479133605957 ], "cluster": 2.0 }, { "idx": 20, "title": "Plot-scale assessment of soil freeze/thaw detection and variability with impedance probes: implications for remote sensing validation networks", "abstract": "Several large in-situ soil moisture-monitoring networks currently exist over seasonally frozen regions that may have use for the validation of remote sensing soil freeze/thaw (F/T) products. However, further understanding of how the existing network instrumentation responds to changes in near surface soil F/T is recommended. This case study describes the results of a small plot-scale (7 x 7 m) study from November 2013 through April 2014 instrumented with 36 impedance probes. Soil temperature and real dielectric permittivity (epsilon'(r)) were measured every 15 minutes during F/T transition periods at shallow soil depths (0-10 cm). Categorical soil temperature and real dielectric permittivity techniques were used to define the soil F/T state during these periods. Results demonstrate that both methods for detecting soil F/T have strong agreement (84.7-95.6%) during the fall freeze but weak agreement (53.3-60.9%) during the spring thaw. Bootstrapping results demonstrated both techniques showed a mean difference within +/- 1.0 degrees C and +/- 1.4 epsilon'(r) between the standard 5 cm below surface measurement depth and probes at 2, 10 and integrated 0-5.7 cm depths installed within the same study plot. Overall this study demonstrates that the Hydra Probe offers promise for near surface soil F/T detection using existing soil moisture monitoring networks particularly for the fall freeze.", "authors": [ "Williamson, Matthew", "Adams, Justin R.", "Berg, Aaron A.", "Derksen, Chris", "Toose, Peter", "Walker, Anne" ], "keywords": [ "frozen soils", "Hydra Probe", "impedance probes", "remote sensing", "soil freeze/thaw", "soil moisture probes" ], "year": "2018", "source": "HYDROLOGY RESEARCH", "publication_type": "J", "point2d": [ -74.98251342773438, 25.73995018005371 ], "cluster": 2.0 }, { "idx": 21, "title": "L-band radiometry freeze/thaw validation using air temperature and ground measurements", "abstract": "Assessment of remote sensing derived freeze/thaw products from L-band radiometry requires ground validation. There is growing interest in utilizing soil moisture networks to meet this validation requirement, although it remains unclear whether the current configuration of these networks is appropriate. To address this issue, a small-scale L-band radiometry study was conducted from November 2014 to April 2015 to capture F/T events. Soil moisture probes measuring soil temperature and real dielectric permittivity were installed within a surface-based L-band radiometer footprint vertically at the surface and horizontally at 2.5, 5 and 10cm depths. A binary freeze/thaw product was derived using radiometer brightness temperatures and compared to the binary F/T classification using soil temperature, real dielectric permittivity and air temperature measurements. The results of the study found that shallow probe depths (vertical and 2.5cm) resulted in an improvement in the radiometer F/T product accuracy over the standard 5cm instrument depth currently utilized at soil moisture networks. Air temperature based approaches for validation result in lower accuracy for F/T events with no snow or wet snow, but performed similarly to soil measurements of temperature and permittivity during dry snow F/T events.", "authors": [ "Williamson, Matthew", "Rowlandson, Tracy L.", "Berg, Aaron A.", "Roy, Alexandre", "Toose, Peter", "Derksen, Chris", "Arnold, Lauren", "Tetlock, Erica" ], "keywords": [ "" ], "year": "2018", "source": "REMOTE SENSING LETTERS", "publication_type": "J", "point2d": [ -72.97332000732422, 24.83884048461914 ], "cluster": 2.0 }, { "idx": 22, "title": "Adapting forest management to climate change: The state of science and applications in Canada and the United States", "abstract": "Over the last decade, considerable progress has been made in developing vulnerability assessment tools and in applying these methodologies to identify and implement climate change adaptation approaches for forest ecosystems and forest management organizations in Canada and the United States. However, given that adaptation processes are in early stages, evaluation of approaches across agency, organizational, and geographic boundaries is critical. Thus, we conducted a qualitative comparison of three conceptual frameworks for climate change vulnerability assessment and adaptation efforts in the Canadian and United States forestry agency contexts. We focus our comparison on components of the conceptual frameworks, development process, intended users, similarities and differences in institutional contexts (geographic and organizational), and implementation. Finally, we present case studies to illustrate how the frameworks have been implemented on the ground and in different contexts. Despite different trajectories of development, the Canadian and US forest agencies have developed similar conceptual frameworks for vulnerability assessment and adaptation. We found that key components of the conceptual frameworks included: establishing a science-management partnership; evaluating current forest conditions and management objectives; conducting detailed science-based vulnerability assessments; developing adaptation approaches and on-the-ground tactics; implementing adaptation tactics; and monitoring outcomes and adjusting as needed. However, the contexts in which these frameworks are implemented vary considerably within and between countries, mostly because of differences in land ownership, management norms, and organizational cultures. On-the-ground applications, although slow to develop, are beginning to proliferate, providing examples that can be emulated by others. A strategy for accelerating implementation of adaptation in Canada and the United States is suggested, building on successes by federal agencies and extending to public, private, and crown lands.", "authors": [ "Halofsky, Jessica E.", "Andrews-Key, Sheri A.", "Edwards, Jason E.", "Johnston, Mark H.", "Nelson, Harry W.", "Peterson, David L.", "Schmitt, Kristen M.", "Swanston, Christopher W.", "Williamson, Tim B." ], "keywords": [ "Climate change", "Vulnerability assessment", "Adaptation", "Community of practice", "Science-management partnerships", "Sustainable forest management" ], "year": "2018", "source": "FOREST ECOLOGY AND MANAGEMENT", "publication_type": "J", "point2d": [ -0.08342764526605606, 45.99549865722656 ], "cluster": 15.0 }, { "idx": 24, "title": "The Persistence of Brines in Sedimentary Basins", "abstract": "Brines are commonly found at depth in sedimentary basins. Many of these brines are known to be connate waters that have persisted since the early Paleozoic Era. Yet questions remain about their distribution and mechanisms for retention at depth in the Earth's crust. Here we demonstrate that there is insufficient topography to drive these dense fluids from the bottom of deep sedimentary basins. Our assessment based on driving force ratio indicates that sedimentary basins with driving force ratio > 1 contain connate waters and frequently host large evaporite deposits. These stagnant conditions appear to be relatively stable over geological time and insensitive to factors such as glaciations, erosion, compaction, and hydrocarbon generation.", "authors": [ "Ferguson, Grant", "McIntosh, Jennifer C.", "Grasby, Stephen E.", "Hendry, M. Jim", "Jasechko, Scott", "Lindsay, Matthew B. J.", "Luijendijk, Elco" ], "keywords": [ "brines", "sedimentary basins", "variable density flow", "connate water" ], "year": "2018", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ 6.583563804626465, 24.42316246032715 ], "cluster": 18.0 }, { "idx": 25, "title": "Salt dissolution and permeability in the Western Canada Sedimentary Basin", "abstract": "Extensive dissolution of evaporites has occurred in the Williston Basin, Canada, but it is unclear what effect this has had on bulk permeability. The bulk of this dissolution has occurred from the Prairie Evaporite Formation, which is predominantly halite and potash. However, minor evaporite beds and porosity infilling have also been removed from the overlying Dawson Bay and Souris River formations, which are predominantly carbonates. This study examines whether permeability values in the Dawson Bay and Souris River formations have been affected by dissolution, by analyzing 142 drillstem tests from those formations. For both the Dawson Bay and Souris River formations, the highest permeabilities were found in areas where halite dissolution had occurred. However, the mean permeabilities were not statistically different in areas of halite dissolution compared to those containing connate water. Subsequent precipitation of anhydrite is known to have clogged pore spaces and fractures in some instances. Geochemical relationships found here support this idea but there is no statistically significant relationship between anhydrite saturation and permeability. Geomechanical effects, notably closure of fractures due to collapse, could be a mitigating factor. The results indicate that coupling dissolution and precipitation to changes in permeability in regional flow models remains a significant challenge.", "authors": [ "Woroniuk, Blake", "Tipton, Kristl", "Grasby, Stephen E.", "McIntosh, Jennifer C.", "Ferguson, Grant" ], "keywords": [ "Hydraulic properties", "Hydrochemistry", "Canada", "Carbonate rocks", "Evaporites" ], "year": "2019", "source": "HYDROGEOLOGY JOURNAL", "publication_type": "J", "point2d": [ 15.889739036560059, 42.685638427734375 ], "cluster": 18.0 }, { "idx": 26, "title": "Salt dissolution and permeability in the Western Canada Sedimentary Basin", "abstract": "Extensive dissolution of evaporites has occurred in the Williston Basin, Canada, but it is unclear what effect this has had on bulk permeability. The bulk of this dissolution has occurred from the Prairie Evaporite Formation, which is predominantly halite and potash. However, minor evaporite beds and porosity infilling have also been removed from the overlying Dawson Bay and Souris River formations, which are predominantly carbonates. This study examines whether permeability values in the Dawson Bay and Souris River formations have been affected by dissolution, by analyzing 142 drillstem tests from those formations. For both the Dawson Bay and Souris River formations, the highest permeabilities were found in areas where halite dissolution had occurred. However, the mean permeabilities were not statistically different in areas of halite dissolution compared to those containing connate water. Subsequent precipitation of anhydrite is known to have clogged pore spaces and fractures in some instances. Geochemical relationships found here support this idea but there is no statistically significant relationship between anhydrite saturation and permeability. Geomechanical effects, notably closure of fractures due to collapse, could be a mitigating factor. The results indicate that coupling dissolution and precipitation to changes in permeability in regional flow models remains a significant challenge.", "authors": [ "Woroniuk, Blake", "Tipton, Kristl", "Grasby, Stephen E.", "McIntosh, Jennifer C.", "Ferguson, Grant" ], "keywords": [ "Hydraulic properties", "Hydrochemistry", "Canada", "Carbonate rocks", "Evaporites" ], "year": "2019", "source": "HYDROGEOLOGY JOURNAL", "publication_type": "J", "point2d": [ 15.889739036560059, 42.685638427734375 ], "cluster": 18.0 }, { "idx": 27, "title": "Salt dissolution and permeability in the Western Canada Sedimentary Basin", "abstract": "Extensive dissolution of evaporites has occurred in the Williston Basin, Canada, but it is unclear what effect this has had on bulk permeability. The bulk of this dissolution has occurred from the Prairie Evaporite Formation, which is predominantly halite and potash. However, minor evaporite beds and porosity infilling have also been removed from the overlying Dawson Bay and Souris River formations, which are predominantly carbonates. This study examines whether permeability values in the Dawson Bay and Souris River formations have been affected by dissolution, by analyzing 142 drillstem tests from those formations. For both the Dawson Bay and Souris River formations, the highest permeabilities were found in areas where halite dissolution had occurred. However, the mean permeabilities were not statistically different in areas of halite dissolution compared to those containing connate water. Subsequent precipitation of anhydrite is known to have clogged pore spaces and fractures in some instances. Geochemical relationships found here support this idea but there is no statistically significant relationship between anhydrite saturation and permeability. Geomechanical effects, notably closure of fractures due to collapse, could be a mitigating factor. The results indicate that coupling dissolution and precipitation to changes in permeability in regional flow models remains a significant challenge.", "authors": [ "Woroniuk, Blake", "Tipton, Kristl", "Grasby, Stephen E.", "McIntosh, Jennifer C.", "Ferguson, Grant" ], "keywords": [ "Hydraulic properties", "Hydrochemistry", "Canada", "Carbonate rocks", "Evaporites" ], "year": "2019", "source": "HYDROGEOLOGY JOURNAL", "publication_type": "J", "point2d": [ 15.889739036560059, 42.685638427734375 ], "cluster": 18.0 }, { "idx": 28, "title": "The predictability of a lake phytoplankton community, over time-scales of hours to years", "abstract": "Forecasting changes to ecological communities is one of the central challenges in ecology. However, nonlinear dependencies, biotic interactions and data limitations have limited our ability to assess howpredictable communities are. Here, we used a machine learning approach and environmental monitoring data (biological, physical and chemical) to assess the predictability of phytoplankton celldensity in one lake across an unprecedented range of time-scales. Communities were highly predictable over hours to months: model R-2 decreased from 0.89 at 4hours to 0.74 at 1month, and in a long-term dataset lacking fine spatial resolution, from 0.46 at 1month to 0.32 at 10years. When cyanobacterial and eukaryotic algal cell densities were examined separately, model-inferred environmental growth dependencies matched laboratory studies, and suggested novel trade-offs governing their competition. High-frequency monitoring and machine learning can set prediction targets for process-based models and help elucidate the mechanisms underlying ecological dynamics.", "authors": [ "Thomas, Mridul K.", "Fontana, Simone", "Reyes, Marta", "Kehoe, Michael", "Pomati, Francesco" ], "keywords": [ "Cyanobacteria", "environmental monitoring", "forecasting", "machine learning", "phytoplankton", "prediction", "time series" ], "year": "2018", "source": "ECOLOGY LETTERS", "publication_type": "J", "point2d": [ 59.492462158203125, 19.317216873168945 ], "cluster": 19.0 }, { "idx": 29, "title": "Boreal tree hydrodynamics: asynchronous, diverging, yet complementary", "abstract": "Water stress has been identified as a key mechanism of the contemporary increase in tree mortality rates in northwestern North America. However, a detailed analysis of boreal tree hydrodynamics and their interspecific differences is still lacking. Here we examine the hydraulic behaviour of co-occurring larch (Larix laricina) and black spruce (Picea mariana), two characteristic boreal tree species, near the southern limit of the boreal ecozone in central Canada. Sap flux density (J(s)), concurrently recorded stem radius fluctuations and meteorological conditions are used to quantify tree hydraulic functioning and to scrutinize tree water-use strategies. Our analysis revealed asynchrony in the diel hydrodynamics of the two species with the initial rise in J(s) occurring 2 h earlier in larch than in black spruce. Interspecific differences in larch and black spruce crown architecture explained the observed asynchrony in their hydraulic functioning. Furthermore, the two species exhibited diverging stomatal regulation strategies with larch and black spruce employing relatively isohydric and anisohydric behaviour, respectively. Such asynchronous and diverging tree-level hydrodynamics provide new insights into the ecosystem-level complementarity in tree form and function, with implications for understanding boreal forests' water and carbon dynamics and their resilience to environmental stress.", "authors": [ "Pappas, Christoforos", "Matheny, Ashley M.", "Baltzer, Jennifer L.", "Barr, Alan G.", "Black, T. Andrew", "Bohrer, Gil", "Detto, Matteo", "Maillet, Jason", "Roy, Alexandre", "Sonnentag, Oliver", "Stephens, Jilmarie" ], "keywords": [ "boreal forest", "crown complementarity", "dendrometers", "isohydricity", "Larix laricina (larch, tamarack)", "Picea mariana (black spruce)", "plant hydraulics", "sap flow" ], "year": "2018", "source": "TREE PHYSIOLOGY", "publication_type": "J", "point2d": [ -53.52781677246094, 71.84119415283203 ], "cluster": 3.0 }, { "idx": 30, "title": "Minor contribution of overstorey transpiration to landscape evapotranspiration in boreal permafrost peatlands", "abstract": "e Evapotranspiration (ET) is a key component of the water cycle, whereby accurate partitioning of ET into evaporation and transpiration provides important information about the intrinsically coupled carbon, water, and energy fluxes. Currently, global estimates of partitioned evaporative and transpiration fluxes remain highly uncertain, especially for high-latitude ecosystems where measurements are scarce. Forested peat plateaus underlain by permafrost and surrounded by permafrost-free wetlands characterize approximately 60% (7.0x10(7)km(2)) of Canadian peatlands. In this study, 22 Picea mariana (black spruce) individuals, the most common tree species of the North American boreal forest, were instrumented with sap flow sensors within the footprint of an eddy covariance tower measuring ET from a forest-wetland mosaic landscape. Sap flux density (J(S)), together with remote sensing data and in situ measurements of canopy structure, was used to upscale tree-level J(S) to overstorey transpiration (T-BS). Black spruce trees growing in nutrient-poor permafrost peat soils wre found to have lower mean J(S) than those growing in mineral soils. Overall, T-BS contributed less than 1% to landscape ET. Climate-change-induced forest loss and the expansion of wetlands may further minimize the contributions of T-BS to ET and increase the contribution of standing water.", "authors": [ "Warren, Rebecca K.", "Pappas, Christoforos", "Helbig, Manuel", "Chasmer, Laura E.", "Berg, Aaron A.", "Baltzer, Jennifer L.", "Quinton, William L.", "Sonnentag, Oliver" ], "keywords": [ "boreal forest", "eddy covariance", "evapotranspiration", "peatlands", "permafrost", "sap flow", "wetlands" ], "year": "2018", "source": "ECOHYDROLOGY", "publication_type": "J", "point2d": [ -20.251632690429688, 57.99059295654297 ], "cluster": 3.0 }, { "idx": 32, "title": "Inconsequential effects of flooding in 2014 on lakes in the Peace-Athabasca Delta (Canada) due to long-term drying", "abstract": "Climate-driven decline in freshwater supplied by rivers draining the hydrographic apex of western North America has ramifications for downstream ecosystems and society. For the Peace-Athabasca Delta (PAD), floods from the Peace and Athabasca rivers are critical for sustaining abundant shallow water habitat, but their frequency has been in decline for decades over much of its area. Here, we assess current hydrological and limnological status in the PAD by integrating spatial and temporal data. Analysis of water isotope compositions and water chemistry measured at numerous lakes across the delta shows that hydro-limnological effects of the large-scale ice-jam flood event of 2014 failed to persist beyond the early ice-free season of 2015. Isotope-inferred paleohydrological records from five hydrologically representative lakes in the PAD indicate that periodic desiccation during the Little Ice Age occurred at the most elevated basin in response to locally arid climatic conditions, yet other lower elevation sites were influenced by high water level on Lake Athabasca owing to increased snowmelt- and glacier-derived river discharge. In contrast, water isotope data during the past 15 yr at all five lakes consistently document the strong role of evaporation, a trend which began in the early to mid-20th century according to sediment records and is indicative of widespread aridity unprecedented during the past 400 yr. We suggest that integration of hydrological and limnological approaches over space and time is needed to inform assessment of contemporary lake conditions in large, complex floodplain landscapes.", "authors": [ "Remmer, Casey R.", "Klemt, Wynona H.", "Wolfe, Brent B.", "Hall, Roland, I" ], "keywords": [ "" ], "year": "2018", "source": "LIMNOLOGY AND OCEANOGRAPHY", "publication_type": "J", "point2d": [ 4.413632869720459, 13.679890632629395 ], "cluster": 13.0 }, { "idx": 33, "title": "Quantification of uncertainties in conifer sap flow measured with the thermal dissipation method", "abstract": "Trees play a key role in the global hydrological cycle and measurements performed with the thermal dissipation method (TDM) have been crucial in providing whole-tree water-use estimates. Yet, different data processing to calculate whole-tree water use encapsulates uncertainties that have not been systematically assessed. We quantified uncertainties in conifer sap flux density (F-d) and stand water use caused by commonly applied methods for deriving zero-flow conditions, dampening and sensor calibration. Their contribution has been assessed using a stem segment calibration experiment and 4yr of TDM measurements in Picea abies and Larix decidua growing in contrasting environments. Uncertainties were then projected on TDM data from different conifers across the northern hemisphere. Commonly applied methods mostly underestimated absolute F-d. Lacking a site- and species-specific calibrations reduced our stand water-use measurements by 37% and induced uncertainty in northern hemisphere F-d. Additionally, although the interdaily variability was maintained, disregarding dampening and/or applying zero-flow conditions that ignored night-time water use reduced the correlation between environment and F-d. The presented ensemble of calibration curves and proposed dampening correction, together with the systematic quantification of data-processing uncertainties, provide crucial steps in improving whole-tree water-use estimates across spatial and temporal scales.", "authors": [ "Peters, Richard L.", "Fonti, Patrick", "Frank, David C.", "Poyatos, Rafael", "Pappas, Christoforos", "Kahmen, Ansgar", "Carraro, Vinicio", "Prendin, Angela Luisa", "Schneider, Loic", "Baltzer, Jennifer L.", "Baron-Gafford, Greg A.", "Dietrich, Lars", "Heinrich, Ingo", "Minor, Rebecca L.", "Sonnentag, Oliver", "Matheny, Ashley M.", "Wightman, Maxwell G.", "Steppe, Kathy" ], "keywords": [ "calibration", "night-time transpiration", "sap flux density", "thermal dissipation probes", "transpiration", "uncertainty analysis", "wounding effects" ], "year": "2018", "source": "NEW PHYTOLOGIST", "publication_type": "J", "point2d": [ -57.29846954345703, 51.99534225463867 ], "cluster": 3.0 }, { "idx": 34, "title": "Missing pieces to modeling the Arctic-Boreal puzzle", "abstract": "NASA has launched the decade-long Arctic-Boreal Vulnerability Experiment (ABoVE). While the initial phases focus on field and airborne data collection, early integration with modeling activities is important to benefit future modeling syntheses. We compiled feedback from ecosystem modeling teams on key data needs, which encompass carbon biogeochemistry, vegetation, permafrost, hydrology, and disturbance dynamics. A suite of variables was identified as part of this activity with a critical requirement that they are collected concurrently and representatively over space and time. Individual projects in ABoVE may not capture all these needs, and thus there is both demand and opportunity for the augmentation of field observations, and synthesis of the observations that are collected, to ensure that science questions and integrated modeling activities are successfully implemented.", "authors": [ "Fisher, Joshua B.", "Hayes, Daniel J.", "Schwalm, Christopher R.", "Huntzinger, Deborah N.", "Stofferahn, Eric", "Schaefer, Kevin", "Luo, Yiqi", "Wullschleger, Stan D.", "Goetz, Scott", "Miller, Charles E.", "Griffith, Peter", "Chadburn, Sarah", "Chatterjee, Abhishek", "Ciais, Philippe", "Douglas, Thomas A.", "Genet, Helene", "Ito, Akihiko", "Neigh, Christopher S. R.", "Poulter, Benjamin", "Rogers, Brendan M.", "Sonnentag, Oliver", "Tian, Hanqin", "Wang, Weile", "Xue, Yongkang", "Yang, Zong-Liang", "Zeng, Ning", "Zhang, Zhen" ], "keywords": [ "ABoVE", "arctic", "arctic boreal vulnerability experiment", "boreal", "model", "requirements", "uncertainty" ], "year": "2018", "source": "ENVIRONMENTAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -42.07714080810547, 51.977806091308594 ], "cluster": 17.0 }, { "idx": 35, "title": "Warmer spring conditions increase annual methane emissions from a boreal peat landscape with sporadic permafrost", "abstract": "About a fifth of the global wetland methane emissions originate from boreal peatlands, which represent an important land cover type in boreal landscapes in the sporadic permafrost zone. There, rising air temperatures could lead to warmer spring and longer growing seasons, changing landscape methane emissions. To quantify the effect of warmer spring conditions on methane emissions of a boreal peat landscape in the sporadic permafrost zone of northwestern Canada, we analyzed four years (2013-2016) of methane fluxes measured with the eddy covariance technique and long-term (1951-2016) meteorological observations from a nearby climate station. In May, after snowmelt was complete, mean air temperatures were more than 2 degrees C warmer in 2013, 2015, and 2016 than in 2014. Mean growing season (May-August) air temperatures, in contrast, differed by less than 1 degrees C over the four years. WarmerMay air temperatures caused earlier wetland soil warming, with temperatures rising from similar to 0 degrees C to > 12 degrees C 25 to 40 days earlier and leading to similar to 6 degrees C warmer mean soil temperatures between May and June. However, from July to August, soil temperatures were similar among years. Mean May to August and annual methane emissions (6.4 g CH4 m(-2) and 9.4 g CH4 m(-2), respectively) of years with warmer spring (i.e. May) temperatures exceeded emissions during the cooler year by 20%-30% (4.5 g CH4 m(-2) and 7.2 g CH4 m(-2), respectively). Among years with warmer springs, growing season methane emissions varied little (+/- 0.5 g CH4 m(-2)). The observed interannual differences are most likely caused by a strong soil temperature control on methane fluxes and large soil temperature differences during the spring. Thus, in a warming climate, methane emissions from waterlogged boreal peat landscapes at the southern limit of permafrost are likely to increase in response to more frequent occurrences of warm springs.", "authors": [ "Helbig, Manuel", "Quinton, William L.", "Sonnentag, Oliver" ], "keywords": [ "methane", "peatland", "climate change", "permafrost", "soil temperature", "vegetation productiviy" ], "year": "2017", "source": "ENVIRONMENTAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -30.541181564331055, 62.41166687011719 ], "cluster": 9.0 }, { "idx": 36, "title": "Non-uniform growth dynamics of a dominant boreal tree species (Picea mariana) in the face of rapid climate change", "abstract": "Northwestern Canada's boreal forest has experienced rapid warming, drying, and changes to permafrost, yet the growth responses and mechanisms driving productivity have been under-studied at broad scales. Forest responses are largely driven by black spruce (Picea mariana (Mill.) B.S.P.) - the region's most widespread and dominant tree. We collected tree ring samples from four black spruce-dominated sites across 15 degrees of latitude, spanning gradients in climate and permafrost. We investigated (i) differences in growth patterns, (ii) variations in climatic drivers of growth, and (iii) trends in water use efficiency (WUE) through C-13 isotope analysis from 1945 to 2006. We found positive growth trends at all sites except those at mid-latitude, where rapid permafrost thaw drove declines. Annual growth was lowest at the tree limit site and highest at the tree line. Climatic drivers of these growth patterns varied; positive growth responses at the northerly sites were associated with warmer winters, whereas Delta C-13 trends and climate-growth responses at mid-latitude sites indicated that growth was limited by moisture availability. Delta C-13 signatures indicated increased WUE at the southernmost site, with no significant trends at northern sites. These results suggest that warming will increase the growth of trees at the northern extent of black spruce, but southerly areas may face drought stress if precipitation does not balance evapotranspiration.", "authors": [ "Sniderhan, Anastasia E.", "Mamet, Steven D.", "Baltzer, Jennifer L." ], "keywords": [ "Picea mariana", "black spruce", "dendrochronology", "stable carbon isotope", "climate warming" ], "year": "2021", "source": "CANADIAN JOURNAL OF FOREST RESEARCH", "publication_type": "J", "point2d": [ -48.53281021118164, 68.20454406738281 ], "cluster": 17.0 }, { "idx": 37, "title": "Mercury and omega-3 fatty acid profiles in freshwater fish of the Dehcho Region, Northwest Territories: Informing risk benefit assessments", "abstract": "Traditional foods have significant nutritional, sociocultural and economic value in subarctic First Nations communities of the Northwest Territories, and play a crucial role in promoting cultural continuity and sovereignty. Omega-3 polyunsaturated fatty acids (N-3 PUFAs), including eicosapentaenoic (EPA) and docosahexaenoic acid (DHA), carry significant benefits for neurocognitive development and cardiovascular health. However, the health risks posed by methylmercury may serve to undermine the benefits of fish consumption in Northern Indigenous communities. The objective of this study was to characterize profiles for mercury (Hg) and fatty acids in fish species harvested across lakes of the Dehcho Region, in the Mackenzie Valley of the Northwest Territories, to better understand the risks and benefits associated with traditional foods. Hg levels increased with trophic position, with the highest levels found in Burbot, Lake Trout, Walleye, and Northern Pike. Lake Trout, along with planktivorous species including Lake Whitefish, Cisco, and Sucker, demonstrated higher N-3 PUFAs than other species. Negative associations were observed between Hg and N-3 PUFAs in Lake Trout, Northern Pike, Walleye and Burbot. Further stratifying these relationships revealed significant interactions by lake. Significant differences observed in fatty acid and Hg profiles across lakes underscore the importance of considering both species-and lake-specific findings. This growing dataset of freshwater fish of the Dehcho will inform future efforts to characterize human Hg exposure profiles using probabilistic dose reconstruction models. (C) 2018 Elsevier B.V. All rights reserved.", "authors": [ "Laird, Matthew J.", "Henao, Juan J. Aristizabal", "Reyes, Ellen S.", "Stark, Ken D.", "Low, George", "Swanson, Heidi K.", "Laird, Brian D." ], "keywords": [ "Mercury", "Omega-3 fatty acids", "First Nations", "Risk-benefit assessment", "Fish consumption", "Subarctic" ], "year": "2018", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 76.88211059570312, -11.317376136779785 ], "cluster": 0.0 }, { "idx": 38, "title": "Design of a human biomonitoring community-based project in the Northwest Territories, Mackenzie Valley Canada, to investigate the links between nutrition, contaminants and country foods", "abstract": "Community-based projects place emphasis on a collaborative approach and facilitate research among Indigenous populations regarding local issues and challenges, such as traditional foods consumption, climate change and health safety. Country foods (locally harvested fish, game birds, land animals and plants), which contribute to improved food security, can also be a primary route of contaminant exposure among populations in remote regions. A community-based project was launched in the Dehcho and Sahtu regions of the Northwest Territories (Canada) to: 1) assess contaminants exposure and nutrition status; 2) investigate the role of country food on nutrient and contaminant levels and 3) understand the determinants of message perception on this issue. Consultation with community members, leadership, local partners and researchers was essential to refine the design of the project and implement it in a culturally relevant way. This article details the design of a community-based biomonitoring study that investigates country food use, contaminant exposure and nutritional status in Canadian subarctic First Nations in the Dehcho and Sahtu regions. Results will support environmental health policies in the future for these communities. The project was designed to explore the risks and benefits of country foods and to inform the development of public health strategies.", "authors": [ "Ratelle, Mylene", "Laird, Matthew", "Majowicz, Shannon", "Skinner, Kelly", "Swanson, Heidi", "Laird, Brian" ], "keywords": [ "Dene", "First Nations", "biomonitoring", "contaminants", "traditional foods", "north", "biomarker", "exposure", "risk assessment", "community" ], "year": "2018", "source": "INTERNATIONAL JOURNAL OF CIRCUMPOLAR HEALTH", "publication_type": "J", "point2d": [ 75.4574966430664, -20.42500877380371 ], "cluster": 7.0 }, { "idx": 39, "title": "Reviews and syntheses: Changing ecosystem influences on soil thermal regimes in northern high-latitude permafrost regions", "abstract": "Soils in Arctic and boreal ecosystems store twice as much carbon as the atmosphere, a portion of which may be released as high-latitude soils warm. Some of the uncertainty in the timing and magnitude of the permafrost-climate feedback stems from complex interactions between ecosystem properties and soil thermal dynamics. Terrestrial ecosystems fundamentally regulate the response of permafrost to climate change by influencing surface energy partitioning and the thermal properties of soil itself. Here we review how Arctic and boreal ecosystem processes influence thermal dynamics in permafrost soil and how these linkages may evolve in response to climate change. While many of the ecosystem characteristics and processes affecting soil thermal dynamics have been examined individually (e.g., vegetation, soil moisture, and soil structure), interactions among these processes are less understood. Changes in ecosystem type and vegetation characteristics will alter spatial patterns of interactions between climate and permafrost. In addition to shrub expansion, other vegetation responses to changes in climate and rapidly changing disturbance regimes will affect ecosystem surface energy partitioning in ways that are important for permafrost. Lastly, changes in vegetation and ecosystem distribution will lead to regional and global biophysical and biogeochemical climate feedbacks that may compound or offset local impacts on permafrost soils. Consequently, accurate prediction of the permafrost carbon climate feedback will require detailed understanding of changes in terrestrial ecosystem distribution and function, which depend on the net effects of multiple feedback processes operating across scales in space and time.", "authors": [ "Loranty, Michael M.", "Abbott, Benjamin W.", "Blok, Daan", "Douglas, Thomas A.", "Epstein, Howard E.", "Forbes, Bruce C.", "Jones, Benjamin M.", "Kholodov, Alexander L.", "Kropp, Heather", "Malhotra, Avni", "Mamet, Steven D.", "Myers-Smith, Isla H.", "Natali, Susan M.", "O'Donnell, Jonathan A.", "Phoenix, Gareth K.", "Rocha, Adrian V.", "Sonnentag, Oliver", "Tape, Ken D.", "Walker, Donald A." ], "keywords": [ "" ], "year": "2018", "source": "BIOGEOSCIENCES", "publication_type": "J", "point2d": [ -35.27045440673828, 50.44099807739258 ], "cluster": 17.0 }, { "idx": 40, "title": "Ancillary vegetation measurements at ICOS ecosystem stations", "abstract": "The Integrated Carbon Observation System is a Pan-European distributed research infrastructure that has as its main goal to monitor the greenhouse gas balance of Europe. The ecosystem component of Integrated Carbon Observation System consists of a multitude of stations where the net greenhouse gas exchange is monitored continuously by eddy covariance measurements while, in addition many other measurements are carried out that are a key to an understanding of the greenhouse gas balance. Amongst them are the continuous meteorological measurements and a set of non-continuous measurements related to vegetation. The latter include Green Area Index, aboveground biomass and litter biomass. The standardized methodology that is used at the Integrated Carbon Observation System ecosystem stations to monitor these vegetation related variables differs between the ecosystem types that are represented within the network, whereby in this paper we focus on forests, grasslands, croplands and mires. For each of the variables and ecosystems a spatial and temporal sampling design was developed so that the variables can be monitored in a consistent way within the ICOS network. The standardisation of the methodology to collect Green Area Index, above ground biomass and litter biomass and the methods to evaluate the quality of the collected data ensures that all stations within the ICOS ecosystem network produce data sets with small and similar errors, which allows for inter-comparison comparisons across the Integrated Carbon Observation System ecosystem network.", "authors": [ "Gielen, Bert", "Acosta, Manuel", "Altimir, Nuria", "Buchmann, Nina", "Cescatte, Alessandro", "Ceschia, Eric", "Fleck, Stefan", "Hortnagal, Lukas", "Klumpp, Katja", "Kolari, Pasi", "Lohile, Annalea", "Loustau, Denis", "Maranon-Jimenez, Sara", "Manisp, Languy", "Matteucci, Giorgio", "Merbold, Lutz", "Metzger, Christine", "Moureaux, Christine", "Montagnani, Leonardo", "Nilsson, Mats B.", "Osborne, Bruce", "Papale, Dario", "Pavelka, Marian", "Saunders, Matthew", "Simioni, Guillaume", "Soudani, Kamel", "Sonnentag, Oliver", "Tallec, Tiphaine", "Tuittila, Eeva-Stiina", "Peichl, Matthias", "Pokorny, Radek", "Vincke, Caroline", "Wohljahrt, Georg" ], "keywords": [ "ICOS", "protocol", "Green Area Index", "aboveground biomass", "litter biomass" ], "year": "2018", "source": "INTERNATIONAL AGROPHYSICS", "publication_type": "J", "point2d": [ -48.10752487182617, 50.67497253417969 ], "cluster": 17.0 }, { "idx": 41, "title": "Towards long-term standardised carbon and greenhouse gas observations for monitoring Europe's terrestrial ecosystems: a review", "abstract": "Research infrastructures play a key role in launching a new generation of integrated long-term, geographically distributed observation programmes designed to monitor climate change, better understand its impacts on global ecosystems, and evaluate possible mitigation and adaptation strategies. The pan-European Integrated Carbon Observation System combines carbon and greenhouse gas (GHG; CO2, CH4, N2O, H2O) observations within the atmosphere, terrestrial ecosystems and oceans. High-precision measurements are obtained using standardised methodologies, are centrally processed and openly available in a traceable and verifiable fashion in combination with detailed metadata. The Integrated Carbon Observation System ecosystem station network aims to sample climate and land-cover variability across Europe. In addition to GHG flux measurements, a large set of complementary data (including management practices, vegetation and soil characteristics) is collected to support the interpretation, spatial upscaling and modelling of observed ecosystem carbon and GHG dynamics. The applied sampling design was developed and formulated in protocols by the scientific community, representing a trade-off between an ideal dataset and practical feasibility. The use of open-access, high-quality and multi-level data products by different user communities is crucial for the Integrated Carbon Observation System in order to achieve its scientific potential and societal value.", "authors": [ "Franz, Daniela", "Acosta, Manuel", "Altimir, Nuria", "Arriga, Nicola", "Arrouays, Dominique", "Aubinet, Marc", "Aurela, Mika", "Ayres, Edward", "Lopez-Ballesteros, Ana", "Barbaste, Mireille", "Berveiller, Daniel", "Biraud, Sebastien", "Boukir, Hakima", "Brown, Timothy", "Bruemmer, Christian", "Buchmann, Nina", "Burba, George", "Carrara, Arnaud", "Cescatti, Allessandro", "Ceschia, Eric", "Clement, Robert", "Cremonese, Edoardo", "Crill, Patrick", "Darenova, Eva", "Dengel, Sigrid", "D'Odorico, Petra", "Filippa, Gianluca", "Fleck, Stefan", "Fratini, Gerardo", "Fuss, Roland", "Gielen, Bert", "Gogo, Sebastien", "Grace, John", "Graf, Alexander", "Grelle, Achim", "Gross, Patrick", "Gruenwald, Thomas", "Haapanala, Sami", "Hehn, Markus", "Heinesch, Bernard", "Heiskanen, Jouni", "Herbst, Mathias", "Herschlein, Christine", "Hortnagl, Lukas", "Hufkens, Koen", "Ibrom, Andreas", "Jolivet, Claudy", "Joly, Lilian", "Jones, Michael", "Kiese, Ralf", "Klemedtsson, Leif", "Kljun, Natascha", "Klumpp, Katja", "Kolari, Pasi", "Kolle, Olaf", "Kowalski, Andrew", "Kutsch, Werner", "Laurila, Tuomas", "de Ligne, Anne", "Linder, Sune", "Lindroth, Anders", "Lohila, Annalea", "Longdoz, Bernhard", "Mammarella, Ivan", "Manise, Tanguy", "Maranon Jimenez, Sara", "Matteucci, Giorgio", "Mauder, Matthias", "Meier, Philip", "Merbold, Lutz", "Mereu, Simone", "Metzger, Stefan", "Migliavacca, Mirco", "Molder, Meelis", "Montagnani, Leonardo", "Moureaux, Christine", "Nelson, David", "Nemitz, Eiko", "Nicolini, Giacomo", "Nilsson, Mats B.", "Op de Beeck, Maarten", "Osborne, Bruce", "Lofvenius, Mikaell Ottosson", "Pavelka, Marian", "Peichl, Matthias", "Peltola, Olli", "Pihlatie, Mari", "Pitacco, Andrea", "Pokorny, Radek", "Pumpanen, Jukka", "Ratie, Celine", "Rebmann, Corinna", "Roland, Marilyn", "Sabbatini, Simone", "Saby, Nicolas P. A.", "Saunders, Matthew", "Schmid, Hans Peter", "Schrumpf, Marion", "Sedlak, Pavel", "Serrano Ortiz, Penelope", "Siebicke, Lukas", "Sigut, Ladislav", "Silvennoinen, Hanna", "Simioni, Guillaume", "Skiba, Ute", "Sonnentag, Oliver", "Soudani, Kamel", "Soule, Patrice", "Steinbrecher, Rainer", "Tallec, Tiphaine", "Thimonier, Anne", "Tuittila, Eeva-Stiina", "Tuovinen, Juha-Pekka", "Vestin, Patrik", "Vincent, Gaelle", "Vincke, Caroline", "Vitale, Domenico", "Waldner, Peter", "Weslien, Per", "Wingate, Lisa", "Wohlfahrt, Georg", "Zahniser, Mark", "Vesala, Timo" ], "keywords": [ "ICOS", "GHG exchange", "carbon cycle", "standardised monitoring", "observational network" ], "year": "2018", "source": "INTERNATIONAL AGROPHYSICS", "publication_type": "J", "point2d": [ -47.17414093017578, 50.651084899902344 ], "cluster": 17.0 }, { "idx": 42, "title": "Dielectric characterization of vegetation at L band using an open-ended coaxial probe", "abstract": "Decoupling the integrated microwave signal originating from soil and vegetation remains a challenge for all microwave remote sensing applications. To improve satellite and airborne microwave data products in forest environments, a precise and reliable estimation of the relative permittivity (epsilon = epsilon' - i epsilon '') of trees is required. We developed an open-ended coaxial probe suitable for in situ permittivity measurements of tree trunks at L-band frequencies (12 GHz). The probe is characterized by uncertainty ratios under 3.3 % for a broad range of relative permittivities (unitless), [2-40] for epsilon' and [0.1-20] for epsilon ''. We quantified the complex number describing the permittivity of seven different tree species in both frozen and thawed states: black spruce, larch, red spruce, balsam fir, red pine, aspen and black cherry. Permittivity variability is substantial and can range up to 300 % for certain species. Our results show that the permittivity of wood is linked to the freeze-thaw state of vegetation and that even short winter thaw events can lead to an increase in vegetation permittivity. The open-ended coaxial probe proved to be precise enough to capture the diurnal cycle of water storage inside the trunk for the length of the growing season.", "authors": [ "Mavrovic, Alex", "Roy, Alexandre", "Royer, Alain", "Filali, Bilal", "Boone, Francois", "Pappas, Christoforos", "Sonnentag, Oliver" ], "keywords": [ "" ], "year": "2018", "source": "GEOSCIENTIFIC INSTRUMENTATION METHODS AND DATA SYSTEMS", "publication_type": "J", "point2d": [ -72.03703308105469, 27.41482162475586 ], "cluster": 3.0 }, { "idx": 44, "title": "eDNA-based bioassessment of coastal sediments impacted by an oil spill", "abstract": "Oil spills offshore can cause long-term ecological effects on coastal marine ecosystems. Despite their important ecological roles in the cycling of energy and nutrients in food webs, effects on bacteria, protists or arthropods are often neglected. Environmental DNA (eDNA) metabarcoding was applied to characterize changes in the structure of micro- and macro-biota communities of surface sediments over a 7 year period since the occurrence of Hebei Spirit oil spill on December 7, 2007. Alterations in diversities and structures of micro- and macro-biota were observed in the contaminated area where concentrations of polycyclic aromatic hydrocarbons were greater. Successions of bacterial, protists and metazoan communities revealed long-term ecological effects of residual oil. Residual oil dominated the largest cluster of the community-environment association network. Presence of bacterial families (Aero-coccaceae and Carnobacteriaceae) and the protozoan family (Platyophryidae) might have conferred sensitivity of communities to oil pollution. Hydrocarbon-degrading bacterial families (Anaerolinaceae, Desulfobacteraceae, Helicobacteraceae and Piscirickettsiaceae) and algal family (Araphid pennate) were resistant to adverse effects of spilt oil. The protistan family (Subulatomonas) and arthropod families (Folsomia, Sarcophagidae Opomyzoidea, and Anomura) appeared to be positively associated with residual oil pollution. eDNA metabarcoding can provide a powerful tool for assessing effects of anthropogenic pollution, such as oil spills on sediment communities and its long-term trends in coastal marine environments. (C) 2018 Elsevier Ltd. All rights reserved.", "authors": [ "Xie, Yuwei", "Zhang, Xiaowei", "Yang, Jianghua", "Kim, Seonjin", "Hong, Seongjin", "Giesy, John P.", "Yim, Un Hyuk", "Shim, Won Joon", "Yu, Hongxia", "Khim, Jong Seong" ], "keywords": [ "Oil spill", "Next-generation sequencing", "Bacteria", "Protist", "Metazoan", "Benthic invertebrates", "Coastal ecosystem" ], "year": "2018", "source": "ENVIRONMENTAL POLLUTION", "publication_type": "J", "point2d": [ 77.21253967285156, 10.694817543029785 ], "cluster": 0.0 }, { "idx": 45, "title": "Perfluorobutanesulfonate Exposure Causes Durable and Transgenerational Dysbiosis of Gut Microbiota in Marine Medaka", "abstract": "Environmental pollutants are known as disruptors of gut microbiota. However, it remains unexplored whether the dysbiosis of gut microbiota by pollutants is durable and transgenerational in teleost. Therefore, this study exposed eggs of marine medaka to environmentally realistic concentrations (0, 1.0, 2.9, or 9.5 mu g/L) of perfluorobutanesulfonate (PFBS), a persistent organic pollutant of emerging concern, until sexual maturity. A proportion of F0 adults was dissected after exposure (F0-exposed). Remaining fish were depurated in clean seawater (F0-depurated). F1 offspring were also cultured in clean seawater for a complete life-cycle. Substantial amounts of PFBS were accumulated in F0-exposed intestines, while F1 intestines contained no PFBS. Significant alterations were observed in physiological activities of F0-exposed and F1 medaka. The gut microbial community in F0-exposed, F0-depurated, and F1 medaka were restructured in a concentration-dependent manner by PFBS exposure. Dysbiosis of gut microbiota caused by PFBS exposure was durable in parents and persisted in the offspring. Significant positive correlations were constructed for the genus Cetobacterium with host intestinal epithelial permeability and production of endotoxin lipopolysaccharides. Overall, this study provided the first insight into durable and transgenerational dysbiosis of gut microbiota and intestinal health by PFBS, highlighting the particular susceptibility of gut to xenobiotic stresses.", "authors": [ "Chen, Lianguo", "Lam, James C. W.", "Hu, Chenyan", "Tsui, Mirabelle M. P.", "Wang, Qi", "Giesy, John P.", "Lam, Paul K. S." ], "keywords": [ "" ], "year": "2018", "source": "ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS", "publication_type": "J", "point2d": [ 79.96104431152344, 3.538215160369873 ], "cluster": 0.0 }, { "idx": 48, "title": "Scale Interactions in Turbulence for Mountain Blowing Snow", "abstract": "Blowing snow particle transport responds to wind motions across many length and time scales. This coupling is nonlinear by nature and complicated in atmospheric flows where eddies of many sizes are superimposed. In mountainous terrain, wind flow descriptions are further complicated by topographically influenced or enhanced flows. To improve the current understanding and modeling of blowing snow transport in complex terrain, statistically significant timing and frequencies of wind-snow coupling were identified in high-frequency observations of surface blowing snow and near-surface turbulence from a mountain field site in the Canadian Rockies. Investigation of the mechanisms influencing near-surface, high-frequency turbulence and snow concentration fluctuations provided strong evidence for amplitude modulation from large-scale motions. The large-scale atmospheric motions modulating near-surface turbulence and snow transport were then compared to specific quadrant analysis structures recently identified as relevant for outdoor blowing snow transport. The results suggest that large atmospheric structures modulate the amplitude of high-frequency turbulence and modify turbulence statistics typically used to model blowing snow. Additionally, blowing snow was preferentially redistributed under the footprint of these same sweep motions, with both low-and high-frequency coherence increasing in their presence.", "authors": [ "Aksamit, N. O.", "Pomeroy, J. W." ], "keywords": [ "" ], "year": "2018", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -56.303993225097656, -10.965036392211914 ], "cluster": 12.0 }, { "idx": 49, "title": "Scale Interactions in Turbulence for Mountain Blowing Snow", "abstract": "Blowing snow particle transport responds to wind motions across many length and time scales. This coupling is nonlinear by nature and complicated in atmospheric flows where eddies of many sizes are superimposed. In mountainous terrain, wind flow descriptions are further complicated by topographically influenced or enhanced flows. To improve the current understanding and modeling of blowing snow transport in complex terrain, statistically significant timing and frequencies of wind-snow coupling were identified in high-frequency observations of surface blowing snow and near-surface turbulence from a mountain field site in the Canadian Rockies. Investigation of the mechanisms influencing near-surface, high-frequency turbulence and snow concentration fluctuations provided strong evidence for amplitude modulation from large-scale motions. The large-scale atmospheric motions modulating near-surface turbulence and snow transport were then compared to specific quadrant analysis structures recently identified as relevant for outdoor blowing snow transport. The results suggest that large atmospheric structures modulate the amplitude of high-frequency turbulence and modify turbulence statistics typically used to model blowing snow. Additionally, blowing snow was preferentially redistributed under the footprint of these same sweep motions, with both low-and high-frequency coherence increasing in their presence.", "authors": [ "Aksamit, N. O.", "Pomeroy, J. W." ], "keywords": [ "" ], "year": "2018", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -56.303993225097656, -10.965036392211914 ], "cluster": 12.0 }, { "idx": 50, "title": "Water and energy fluxes over northern prairies as affected by chinook winds and winter precipitation", "abstract": "Chinooks are the North American variety of foehn: strong, warm and dry winds that descend lee mountain slopes. The strong wind speeds, high temperatures and substantial humidity deficits have been hypothesized to remove important prairie near-surface water storage from agricultural fields via evaporation, sublimation and blowing snow, as well as change the phase of near surface water via snowmelt and ground thaw. This paper presents observations of surface energy and water balances from eddy covariance instrumentation deployed at three open sites in southern Alberta, Canada during winter 2011-2012. Energy balances, snow and soil moisture budgets of three select chinook events were analysed in detail. These three events ranged in duration from two to nine days, and are representative of winter through early spring chinooks. Precipitation data from gauges and reanalyses (CaPA and ERA-interim) were used to assess water balances. Variations in precipitation and snow packs caused the greatest differences in energy and water balances. Cumulative winter precipitation varied by a factor of two over the three sites: heaviest at the more northern site immediately east of the Rocky Mountains and lightest at the easternmost and southernmost site. The temporal progression of chinook-driven surface water loss is explained, beginning with strong blowing snow events through to evaporation of meltwater as snowpacks disappear. At the two sites with considerable winter precipitation and snowcover, large upward latent heat fluxes, often exceeding 100 W m(-2), were driven by downward sensible heat fluxes but were unrelated to net radiation. Conversely, at the southernmost site with little snowcover, upward latent heat fluxes were much smaller (less than 50 W m(-2)) and were associated with periods of positive net radiation. Upward sensible heat fluxes during periods of positive net radiation were observed at this site throughout winter, but were not observed at the more northerly sites until March when the snowcovers ablated. Daily sublimation plus evaporation rates during chinooks at the sites with heaviest and lightest precipitation were 1.3-2.1 mm/day and 0.1-0.3 mm/day, respectively. Evaporation of soil water occurred while soils were partially to fully unfrozen in November. There was little change in soil water content between fall freeze-up and spring thaw (December through most of March), indicating that over-winter infiltration was balanced by soil water evaporation and both terms were likely to be small. Winter precipitation resulted in only 2% to 4% increases in near-surface water storage at the more northern sites with greater precipitation, whereas there was a net loss over winter at the southernmost site.", "authors": [ "MacDonald, Matthew K.", "Pomeroy, John W.", "Essery, Richard L. H." ], "keywords": [ "Latent heat", "Sublimation", "Evaporation", "Snow", "Eddy covariance", "Hydrology" ], "year": "2018", "source": "AGRICULTURAL AND FOREST METEOROLOGY", "publication_type": "J", "point2d": [ -29.696762084960938, 7.974505424499512 ], "cluster": 12.0 }, { "idx": 51, "title": "Modeling the exposure of wild fish to endocrine active chemicals: Potential linkages of total estrogenicity to field-observed intersex", "abstract": "Decades of studies on endocrine disruption have suggested the need to manage the release of key estrogens from municipal wastewater treatment plants (WWTP). However, the proposed thresholds are below the detection limits of most routine chemical analysis, thereby restricting the ability of watershed managers to assess the environmental exposure appropriately. In this study, we demonstrated the utility of a mechanistic model to address the data gaps on estrogen exposure. Concentrations of the prominent estrogenic contaminants in wastewaters (estrone, estradiol, and ethinylestradiol) were simulated in the Grand River in southern Ontario (Canada) for nine years, including a period when major WWTP upgrades occurred. The predicted concentrations expressed as total estrogenicity (E2 equivalent concentrations) were contrasted to a key estrogenic response (i.e., intersex) in rainbow darter (Etheostoma caeruleum), a wild sentinel fish species. A predicted total estrogenicity in the river of >= 10 ng/L E2 equivalents was associated with high intersex incidence and severity, whereas concentrations <0.1 ng/L E2 equivalents were associated with minimal intersex expression. Exposure to a predicted river concentration of 0.4 ng/ L E2 equivalents, the environmental quality standard (EQS) proposed by the European Union for estradiol, was associated with 34% (95% CI:30-38) intersex incidence and a very low severity score of 0.6 (95% CI:0.5-0.7). This exposure is not predicted to cause adverse effects in rainbow darter. The analyses completed in this study were only based on the predicted presence of three major estrogens (El, E2, EE2), so caution must be exercised when interpreting the results. Nevertheless, this study illustrates the use of models for exposure assessment, especially when measured data are not available. (C) 2018 Elsevier Ltd. All rights reserved.", "authors": [ "Arlos, Maricor J.", "Parker, Wayne J.", "Bicudo, Jose R.", "Law, Pam", "Hicks, Keegan A.", "Fuzzen, Meghan L. M.", "Andrews, Susan A.", "Servos, Mark R." ], "keywords": [ "Estrogen", "Intersex", "Water quality model", "Exposure assessment", "Wastewater", "Rainbow darter" ], "year": "2018", "source": "WATER RESEARCH", "publication_type": "J", "point2d": [ 72.79966735839844, -4.913776874542236 ], "cluster": 0.0 }, { "idx": 52, "title": "Multi-year prediction of estrogenicity in municipal wastewater effluents", "abstract": "In this study, the estrogenicity of two major wastewater treatment plant(WWTP) effluents located in the central reaches of the Grand River watershed in southern Ontario was estimated using population demographics, excretion rates, and treatment plant-specific removals. Due to the lack of data on estrogen concentrations from direct measurements at WWTPs, the treatment efficiencies through the plants were estimated using the information obtained from an effects-directed analysis. The results show that this approach could effectively estimate the estrogenicity of WWTP effluents, both before and after major infrastructure upgrades were made at the Kitchener WWTP. The model was then applied to several possible future scenarios including population growth and river low flow conditions. The scenario analyses showed that post-upgrade operation of the Kitchener WWTP will not release highly estrogenic effluent under the 2041 projected population increase (36%) or summer low flows. Similarly, the Waterloo WWTP treatment operation is also expected to improve once the upgrades have been fully implemented and is expected to effectively treat estrogens even under extreme scenarios of population growth and river flows. The developed model may be employed to support decision making on wastewater management strategies designed for environmental protection, especially on reducing the endocrine effects in fish exposed to WWTP effluents. (C) 2017 Elsevier B.V. All rights reserved.", "authors": [ "Arlos, Maricor J.", "Parker, Wayne J.", "Bicudo, Jose R.", "Law, Pam", "Marjan, Patricija", "Andrews, Susan A.", "Servos, Mark R." ], "keywords": [ "Estrogenicity", "Endocrine disruption", "Wastewater", "Effluent", "Water treatment", "Model" ], "year": "2018", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 72.09253692626953, -5.390752792358398 ], "cluster": 0.0 }, { "idx": 53, "title": "Impacts of wastewater treatment plant effluent on energetics and stress response of rainbow darter (Etheostoma caeruleum) in the Grand River watershed", "abstract": "The objective of this study was to assess the effects of municipal wastewater treatment plant effluent on the energetics and stress response of rainbow darter (Etheostoma caerulewn). Male and female rainbow darter were collected upstream and downstream of the Waterloo WWTP in the Grand River watershed, ON, Canada. To assess the effects of wastewater treatment plant effluent on whole-body and tissue specific metabolic capacity, closed-chamber respirometry and muscle-enzyme activity analyses were performed. Plasma cortisol was also collected from fish before and after an acute air-exposure stressor to evaluate the cortisol stress response in fish exposed to additional stressors. Male and female rainbow darter collected downstream of the effluent had higher oxygen consumption rates, while differences in enzyme activities were primarily associated with sex rather than collection site. No impairment in the cortisol stress response between downstream and upstream fish was observed, however baseline cortisol levels in female fish from the downstream site were significantly higher compared to other baseline groups. Stress-induced cortisol levels were also higher in female fish from both sites when compared to their male counterparts. Overall, this study demonstrates that chronic exposure to WWTP effluent impacts whole-body metabolic performance. This study was also able to demonstrate that sex-differences are a key determinant of various metabolic changes in response to physiological stress, thereby, providing a novel avenue to be considered and further explored.", "authors": [ "Mehdi, Hossein", "Dickson, Fiona H.", "Bragg, Leslie M.", "Servos, Mark R.", "Craig, Paul M." ], "keywords": [ "Rainbow darter", "Energetics", "Stress response", "Wastewater treatment plant effluent", "Metabolism" ], "year": "2018", "source": "COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY", "publication_type": "J", "point2d": [ 73.12995910644531, -0.714694619178772 ], "cluster": 0.0 }, { "idx": 54, "title": "Nutrient Release from Living and Terminated Cover Crops Under Variable Freeze-Thaw Cycles", "abstract": "Cover crops (CC) are planted into fields during the non-growing season as a best management practice (BMP) for agronomic and environmental benefits. However, freeze-thaw cycles (FTC) may increase the availability of water extractable P (WEP) from damaged plant tissues, leading some to question their efficacy as a nutrient BMP due to their potential to release P during snowmelt. The objectives of this study were to experimentally determine the influence of: (1) FTC magnitude (4 degrees C, -4 to 4 degrees C, -18 to 4 degrees C, and -18 to 10 degrees C), (2) CC species [ cereal rye (Secale cereale L.), oilseed radish (Raphanus sativus L. var. oleoferus Metzg Stokes), red clover (Trifolium pratense L.), oat (Avena sativa L.), and hairy vetch (Vicia villosa Roth)], and (3) termination using herbicide on the magnitude of WEP, NH4+, and NO3- release. Shoot tissue clippings underwent five FTC followed by extraction. Large magnitude FTC from -18 to 4 and -18 to 10 degrees C (heavy frost) elevated WEP release, whereas the -4 to 4 degrees C (light frost) treatment did not. Responses varied with plant type, where frost-intolerant species released more WEP than frost-tolerant species. In contrast, NH4+, and NO3- release did not increase following FTC. Termination elevated WEP and NH4+ release across all temperature treatments. The use of CC as a nutrient BMP should be used with caution in some regions, but in areas with mild winter climates, growing frost tolerant species without termination may reduce the risk of P leaching from vegetation in winter and early spring.", "authors": [ "Cober, James R.", "Macrae, Merrin L.", "Van Eerd, Laura L." ], "keywords": [ "" ], "year": "2018", "source": "AGRONOMY JOURNAL", "publication_type": "J", "point2d": [ 29.057859420776367, 19.646108627319336 ], "cluster": 3.0 }, { "idx": 55, "title": "A modelling framework to simulate field-scale nitrate response and transport during snowmelt: The WINTRA model", "abstract": "Modelling nutrient transport during snowmelt in cold regions remains a major scientific challenge. A key limitation of existing nutrient models for application in cold regions is the inadequate representation of snowmelt, including hydrological and biogeochemical processes. This brief period can account for more than 80% of the total annual surface runoff in the Canadian Prairies and Northern Canada and processes such as atmospheric deposition, overwinter redistribution of snow, ion exclusion from snow crystals, frozen soils, and snow-covered area depletion during melt influence the distribution and release of snow and soil nutrients, thus affecting the timing and magnitude of snowmelt runoff nutrient concentrations. Research in cold regions suggests that nitrate (NO3) runoff at the field-scale can be divided into 5 phases during snowmelt. In the first phase, water and ions originating from ion-rich snow layers travel and diffuse through the snowpack. This process causes ion concentrations in runoff to gradually increase. The second phase occurs when this snow ion meltwater front has reached the bottom of the snowpack and forms runoff to the edge-of-the-field. During the third and fourth phases, the main source of NO3 transitions from the snowpack to the soil. Finally, the fifth and last phase occurs when the snow has completely melted, and the thawing soil becomes the main source of NO3 to the stream. In this research, a process-based model was developed to simulate hourly export based on this 5-phase approach. Results from an application in the Red River Basin of southern Manitoba, Canada, shows that the model can adequately capture the dynamics and rapid changes of NO3 concentrations during this period at relevant temporal resolutions. This is a significant achievement to advance the current nutrient modelling paradigm in cold climates, which is generally limited to satisfactory results at monthly or annual resolutions. The approach can inform catchment-scale nutrient models to improve simulation of this critical snowmelt period.", "authors": [ "Costa, Diogo", "Roste, Jennifer", "Pomeroy, John", "Baulch, Helen", "Elliott, Jane", "Wheater, Howard", "Westbrook, Cherie" ], "keywords": [ "agriculture", "nitrate", "nutrient exports", "nutrient model", "snow", "winter" ], "year": "2017", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 24.97844123840332, 14.60555362701416 ], "cluster": 12.0 }, { "idx": 56, "title": "A modelling framework to simulate field-scale nitrate response and transport during snowmelt: The WINTRA model", "abstract": "Modelling nutrient transport during snowmelt in cold regions remains a major scientific challenge. A key limitation of existing nutrient models for application in cold regions is the inadequate representation of snowmelt, including hydrological and biogeochemical processes. This brief period can account for more than 80% of the total annual surface runoff in the Canadian Prairies and Northern Canada and processes such as atmospheric deposition, overwinter redistribution of snow, ion exclusion from snow crystals, frozen soils, and snow-covered area depletion during melt influence the distribution and release of snow and soil nutrients, thus affecting the timing and magnitude of snowmelt runoff nutrient concentrations. Research in cold regions suggests that nitrate (NO3) runoff at the field-scale can be divided into 5 phases during snowmelt. In the first phase, water and ions originating from ion-rich snow layers travel and diffuse through the snowpack. This process causes ion concentrations in runoff to gradually increase. The second phase occurs when this snow ion meltwater front has reached the bottom of the snowpack and forms runoff to the edge-of-the-field. During the third and fourth phases, the main source of NO3 transitions from the snowpack to the soil. Finally, the fifth and last phase occurs when the snow has completely melted, and the thawing soil becomes the main source of NO3 to the stream. In this research, a process-based model was developed to simulate hourly export based on this 5-phase approach. Results from an application in the Red River Basin of southern Manitoba, Canada, shows that the model can adequately capture the dynamics and rapid changes of NO3 concentrations during this period at relevant temporal resolutions. This is a significant achievement to advance the current nutrient modelling paradigm in cold climates, which is generally limited to satisfactory results at monthly or annual resolutions. The approach can inform catchment-scale nutrient models to improve simulation of this critical snowmelt period.", "authors": [ "Costa, Diogo", "Roste, Jennifer", "Pomeroy, John", "Baulch, Helen", "Elliott, Jane", "Wheater, Howard", "Westbrook, Cherie" ], "keywords": [ "agriculture", "nitrate", "nutrient exports", "nutrient model", "snow", "winter" ], "year": "2017", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 24.987056732177734, 14.137246131896973 ], "cluster": 12.0 }, { "idx": 57, "title": "Local-Scale Advection of Sensible and Latent Heat During Snowmelt", "abstract": "The breakup of snow cover into patches during snowmelt leads to a dynamic, heterogeneous land surface composed of melting snow, and wet and dry soil and plant surfaces. Energy exchange with the atmosphere is therefore complicated by horizontal gradients in surface temperature and humidity as snow surface temperature and humidity are regulated by the phase change of melting snow unlike snow-free areas. Airflow across these surface transitions results in local-scale advection of energy that has been documented as sensible heat during snowmelt, while latent heat advection has received scant attention. Herein, results are presented from an experiment measuring near-surface profiles of air temperature and humidity across snow-free to snow-covered transitions that demonstrates that latent heat advection can be the same order of magnitude as sensible heat advection and is therefore an important source of snowmelt energy. Latent heat advection is conditional on an upwind source of water vapor from a wetted snow-free surface. Plain Language Summary During snowmelt snow cover becomes heterogeneous and lateral transfer of energy between bare and snow surfaces is an important but underrepresented component of the surface energy balance. To date, there have been no observations of latent heat advection which is the energy transfer associated with evaporation from ponded melt-water and subsequent condensation upon downwind snow patches. This paper presents observations and a conceptual framework that is used to quantify this previously undocumented energy balance component. Latent heat advection can represent up to 33% of the snowmelt energy which has large implications for the snowmelt process. This work demonstrates that both sensible and latent heat advection processes need to be included in future snow modeling efforts in order to improve snowmelt predictions which have wide ranging water resource management implications.", "authors": [ "Harder, Phillip", "Pomeroy, John W.", "Helgason, Warren" ], "keywords": [ "" ], "year": "2017", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -44.66366958618164, -4.543794631958008 ], "cluster": 12.0 }, { "idx": 58, "title": "Local-Scale Advection of Sensible and Latent Heat During Snowmelt", "abstract": "The breakup of snow cover into patches during snowmelt leads to a dynamic, heterogeneous land surface composed of melting snow, and wet and dry soil and plant surfaces. Energy exchange with the atmosphere is therefore complicated by horizontal gradients in surface temperature and humidity as snow surface temperature and humidity are regulated by the phase change of melting snow unlike snow-free areas. Airflow across these surface transitions results in local-scale advection of energy that has been documented as sensible heat during snowmelt, while latent heat advection has received scant attention. Herein, results are presented from an experiment measuring near-surface profiles of air temperature and humidity across snow-free to snow-covered transitions that demonstrates that latent heat advection can be the same order of magnitude as sensible heat advection and is therefore an important source of snowmelt energy. Latent heat advection is conditional on an upwind source of water vapor from a wetted snow-free surface. Plain Language Summary During snowmelt snow cover becomes heterogeneous and lateral transfer of energy between bare and snow surfaces is an important but underrepresented component of the surface energy balance. To date, there have been no observations of latent heat advection which is the energy transfer associated with evaporation from ponded melt-water and subsequent condensation upon downwind snow patches. This paper presents observations and a conceptual framework that is used to quantify this previously undocumented energy balance component. Latent heat advection can represent up to 33% of the snowmelt energy which has large implications for the snowmelt process. This work demonstrates that both sensible and latent heat advection processes need to be included in future snow modeling efforts in order to improve snowmelt predictions which have wide ranging water resource management implications.", "authors": [ "Harder, Phillip", "Pomeroy, John W.", "Helgason, Warren" ], "keywords": [ "" ], "year": "2017", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -44.66366958618164, -4.543794631958008 ], "cluster": 12.0 }, { "idx": 59, "title": "Supply and Transport Limitations on Phosphorus Losses from Agricultural Fields in the Lower Great Lakes Region, Canada", "abstract": "Phosphorus (P) mobilization in agricultural landscapes is regulated by both hydrologic (transport) and biogeochemical (supply) processes interacting within soils; however, the dominance of these controls can vary spatially and temporally. In this study, we analyzed a 5-yr dataset of stormflow events across nine agricultural fields in the lower Great Lakes region of Ontario, Canada, to determine if edge-of-field surface runoff and tile drainage losses (total and dissolved reactive P) were limited by transport mechanisms or P supply. Field sites ranged from clay loam, silt loam, to sandy loam textures. Findings indicate that biogeochemical processes (P supply) were more important for tile drain P loading patterns (i.e., variable flow-weighted mean concentrations ([C-f]) across a range of flow regimes) relative to surface runoff, which trended toward a more chemostatic or transport-limited response. At two sites with the same soil texture, higher tile [C-f] and greater transport limitations were apparent at the site with higher soil available P (STP); however, STP did not significantly correlate with tile [C-f] or P loading patterns across the nine sites. This may reflect that the fields were all within a narrow STP range and were not elevated in STP concentrations (Olsen-P, <= 25 mg kg(-1)). For the study sites where STP was maintained at reasonable concentrations, hydrology was less of a driving factor for tile P loadings, and thus management strategies that limit P supply may be an effective way to reduce P losses from fields (e.g., timing of fertilizer application).", "authors": [ "Plach, Janina M.", "Macrae, Merrin L.", "Ali, Genevieve A.", "Brunke, Richard R.", "English, Michael C.", "Ferguson, Gabrielle", "Lam, W. Vito", "Lozier, Tatianna M.", "McKague, Kevin", "O'Halloran, Ivan P.", "Opolko, Gilian", "Van Esbroeck, Christopher J." ], "keywords": [ "" ], "year": "2018", "source": "JOURNAL OF ENVIRONMENTAL QUALITY", "publication_type": "J", "point2d": [ 38.24628829956055, 18.370349884033203 ], "cluster": 10.0 }, { "idx": 60, "title": "Mapping Canadian wildland fire interface areas", "abstract": "Destruction of human-built structures occurs in the wildland-urban interface' (WUI) - where homes or other burnable community structures meet with or are interspersed within wildland fuels. To mitigate WUI fires, basic information such as the location of interface areas is required, but such information is not available in Canada. Therefore, in this study, we produced the first national map of WUI in Canada. We also extended the WUI concept to address potentially vulnerable industrial structures and infrastructure that are not traditionally part of the WUI, resulting in two additional maps: a 'wildland-industrial interface' map (i.e. the interface of wildland fuels and industrial structures, denoted here as WUI-Ind) and a 'wildland-infrastructure interface' map (i.e. the interface of wildland fuels and infrastructure such as roads and railways, WUI-Inf). All three interface types (WUI, WUI-Ind, WUI-Inf) were defined as areas of wildland fuels within a variable-width buffer (maximum distance: 2400 m) from potentially vulnerable structures or infrastructure. Canada has 32.3 million ha of WUI (3.8% of total national land area), 10.5 million ha of WUI-Ind (1.2%) and 109.8 million ha of WUI-Inf (13.0%). The maps produced here provide a baseline for future research and have a wide variety of practical applications.", "authors": [ "Johnston, Lynn M.", "Flannigan, Mike D." ], "keywords": [ "communities", "fuels", "values", "wildland-industrial interface", "wildland-infrastructure interface", "wildland-urban interface" ], "year": "2018", "source": "INTERNATIONAL JOURNAL OF WILDLAND FIRE", "publication_type": "J", "point2d": [ -2.505058526992798, 48.24781036376953 ], "cluster": 15.0 }, { "idx": 61, "title": "Multi-objective unstructured triangular mesh generation for use in hydrological and land surface models", "abstract": "Unstructured triangular meshes are an efficient and effective landscape representation that are suitable for use in distributed hydrological and land surface models. Their variable spatial resolution provides similar spatial performance to high-resolution structured grids while using only a fraction of the number of elements. Many existing triangulation methods either sacrifice triangle quality to introduce variable resolution or maintain well formed uniform meshes at the expense of variable triangle resolution. They are also generally constructed to only fulfil topographic constraints. However, distributed hydrological and land surface models require triangles of varying resolution to provide landscape representations that accurately represent the spatial heterogeneity of driving meteorology, physical parameters and process operation in the simulation domain. As such, mesh generators need to constrain the unstructured mesh to not only topography but to other important surface and sub-surface features. This work presents novel multi-objective unstructured mesh generation software that allows mesh generation to be constrained to an arbitrary number of important features while maintaining a variable spatial resolution. Triangle quality is supported as well as a smooth gradation from small to large triangles. Including these additional constraints results in a better representation of spatial heterogeneity than from classic topography-only constraints.", "authors": [ "Marsh, Christopher B.", "Spiteri, Raymond J.", "Pomeroy, John W.", "Wheater, Howard S." ], "keywords": [ "Hydrology", "Mesh generation", "Modelling", "Unstructured grid", "Multi-objective refinement" ], "year": "2018", "source": "COMPUTERS & GEOSCIENCES", "publication_type": "J", "point2d": [ 9.895925521850586, -39.50526809692383 ], "cluster": 12.0 }, { "idx": 62, "title": "Multi-objective unstructured triangular mesh generation for use in hydrological and land surface models", "abstract": "Unstructured triangular meshes are an efficient and effective landscape representation that are suitable for use in distributed hydrological and land surface models. Their variable spatial resolution provides similar spatial performance to high-resolution structured grids while using only a fraction of the number of elements. Many existing triangulation methods either sacrifice triangle quality to introduce variable resolution or maintain well formed uniform meshes at the expense of variable triangle resolution. They are also generally constructed to only fulfil topographic constraints. However, distributed hydrological and land surface models require triangles of varying resolution to provide landscape representations that accurately represent the spatial heterogeneity of driving meteorology, physical parameters and process operation in the simulation domain. As such, mesh generators need to constrain the unstructured mesh to not only topography but to other important surface and sub-surface features. This work presents novel multi-objective unstructured mesh generation software that allows mesh generation to be constrained to an arbitrary number of important features while maintaining a variable spatial resolution. Triangle quality is supported as well as a smooth gradation from small to large triangles. Including these additional constraints results in a better representation of spatial heterogeneity than from classic topography-only constraints.", "authors": [ "Marsh, Christopher B.", "Spiteri, Raymond J.", "Pomeroy, John W.", "Wheater, Howard S." ], "keywords": [ "Hydrology", "Mesh generation", "Modelling", "Unstructured grid", "Multi-objective refinement" ], "year": "2018", "source": "COMPUTERS & GEOSCIENCES", "publication_type": "J", "point2d": [ 10.09065055847168, -39.10222244262695 ], "cluster": 12.0 }, { "idx": 63, "title": "Peatland water repellency: Importance of soil water content, moss species, and burn severity", "abstract": "Wildfire is the largest disturbance affecting peatlands, with northern peat reserves expected to become more vulnerable to wildfire as climate change enhances the length and severity of the fire season. Recent research suggests that high water table positions after wildfire are critical to limit atmospheric carbon losses and enable the re-establishment of keystone peatland mosses (i.e. Sphagnum). Post-fire recovery of the moss surface in Sphagnum-feathermoss peatlands, however, has been shown to be limited where moss type and burn severity interact to result in a water repellent surface. While in situ measurements of moss water repellency in peatlands have been shown to be greater for feathermoss in both a burned and unburned state in comparison to Sphagnum moss, it is difficult to separate the effect of water content from species. Consequently, we carried out a laboratory based drying experiment where we compared the water repellency of two dominant peatland moss species, Sphagnum and feathermoss, for several burn severity classes including unburned samples. The results suggest that water repellency in moss is primarily controlled by water content, where a sharp threshold exists at gravimetric water contents (GWC) lower than similar to 1.4 g g(-1). While GWC is shown to be a strong predictor of water repellency, the effect is enhanced by burning. Based on soil water retention curves, we suggest that it is highly unlikely that Sphagnum will exhibit strong hydrophobic conditions under field conditions. (C) 2017 Elsevier B.V. All rights reserved.", "authors": [ "Moore, P. A.", "Lukenbach, M. C.", "Kettridge, N.", "Petrone, R. M.", "Devito, K. J.", "Waddington, J. M." ], "keywords": [ "Water repellency", "Moss", "Sphagnum", "Feathermoss", "Wildfire", "Peatland" ], "year": "2017", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -9.029684066772461, 68.88170623779297 ], "cluster": 9.0 }, { "idx": 64, "title": "A spatial evaluation of global wildfire-water risks to human and natural systems", "abstract": "The large mediatic coverage of recent massive wildfires across the world has emphasized the vulnerability of freshwater resources. The extensive hydrogeomorphic effects from a wildfire can impair the ability of watersheds to provide safe drinking water to downstream communities and high-quality water to maintain riverine ecosystem health. Safeguarding water use for human activities and ecosystems is required for sustainable development; however, no global assessment of wildfire impacts on water supply is currently available. Here, we provide the first global evaluation of wildfire risks to water security, in the form of a spatially explicit index. We adapted the Driving forces-Pressure-State-Impact-Response risk analysis framework to select a comprehensive set of indicators of fire activity and water availability, which we then aggregated to a single index of wildfire-water risk using a simple additive weighted model. Our results show that water security in many regions of the world is potentially vulnerable, regardless of socio-economic status. However, in developing countries, a critical component of the risk is the lack of socio-economic capability to respond to disasters. Our work highlights the importance of addressing wildfire-induced risks in the development of water security policies; the geographic differences in the components of the overall risk could help adapting those policies to different regional contexts. Crown Copyright (C) 2017 Published by Elsevier B.V. All rights reserved.", "authors": [ "Robinne, Francois -Nicolas", "Bladon, Kevin D.", "Miller, Carol", "Parisien, Marc-Andre", "Mathieu, Jerome", "Flannigan, Mike D." ], "keywords": [ "Water security", "Wildland fire", "Natural disaster", "Emerging risk", "DPSIR framework" ], "year": "2018", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 21.154600143432617, -28.1239070892334 ], "cluster": 11.0 }, { "idx": 65, "title": "Did enhanced afforestation cause high severity peat burn in the Fort McMurray Horse River wildfire?", "abstract": "Climate change mediated drying of boreal peatlands is expected to enhance peatland afforestation and wildfire vulnerability. The water table depth-afforestation feedback represents a positive feedback that can enhance peat drying and consolidation and thereby increase peat burn severity; exacerbating the challenges and costs of wildfire suppression efforts and potentially shifting the peatland to a persistent source of atmospheric carbon. To address this wildfire management challenge, we examined burn severity across a gradient of drying in a black spruce dominated peatland that was partially drained in 1975-1980 and burned in the 2016 Fort McMurray Horse River wildfire. We found that post-drainage black spruce annual ring width increased substantially with intense drainage. Average (+/- SD) basal diameter was 2.6 +/- 1.2 cm, 3.2 +/- 2.0 cm and 7.9 +/- 4.7 cm in undrained (UD), moderately drained (MD) and heavily drained (HD) treatments, respectively. Depth of burn was significantly different between treatments (p < 0.001) and averaged (+/- SD) 2.5 +/- 3.5 cm, 6.4 +/- 5.0 cm and 36.9 +/- 29.6 cm for the UD, MD and HD treatments, respectively. The high burn severity in the HD treatment included 38% of the treatment that experienced combustion of the entire peat profile, and we estimate that overall 51% of the HD pre-burn peat carbon stock was lost. We argue that the HD treatment surpassed an ecohydrological tipping point to high severity peat burn that may be identified using black spruce stand characteristics in boreal plains bogs. While further studies are needed, we believe that quantifying this threshold will aid in developing effective adaptive management techniques and protecting boreal peatland carbon stocks.", "authors": [ "Wilkinson, S. L.", "Moore, P. A.", "Flannigan, M. D.", "Wotton, B. M.", "Waddington, J. M." ], "keywords": [ "peatland", "afforestation", "wildfire", "tipping point", "land management", "Sphagnum", "burn severity" ], "year": "2018", "source": "ENVIRONMENTAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -13.143780708312988, 70.0898208618164 ], "cluster": 9.0 }, { "idx": 68, "title": "A comparative analysis of practitioners' experience in sediment remediation projects to highlight best practices", "abstract": "The Randle Reef contaminated site, located in the southwest corner of Hamilton Harbour, is approximately 60 hectares in size. This site contains approximately 695,000 m(3) of sediment contaminated with polycyclic aromatic hydrocarbons (PAHs) and metals. The complex Randle Reef sediment remediation project is finally coming to fruition after more than 30 years of study, discussion, collaborations, stakeholder consensus-building, and debate. This paper unravels the reasons behind the delays associated with implementing sediment management at the Randle Reef site. In-depth interviews with experts and professionals from organizations who are/were involved in the project were conducted to identify the nature of performance in five theme areas that are important for successful action namely: (1) participation of appropriate actors with common objectives; (2) funding and resources; (3) decision-making process; (4) research and technology development; and (5) public and political support. It is evident from this study that the hurdles to progress with addressing contaminated sediment sites involve technical, political, regulatory as well as social challenges. We offer potential solutions and a series of recommendations based on experts' first-hand experience with the management of such complex sites to inform how future remediation projects can overcome obstacles.", "authors": [ "Jawed, Zobia", "Krantzberg, Gail" ], "keywords": [ "decision-making process", "Great Lakes areas of concern", "Hamilton Harbour Remedial Action Plan", "Randle Reef sediment remediation", "sediment management" ], "year": "2019", "source": "WATER QUALITY RESEARCH JOURNAL OF CANADA", "publication_type": "J", "point2d": [ 53.09587097167969, -4.877032279968262 ], "cluster": 4.0 }, { "idx": 69, "title": "Legacy nitrogen may prevent achievement of water quality goals in the Gulf of Mexico", "abstract": "In August 2017, the Gulf of Mexico's hypoxic zone was declared to be the largest ever measured. It has been estimated that a 60% decrease in watershed nitrogen (N) loading may be necessary to adequately reduce eutrophication in the Gulf. However, to date there has been no rigorous assessment of the effect of N legacies on achieving water quality goals. In this study, we show that even if agricultural N use became 100% efficient, it would take decades to meet target N loads due to legacy N within the Mississippi River basin. Our results suggest that both long-term commitment and large-scale changes in agricultural management practices will be necessary to decrease Mississippi N loads and to meet current goals for reducing the size of the Gulf hypoxic zone.", "authors": [ "Van Meter, K. J.", "Van Cappellen, P.", "Basu, N. B." ], "keywords": [ "" ], "year": "2018", "source": "SCIENCE", "publication_type": "J", "point2d": [ 34.608455657958984, 2.249940872192383 ], "cluster": 19.0 }, { "idx": 70, "title": "Time lags in watershed-scale nutrient transport: an exploration of dominant controls", "abstract": "Unprecedented decreases in atmospheric nitrogen (N) deposition together with increases in agricultural N-use efficiency have led to decreases in net anthropogenic N inputs in many eastern US and Canadian watersheds as well as in Europe. Despite such decreases, N concentrations in streams and rivers continue to increase, and problems of coastal eutrophication remain acute. Such a mismatch between N inputs and outputs can arise due to legacy N accumulation and subsequent lag times between implementation of conservation measures and improvements in water quality. In the present study, we quantified such lag times by pairing long-term N input trajectories with stream nitrate concentration data for 16 nested subwatersheds in a 6800 km(2), Southern Ontario watershed. Our results show significant nonlinearity between N inputs and outputs, with a strong hysteresis effect indicative of decadal-scale lag times. The mean annual lag time was found to be 24.5 years, with lags varying seasonally, likely due to differences in N-delivery pathways. Lag times were found to be negatively correlated with both tile drainage and watershed slope, with tile drainage being a dominant control in fall and watershed slope being significant during the spring snowmelt period. Quantification of such lags will be crucial to policy-makers as they struggle to set appropriate goals for water quality improvement in human-impacted watersheds.", "authors": [ "Van Meter, K. J.", "Basu, N. B." ], "keywords": [ "nutrients", "nitrogen", "time lag", "watersheds", "water quality" ], "year": "2017", "source": "ENVIRONMENTAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ 28.6340389251709, 3.9177439212799072 ], "cluster": 10.0 }, { "idx": 71, "title": "Environmental Indicator Principium with Case References to Agricultural Soil, Water, and Air Quality and Model-Derived Indicators", "abstract": "Environmental indicators are powerful tools for tracking environmental changes, measuring environmental performance, and informing policymakers. Many diverse environmental indicators, including agricultural environmental indicators, are currently in use or being developed. This special collection of technical papers expands on the peer-reviewed literature on environmental indicators and their application to important current issues in the following areas: (i) model-derived indicators to indicate phosphorus losses from arable land to surface runoff and subsurface drainage, (ii) glutathione-ascorbate cycle-related antioxidants as early-warning bioindicators of polybrominated diphenyl ether toxicity in mangroves, and (iii) assessing the effectiveness of using organic matrix biobeds to limit herbicide dissipation from agricultural fields, thereby controlling on-farm point-source pollution. This introductory review also provides an overview of environmental indicators, mainly for agriculture, with examples related to the quality of the agricultural soil-water-air continuum and the application of model-derived indicators. Current knowledge gaps and future lines of investigation are also discussed. It appears that environmental indicators, particularly those for agriculture, work efficiently at the field, catchment, and local scales and serve as valuable metrics of system functioning and response; however, these indicators need to be refined or further developed to comprehensively meet community expectations in terms of providing a consistent picture of relevant issues and/or allowing comparisons to be made nationally or internationally.", "authors": [ "Zhang, T. Q.", "Zheng, Z. M.", "Lal, R.", "Lin, Z. Q.", "Sharpley, A. N.", "Shober, A. L.", "Smith, D.", "Tan, C. S.", "Van Cappellen, P." ], "keywords": [ "" ], "year": "2018", "source": "JOURNAL OF ENVIRONMENTAL QUALITY", "publication_type": "J", "point2d": [ 56.54096603393555, -20.539554595947266 ], "cluster": 10.0 }, { "idx": 72, "title": "Phosphorus and nitrogen trajectories in the Mediterranean Sea (1950-2030): Diagnosing basin-wide anthropogenic nutrient enrichment", "abstract": "Human activities have significantly modified the inputs of land-derived phosphorus (P) and nitrogen (N) to the Mediterranean Sea (MS). Here, we reconstruct the external inputs of reactive P and N to the Western Mediterranean Sea (WMS) and Eastern Mediterranean Sea (EMS) over the period 1950-2030. We estimate that during this period the land derived P and N loads increased by factors of 3 and 2 to the WMS and EMS, respectively, with reactive P inputs peaking in the 1980s but reactive N inputs increasing continuously from 1950 to 2030. The temporal variations in reactive P and N inputs are imposed in a coupled P and N mass balance model of the MS to simulate the accompanying changes in water column nutrient distributions and primary production with time. The key question we address is whether these changes are large enough to be distinguishable from variations caused by confounding factors, specifically the relatively large inter-annual variability in thermohaline circulation (THC) of the MS. Our analysis indicates that for the intermediate and deep water masses of the MS the magnitudes of changes in reactive P concentrations due to changes in anthropogenic inputs are relatively small and likely difficult to diagnose because of the noise created by the natural circulation variability. Anthropogenic N enrichment should be more readily detectable in time series concentration data for dissolved organic N (DON) after the 1970s, and for nitrate (NO3) after the 1990s. The DON concentrations in the EMS are predicted to exhibit the largest anthropogenic enrichment signature. Temporal variations in annual primary production over the 1950-2030 period are dominated by variations in deep-water formation rates, followed by changes in riverine P inputs for the WMS and atmospheric P deposition for the EMS. Overall, our analysis indicates that the detection of basin-wide anthropogenic nutrient concentration trends in the MS is rendered difficult due to: (1) the Atlantic Ocean contributing the largest reactive P and N inputs to the MS, hence diluting the anthropogenic nutrient signatures, (2) the anti-estuarine circulation removing at least 45% of the anthropogenic nutrients inputs added to both basins of the MS between 1950 and 2030, and (3) variations in intermediate and deep water formation rates that add high natural noise to the P and N concentration trajectories.", "authors": [ "Powley, Helen R.", "Krom, Michael D.", "Van Cappellen, Philippe" ], "keywords": [ "Mediterranean Sea", "Phosphorus", "Nitrogen", "Nutrient enrichment", "Thermohaline circulation", "Primary production" ], "year": "2018", "source": "PROGRESS IN OCEANOGRAPHY", "publication_type": "J", "point2d": [ 31.282699584960938, 0.13658861815929413 ], "cluster": 19.0 }, { "idx": 73, "title": "The role of groundwater discharge fluxes on Si:P ratios in a major tributary to Lake Erie", "abstract": "Groundwater discharge can be a major source of nutrients to river systems. Although quantification of ground-water nitrate loading to streams is common, the dependence of surface water silicon ( Si) and phosphorus (P) concentrations on groundwater sources has rarely been determined. Additionally, the ability of groundwater discharge to drive surface water Si:P ratios has not been contextualized relative to riverine inputs or in-stream transformations. In this study, we quantify the seasonal dynamics of Si and P cycles in the Grand River (GR) watershed, the largest Canadian watershed draining into Lake Erie, to test our hypothesis that regions of Si-rich groundwater discharge increase surface water Si:P ratios. Historically, both the GR and Lake Erie have been considered stoichiometrically P-limited, where the molar Si:P ratio is greater than the similar to 16:1 phytoplankton uptake ratio. However, recent trends suggest that eastern Lake Erie may be approaching Si-limitation. We sampled groundwater and surface water for dissolved and reactive particulate Si as well as total dissolved P for 12 months within and downstream of a 50-km reach of high groundwater discharge. Our results indicate that groundwater Si:P ratios are lower than the corresponding surface water and that groundwater is a significant source of bioavailable P to surface water. Despite these observations, the watershed remains P-limited for the majority of the year, with localized periods of Si-limitation. We further find that groundwater Si:P ratios are a relatively minor driver of surface water Si:P, but that the magnitude of Si and P loads from groundwater represent a large proportion of the overall fluxes to Lake Erie. (C) 2017 Elsevier B.V. All rights reserved.", "authors": [ "Maavara, Taylor", "Slowinski, Stephanie", "Rezanezhad, Fereidoun", "Van Meter, Kimberly", "Van Cappellen, Philippe" ], "keywords": [ "Phosphorus", "Silicon", "Lake Erie", "Grand River", "Nutrient ratios", "Groundwater discharge" ], "year": "2018", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 42.61582565307617, 9.975491523742676 ], "cluster": 19.0 }, { "idx": 74, "title": "A diagnostic approach to constraining flow partitioning in hydrologic models using a multiobjective optimization framework", "abstract": "Hydrologic models are often tasked with replicating historical hydrographs but may do so without accurately reproducing the internal hydrological functioning of the watershed, including the flow partitioning, which is critical for predicting solute movement through the catchment. Here we propose a novel partitioning-focused calibration technique that utilizes flow-partitioning coefficients developed based on the pioneering work of L'vovich (1979). Our hypothesis is that inclusion of the L'vovich partitioning relations in calibration increases model consistency and parameter identifiability and leads to superior model performance with respect to flow partitioning than using traditional hydrological signatures (e.g., flow duration curve indices) alone. The L'vovich approach partitions the annual precipitation into four components (quick flow, soil wetting, slow flow, and evapotranspiration) and has been shown to work across a range of climatic and landscape settings. A new diagnostic multicriteria model calibration methodology is proposed that first quantifies four calibration measures for watershed functions based on the L'vovich theory, and then utilizes them as calibration criteria. The proposed approach is compared with a traditional hydrologic signature-based calibration for two conceptual bucket models. Results reveal that the proposed approach not only improves flow partitioning in the model compared to signature-based calibration but is also capable of diagnosing flow-partitioning inaccuracy and suggesting relevant model improvements. Furthermore, the proposed partitioning-based calibration approach is shown to increase parameter identifiability. This model calibration approach can be readily applied to other models. Plain Language Summary Hydrologic models are often tasked with replicating historical hydrographs but may do so without accurately reproducing the internal hydrological functioning of the watershed, including the flow partitioning between low and high flows, which is critical for predicting solute movement through the catchment. Here we propose a novel model calibration framework that utilizes an empirical understanding about flow partitioning developed by L'vovich (1979) to constrain the outcomes of watershed models. Our hypothesis is that this approach increases model consistency leads to superior model performance. This method is also capable of diagnosing model structural errors (in flow partitioning) and suggesting relevant model improvements. Overall, this work is a step toward getting the right answer from hydrologic model for the right reasons.", "authors": [ "Shafii, Mahyar", "Basu, Nandita", "Craig, James R.", "Schiff, Sherry L.", "Van Cappellen, Philippe" ], "keywords": [ "" ], "year": "2017", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 7.525932312011719, -61.20933532714844 ], "cluster": 16.0 }, { "idx": 77, "title": "Evaluation of Integrated Multisatellite Retrievals for GPM (IMERG) over Southern Canada against Ground Precipitation Observations: A Preliminary Assessment", "abstract": "The Global Precipitation Measurement (GPM) mission offers new opportunities for modeling a range of physical/hydrological processes at higher resolutions, especially for remote river systems where the hydro-meteorological monitoring network is sparse and weather radar is not readily available. In this study, the recently released Integrated Multisatellite Retrievals for GPM[version 03 (V03) IMERG Final Run] product with high spatiotemporal resolution of 0.1 degrees and 30 min is evaluated against ground-based reference measurements (at the 6-hourly, daily, and monthly time scales) over different terrestrial ecozones of southern Canada within a 23-month period from 12 March 2014 to 31 January 2016. While IMERG and ground-based observations show similar regional variations of mean daily precipitation, IMERG tends to overestimate higher monthly precipitation amounts over the Pacific Maritime ecozone. Results from using continuous as well as categorical skill metrics reveal that IMERG shows more satisfactory agreement at the daily and the 6-hourly time scales for the months of June-September, unlike November-March. In terms of precipitation extremes (defined by the 75th percentile threshold for reference data), apart from a tendency toward over-detection of heavy precipitation events, IMERG captured well the distribution of heavy precipitation amounts and observed wet/dry spell length distributions over most ecozones. However, low skill was found over large portions of the Montane Cordillera ecozone and a few stations in the Prairie ecozone. This early study highlights a potential applicability of V03 IMERG Final Run as a reliable source of precipitation estimates in diverse water resources and hydrometeorological applications for different regions in southern Canada.", "authors": [ "Asong, Z. E.", "Razavi, S.", "Wheater, H. S.", "Wong, J. S." ], "keywords": [ "" ], "year": "2017", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -47.53424072265625, -41.95220947265625 ], "cluster": 1.0 }, { "idx": 78, "title": "The economic value of river restoration", "abstract": "", "authors": [ "Brouwer, Roy", "Sheremet, Oleg" ], "keywords": [ "" ], "year": "2017", "source": "WATER RESOURCES AND ECONOMICS", "publication_type": "J", "point2d": [ 60.53920364379883, -48.08370590209961 ], "cluster": 11.0 }, { "idx": 79, "title": "RADARSAT-2-based digital elevation models derived from InSAR for high latitudes of northern Canada", "abstract": "The accuracy of digital elevation models (DEMs) plays an important role in many terrain-related applications, particular in high northern latitudes where there is uncertainty in DEMs. Using the interferometric synthetic aperture radar techniques, this study examined how different RADARSAT-2 beam modes can be used to generate DEMs with high accuracy. Using a conventional interferometry method, the Spotlight DEM shows the highest accuracy among all studied DEM products, with the root-mean-square error (RMSE) ranging from 13.9 to 17.4 m, followed by the F0W3 DEM and U26W2 DEM. The error sources in DEM generation due to uncertainty in perpendicular baseline and atmospheric delay are likely more important than the random phase noise caused by volume scattering and environmental changes during synthetic aperture radar (SAR) acquisitions. The small baselines subset (SBAS) method did not significantly improve DEM quality due to the limitation of the number of SAR images in this study. The integration of both Spotlight conventional DEMs and SBAS DEM considerably improved results yielding high-quality DEMs for the study area, with an RMSE of 9.7 m. Further studies are necessary to quantitatively evaluate the effects of surface motion as well as the orbital and atmospheric errors on the DEM accuracy. The Slave River Delta in the Northwest Territories of Canada was used as a test case. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)", "authors": [ "Chu, Thuan", "Das, Apurba", "Lindenschmidt, Karl-Erich" ], "keywords": [ "RADARSAT-2", "interferometric synthetic aperture radar", "digital elevation models", "Slave River", "high northern latitudes" ], "year": "2017", "source": "JOURNAL OF APPLIED REMOTE SENSING", "publication_type": "J", "point2d": [ -74.22428894042969, 7.960860729217529 ], "cluster": 8.0 }, { "idx": 80, "title": "A novel stochastic method for reconstructing daily precipitation times-series using tree-ring data from the western Canadian Boreal Forest", "abstract": "Tree ring data provide proxy records of historical hydroclimatic conditions that are widely used for reconstructing precipitation time series. Most previous applications are limited to annual time scales, though information about daily precipitation would enable a range of additional analyses of environmental processes to be investigated and modelled. We used statistical downscaling to simulate stochastic daily precipitation ensembles using dendrochronological data from the western Canadian boreal forest. The simulated precipitation series were generally consistent with observed precipitation data, though reconstructions were poorly constrained during short periods of forest pest outbreaks. The proposed multiple temporal scale precipitation reconstruction can generate annual daily maxima and persistent monthly wet and dry episodes, so that the observed and simulated ensembles have similar precipitation characteristics (i.e. magnitude, peak, and duration)-an improvement on previous modelling studies. We discuss how ecological disturbances may limit reconstructions by inducing non-linear responses in tree growth, and conclude with suggestions of possible applications and further development of downscaling methods for dendrochronological data. Crown Copyright (C) 2017 Published by Elsevier GmbH. All rights reserved.", "authors": [ "Chun, K. P.", "Mamet, S. D.", "Metsaranta, J.", "Barr, A.", "Johnstone, J.", "Wheater, H." ], "keywords": [ "Tree rings", "Statistical downscaling", "Boreal forest", "Stochastic precipitation generation", "Droughts" ], "year": "2017", "source": "DENDROCHRONOLOGIA", "publication_type": "J", "point2d": [ -42.315956115722656, 71.28041076660156 ], "cluster": 14.0 }, { "idx": 81, "title": "A numerical model for the simulation of snowpack solute dynamics to capture runoff ionic pulses during snowmelt: The PULSE model", "abstract": "Early ionic pulse during spring snow-melt can account for a significant portion of the total annual nutrient load in seasonally snow-covered areas. Ionic pulses are a consequence of snow grain core to surface ion segregation during metamorphism, a process commonly referred to as ion exclusion. While numerous studies have provided quantitative measurements of this phenomenon, very few process-based mathematical models have been proposed for diagnostic and prognostic investigations. A few early modelling attempts have been successful in capturing this process assuming transport through porous media with variable porosity. However, this process is represented in models in ways that misalign with the mechanistic view of the process described in the literature. In this research, a process-based model is proposed that can simulated ionic pulses in runoff by emulating solute leaching from snow grains during melt and the subsequent vertical solute transport by meltwater through the snowpack. To facilitate its use without the need for snow-physics' models, simplified alternative methods are proposed to estimate some of the variables required by the model. The model was applied to two regions, and a total of 4 study sites, that are subject to significantly different winter climatic and hydrological conditions. Comparison between observations and simulation results suggest that the model can capture well the overall snow melt runoff concentration pattern, including both the timing and magnitude of the early melt ionic pulse. The model enables the prediction of concentration profiles of the dry (snow) and liquid (wet) fractions within the snow matrix for the first time. Although there is a computational cost associated with the proposed modelling framework, this study demonstrates that it can provide more detailed information about the reallocation and transport of ions through snowpacks, which can ultimately be used to improve nutrient transport predictions during snowmelt.", "authors": [ "Costa, Diogo", "Pomeroy, John", "Wheater, Howard" ], "keywords": [ "Nutrient exports", "Cryosphere", "Meltwater", "Nutrient dynamics", "Preferential elution", "Numerical modelling" ], "year": "2018", "source": "ADVANCES IN WATER RESOURCES", "publication_type": "J", "point2d": [ -25.35637664794922, 22.700984954833984 ], "cluster": 12.0 }, { "idx": 82, "title": "Sustainable Ice-Jam Flood Management for Socio-Economic and Socio-Ecological Systems", "abstract": "Ice jams are critical components of the hydraulic regimes of rivers in cold regions. In addition to contributing to the maintenance of wetland ecology, including aquatic animals and waterfowl, ice jams provide essential moisture and nutrient replenishment to perched lakes and ponds in northern inland deltas. However, river ice-jam flooding can have detrimental impacts on in-stream aquatic ecosystems, cause damage to property and infrastructure, and present hazards to riverside communities. In order to maintain sustainable communities and ecosystems, ice-jam flooding must be both mitigated and promoted. This study reviews various flood management strategies used worldwide, and points to the knowledge gaps in these strategies. The main objective of the paper is to provide a framework for a sustainable ice-jam flood management strategy in order to better protect riverine socio-economic and socio-ecological systems. Sustainable flood management must be a carefully adopted and integrated strategy that includes both economic and ecological perspectives in order to mitigate ice-jam flooding in riverside socio-economic systems, while at the same time promoting ice-jam flooding of riverine socio-ecological systems such as inland deltas.", "authors": [ "Das, Apurba", "Reed, Maureen", "Lindenschmidt, Karl-Erich" ], "keywords": [ "ice jam flooding", "sustainable flood management", "socio-economic system", "socio-ecological system" ], "year": "2018", "source": "WATER", "publication_type": "J", "point2d": [ -5.710338115692139, -35.62479019165039 ], "cluster": 11.0 }, { "idx": 83, "title": "Influence of snowpack and melt energy heterogeneity on snow cover depletion and snowmelt runoff simulation in a cold mountain environment", "abstract": "The spatial heterogeneity of mountain snow cover and ablation is important in controlling patterns of snow cover depletion (SCD), meltwater production, and runoff, yet is not well-represented in most large-scale hydrological models and land surface schemes. Analyses were conducted in this study to examine the influence of various representations of snow cover and melt energy heterogeneity on both simulated SCD and stream discharge from a small alpine basin in the Canadian Rocky Mountains. Simulations were performed using the Cold Regions Hydrological Model (CRHM), where point-scale snowmelt computations were made using a snowpack energy balance formulation and applied to spatial frequency distributions of snow water equivalent (SWE) on individual slope-, aspect-, and landcover-based hydrological response units (HRUs) in the basin. Hydrological routines were added, to represent the vertical and lateral transfers of water through the basin and channel system. From previous studies it is understood that the heterogeneity of late winter SWE is a primary control on patterns of SCD. The analyses here showed that spatial variation in applied melt energy, mainly due to differences in net radiation, has an important influence on SCD at multiple scales and basin discharge, and cannot be neglected without serious error in the prediction of these variables. A single basin SWE distribution using the basin wide mean SWE (SWE) and coefficient of variation (CV; standard deviation/mean) was found to represent the fine-scale spatial heterogeneity of SWE sufficiently well. Simulations that accounted for differences in (SWE) among HRUs but neglected the sub-HRU heterogeneity of SWE were found to yield similar discharge results as simulations that included this heterogeneity, while SCD was poorly represented, even at the basin level. Finally, applying point-scale snowmelt computations based on a single SWE depth for each HRU (thereby neglecting spatial differences in internal snowpack energetics over the distributions) was found to yield similar SCD and discharge results as simulations that resolved internal energy differences. Spatial/internal snowpack melt energy effects are more pronounced at times earlier in spring before the main period of snowmelt and SCD, as shown in previously published work. The paper discusses the importance of these findings as they apply to the warranted complexity of snowmelt process simulation in cold mountain environments, and shows how the end-of-winter SWE distribution represents an effective means of resolving snow cover heterogeneity at multiple scales for modelling, even in steep and complex terrain. (C) 2017 The Author(s). Published by Elsevier B.V.", "authors": [ "DeBeer, Chris M.", "Pomeroy, John W." ], "keywords": [ "Mountain", "Snowmelt", "Snow cover depletion", "Runoff", "Modelling" ], "year": "2017", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -40.14369583129883, -10.533437728881836 ], "cluster": 12.0 }, { "idx": 84, "title": "Influence of snowpack and melt energy heterogeneity on snow cover depletion and snowmelt runoff simulation in a cold mountain environment", "abstract": "The spatial heterogeneity of mountain snow cover and ablation is important in controlling patterns of snow cover depletion (SCD), meltwater production, and runoff, yet is not well-represented in most large-scale hydrological models and land surface schemes. Analyses were conducted in this study to examine the influence of various representations of snow cover and melt energy heterogeneity on both simulated SCD and stream discharge from a small alpine basin in the Canadian Rocky Mountains. Simulations were performed using the Cold Regions Hydrological Model (CRHM), where point-scale snowmelt computations were made using a snowpack energy balance formulation and applied to spatial frequency distributions of snow water equivalent (SWE) on individual slope-, aspect-, and landcover-based hydrological response units (HRUs) in the basin. Hydrological routines were added, to represent the vertical and lateral transfers of water through the basin and channel system. From previous studies it is understood that the heterogeneity of late winter SWE is a primary control on patterns of SCD. The analyses here showed that spatial variation in applied melt energy, mainly due to differences in net radiation, has an important influence on SCD at multiple scales and basin discharge, and cannot be neglected without serious error in the prediction of these variables. A single basin SWE distribution using the basin wide mean SWE (SWE) and coefficient of variation (CV; standard deviation/mean) was found to represent the fine-scale spatial heterogeneity of SWE sufficiently well. Simulations that accounted for differences in (SWE) among HRUs but neglected the sub-HRU heterogeneity of SWE were found to yield similar discharge results as simulations that included this heterogeneity, while SCD was poorly represented, even at the basin level. Finally, applying point-scale snowmelt computations based on a single SWE depth for each HRU (thereby neglecting spatial differences in internal snowpack energetics over the distributions) was found to yield similar SCD and discharge results as simulations that resolved internal energy differences. Spatial/internal snowpack melt energy effects are more pronounced at times earlier in spring before the main period of snowmelt and SCD, as shown in previously published work. The paper discusses the importance of these findings as they apply to the warranted complexity of snowmelt process simulation in cold mountain environments, and shows how the end-of-winter SWE distribution represents an effective means of resolving snow cover heterogeneity at multiple scales for modelling, even in steep and complex terrain. (C) 2017 The Author(s). Published by Elsevier B.V.", "authors": [ "DeBeer, Chris M.", "Pomeroy, John W." ], "keywords": [ "Mountain", "Snowmelt", "Snow cover depletion", "Runoff", "Modelling" ], "year": "2017", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -40.19818878173828, -10.047444343566895 ], "cluster": 12.0 }, { "idx": 85, "title": "An Integrated Modelling System to Predict Hydrological Processes under Climate and Land-Use/Cover Change Scenarios", "abstract": "This study proposes an integrated modeling system consisting of the physically-based MIKE SHE/MIKE 11 model, a cellular automata model, and general circulation models (GCMs) scenarios to investigate the independent and combined effects of future climate and land-use/land-cover (LULC) changes on the hydrology of a river system. The integrated modelling system is applied to the Elbow River watershed in southern Alberta, Canada in conjunction with extreme GCM scenarios and two LULC change scenarios in the 2020s and 2050s. Results reveal that LULC change substantially modifies the river flow regime in the east sub-catchment, where rapid urbanization is occurring. It is also shown that the change in LULC causes an increase in peak flows in both the 2020s and 2050s. The impacts of climate and LULC change on streamflow are positively correlated in winter and spring, which intensifies their influence and leads to a significant rise in streamflow, and, subsequently, increases the vulnerability of the watershed to spring floods. This study highlights the importance of using an integrated modeling approach to investigate both the independent and combined impacts of climate and LULC changes on the future of hydrology to improve our understanding of how watersheds will respond to climate and LULC changes.", "authors": [ "Farjad, Babak", "Gupta, Anil", "Razavi, Saman", "Faramarzi, Monireh", "Marceau, Danielle J." ], "keywords": [ "hydrology", "climate change", "hydrological modeling", "cellular automata", "land-use change", "MIKE SHE", "MIKE 11" ], "year": "2017", "source": "WATER", "publication_type": "J", "point2d": [ -23.394136428833008, -22.367904663085938 ], "cluster": 16.0 }, { "idx": 86, "title": "A review and synthesis of hysteresis in hydrology and hydrological modeling: Memory, path-dependency, or missing physics?", "abstract": "Hysteresis is a widely reported phenomenon in natural and engineered systems across different temporal and spatial scales. Its definition is non-unique and rather context-dependent, while systems with hysteretic behavior, including hydrological systems, are commonly referred to as path-dependent systems or systems with memory. Despite widespread existence of hysteretic processes, the current generation of hydrologic models do not directly account for hysteresis. In this paper, we review the fundamentals, theories, and general properties of hysteresis in the broad scientific literature and then focus on its representations in hydrological sciences. Through illustrative examples, we show how an incomplete understanding or representation of the underlying processes in a system can lead to considering the system as being path-dependent. We argue that, in most cases, hysteresis is a manifestation of our dimensionality-reducing approach to process understanding and representation. We further explain that modelling hysteresis in an ideal world requires a full-dimensional process representation, based on a perfect understanding of the processes, their heterogeneity, and their spatio-temporal scale dependency. We discuss, however, that the missing dimensions/physics in a hydrologic model may be compensated to some extent by enabling the model with formal hysteretic components. Moreover, we show that the conventional model structure and parameterization may be designed in a way to partially reproduce a desired hysteretic behavior.", "authors": [ "Gharari, S.", "Razavi, S." ], "keywords": [ "Hysteresis", "Hydrology", "Modelling", "Preisach", "Path-dependency", "Memory" ], "year": "2018", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -14.78935432434082, -58.92816162109375 ], "cluster": 16.0 }, { "idx": 88, "title": "Revisiting the Basis of Sensitivity Analysis for Dynamical Earth System Models", "abstract": "This paper investigates the problem of global sensitivity analysis (GSA) of Dynamical Earth System Models and proposes a basis for how such analyses should be performed. We argue that (a) performance metric-based approaches to parameter GSA are actually identifiability analyses, (b) the use of a performance metric to assess sensitivity unavoidably distorts the information provided by the model about relative parameter importance, and (c) it is a serious conceptual flaw to interpret the results of such an analysis as being consistent and accurate indications of the sensitivity of the model response to parameter perturbations. Further, because such approaches depend on availability of system state/output observational data, the analysis they provide is necessarily incomplete. Here we frame the GSA problem from first principles, using trajectories of the partial derivatives of model outputs with respect to controlling factors as the theoretical basis for sensitivity, and construct a global sensitivity matrix from which statistical indices of total period time-aggregate parameter importance, and time series of time-varying parameter importance, can be inferred. We demonstrate this framework using the HBV-SASK conceptual hydrologic model applied to the Oldman basin in Canada and show that it disagrees with performance metric-based methods regarding which parameters exert the strongest controls on model behavior. Further, it is highly efficient, requiring less than 1,000 base samples to obtain stable and robust parameter importance assessments for our 10-parameter example. Plain Language Summary When developing and using computer-based models to (a) understand Earth and environmental systems, (b) make predictions, and/or (c) make management or policy decisions, it is very important to know which factors most strongly control the behaviors of the model. Tools to determine this are called sensitivity analysis (SA) methods. This paper shows that the use of model performance metrics to assess sensitivity is based in faulty reasoning. By framing the problem from first principles, a logical approach is developed that provides accurate and cost-effective assessments of both time-aggregate and time-varying parameter importance. Because the approach does not require availability of system output data, it enables a comprehensive assessment and can be applied to historical and predictive conditions, as well as to future scenarios.", "authors": [ "Gupta, Hoshin, V", "Razavi, Saman" ], "keywords": [ "Parameter importance analysis", "global sensitivity analysis", "global sensitivity matrix", "time-varying sensitivity", "dynamical systems", "efficiency and robustness" ], "year": "2018", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 8.912900924682617, -72.97852325439453 ], "cluster": 16.0 }, { "idx": 89, "title": "Multicriteria sensitivity analysis as a diagnostic tool for understanding model behaviour and characterizing model uncertainty", "abstract": "Complex hydrological models are being increasingly used nowadays for many purposes such as studying the impact of climate and land-use change on water resources. However, building a high-fidelity model, particularly at large scales, remains a challenging task, due to complexities in model functioning and behaviour and uncertainties in model structure, parameterization, and data. Global sensitivity analysis (GSA), which characterizes how the variation in the model response is attributed to variations in its input factors (e.g., parameters and forcing data), provides an opportunity to enhance the development and application of these complex models. In this paper, we advocate using GSA as an integral part of the modelling process by discussing its capabilities as a tool for diagnosing model structure and detecting potential defects, identifying influential factors, characterizing uncertainty, and selecting calibration parameters. Accordingly, we conduct a comprehensive GSA of a complex land surface-hydrology model, Modelisation Environmentale-Surface et Hydrologie (MESH), which combines the Canadian land surface scheme with a hydrological routing component, WATROUTE. Various GSA experiments are carried out using a new technique, called Variogram Analysis of Response Surfaces, for alternative hydroclimatic conditions in Canada using multiple criteria, various model configurations, and a full set of model parameters. Results from this study reveal that, in addition to different hydroclimatic conditions and SA criteria, model configurations can also have a major impact on the assessment of sensitivity. GSA can identify aspects of the model internal functioning that are counter-intuitive and thus help the modeller to diagnose possible model deficiencies and make recommendations for improving development and application of the model. As a specific outcome of this work, a list of the most influential parameters for the MESH model is developed. This list, along with some specific recommendations, is expected to assist the wide community of MESH and Canadian land surface scheme users, to enhance their modelling applications.", "authors": [ "Haghnegahdar, Amin", "Razavi, Saman", "Yassin, Fuad", "Wheater, Howard" ], "keywords": [ "CLASS", "hydrological modelling", "land surface modelling", "MESH", "model calibration", "model diagnostics", "sensitivity analysis", "uncertainty analysis", "VARS" ], "year": "2017", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 5.864922046661377, -69.88680267333984 ], "cluster": 16.0 }, { "idx": 90, "title": "Insights into sensitivity analysis of Earth and environmental systems models: On the impact of parameter perturbation scale", "abstract": "This paper investigates the commonly overlooked sensitivity of sensitivity analysis (SA) to what we refer to as parameter perturbation scale, which can be defined as a prescribed size of the sensitivityrelated neighbourhood around any point in the parameter space (analogous to step size Dx for numerical estimation of derivatives). We discuss that perturbation scale is inherent to any (local and global) SA approach, and explain how derivative-based SA approaches (e.g., method of Morris) focus on small-scale perturbations, while variance-based approaches (e.g., method of Sobol) focus on large-scale perturbations. We employ a novel variogram-based approach, called Variogram Analysis of Response Surfaces (VARS), which bridges derivative-and variance-based approaches. Our analyses with different real-world environmental models demonstrate significant implications of subjectivity in the perturbation-scale choice and the need for strategies to address these implications. It is further shown how VARS can uniquely characterize the perturbation-scale dependency and generate sensitivity measures that encompass all sensitivity-related information across the full spectrum of perturbation scales. (C) 2017 Elsevier Ltd. All rights reserved.", "authors": [ "Haghnegahdar, Amin", "Razavi, Saman" ], "keywords": [ "Sensitivity analysis", "Perturbation scale", "VARS", "Environmental modelling", "MESH", "SWAT", "HydroGeoSphere" ], "year": "2017", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 6.971069812774658, -74.84606170654297 ], "cluster": 16.0 }, { "idx": 91, "title": "Modeling the Snowpack Energy Balance during Melt under Exposed Crop Stubble", "abstract": "On the Canadian Prairies, agricultural practices result in millions of hectares of standing crop stubble that gradually emerges during snowmelt. The importance of stubble in trapping wind-blown snow and retaining winter snowfall has been well demonstrated. However, stubble is not explicitly accounted for in hydrological or energy balance snowmelt models. This paper relates measurable stubble parameters (height, width, areal density, and albedo) to the snowpack energy balance and snowmelt with the new, physically based Stubble-Snow-Atmosphere Model (SSAM). Novel process representations of SSAM quantify the attenuation of shortwave radiation by exposed stubble, the sky and vegetation view factors needed to solve longwave radiation terms, and a resistance scheme for stubble-snow-atmosphere fluxes to solve for surface temperatures and turbulent fluxes. SSAM results were compared to observations of radiometric snow-surface temperature, stubble temperature, snow-surface solar irradiance, areal-average turbulent fluxes, and snow water equivalent from two intensive field campaigns during snowmelt in 2015 and 2016 over wheat and canola stubble in Saskatchewan, Canada. Uncalibrated SSAM simulations compared well with these observations, providing confidence in the model structure and parameterization. A sensitivity analysis conducted using SSAM revealed compensatory relationships in energy balance terms that result in a small increase in net snowpack energy as stubble exposure increases.", "authors": [ "Harder, Phillip", "Helgason, Warren D.", "Pomeroy, John W." ], "keywords": [ "" ], "year": "2018", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -29.405261993408203, 9.572497367858887 ], "cluster": 12.0 }, { "idx": 92, "title": "Implications of stubble management on snow hydrology and meltwater partitioning", "abstract": "Spring snowmelt is the most important hydrological event in agricultural cold regions, recharging soil moisture and generating the majority of annual runoff. Melting agricultural snowcovers are patchy, which leads to melt rate enhancement by energy advection from warm moist snow-free surfaces to cool dry snowcovers. Agricultural snowmelt is also impacted by crop residue. Adoption of zero-tillage agricultural practices means vast areas of the Canadian Prairies are now characterized by standing crop stubble. Stubble influences snow accumulation through blowing snow processes and snowmelt through the impact of emerging stubble upon the surface energy balance. Unfortunately, stubble emergence and advection to patchy snowcovers are unaccounted for in snow hydrology models and a complete process description has been unavailable. Here, both advection and stubble influences on snowmelt hydrology are modelled by coupling new stubble-snow-atmosphere surface energy balance and advection models to existing blowing snow and frozen soil infiltration models. Long-term meteorological datasets from sub-humid and semi-arid locations in Saskatchewan, Canada are used to quantify the influence of stubble characteristics on accumulation, melt, and meltwater partitioning processes with respect to interannual variability, antecedent soil moisture, and climatic differences on the Canadian Prairies. The hydrological response to increasing stubble height is increased meltwater, melt rate, infiltration, and runoff, and negligible changes in melt duration. The response of these processes to changes in stubble height was more pronounced at a semi-arid site versus a sub-humid site as stubble more effectively suppresses blowing snow sublimation in the windier, drier semi-arid environment of southwestern Saskatchewan. Recommendations for stubble management to meet specific runoff or infiltration objectives are summarised; stubble management can be an effective tool to influence infiltration where soils are dry and runoff where soils are wet. This framework allows the diagnosis of the influence of stubble management on meltwater partitioning in cold agricultural regions.", "authors": [ "Harder, Phillip", "Pomeroy, John W.", "Helgason, Warren D." ], "keywords": [ "Snowmelt", "Blowing Snow", "Frozen Soil Infiltration", "Stubble Management", "Canadian Prairies" ], "year": "2019", "source": "CANADIAN WATER RESOURCES JOURNAL", "publication_type": "J", "point2d": [ -29.3458309173584, 10.196845054626465 ], "cluster": 12.0 }, { "idx": 93, "title": "A simple model for local-scale sensible and latent heat advection contributions to snowmelt", "abstract": "Local-scale advection of energy from warm snow-free surfaces to cold snow-covered surfaces is an important component of the energy balance during snow-cover depletion. Unfortunately, this process is difficult to quantify in one-dimensional snowmelt models. This paper proposes a simple sensible and latent heat advection model for snowmelt situations that can be readily coupled to one-dimensional energy balance snowmelt models. An existing advection parameterization was coupled to a conceptual frozen soil infiltration surface water retention model to estimate the areal average sensible and latent heat advection contributions to snowmelt. The proposed model compared well with observations of latent and sensible heat advection, providing confidence in the process parameterizations and the assumptions applied. Snow-covered area observations from unmanned aerial vehicle imagery were used to update and evaluate the scaling properties of snow patch area distribution and lengths. Model dynamics and snowmelt implications were explored within an idealized modelling experiment, by coupling to a one-dimensional energy balance snowmelt model. Dry, snow-free surfaces were associated with advection of dry air that compensated for positive sensible heat advection fluxes and so limited the net influence of advection on snowmelt. Latent and sensible heat advection fluxes both contributed positive fluxes to snow when snow-free surfaces were wet and enhanced net advection contributions to snowmelt. The increased net advection fluxes from wet surfaces typically develop towards the end of snowmelt and offset decreases in the one-dimensional areal average melt energy that declines with snow-covered area. The new model can be readily incorporated into existing one-dimensional snowmelt hydrology and land surface scheme models and will foster improvements in snowmelt understanding and predictions.", "authors": [ "Harder, Phillip", "Pomeroy, John W.", "Helgason, Warren D." ], "keywords": [ "" ], "year": "2019", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -45.02628707885742, -6.018920421600342 ], "cluster": 12.0 }, { "idx": 95, "title": "Simulation of Capillary Pressure Overshoot in Snow Combining Trapping of the Wetting Phase With a Nonequilibrium Richards Equation Model", "abstract": "The timing and magnitude of snowmelt discharge and subsequent runoff are controlled by both matrix and preferential flows of water through snowpacks. Matrix flow can be estimated using the Richards equation, and recently, preferential flow in snowpacks has been represented in 2D and 3D models. A challenge for representing preferential flow through porous media in 2D or 3D is capillary pressure overshoot in 1D. Soil studies have developed sophisticated and largely realistic approaches to represent capillary pressure overshoot, but it has not been addressed in snowpack water flow models. Here a 1D nonequilibrium Richards equation model is implemented with dynamic capillary pressure and is combined with a new concept of entrapment of liquid water within the pore space. This new model well represented capillary pressure overshoot, as estimated by published capillary pressure measurements in snow samples of various grain sizes under different rates of liquid water infiltration. Three model parameters were calibrated, and their impacts on model outputs were evaluated. This improvement is a substantial step toward better understanding and simulating physical processes occurring while liquid water percolates an initially dry snowpack.", "authors": [ "Leroux, Nicolas R.", "Pomeroy, John W." ], "keywords": [ "unsaturated flow", "snow", "capillary overshoot", "saturation overshoot", "Richards equation", "entrapment of wetting phase" ], "year": "2019", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -32.20612335205078, 21.5893497467041 ], "cluster": 12.0 }, { "idx": 96, "title": "The potential of water markets to allocate water between industry, agriculture, and public water utilities as an adaptation mechanism to climate change", "abstract": "One of the climate change scenarios that have been developed for the Netherlands predicts hotter and drier summers and a substantial drop in river discharge. This might lead to water scarcity with detrimental economic and environmental effects. Among the possible adaptation responses to climate change-induced water scarcity, the re-allocation of water resources among competing uses should also be considered. In this paper, we extend and apply a computable general equilibrium (CGE) model to assess the potential of water markets (water allocation according to its shadow price) to guide the allocation of scarce water across agriculture, manufacturing, and public water supply. We develop four scenarios in which the scope of water markets is increased from industry-specific to economy-wide. The results show that the agricultural sector bears nearly all of the losses from a new water-scarce climate, while the manufacturing sectors are able to mitigate their losses to a large extent by technical measures. Extending the scope of water markets unambiguously increases economic output and results in a re-allocation of water to the manufacturing sector from the agricultural sector and from public water services. If, perhaps for political reasons, public water services are excluded from water trading, water is re-allocated from agriculture to manufacturing. Depending on which sectors are included, the construction of a water market can have negative or positive effects on a sector's output, and although the implementation of water markets may be positive for overall economic output and can hence assist adaptation, the effect on vulnerable or societally sensitive economic sectors, such as public water, should be taken into account when implementing such a market.", "authors": [ "Koopman, Jason F. L.", "Kuik, Onno", "Tol, Richard S. J.", "Brouwer, Roy" ], "keywords": [ "Climate change", "Water scarcity", "Water markets", "Computable general equilibrium" ], "year": "2017", "source": "MITIGATION AND ADAPTATION STRATEGIES FOR GLOBAL CHANGE", "publication_type": "J", "point2d": [ 38.771278381347656, -53.58058166503906 ], "cluster": 11.0 }, { "idx": 97, "title": "The June 2013 Alberta Catastrophic Flooding Event: Part 1Climatological aspects and hydrometeorological features", "abstract": "In June 2013, excessive rainfall associated with an intense weather system triggered severe flooding in southern Alberta, which became the costliest natural disaster in Canadian history. This article provides an overview of the climatological aspects and large-scale hydrometeorological features associated with the flooding event based upon information from a variety of sources, including satellite data, upper air soundings, surface observations and operational model analyses. The results show that multiple factors combined to create this unusually severe event. The event was characterized by a slow-moving upper level low pressure system west of Alberta, blocked by an upper level ridge, while an associated well-organized surface low pressure system kept southern Alberta, especially the eastern slopes of the Rocky Mountains, in continuous precipitation for up to two days. Results from air parcel trajectory analysis show that a significant amount of the moisture originated from the central Great Plains, transported into Alberta by a southeasterly low level jet. The event was first dominated by significant thunderstorm activity, and then evolved into continuous precipitation supported by the synoptic-scale low pressure system. Both the thunderstorm activity and upslope winds associated with the low pressure system produced large rainfall amounts. A comparison with previous similar events occurring in the same region suggests that the synoptic-scale features associated with the 2013 rainfall event were not particularly intense; however, its storm environment was the most convectively unstable. The system also exhibited a relatively high freezing level, which resulted in rain, rather than snow, mainly falling over the still snow-covered mountainous areas. Melting associated with this rain-on-snow scenario likely contributed to downstream flooding. Furthermore, above-normal snowfall in the preceding spring helped to maintain snow in the high-elevation areas, which facilitated the rain-on-snow event. Copyright (c) 2016 John Wiley & Sons, Ltd.", "authors": [ "Liu, A. Q.", "Mooney, C.", "Szeto, K.", "Theriault, J. M.", "Kochtubajda, B.", "Stewart, R. E.", "Boodoo, S.", "Goodson, R.", "Li, Y.", "Pomeroy, J." ], "keywords": [ "Alberta flooding", "climate", "hydrometeorological features", "synoptic conditions", "moisture transport", "rain-on-snow" ], "year": "2016", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -44.212501525878906, -22.190855026245117 ], "cluster": 1.0 }, { "idx": 98, "title": "Coherence of Radarsat-2, Sentinel-1, and ALOS-1 PALSAR for monitoring spatiotemporal variations of river ice covers", "abstract": "Monitoring spatiotemporal variations of river ice covers is critical for selecting safe ice transportation routes. The coherence of synthetic aperture radar (SAR) interferometry (InSAR) conveys important information on variations of river ice characteristics. However, limited research has been conducted to determine the coherence of multi-frequency L-band ALOS-1 PALSAR, C-band Sentinel-1, and Radarsat-2 images, for such applications. This study was piloted using imagery acquired from the Slave River Delta, Canada, to fill this knowledge gap. The findings were validated using ice core data extracted near Fort Smith. The results indicate that the revisit interval of the satellite is a governing factor of InSAR coherence loss. The ALOS-1 PALSAR images have the smallest coherence mainly due to the 46-day revisit interval and are the least promising for monitoring spatiotemporal variations of river ice covers. Coherence of both Sentinel-1A with a 12-day revisit interval and Radarsat-2 images with a 24-day revisit interval is an important aid for determining safe ice crossings.", "authors": [ "Li, Zhaoqin", "Lindenschmidt, Karl-Erich" ], "keywords": [ "" ], "year": "2018", "source": "CANADIAN JOURNAL OF REMOTE SENSING", "publication_type": "J", "point2d": [ -77.12602996826172, 7.6779985427856445 ], "cluster": 2.0 }, { "idx": 99, "title": "Monitoring river ice cover development using the Freeman-Durden decomposition of quad-pol Radarsat-2 images", "abstract": "The monitoring of river ice development is a crucial guidance indicator to establish safe crossings along river ice covers. This is the first study, based on our knowledge, to understand the interactions between river ice cover structures and radar signals and to further monitor ice development using C-band synthetic aperture radar images. The study was applied to the Slave River, Canada, using the Freeman-Durden decomposition of quad-pol C-band Radarsat-2 FQ14W images and ice core crystallography analysis. Results demonstrate that the combination of volume and surface scattering can be used to monitor ice cover development that cannot be interpreted from single polarization images, such as Radarsat-2 spotlight images used in this study. These results indicate that the decomposed quad-pol Radarsat-2 images can provide a more effective guide than the single-pol Radarsat-2 SLA images to select safe ice transportation routes. This decomposition approach can be extended to other snow and ice covered rivers. (C) 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)", "authors": [ "Lindenschmidt, Karl-Erich", "Li, Zhaoqin" ], "keywords": [ "Freeman-Durden decomposition", "quad-pol Radarsat-2", "river ice development", "ice thickness", "ice crystallography analysis" ], "year": "2018", "source": "JOURNAL OF APPLIED REMOTE SENSING", "publication_type": "J", "point2d": [ -77.85234832763672, 8.660428047180176 ], "cluster": 2.0 }, { "idx": 100, "title": "Future changes to drought characteristics over the Canadian Prairie Provinces based on NARCCAP multi-RCM ensemble", "abstract": "This study assesses projected changes to drought characteristics in Alberta, Saskatchewan and Manitoba, the prairie provinces of Canada, using a multi-regional climate model (RCM) ensemble available through the North American Regional Climate Change Assessment Program. Simulations considered include those performed with six RCMs driven by National Center for Environmental Prediction reanalysis II for the 1981-2003 period and those driven by four Atmosphere-Ocean General Circulation Models for the 1970-1999 and 2041-2070 periods (i.e. eleven current and the same number of corresponding future period simulations). Drought characteristics are extracted using two drought indices, namely the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI). Regional frequency analysis is used to project changes to selected 20- and 50-year regional return levels of drought characteristics for fifteen homogeneous regions, covering the study area. In addition, multivariate analyses of drought characteristics, derived on the basis of 6-month SPI and SPEI values, are developed using the copula approach for each region. Analysis of multi-RCM ensemble-averaged projected changes to mean and selected return levels of drought characteristics show increases over the southern and south-western parts of the study area. Based on bi- and trivariate joint occurrence probabilities of drought characteristics, the southern regions along with the central regions are found highly drought vulnerable, followed by the southwestern and southeastern regions. Compared to the SPI-based analysis, the results based on SPEI suggest drier conditions over many regions in the future, indicating potential effects of rising temperatures on drought risks. These projections will be useful in the development of appropriate adaptation strategies for the water and agricultural sectors, which play an important role in the economy of the study area.", "authors": [ "Masud, M. B.", "Khaliq, M. N.", "Wheater, H. S." ], "keywords": [ "Drought characteristics", "Copula", "Multivariate frequency analysis", "Multivariate homogeneity testing", "Regional climate model", "NARCCAP", "Canadian Prairie Provinces" ], "year": "2017", "source": "CLIMATE DYNAMICS", "publication_type": "J", "point2d": [ -33.53013610839844, -39.60454177856445 ], "cluster": 1.0 }, { "idx": 101, "title": "Projected changes to short- and long-duration precipitation extremes over the Canadian Prairie Provinces", "abstract": "The effects of climate change on April-October short- and long-duration precipitation extremes over the Canadian Prairie Provinces were evaluated using a multi-Regional Climate Model (RCM) ensemble available through the North American Regional Climate Change Assessment Program. Simulations considered include those performed with six RCMs driven by the National Centre for Environmental Prediction (NCEP) reanalysis II product for the 1981-2000 period and those driven by four Atmosphere-Ocean General Circulation Models (AOGCMs) for the current 1971-2000 and future 2041-2070 periods (i.e. a total of 11 current-to-future period simulation pairs). A regional frequency analysis approach was used to develop 2-, 5-, 10-, 25-, and 50-year return values of precipitation extremes from NCEP and AOGCM-driven current and future period simulations that respectively were used to study the performance of RCMs and projected changes for selected return values at regional, grid-cell and local scales. Performance errors due to internal dynamics and physics of RCMs studied for the 1981-2000 period reveal considerable variation in the performance of the RCMs. However, the performance errors were found to be much smaller for RCM ensemble averages than for individual RCMs. Projected changes in future climate to selected regional return values of short-duration (e.g. 15- and 30-min) precipitation extremes and for longer return periods (e.g. 50-year) were found to be mostly larger than those to the longer duration (e.g. 24- and 48-h) extremes and short return periods (e.g. 2-year). Overall, projected changes in precipitation extremes were larger for southeastern regions followed by southern and northern regions and smaller for southwestern and western regions of the study area. The changes to return values were also found to be statistically significant for the majority of the RCM-AOGCM simulation pairs. These projections might be useful as a key input for the future planning of urban drainage infrastructure and development of strategic climate change adaptation measures.", "authors": [ "Masud, M. B.", "Khaliq, M. N.", "Wheater, H. S." ], "keywords": [ "Climate change", "Precipitation extremes", "Regional frequency analysis", "NARCCAP", "Canadian Prairie Provinces" ], "year": "2017", "source": "CLIMATE DYNAMICS", "publication_type": "J", "point2d": [ -33.032859802246094, -40.27763748168945 ], "cluster": 1.0 }, { "idx": 102, "title": "Estimating Sediment Loadings in the South Saskatchewan River Catchment", "abstract": "In river catchments, sediment fluxes facilitate the transport of nutrients and pollutants and reduce water quality, potentially impacting water body health and altering ecosystem functioning. Sediment transport processes also modify the morphology of catchments, and sediment deposition can reduce flow capacity in rivers and water storage capacity in reservoirs and lakes. In this paper, estimates of suspended sediment yields and concentrations in the South Saskatchewan River catchment located in western Canada are presented. The results stem from a SPARROW model, which indicates that the dominant sources of sediment are represented by agricultural fields and urbanized lands. Analyses of sediment retention in the major catchment reservoirs indicate that, as expected, reservoir storage capacity is negatively correlated with reservoir storage reduction and positively correlated with retention rate. Additionally, reservoir lifespans range from less than 100 years to over 9000 years. The results presented here will be useful to complement local environmental guidelines to allow better management of sediment erosion and deposition in the South Saskatchewan River catchment.", "authors": [ "Morales-Marin, L. A.", "Wheater, H. S.", "Lindenschmidt, K. E." ], "keywords": [ "Sediment loads", "South Saskatchewan River", "SPARROW", "Reservoir retention" ], "year": "2018", "source": "WATER RESOURCES MANAGEMENT", "publication_type": "J", "point2d": [ 39.206085205078125, -9.69706916809082 ], "cluster": 10.0 }, { "idx": 103, "title": "Assessment of nutrient loadings of a large multipurpose prairie reservoir", "abstract": "The relatively low water flow velocities in reservoirs cause them to have high capacities for retaining sed-iments and pollutants, which can lead to a reduction in downstream nutrient loading. Hence, nutrients can progressively accumulate in reservoirs, resulting in the deterioration of aquatic ecosystems and water quality. Lake Diefenbaker (LD) is a large multipurpose reservoir, located on the South Saskatchewan River (SSR), that serves as a major source of freshwater in Saskatchewan, Canada. Over the past several years, changes in land use (e.g. expansion of urban areas and industrial developments) in the reservoir's catchment have heightened concerns about future water quality in the catchment and in the reservoir. Intensification of agricultural activities has led to an increase in augmented the application of manure and fertilizer for crops and pasture. Although previous research has attempted to quantify nutrient retention in LD, there is a knowledge gap related to the identification of major nutrient sources and quantification of nutrient export from the catchment at different spatial scales. Using the SPAtially Referenced Regression On Watershed (SPARROW) model, this gap has been addressed by assessing water quality regionally, and identifying spatial patterns of factors and processes that affect water quality in the LD catchment. Model results indicate that LD retains about 70% of the inflowing total nitrogen (TN) and 90% of the inflowing total phosphorus (TP) loads, of which fertilizer and manure applied to agricultural fields contribute the greatest proportion. The SPARROW model will be useful as a tool to guide the optimal implementation of nutrient management plans to reduce nutrient inputs to LD. (C) 2017 Elsevier B.V. All rights reserved.", "authors": [ "Morales-Marin, L. A.", "Wheater, H. S.", "Lindenschmidt, K. E." ], "keywords": [ "Nutrient loadings", "Prairie reservoir", "River catchment", "Manure and fertilizer", "SPARROW" ], "year": "2017", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ 37.455867767333984, -10.034273147583008 ], "cluster": 10.0 }, { "idx": 104, "title": "Wetlands, Flood Control and Ecosystem Services in the Smith Creek Drainage Basin: A Case Study in Saskatchewan, Canada", "abstract": "This paper applies a social return on investment (SROI) analysis to the issue of flood control and wetland conservation in the Smith Creek basin of southeastern Saskatchewan, Canada. Basin hydrological modeling applied to wetland loss and restoration scenarios in the study area provides local estimates of the ecosystem service (ES) provision related to flood control and nutrient removal. Locally appropriate monetary values are applied to these services to gauge the cost effectiveness of wetland conservation funding at two levels: flood control capacity alone and then incorporating a suite of ES. SROI ratios for flood control alone provide ratios between 3.17 (retention) and 0.80 (full restoration) over 30 years; when other ES are included, the ratios increase, ranging from 7.70 (retention) to 2.98 (full restoration) over 30 years. Retention of existing wetlands provides the highest SROI and therefore we argue that government policy should focus on preventing further loss of wetlands as a strategic investment opportunity. Overall, these results indicate that wetland retention is an economically viable solution to limit the financial, social and environmental damages of flooding in Saskatchewan specifically and the Prairie Pothole Region (PPR) generally.", "authors": [ "Pattison-Williams, John K.", "Pomeroy, John W.", "Badiou, Pascal", "Gabor, Shane" ], "keywords": [ "Wetland conservation", "Flood reduction", "Ecosystem Services", "Basin modeling", "Social return on investment" ], "year": "2018", "source": "ECOLOGICAL ECONOMICS", "publication_type": "J", "point2d": [ 50.62616729736328, -41.89573669433594 ], "cluster": 11.0 }, { "idx": 105, "title": "The significance of spatial variability of rainfall on simulated runoff: an evaluation based on the Upper Lee catchment, UK", "abstract": "The significance of spatial variability of rainfall on runoff is explored as a function of catchment scale and type, and antecedent conditions via the continuous time, semi-distributed probability distributed model (PDM) hydrological model applied to the Upper Lee catchment, UK. The impact of catchment scale and type is assessed using 11 nested catchments, and further assessed by artificially changing the catchment characteristics and translating these to model parameters (MPs) with uncertainty using model regionalisation. Dry and wet antecedent conditions are represented by 'warming up' the model under different rainfall time series. Synthetic rainfall events are introduced to directly relate the change in simulated runoff to the spatial variability of rainfall. Results show that runoff volume and peak are more sensitive to the spatial rainfall for more impermeable catchments; however, this sensitivity is significantly undermined under wet antecedent conditions. Although there is indication that the impact of spatial rainfall on runoff varies as a function of catchment scale, the variability of antecedent conditions between the synthetic catchments seems to mask this significance. Parameter uncertainty analysis highlights the importance of accurately representing the spatial variability of the catchment properties and their translation to MPs when investigating the effects of spatial properties of rainfall on runoff.", "authors": [ "Pechlivanidis, I. G.", "McIntyre, N.", "Wheater, H. S." ], "keywords": [ "antecedent conditions", "catchment type", "PDM model", "semi-distributed modelling", "spatial rainfall", "uncertainty" ], "year": "2017", "source": "HYDROLOGY RESEARCH", "publication_type": "J", "point2d": [ -2.2672224044799805, -62.17949676513672 ], "cluster": 16.0 }, { "idx": 106, "title": "Prewhitening of hydroclimatic time series? Implications for inferred change and variability across time scales", "abstract": "Prewhitening, the process of eliminating or reducing short-term stochastic persistence to enable detection of deterministic change, has been extensively applied to time series analysis of a range of geophysical variables. Despite the controversy around its utility, methodologies for prewhitening time series continue to be a critical feature of a variety of analyses including: trend detection of hydroclimatic variables and reconstruction of climate and/or hydrology through proxy records such as tree rings. With a focus on the latter, this paper presents a generalized approach to exploring the impact of a wide range of stochastic structures of short- and long-term persistence on the variability of hydroclimatic time series. Through this approach, we examine the impact of prewhitening on the inferred variability of time series across time scales. We document how a focus on prewhitened, residual time series can be misleading, as it can drastically distort (or remove) the structure of variability across time scales. Through examples with actual data, we show how such loss of information in prewhitened time series of tree rings (so-called residual chronologies) can lead to the underestimation of extreme conditions in climate and hydrology, particularly droughts, reconstructed for centuries preceding the historical period. (C) 2017 The Authors. Published by Elsevier B.V.", "authors": [ "Razavi, Saman", "Vogel, Richard" ], "keywords": [ "Prewhitening", "Time series analysis", "Hurst effect", "Tree rings", "Paleo-hydrology", "Residual chronology", "Climate variability", "Autoregressive (AR) models" ], "year": "2018", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -41.7369384765625, 72.3551025390625 ], "cluster": 14.0 }, { "idx": 107, "title": "A multi-method Generalized Global Sensitivity Matrix approach to accounting for the dynamical nature of earth and environmental systems models", "abstract": "Many applications of global sensitivity analysis (GSA) do not adequately account for the dynamical nature of earth and environmental systems models. Gupta and Razavi (2018) highlight this fact and develop a sensitivity analysis framework from first principles, based on the sensitivity information contained in trajectories of partial derivatives of the dynamical model responses with respect to controlling factors. Here, we extend and generalize that framework to accommodate any GSA philosophy, including derivative-based approaches (such as Morris and DELSA), direct-response-based approaches (such as the variance-based Sobol', distribution-based PAWN, and higher-moment-based methods), and unifying variogram-based approaches (such as VARS). The framework is implemented within the VARS-TOOL software toolbox and demonstrated using the HBV-SASK model applied to the Oldman Watershed, Canada. This enables a comprehensive multi-variate investigation of the influence of parameters and forcings on different modeled state variables and responses, without the need for observational data regarding those responses.", "authors": [ "Razavi, Saman", "Gupta, Hoshin V." ], "keywords": [ "Global sensitivity analysis", "Time-varying sensitivity analysis", "Parameter importance", "Uncertainty", "Variogram analysis of response surfaces (VARS)", "Sobol'", "Morris", "Progressive Latin hypercube sampling (PLHS)", "Dynamical systems models", "Performance metrics", "Sensitivity indices" ], "year": "2019", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 7.0473504066467285, -73.64781188964844 ], "cluster": 16.0 }, { "idx": 108, "title": "Trends in the Timing and Magnitude of Ice-Jam Floods in Canada", "abstract": "Ice-jam floods (IJFs) are important hydrological and hydraulic events in the northern hemisphere that are of major concern for citizens, authorities, insurance companies and government agencies. In recent years, there have been advances in assessing and quantifying climate change impacts on river ice processes, however, an understanding of climate change and regulation impacts on the timing and magnitude of IJFs remains limited. This study presents a global overview of IJF case studies and discusses IJF risks in North America, one of the most IJF prone regions according to literature. Then an assessment of shifts in the timing and magnitude of IJFs in Canada is presented analyzing flow data from 1107 hydrometric stations across Canada for the period from 1903 to 2015. The analyses show clear signals of climate change and regulation impacts in the timing and magnitude of IJFs, particularly in small basins.", "authors": [ "Rokaya, Prabin", "Budhathoki, Sujata", "Lindenschmidt, Karl-Erich" ], "keywords": [ "" ], "year": "2018", "source": "SCIENTIFIC REPORTS", "publication_type": "J", "point2d": [ -7.852047920227051, -38.059043884277344 ], "cluster": 1.0 }, { "idx": 109, "title": "Improving in-lake water quality modeling using variable chlorophyll a/algal biomass ratios", "abstract": "Algal simulations in many water quality models perform poorly because of oversimplifications in the process descriptions of the algae growth mechanisms. In this study, algae simulations were improved by implementing variable chlorophyll a/algal biomass ratios in the CE-QUAL-W2 model, a sophisticated two-dimensional laterally-averaged water quality model. Originally a constant in the model, the chlorophyll a/algal biomass ratio was reprogrammed to vary according to the nutrient and light limiting conditions in the water column. The modified model was tested on Lake Diefenbaker, a prairie reservoir in Saskatchewan, Canada, where, similar to many other lakes in the world, field observations confirm variable spatiotemporal ratios between chlorophyll a and algal biomass. The modified version yielded more accurate simulations compared to the standard version and provides a promising algorithm to improve results for many lakes and reservoirs globally. (C) 2017 Elsevier Ltd. All rights reserved.", "authors": [ "Sadeghian, Amir", "Chapra, Steven C.", "Hudson, Jeff", "Wheater, Howard", "Lindenschmidt, Karl-Erich" ], "keywords": [ "Lake diefenbaker", "Water quality modeling", "CE-QUAL-W2", "Algal stoichiometry", "Chlorophyll a/algal biomass ratio" ], "year": "2018", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 58.83272933959961, 22.02583122253418 ], "cluster": 19.0 }, { "idx": 110, "title": "Sediment plume model-a comparison between use of measured turbidity data and satellite images for model calibration", "abstract": "In this study, we built a two-dimensional sediment transport model of Lake Diefenbaker, Saskatchewan, Canada. It was calibrated by using measured turbidity data from stations along the reservoir and satellite images based on a flood event in 2013. In June 2013, there was heavy rainfall for two consecutive days on the frozen and snow-covered ground in the higher elevations of western Alberta, Canada. The runoff from the rainfall and the melted snow caused one of the largest recorded inflows to the headwaters of the South Saskatchewan River and Lake Diefenbaker downstream. An estimated discharge peak of over 5200 m(3)/s arrived at the reservoir inlet with a thick sediment front within a few days. The sediment plume moved quickly through the entire reservoir and remained visible from satellite images for over 2 weeks along most of the reservoir, leading to concerns regarding water quality. The aims of this study are to compare, quantitatively and qualitatively, the efficacy of using turbidity data and satellite images for sediment transport model calibration and to determine how accurately a sediment transport model can simulate sediment transport based on each of them. Both turbidity data and satellite images were very useful for calibrating the sediment transport model quantitatively and qualitatively. Model predictions and turbidity measurements show that the flood water and suspended sediments entered upstream fairly well mixed and moved downstream as overflow with a sharp gradient at the plume front. The model results suggest that the settling and resuspension rates of sediment are directly proportional to flow characteristics and that the use of constant coefficients leads to model underestimation or overestimation unless more data on sediment formation become available. Hence, this study reiterates the significance of the availability of data on sediment distribution and characteristics for building a robust and reliable sediment transport model.", "authors": [ "Sadeghian, Amir", "Hudson, Jeff", "Wheater, Howard", "Lindenschmidt, Karl-Erich" ], "keywords": [ "South Saskatchewan River", "Lake Diefenbaker", "Sedimentation", "Erosion", "Satellite images", "MODIS", "CE-QUAL-W2" ], "year": "2017", "source": "ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH", "publication_type": "J", "point2d": [ 40.367652893066406, -7.665035724639893 ], "cluster": 18.0 }, { "idx": 111, "title": "On the appropriate definition of soil profile configuration and initial conditions for land surface-hydrology models in cold regions", "abstract": "Arctic and subarctic regions are amongst the most susceptible regions on Earth to global warming and climate change. Understanding and predicting the impact of climate change in these regions require a proper process representation of the interactions between climate, carbon cycle, and hydrology in Earth system models. This study focuses on land surface models (LSMs) that represent the lower boundary condition of general circulation models (GCMs) and regional climate models (RCMs), which simulate climate change evolution at the global and regional scales, respectively. LSMs typically utilize a standard soil configuration with a depth of no more than 4 m, whereas for cold, permafrost regions, field experiments show that attention to deep soil profiles is needed to understand and close the water and energy balances, which are tightly coupled through the phase change. To address this gap, we design and run a series of model experiments with a one-dimensional LSM, called CLASS (Canadian Land Surface Scheme), as embedded in the MESH (Modelisation Environmentale Communautaire - Surface and Hydrology) modelling system, to (1) characterize the effect of soil profile depth under different climate conditions and in the presence of parameter uncertainty; (2) assess the effect of including or excluding the geothermal flux in the LSM at the bottom of the soil column; and (3) develop a methodology for temperature profile initialization in permafrost regions, where the system has an extended memory, by the use of paleo-records and bootstrapping. Our study area is in Norman Wells, Northwest Territories of Canada, where measurements of soil temperature profiles and historical re-constructed climate data are available. Our results demonstrate a dominant role for parameter uncertainty, that is often neglected in LSMs. Considering such high sensitivity to parameter values and dependency on the climate condition, we show that a minimum depth of 20m is essential to adequately represent the temperature dynamics. We further show that our proposed initialization procedure is effective and robust to uncertainty in paleo-climate reconstructions and that more than 300 years of reconstructed climate time series are needed for proper model initialization.", "authors": [ "Sapriza-Azuri, Gonzalo", "Gamazo, Pablo", "Razavi, Saman", "Wheater, Howard S." ], "keywords": [ "" ], "year": "2018", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -29.6769962310791, -0.6019651293754578 ], "cluster": 1.0 }, { "idx": 112, "title": "Simulating the convective precipitation diurnal cycle in North America's current and future climate", "abstract": "Convection-permitting models (CPM) with at least 4 km horizontal grid spacing enable the cumulus parameterization to be switched off and thus simulate convective processes more realistically than coarse resolution models. This study investigates if a North American scale CPM can reproduce the observed warm season precipitation diurnal cycle on a climate scale. Potential changes in the precipitation diurnal cycle characteristics at the end of the twenty first century are also investigated using the pseudo global warming approach under a high-end anthropogenic emission scenario (RCP8.5). Simulations are performed with the Advanced Research Weather Research and Forecasting (ARW-WRF) model with 4-km horizontal grid spacing. Results from the WRF historical run (2001-2013) are evaluated against hourly precipitation from 2903 weather stations and a gridded hourly precipitation product in the U.S. The magnitude and timing of the diurnal cycle peak are realistically simulated in most of the U.S. and southern Canada. The model also captures the transition from afternoon precipitation peaks eastward of the Rocky Mountains to night peaks in the central U.S., which is related to propagating mesoscale convective systems. However, the historical climate simulation does not capture the observed early morning peaks in the central U.S. and overestimates the magnitude of the diurnal precipitation peak in the southeast region. In the simulation of the future climate, both the precipitation amount of the diurnal cycle and precipitation intensity increase throughout the domain, along with an increase in precipitation frequency in the northern region of the domain in May. These increases indicate a clear intensification of the hydrologic cycle during the warm season with potential impacts on future water resources, agriculture, and flooding.", "authors": [ "Scaff, Lucia", "Prein, Andreas F.", "Li, Yanping", "Liu, Changhai", "Rasmussen, Roy", "Ikeda, Kyoko" ], "keywords": [ "Convection-permitting modeling", "Precipitation diurnal cycle", "North America", "Weather Research and Forecasting model", "Pseudo global warming approach", "Climate change" ], "year": "2020", "source": "CLIMATE DYNAMICS", "publication_type": "J", "point2d": [ -52.04164123535156, -59.66806411743164 ], "cluster": 14.0 }, { "idx": 113, "title": "Simulating the convective precipitation diurnal cycle in North America's current and future climate", "abstract": "Convection-permitting models (CPM) with at least 4 km horizontal grid spacing enable the cumulus parameterization to be switched off and thus simulate convective processes more realistically than coarse resolution models. This study investigates if a North American scale CPM can reproduce the observed warm season precipitation diurnal cycle on a climate scale. Potential changes in the precipitation diurnal cycle characteristics at the end of the twenty first century are also investigated using the pseudo global warming approach under a high-end anthropogenic emission scenario (RCP8.5). Simulations are performed with the Advanced Research Weather Research and Forecasting (ARW-WRF) model with 4-km horizontal grid spacing. Results from the WRF historical run (2001-2013) are evaluated against hourly precipitation from 2903 weather stations and a gridded hourly precipitation product in the U.S. The magnitude and timing of the diurnal cycle peak are realistically simulated in most of the U.S. and southern Canada. The model also captures the transition from afternoon precipitation peaks eastward of the Rocky Mountains to night peaks in the central U.S., which is related to propagating mesoscale convective systems. However, the historical climate simulation does not capture the observed early morning peaks in the central U.S. and overestimates the magnitude of the diurnal precipitation peak in the southeast region. In the simulation of the future climate, both the precipitation amount of the diurnal cycle and precipitation intensity increase throughout the domain, along with an increase in precipitation frequency in the northern region of the domain in May. These increases indicate a clear intensification of the hydrologic cycle during the warm season with potential impacts on future water resources, agriculture, and flooding.", "authors": [ "Scaff, Lucia", "Prein, Andreas F.", "Li, Yanping", "Liu, Changhai", "Rasmussen, Roy", "Ikeda, Kyoko" ], "keywords": [ "Convection-permitting modeling", "Precipitation diurnal cycle", "North America", "Weather Research and Forecasting model", "Pseudo global warming approach", "Climate change" ], "year": "2020", "source": "CLIMATE DYNAMICS", "publication_type": "J", "point2d": [ -52.335784912109375, -60.0145149230957 ], "cluster": 14.0 }, { "idx": 114, "title": "Progressive Latin Hypercube Sampling: An efficient approach for robust sampling-based analysis of environmental models", "abstract": "Efficient sampling strategies that scale with the size of the problem, computational budget, and users' needs are essential for various sampling-based analyses, such as sensitivity and uncertainty analysis. In this study, we propose a new strategy, called Progressive Latin Hypercube Sampling (PLHS), which sequentially generates sample points while progressively preserving the distributional properties of interest (Latin hypercube properties, space-filling, etc.), as the sample size grows. Unlike Latin hypercube sampling, PLHS generates a series of smaller sub-sets (slices) such that (1) the first slice is Latin hypercube, (2) the progressive union of slices remains Latin hypercube and achieves maximum stratification in any one-dimensional projection, and as such (3) the entire sample set is Latin hypercube. The performance of PLHS is compared with benchmark sampling strategies across multiple case studies for Monte Carlo simulation, sensitivity and uncertainty analysis. Our results indicate that PLHS leads to improved efficiency, convergence, and robustness of sampling-based analyses. (C) 2017 Elsevier Ltd. All rights reserved.", "authors": [ "Sheikholeslami, Razi", "Razavi, Saman" ], "keywords": [ "Design of computer experiments", "Sequential sampling", "Optimal Latin hypercube sampling", "Monte Carlo simulation", "Uncertainty analysis", "Sensitivity analysis" ], "year": "2017", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 8.750000953674316, -77.48096466064453 ], "cluster": 16.0 }, { "idx": 116, "title": "Improved Understanding of River Ice Processes Using Global Sensitivity Analysis Approaches", "abstract": "The high impact of river ice phenomena on the hydrology of cold regions has led to the extensive use of numerical models in simulating and predicting river ice processes. Consequently, there is a need to utilize efficient and robust sensitivity analysis (SA) methods to characterize the role of different parameters on the functioning of these models. To gain greater insight into how the internal parameters affect a river ice model's behavior, this paper presents a comparative performance investigation of the two global SA methods: (1) the recently proposed variogram analysis of response surfaces (VARS); and (2) the widely used regional sensitivity analysis (RSA). The methods were benchmarked on a one-dimensional hydrodynamic river ice model of the Lower Dauphin River, Manitoba, Canada. Furthermore, using a bootstrapping strategy, a procedure was developed to estimate confidence intervals on the resulting sensitivity indices and evaluate reliability of the inferred parameter rankings. Results show that (1) the water levels simulated by the river ice model are most sensitive to the ice cover characteristics (i.e., porosity and thickness at the ice cover front) and upstream discharge; (2) the hydraulic roughness parameters and slush ice properties (i.e., porosity and thickness of the slush pans) are medium-and low-sensitivity parameters, respectively; (3) the VARS and RSA methods provide contradictory assessments regarding the sensitivity of the model output to variations in the slush ice porosity and ice roughness parameters; and (4) the VARS method appears to be superior to RSA in terms of generating robust estimates of the parameter sensitivity rankings. (C) 2017 American Society of Civil Engineers.", "authors": [ "Sheikholeslami, Razi", "Yassin, Fuad", "Lindenschmidt, Karl-Erich", "Razavi, Saman" ], "keywords": [ "Cold regions", "River ice modeling", "Ice-induced floods", "Global sensitivity analysis", "Uncertainty analysis", "Bootstrapping" ], "year": "2017", "source": "JOURNAL OF HYDROLOGIC ENGINEERING", "publication_type": "J", "point2d": [ 3.431640148162842, -70.46233367919922 ], "cluster": 16.0 }, { "idx": 119, "title": "Enhanced identification of a hydrologic model using streamflow and satellite water storage data: A multicriteria sensitivity analysis and optimization approach", "abstract": "Hydrologic model development and calibration have continued in most cases to focus only on accurately reproducing streamflows. However, complex models, for example, the so-called physically based models, possess large degrees of freedom that, if not constrained properly, may lead to poor model performance when used for prediction. We argue that constraining a model to represent streamflow, which is an integrated resultant of many factors across the watershed, is necessary but by no means sufficient to develop a high-fidelity model. To address this problem, we develop a framework to utilize the Gravity Recovery and Climate Experiment's (GRACE) total water storage anomaly data as a supplement to streamflows for model calibration, in a multiobjective setting. The VARS method (Variogram Analysis of Response Surfaces) for global sensitivity analysis is used to understand the model behaviour with respect to streamflow and GRACE data, and the BORG multiobjective optimization method is applied for model calibration. Two subbasins of the Saskatchewan River Basin in Western Canada are used as a case study. Results show that the developed framework is superior to the conventional approach of calibration only to streamflows, even when multiple streamflow-based error functions are simultaneously minimized. It is shown that a range of (possibly false) system trajectories in state variable space can lead to similar (acceptable) model responses. This observation has significant implications for land-surface and hydrologic model development and, if not addressed properly, may undermine the credibility of the model in prediction. The framework effectively constrains the model behaviour (by constraining posterior parameter space) and results in more credible representation of hydrology across the watershed.", "authors": [ "Yassin, Fuad", "Razavi, Saman", "Wheater, Howard", "Sapriza-Azuri, Gonzalo", "Davison, Bruce", "Pietroniro, Alain" ], "keywords": [ "GRACE", "model state variable", "multiobjective optimization", "parameter identification", "Pareto-optimal", "sensitivity analysis" ], "year": "2017", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 6.463139057159424, -68.665283203125 ], "cluster": 16.0 }, { "idx": 120, "title": "The Effect of Coherent Structures in the Atmospheric Surface Layer on Blowing-Snow Transport", "abstract": "While turbulent bursts are considered critical for blowing-snow transport and initiation, the interaction of the airflow with the snow surface is not fully understood. To better characterize the coupling of turbulent structures and blowing-snow transport, observations collected in natural environments at the necessary high-resolution time scales are needed. To address this, high-frequency measurements of turbulence, blowing-snow density and particle velocity were made in the Canadian Rockies. During blowing-snow storms, modified variable-interval time averaging enabled identification of periods of near-surface blowing-snow coupling with shear-stress-producing motions in the lowest 2 m of the atmospheric surface layer. The identification of those turbulent motions responsible for blowing snow yields a better understanding of the event-driven mechanics of initiation and sustained transport. The type of coherent structures generating the Reynolds stress are just as important as the magnitude of the Reynolds stress in initiating and sustaining near-surface blowing snow. Our results suggest that blowing-snow models driven by merely the time-averaged shear stress lack physical realism in the near-surface region. The next phase of the development of blowing-snow models should incorporate parametrizations of coherent turbulent structures.", "authors": [ "Aksamit, Nikolas O.", "Pomeroy, John W." ], "keywords": [ "Blowing snow", "Coherent structures", "Particle tracking velocimetry", "Quadrant analysis", "Variable interval time averaging" ], "year": "2018", "source": "BOUNDARY-LAYER METEOROLOGY", "publication_type": "J", "point2d": [ -55.02497100830078, -11.611592292785645 ], "cluster": 12.0 }, { "idx": 122, "title": "Influence of a rock glacier spring on the stream energy budget and cold-water refuge in an alpine stream", "abstract": "The thermal regimes of alpine streams remain understudied and have important implications for cold-water fish habitat, which is expected to decline due to climatic warming. Previous research has focused on the effects of distributed energy fluxes and meltwater from snowpacks and glaciers on the temperature of mountain streams. This study presents the effects of the groundwater spring discharge from an inactive rock glacier containing little ground ice on the temperature of an alpine stream. Rock glaciers are coarse blocky landforms that are ubiquitous in alpine environments and typically exhibit low groundwater discharge temperatures and resilience to climatic warming. Water temperature data indicate that the rock glacier spring cools the stream by an average of 3 degrees C during July and August and reduces maximum daily temperatures by an average of 5 degrees C during the peak temperature period of the first twoweeks in August, producing a cold-water refuge downstream of the spring. The distributed stream surface and streambed energy fluxes are calculated for the reach along the toe of the rock glacier, and solar radiation dominates the distributed stream energy budget. The lateral advective heat flux generated by the rock glacier spring is compared to the distributed energy fluxes over the study reach, and the spring advective heat flux is the dominant control on stream temperature at the reach scale. This study highlights the potential for coarse blocky landforms to generate climatically resilient cold-water refuges in alpine streams.", "authors": [ "Harrington, Jordan S.", "Hayashi, Masaki", "Kurylyk, Barret L." ], "keywords": [ "energy balance", "fish habitat", "groundwater", "mountain stream", "stream temperature", "thermal regime" ], "year": "2017", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -6.908325672149658, 0.7139581441879272 ], "cluster": 12.0 }, { "idx": 124, "title": "Quantifying projected changes in runoff variability and flow regimes of the Fraser River Basin, British Columbia", "abstract": "In response to ongoing and future-projected global warming, mid-latitude, nival river basins are expected to transition from a snowmelt-dominated flow regime to a nival-pluvial one with an earlier spring freshet of reduced magnitude. There is, however, a rich variation in responses that depends on factors such as the topographic complexity of the basin and the strength of maritime influences. We illustrate the potential effects of a strong maritime influence by studying future changes in cold season flow variability in the Fraser River Basin (FRB) of British Columbia, a large extratropical watershed extending from the Rocky Mountains to the Pacific Coast. We use a process-based hydrological model driven by an ensemble of 21 statistically down-scaled simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5), following the Representative Concentration Pathway 8.5 (RCP 8.5). Warming under RCP 8.5 leads to reduced winter snowfall, shortening the average snow accumulation season by about one-third. Despite this, large increases in cold season rainfall lead to unprecedented cold season peak flows and increased overall runoff variability in the VIC simulations. Increased cold season rainfall is shown to be the dominant climatic driver in the Coast Mountains, contributing 60 % to mean cold season runoff changes in the 2080s. Cold season runoff at the outlet of the basin increases by 70 % by the 2080s, and its interannual variability more than doubles when compared to the 1990s, suggesting substantial challenges for operational flow forecasting in the region. Furthermore, almost half of the basin (45 %) transitions from a snow-dominated runoff regime in the 1990s to a primarily rain-dominated regime in the 2080s, according to a snowmelt pulse detection algorithm. While these projections are consistent with the anticipated transition from a nival to a nival-pluvial hydrologic regime, the marked increase in FRB cold season runoff is likely linked to more frequent landfalling atmospheric rivers in the region projected in the CMIP5 models, providing in-sights for other maritime-influenced extratropical basins.", "authors": [ "Ul Islam, Siraj", "Curry, Charles L.", "Dery, Stephen J.", "Zwiers, Francis W." ], "keywords": [ "" ], "year": "2019", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -20.324495315551758, -29.654590606689453 ], "cluster": 1.0 }, { "idx": 125, "title": "Beaver-mediated water table dynamics in a Rocky Mountain fen", "abstract": "Beaver dams are known to raise water tables in mineral soil environments, but very little is known about their impact in wetlands, such as peatlands. Peatlands tend to have shallow water tables, and the position and tendency of the water table to fluctuate (i.e., stability) is a factor controlling the system's ability to store carbon and water. Many peatland environments, especially fens, offer ideal habitat for beaver, and the potential for beaver dams to influence this link by manipulating water tables requires investigation. Our objective was to determine the influence of beaver dams on the water table dynamics of a Rocky Mountain fen. We monitored water tables in the peatland for 4years while beaver dams were intact and 2years after they were breached by an extreme flood event. We found that, because of the unique way in which dams were built, they connected the peatland to the stream and raised and stabilized already high water tables within a 150-m radius. Beaver-mediated changes to peatland water table regimes have the potential to enhance carbon sequestration and the peatland's ability to respond to external pressures such as climate change. Furthermore, beaver dams increased surface and groundwater storage, which has implications for regional water balances, especially in times of drought.", "authors": [ "Karran, Daniel J.", "Westbrook, Cherie J.", "Bedard-Haughn, Angela" ], "keywords": [ "" ], "year": "2018", "source": "ECOHYDROLOGY", "publication_type": "J", "point2d": [ 11.948476791381836, 1.155502438545227 ], "cluster": 13.0 }, { "idx": 126, "title": "Flood risk management in the Canadian prairie provinces: Defaulting towards flood resistance and recovery versus resilience", "abstract": "Major flood events are likely to happen more frequently and be more severe under changing land use and climatic conditions. Adapting to floods using resilience-based flood risk management (FRM) policies and initiatives is a more appropriate solution than relying solely on flood defence structures or disaster recovery programmes. The primary authority for FRM in Canada is the provinces, but in practice, the policies and responsibilities are distributed across complex, multi-departmental, multi-scalar systems of government. To examine the extent to which institutional arrangements for FRM facilitate or constrain FRM resilience, this paper uses a case study of FRM policies, instruments and practices in the three Canadian prairie provinces where floods have been particularly severe in recent years. Document analysis provided insights into current FRM policies and instruments while semi-structured interviews with 34 individuals working in an FRM capacity informed the roles and responsibilities for FRM implementation. Results indicate that the current FRM policies and instruments across the prairie region have the basic requirements for flood resilience. However, flood resilience is inherently challenged by institutional fragmentation, lack of clarity of FRM roles and responsibilities, and policy layering and competing mandates, which biases FRM towards resistance and recovery solutions. To go beyond solely coordinating flood emergency response and recovery, the paper suggests an overarching regional or national FRM strategy and boundary organisation to coordinate roles and responsibilities for the specific purpose of flood resilience. This requires an agency with the mandate to manage FRM policy instruments, and clearly allocate decision authority amongst the multiple levels and layers of FRM governance.", "authors": [ "Morrison, Alasdair", "Noble, Bram F.", "Westbrook, Cherie J." ], "keywords": [ "" ], "year": "2018", "source": "CANADIAN WATER RESOURCES JOURNAL", "publication_type": "J", "point2d": [ 37.68925476074219, -31.551612854003906 ], "cluster": 4.0 }, { "idx": 127, "title": "Storage, mixing, and fluxes of water in the critical zone across northern environments inferred by stable isotopes of soil water", "abstract": "Quantifying soil water storage, mixing, and release via recharge, transpiration, and evaporation is essential for a better understanding of critical zone processes. Here, we integrate stable isotope (H-2 and O-18 of soil water, precipitation, and groundwater) and hydrometric (soil moisture) data from 5 long-term experimental catchments along a hydroclimatic gradient across northern latitudes: Dry Creek (USA), Bruntland Burn (Scotland), Dorset (Canada), Krycklan (Sweden), and Wolf Creek (Canada). Within each catchment, 6 to 11 isotope sampling campaigns occurred at 2 to 4 sampling locations over at least 1year. Analysis for H-2 and O-18 in the bulk pore water was done for >2,500 soil samples either by cryogenic extraction (Dry Creek) or by direct equilibration (other sites). The results showed a similar general pattern that soil water isotope variability reflected the seasonality of the precipitation input signal. However, pronounced differences among sampling locations occurred regarding the isotopic fractionation due to evaporation. We found that antecedent precipitation volumes mainly governed the fractionation signal, temperature and evaporation rates were of secondary importance, and soil moisture played only a minor role in the variability of soil water evaporation fractionation across the hydroclimatic gradient. We further observed that soil waters beneath conifer trees were more fractionated than beneath heather shrubs or red oak trees, indicating higher soil evaporation rates in coniferous forests. Sampling locations closer to streams were more damped and depleted in their stable isotopic composition than hillslope sites, revealing increased subsurface mixing towards the saturated zone and a preferential recharge of winter precipitation. Bulk soil waters generally comprised a high share of waters older than 14days, which indicates that the water in soil pores are usually not fully replaced by recent infiltration events. The presented stable isotope data of soil water were, thus, a useful tool to track the spatial variability of water fluxes within and from the critical zone. Such data provide invaluable information to improve the representation of critical zone processes in spatially distributed hydrological models.", "authors": [ "Sprenger, Matthias", "Tetzlaff, Doerthe", "Buttle, Jim", "Carey, Sean K.", "McNamara, James P.", "Laudon, Hjalmar", "Shatilla, Nadine J.", "Soulsby, Chris" ], "keywords": [ "critical zone", "evaporation", "fractionation", "northern environments", "soil hydrology", "stable isotopes" ], "year": "2018", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -10.736861228942871, 22.848642349243164 ], "cluster": 3.0 }, { "idx": 128, "title": "Storage, mixing, and fluxes of water in the critical zone across northern environments inferred by stable isotopes of soil water", "abstract": "Quantifying soil water storage, mixing, and release via recharge, transpiration, and evaporation is essential for a better understanding of critical zone processes. Here, we integrate stable isotope (H-2 and O-18 of soil water, precipitation, and groundwater) and hydrometric (soil moisture) data from 5 long-term experimental catchments along a hydroclimatic gradient across northern latitudes: Dry Creek (USA), Bruntland Burn (Scotland), Dorset (Canada), Krycklan (Sweden), and Wolf Creek (Canada). Within each catchment, 6 to 11 isotope sampling campaigns occurred at 2 to 4 sampling locations over at least 1year. Analysis for H-2 and O-18 in the bulk pore water was done for >2,500 soil samples either by cryogenic extraction (Dry Creek) or by direct equilibration (other sites). The results showed a similar general pattern that soil water isotope variability reflected the seasonality of the precipitation input signal. However, pronounced differences among sampling locations occurred regarding the isotopic fractionation due to evaporation. We found that antecedent precipitation volumes mainly governed the fractionation signal, temperature and evaporation rates were of secondary importance, and soil moisture played only a minor role in the variability of soil water evaporation fractionation across the hydroclimatic gradient. We further observed that soil waters beneath conifer trees were more fractionated than beneath heather shrubs or red oak trees, indicating higher soil evaporation rates in coniferous forests. Sampling locations closer to streams were more damped and depleted in their stable isotopic composition than hillslope sites, revealing increased subsurface mixing towards the saturated zone and a preferential recharge of winter precipitation. Bulk soil waters generally comprised a high share of waters older than 14days, which indicates that the water in soil pores are usually not fully replaced by recent infiltration events. The presented stable isotope data of soil water were, thus, a useful tool to track the spatial variability of water fluxes within and from the critical zone. Such data provide invaluable information to improve the representation of critical zone processes in spatially distributed hydrological models.", "authors": [ "Sprenger, Matthias", "Tetzlaff, Doerthe", "Buttle, Jim", "Carey, Sean K.", "McNamara, James P.", "Laudon, Hjalmar", "Shatilla, Nadine J.", "Soulsby, Chris" ], "keywords": [ "critical zone", "evaporation", "fractionation", "northern environments", "soil hydrology", "stable isotopes" ], "year": "2018", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -10.736861228942871, 22.848642349243164 ], "cluster": 3.0 }, { "idx": 129, "title": "Globally scalable alpine snow metrics", "abstract": "Horizontal and altitudinal redistribution of snow by wind transport and avalanches can be important controls on small- and large-scale snow accumulation patterns that control meltwater supply in alpine environments. Redistribution processes control the spatial variability of snow accumulation, which not only controls meltwater supply, but also regulates snowmelt timing, duration, and rates, as well as snow-covered area depletion and the variable contributing area for meltwater runoff generation. However, most hydrological models and land surface schemes do not consider snow redistribution processes, and those that do are difficult to verify without spatially distributed snow depth measurements. These are rarely available in both high resolution and covering large scales. As an increased number of hydrological models include snow redistribution processes there is a need for additional snowcover metrics to verify snow redistribution schemes over large areas using readily available data. This study develops novel high-resolution (20 m), snowcover indices from remotely sensed imagery (Landsat-8 and Sentinel-2) to evaluate snow redistribution models over alpine areas without in-situ or airborne snow observations. A snowcover absence (SA) index, calculated from snow-free areas during the winter, identifies areas of wind erosion or avalanche source areas. A snowcover persistence (SP) index, calculated from snow-covered areas during the summer, identifies snow deposition in drifts and avalanche deposits. The snowcover indices captured the relative differences in surface observations of snow presence and absence between exposed and sheltered sites on an intensely instrumented ridge in the Canadian Rockies Hydrological Observatory. Within the Tuolumne River Basin in central California (1100 km(2)), the SP index captured roughly half of the spatial variability (R-2 = 0.49 to 0.56) in peak SWE as estimated from airborne LiDAR-derived snow depths. At the individual mountain ridge scale (similar to 800 m), variability in both ablation and snow redistribution controlled the SP patterns over 7979 ridges. Differences in shortwave irradiance explained 76% of the SP variance across ridges, but could not explain smaller-scale (similar to 100 m) SP peaks that are associated with snowdrifts and avalanche deposits. The snowcover indices can be used to evaluate snow redistribution models of the finer scale impacts of snow redistribution by wind and gravity as long as the larger scale influences of spatially variable solar irradiance effects are also simulated.", "authors": [ "Wayand, Nicholas E.", "Marsh, Christopher B.", "Shea, Joseph M.", "Pomeroy, John W." ], "keywords": [ "Snowcovered area", "Blowing snow", "Avalanches", "Snow ablation", "Landsat 8", "Sentinel 2", "Google earth engine" ], "year": "2018", "source": "REMOTE SENSING OF ENVIRONMENT", "publication_type": "J", "point2d": [ -54.10395431518555, -2.7444419860839844 ], "cluster": 8.0 }, { "idx": 130, "title": "A long-term, temporally consistent, gridded daily meteorological dataset for northwestern North America", "abstract": "We describe a spatially contiguous, temporally consistent high-resolution gridded daily meteorological dataset for northwestern North America. This >4 million km(2) region has high topographic relief, seasonal snowpack, permafrost and glaciers, crosses multiple jurisdictional boundaries and contains the entire Yukon, Mackenzie, Saskatchewan, Fraser and Columbia drainages. We interpolate daily station data to 1/16 degrees spatial resolution using a high-resolution monthly 1971-2000 climatology as a predictor in a thin-plate spline interpolating algorithm. Only temporally consistent climate stations with at least 40 years of record are included. Our approach is designed to produce a dataset well suited for driving hydrological models and training statistical downscaling schemes. We compare our results to two commonly used datasets and show improved performance for climate means, extremes and variability. When used to drive a hydrologic model, our dataset also outperforms these datasets for runoff ratios and streamflow trends in several, high elevation, sub-basins of the Fraser River.", "authors": [ "Werner, A. T.", "Schnorbus, M. A.", "Shrestha, R. R.", "Cannon, A. J.", "Zwiers, F. W.", "Dayon, G.", "Anslow, F." ], "keywords": [ "" ], "year": "2019", "source": "SCIENTIFIC DATA", "publication_type": "J", "point2d": [ -21.720314025878906, -32.49340057373047 ], "cluster": 1.0 }, { "idx": 131, "title": "Assessing the quality of the streamflow record for a long-term reference hydrometric station: Bow River at Banff", "abstract": "The operational history of one of Canada's longest operating hydrometric stations is reviewed in detail, including flood estimates that precede formal hydrometric monitoring. The assessment inspects the early and operational history, the published streamflow record and the stage-discharge measurements collected since 1909. Methods used to estimate pre-operational high flows and the operational history are reviewed to establish potential issues with changes in technology, location and measurement sections. The streamflow record is screened for discontinuities and change. The stage-discharge measurements used to establish the rating curve for open-water and ice-covered periods are assessed and used to establish the degree of support for the published data over the period of record. In the period 1882 to 1909, occasional high-stage estimates were used to estimate peak discharge, but with considerable uncertainty due to lack of stream velocity measurements and bed profiles. For the period 1909-1914 it is difficult to confirm the validity of the data as benchmarks and gauge corrections are unclear. Since 1922 when the station was established in its present location, many changes in the technology used for recording stage and measuring discharge have occurred. Rating curve support for high and low flows has varied over the period of record, particularly after cableway measurements of high flows were recently abandoned. Several important quality issues were identified that may require user caution, most notably an inconsistency with respect to the recording of winter ice-cover. These changes and issues have not affected the quality of the record in any substantial way. The stability of the flow control has remained remarkably consistent, resulting in high data quality for most of the period of record.", "authors": [ "Whitfield, Paul H.", "Pomeroy, John W." ], "keywords": [ "" ], "year": "2017", "source": "CANADIAN WATER RESOURCES JOURNAL", "publication_type": "J", "point2d": [ 0.552892804145813, -8.904498100280762 ], "cluster": 18.0 }, { "idx": 132, "title": "Probable Maximum Precipitation: Its Estimation and Uncertainty Quantification Using Bivariate Extreme Value Analysis", "abstract": "Probable maximum precipitation (PMP) is the key parameter used to estimate the probable maximum flood (PMF), both of which are important for dam safety and civil engineering purposes. The usual operational procedure for obtaining PMP values, which is based on a moisture maximization approach, produces a single PMP value without an estimate of its uncertainty. We therefore propose a probabilistic framework based on a bivariate extreme value distribution to aid in the interpretation of these PMP values. This 1) allows us to evaluate estimates from the operational procedure relative to an estimate of a plausible distribution of PMP values, 2) enables an evaluation of the uncertainty of these values, and 3) provides clarification of the impact of the assumption that a PMP event occurs under conditions of maximum moisture availability. Results based on a 50-yr Canadian Centre for Climate Modelling and Analysis Regional Climate Model (CanRCM4) simulation over North America reveal that operational PMP estimates are highly uncertain and suggest that the assumption that PMP events have maximum moisture availability may not be valid. Specifically, in the climate simulated by CanRCM4, the operational approach applied to 50-yr data records produces a value that is similar to the value that is obtained in our approach when assuming complete dependence between extreme precipitation efficiency and extreme precipitable water. In contrast, our results suggest weaker than complete dependence. Estimates from the operational approach are 15% larger on average over North America than those obtained when accounting for the dependence between precipitation efficiency and precipitable water extremes realistically. A difference of this magnitude may have serious implications in engineering design.", "authors": [ "Ben Alaya, M. A.", "Zwiers, F.", "Zhang, X." ], "keywords": [ "" ], "year": "2018", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -28.643733978271484, -50.73713684082031 ], "cluster": 16.0 }, { "idx": 133, "title": "Evaluation and Comparison of CanRCM4 and CRCM5 to Estimate Probable Maximum Precipitation over North America", "abstract": "Recently dam managers have begun to use data produced by regional climate models to estimate how probable maximum precipitation (PMP) might evolve in the future. Before accomplishing such a task, it is essential to assess PMP estimates derived from regional climate models (RCMs). In the current study PMP over North America estimated from two Canadian RCMs, CanRCM4 and CRCM5, is compared with estimates derived from three reanalysis products: ERA-Interim, NARR, and CFSR. An additional hybrid dataset (MSWEP-ERA) produced by combining precipitation from the Multi-Source Weighted-Ensemble Precipitation (MSWEP) dataset and precipitable water (PW) from ERA-Interim is also considered to derive PMP estimates that can serve as a reference. A recently developed approach using a statistical bivariate extreme values distribution is used to provide a probabilistic description of the PMP estimates using the moisture maximization method. Such a probabilistic description naturally allows an assessment of PMP estimates that includes quantification of their uncertainty. While PMP estimates based on the two RCMs exhibit spatial patterns similar to those of MSWEP-ERA and the three sets of reanalyses on the continental scale over North America, CanRCM4 has a tendency for overestimation while CRCM5 has a tendency for modest underestimation. Generally, CRCM5 shows good agreement with ERA-Interim, while CanRCM4 is more comparable to CFSR. Overall, the good ability of the two RCMs to reproduce the major characteristics of the different components involved in the estimation of PMP suggests that they may be useful tools for PMP estimation that could serve as a basis for flood studies at the basin scale.", "authors": [ "Ben Alaya, M. A.", "Zwiers, F.", "Zhang, X." ], "keywords": [ "North America", "Extreme events", "Precipitation", "Statistical techniques", "Reanalysis data", "Regional models" ], "year": "2019", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -27.836841583251953, -49.13023376464844 ], "cluster": 1.0 }, { "idx": 134, "title": "Probable maximum precipitation in a warming climate over North America in CanRCM4 and CRCM5", "abstract": "In the context of climate change and projected increase in global temperature, the atmosphere's water holding capacity is expected to increase at the Clausius-Clapeyron (C-C) rate by about 7% per 1 degrees C warming. Such an increase may lead to more intense extreme precipitation events and thus directly affect the probable maximum precipitation (PMP), a parameter that is often used for dam safety and civil engineering purposes. We therefore use a statistically motivated approach that quantifies uncertainty and accounts for nonstationarity, which allows us to determine the rate of change of PMP per 1 degrees C warming. This approach, which is based on a bivariate extreme value model of precipitable water (PW) and precipitation efficiency (PE), provides interpretation of how PW and PE may evolve in a warming climate. Nonstationarity is accounted for in this approach by including temperature as a covariate in the bivariate extreme value model. The approach is demonstrated by evaluating and comparing projected changes to 6-hourly PMP from two Canadian regional climate models (RCMs), CanRCM4 and CRCM5, over North America. The main results suggest that, on the continental scale, PMP increases in these models at a rate of approximately 4% per 1 degrees C warming, which is somewhat lower than the C-C rate. At the continental scale, PW extremes increase on average at the rate of 5% per 1 degrees C near surface warming for both RCMs. Most of the PMP increase is caused by the increase in PW extremes with only a minor contribution from changes in PE extremes. Nevertheless, substantial deviations from the average rate of change in PMP rates occur in some areas, and these are mostly caused by sensitivity of PE extremes to near surface warming in these regions.", "authors": [ "Ben Alaya, M. A.", "Zwiers, F. W.", "Zhang, X." ], "keywords": [ "Climate change", "Probable maximum precipitation", "Nonstationarity" ], "year": "2020", "source": "CLIMATIC CHANGE", "publication_type": "J", "point2d": [ -30.086105346679688, -48.03462219238281 ], "cluster": 1.0 }, { "idx": 135, "title": "Probable maximum precipitation in a warming climate over North America in CanRCM4 and CRCM5", "abstract": "In the context of climate change and projected increase in global temperature, the atmosphere's water holding capacity is expected to increase at the Clausius-Clapeyron (C-C) rate by about 7% per 1 degrees C warming. Such an increase may lead to more intense extreme precipitation events and thus directly affect the probable maximum precipitation (PMP), a parameter that is often used for dam safety and civil engineering purposes. We therefore use a statistically motivated approach that quantifies uncertainty and accounts for nonstationarity, which allows us to determine the rate of change of PMP per 1 degrees C warming. This approach, which is based on a bivariate extreme value model of precipitable water (PW) and precipitation efficiency (PE), provides interpretation of how PW and PE may evolve in a warming climate. Nonstationarity is accounted for in this approach by including temperature as a covariate in the bivariate extreme value model. The approach is demonstrated by evaluating and comparing projected changes to 6-hourly PMP from two Canadian regional climate models (RCMs), CanRCM4 and CRCM5, over North America. The main results suggest that, on the continental scale, PMP increases in these models at a rate of approximately 4% per 1 degrees C warming, which is somewhat lower than the C-C rate. At the continental scale, PW extremes increase on average at the rate of 5% per 1 degrees C near surface warming for both RCMs. Most of the PMP increase is caused by the increase in PW extremes with only a minor contribution from changes in PE extremes. Nevertheless, substantial deviations from the average rate of change in PMP rates occur in some areas, and these are mostly caused by sensitivity of PE extremes to near surface warming in these regions.", "authors": [ "Ben Alaya, M. A.", "Zwiers, F. W.", "Zhang, X." ], "keywords": [ "Climate change", "Probable maximum precipitation", "Nonstationarity" ], "year": "2020", "source": "CLIMATIC CHANGE", "publication_type": "J", "point2d": [ -29.158313751220703, -47.961936950683594 ], "cluster": 1.0 }, { "idx": 136, "title": "Probable maximum precipitation in a warming climate over North America in CanRCM4 and CRCM5", "abstract": "In the context of climate change and projected increase in global temperature, the atmosphere's water holding capacity is expected to increase at the Clausius-Clapeyron (C-C) rate by about 7% per 1 degrees C warming. Such an increase may lead to more intense extreme precipitation events and thus directly affect the probable maximum precipitation (PMP), a parameter that is often used for dam safety and civil engineering purposes. We therefore use a statistically motivated approach that quantifies uncertainty and accounts for nonstationarity, which allows us to determine the rate of change of PMP per 1 degrees C warming. This approach, which is based on a bivariate extreme value model of precipitable water (PW) and precipitation efficiency (PE), provides interpretation of how PW and PE may evolve in a warming climate. Nonstationarity is accounted for in this approach by including temperature as a covariate in the bivariate extreme value model. The approach is demonstrated by evaluating and comparing projected changes to 6-hourly PMP from two Canadian regional climate models (RCMs), CanRCM4 and CRCM5, over North America. The main results suggest that, on the continental scale, PMP increases in these models at a rate of approximately 4% per 1 degrees C warming, which is somewhat lower than the C-C rate. At the continental scale, PW extremes increase on average at the rate of 5% per 1 degrees C near surface warming for both RCMs. Most of the PMP increase is caused by the increase in PW extremes with only a minor contribution from changes in PE extremes. Nevertheless, substantial deviations from the average rate of change in PMP rates occur in some areas, and these are mostly caused by sensitivity of PE extremes to near surface warming in these regions.", "authors": [ "Ben Alaya, M. A.", "Zwiers, F. W.", "Zhang, X." ], "keywords": [ "Climate change", "Probable maximum precipitation", "Nonstationarity" ], "year": "2020", "source": "CLIMATIC CHANGE", "publication_type": "J", "point2d": [ -29.667268753051758, -48.824974060058594 ], "cluster": 1.0 }, { "idx": 137, "title": "The changing hail threat over North America in response to anthropogenic climate change", "abstract": "Anthropogenic climate change is anticipated to increase severe thunderstorm potential in North America, but the resulting changes in associated convective hazards are not well known. Here, using a novel modelling approach, we investigate the spatiotemporal changes in hail frequency and size between the present (1971-2000) and future (2041-2070). Although fewer hail days are expected over most areas in the future, an increase in the mean hail size is projected, with fewer small hail events and a shift toward a more frequent occurrence of larger hail. This leads to an anticipated increase in hail damage potential over most southern regions in spring, retreating to the higher latitudes (that is, north of 50 degrees N) and the Rocky Mountains in the summer. In contrast, a dramatic decrease in hail frequency and damage potential is predicted over eastern and southeastern regions in spring and summer due to a significant increase in melting that mitigates gains in hail size from increased buoyancy.", "authors": [ "Brimelow, Julian C.", "Burrows, William R.", "Hanesiak, John M." ], "keywords": [ "" ], "year": "2017", "source": "NATURE CLIMATE CHANGE", "publication_type": "J", "point2d": [ -50.81047439575195, -65.71316528320312 ], "cluster": 14.0 }, { "idx": 138, "title": "Using 4-km WRF CONUS simulations to assess impacts of the surface coupling strength on regional climate simulation", "abstract": "Uncertainties in representing land-atmosphere interactions can substantially influence regional climate simulations. Among these uncertainties, the surface exchange coefficient C-h is a critical parameter, controlling the total energy transported from the land surface to the atmosphere. Although it directly impacts the coupling strength between the surface and atmosphere, it has not been properly evaluated for regional climate models. This study assesses the representation of surface coupling strength in a stand-alone Noah-MP land surface model and in coupled 4-km Weather Research and Forecasting (WRF) model simulations. The data collected at eight FLUXNET sites of the Canadian Carbon Program and seven AMRIFLUX sites are used to evaluate the offline Noah-MP simulations. Nine of these FLUXNET sites are used for the evaluation of the coupled WRF simulations. These sites are categorized into three land use types: grassland, cropland, and forest. The surface exchange coefficients derived using three formulations in Noah-MP simulations are compared to those calculated from observations. Then, the default Czil=0 and new canopy-height dependent Czil are used in coupled WRF simulations over the spring and summer in 2006 to compare their effects on surface heat flux, temperature, and precipitation. When the new canopy-height dependent Czil scheme is used, the simulated C-h exchange coefficient agrees better with observation and improves the daily maximum air temperature and heat flux simulation over grassland and cropland in the US Great Plains. Over grassland, the modeled C-h shows a different diurnal cycle than that for observed C-h, which makes WRF lag behind the observed diurnal cycle of sensible heat flux and temperature. The difference in precipitation between the two schemes is not as clear as the temperature difference because the impact of changing C-h is not local.", "authors": [ "Chen, Liang", "Li, Yanping", "Chen, Fei", "Barlage, Michael", "Zhang, Zhe", "Li, Zhenhua" ], "keywords": [ "Surface exchange coefficient", "Surface coupling strength", "Surface fluxes", "Land-atmosphere interaction" ], "year": "2019", "source": "CLIMATE DYNAMICS", "publication_type": "J", "point2d": [ -60.70546340942383, -52.11027908325195 ], "cluster": 17.0 }, { "idx": 139, "title": "Using 4-km WRF CONUS simulations to assess impacts of the surface coupling strength on regional climate simulation", "abstract": "Uncertainties in representing land-atmosphere interactions can substantially influence regional climate simulations. Among these uncertainties, the surface exchange coefficient C-h is a critical parameter, controlling the total energy transported from the land surface to the atmosphere. Although it directly impacts the coupling strength between the surface and atmosphere, it has not been properly evaluated for regional climate models. This study assesses the representation of surface coupling strength in a stand-alone Noah-MP land surface model and in coupled 4-km Weather Research and Forecasting (WRF) model simulations. The data collected at eight FLUXNET sites of the Canadian Carbon Program and seven AMRIFLUX sites are used to evaluate the offline Noah-MP simulations. Nine of these FLUXNET sites are used for the evaluation of the coupled WRF simulations. These sites are categorized into three land use types: grassland, cropland, and forest. The surface exchange coefficients derived using three formulations in Noah-MP simulations are compared to those calculated from observations. Then, the default Czil=0 and new canopy-height dependent Czil are used in coupled WRF simulations over the spring and summer in 2006 to compare their effects on surface heat flux, temperature, and precipitation. When the new canopy-height dependent Czil scheme is used, the simulated C-h exchange coefficient agrees better with observation and improves the daily maximum air temperature and heat flux simulation over grassland and cropland in the US Great Plains. Over grassland, the modeled C-h shows a different diurnal cycle than that for observed C-h, which makes WRF lag behind the observed diurnal cycle of sensible heat flux and temperature. The difference in precipitation between the two schemes is not as clear as the temperature difference because the impact of changing C-h is not local.", "authors": [ "Chen, Liang", "Li, Yanping", "Chen, Fei", "Barlage, Michael", "Zhang, Zhe", "Li, Zhenhua" ], "keywords": [ "Surface exchange coefficient", "Surface coupling strength", "Surface fluxes", "Land-atmosphere interaction" ], "year": "2019", "source": "CLIMATE DYNAMICS", "publication_type": "J", "point2d": [ -61.02810287475586, -51.81316375732422 ], "cluster": 17.0 }, { "idx": 140, "title": "Risks from Climate Extremes Change Differently from 1.5 degrees C to 2.0 degrees C Depending on Rarity", "abstract": "Parties to the United Nations Framework Convention on Climate Change have agreed to hold the increase in global average temperature to well below 2 degrees C above preindustrial levels and to pursue efforts to limit the temperature increase to 1.5 degrees C. Comparison of the costs and benefits for different warming limits requires an understanding of how risks vary between warming limits. As changes in risk are often associated with changes in exposure due to projected changes in local or regional climate extremes, we analyze differences in the risks of extreme daily temperatures and extreme daily precipitation amounts under different warming limits. We show that global warming of 2 degrees C would result in substantially larger changes in the probabilities of the extreme events than global warming of 1.5 degrees C. For example, over the global land area, the probability of a warm extreme that occurs once every 20 years on average in the current climate is projected to increase 130% and 340% at the 1.5 degrees C and 2.0 degrees C warming levels, respectively (median values). Moreover, the relative changes in probability are larger for rarer, more extreme events, implying that risk assessments need to carefully consider the extreme event thresholds at which vulnerabilities occur.", "authors": [ "Kharin, V. V.", "Flato, G. M.", "Zhang, X.", "Gillett, N. P.", "Zwiers, F.", "Anderson, K. J." ], "keywords": [ "" ], "year": "2018", "source": "EARTHS FUTURE", "publication_type": "J", "point2d": [ -35.90967559814453, -67.40824890136719 ], "cluster": 14.0 }, { "idx": 141, "title": "Characteristics, atmospheric drivers and occurrence patterns of freezing precipitation and ice pellets over the Prairie Provinces and Arctic Territories of Canada: 1964-2005", "abstract": "Freezing precipitation and ice pellet events on the Canadian Prairies and Arctic territories of Canada often lead to major disruptions to air and ground transportation, damage power grids and prevent arctic caribou and other animals from accessing the plants and lichen they depend on for survival. In a warming climate, these hazards and associated impacts will continue to happen, although their spatial and temporal characteristics may vary. In order to address these issues, the occurrence of freezing rain, freezing drizzle, and ice pellets from 1964 to 2005 is examined using hourly weather observations at 27 manned 24 h weather stations across the different climatic regions of the Prairie Provinces and Arctic Territories of Canada. Because of the enormous size of the area and its diverse climatic regions, many temporal and spatial differences in freezing precipitation and ice pellet characteristics occur. The 12 most widespread freezing rain events over the study area are associated with only two atmospheric patterns with one linked to strong warm advection between low and high pressure centres and the other pattern associated with chinooks occurring east of the Rocky Mountains. Given the annual patterns of freezing rain occurrence found in this study, it is proposed that a maximum of five regimes exist and three occur within the Prairies and Arctic. Crown Copyright (C) 2017 Published by Elsevier B.V. All rights reserved.", "authors": [ "Kochtubajda, Bohdan", "Mooney, Curtis", "Stewart, Ronald" ], "keywords": [ "Freezing rain", "Freezing drizzle", "Ice pellets", "Synoptic patterns", "Arctic", "Prairies" ], "year": "2017", "source": "ATMOSPHERIC RESEARCH", "publication_type": "J", "point2d": [ -51.9343376159668, -30.60896873474121 ], "cluster": 1.0 }, { "idx": 142, "title": "How Much Information Is Required to Well Constrain Local Estimates of Future Precipitation Extremes?", "abstract": "Global warming is expected to increase the amount of atmospheric moisture, resulting in heavier extreme precipitation. Various studies have used the historical relationship between extreme precipitation and temperature (temperature scaling) to provide guidance about precipitation extremes in a future warmer climate. Here we assess how much information is required to robustly identify temperature scaling relationships, and whether these relationships are equally effective at different times in the future in estimating precipitation extremes everywhere across North America. Using a large ensemble of 35 North American regional climate simulations of the period 1951-2100, we show that individual climate simulations of length comparable to that of typical instrumental records are unable to constrain temperature scaling relationships well enough to reliably estimate future extremes of local precipitation accumulation for hourly to daily durations in the model's climate. Hence, temperature scaling relationships estimated from the limited historical observations are unlikely to be able to provide reliable guidance for future adaptation planning at local spatial scales. In contrast, well-constrained temperature scaling relations based on multiple regional climate simulations do provide a feasible basis for accurately projecting precipitation extremes of hourly to daily durations in different future periods over more than 90% of the North American land area.", "authors": [ "Li, Chao", "Zwiers, Francis", "Zhang, Xuebin", "Li, Guilong" ], "keywords": [ "subdaily extreme precipitation", "Clausius-Clapeyron relation", "extreme precipitation projection" ], "year": "2019", "source": "EARTHS FUTURE", "publication_type": "J", "point2d": [ -40.283512115478516, -59.91843795776367 ], "cluster": 14.0 }, { "idx": 143, "title": "Mixed precipitation occurrences over southern Quebec, Canada, under warmer climate conditions using a regional climate model", "abstract": "Winter weather events with temperatures near 0 degrees C are often associated with freezing rain. They can have major impacts on the society by causing power outages and disruptions to the transportation networks. Despite the catastrophic consequences of freezing rain, very few studies have investigated how their occurrences could evolve under climate change. This study aims to investigate the change of freezing rain and ice pellets over southern Quebec using regional climate modeling at high resolution. The fifth-generation Canadian Regional Climate Model with climate scenario RCP 8.5 at 0.11 degrees grid mesh was used. The precipitation types such as freezing rain, ice pellets or their combination are diagnosed using five methods (Cantin and Bachand, Bourgouin, Ramer, Czys and, Baldwin). The occurrences of the diagnosed precipitation types for the recent past (1980-2009) are found to be comparable to observations. The projections for the future scenario (2070-2099) suggested a general decrease in the occurrences of mixed precipitation over southern Quebec from October to April. This is mainly due to a decrease in long-duration events (6h). Overall, this study contributes to better understand how the distribution of freezing rain and ice pellets might change in the future using high-resolution regional climate model.", "authors": [ "Matte, Dominic", "Theriault, Julie M.", "Laprise, Rene" ], "keywords": [ "Climate change", "High-resolution climate simulation", "Multiple nesting", "Freezing rain", "Ice pellet", "Precipitation-type algorithm" ], "year": "2019", "source": "CLIMATE DYNAMICS", "publication_type": "J", "point2d": [ -53.89220428466797, -29.829992294311523 ], "cluster": 1.0 }, { "idx": 144, "title": "Indices of Canada's future climate for general and agricultural adaptation applications", "abstract": "This study evaluates regional-scale projections of climate indices that are relevant to climate change impacts in Canada. We consider indices of relevance to different sectors including those that describe heat conditions for different crop types, temperature threshold exceedances relevant for human beings and ecological ecosystems such as the number of days temperatures are above certain thresholds, utility relevant indices that indicate levels of energy demand for cooling or heating, and indices that represent precipitation conditions. Results are based on an ensemble of high-resolution statistically downscaled climate change projections from 24 global climate models (GCMs) under the RCP2.6, RCP4.5, and RCP8.5 emissions scenarios. The statistical downscaling approach includes a bias-correction procedure, resulting in more realistic indices than those computed from the original GCM data. We find that the level of projected changes in the indices scales well with the projected increase in the global mean temperature and is insensitive to the emission scenarios. At the global warming level about 2.1 degrees C above pre-industrial (corresponding to the multi-model ensemble mean for 2031-2050 under the RCP8.5 scenario), there is almost complete model agreement on the sign of projected changes in temperature indices for every region in Canada. This includes projected increases in extreme high temperatures and cooling demand, growing season length, and decrease in heating demand. Models project much larger changes in temperature indices at the higher 4.5 degrees C global warming level (corresponding to 2081-2100 under the RCP8.5 scenario). Models also project an increase in total precipitation, in the frequency and intensity of precipitation, and in extreme precipitation. Uncertainty is high in precipitation projections, with the result that models do not fully agree on the sign of changes in most regions even at the 4.5 degrees C global warming level.", "authors": [ "Li, Guilong", "Zhang, Xuebin", "Cannon, Alex J.", "Murdock, Trevor", "Sobie, Steven", "Zwiers, Francis", "Anderson, Kevin", "Qian, Budong" ], "keywords": [ "" ], "year": "2018", "source": "CLIMATIC CHANGE", "publication_type": "J", "point2d": [ -31.000776290893555, -35.89269256591797 ], "cluster": 1.0 }, { "idx": 145, "title": "Improving the Explicit Prediction of Freezing Rain in a Kilometer-Scale Numerical Weather Prediction Model", "abstract": "A freezing rain event, in which the Meteorological Centre of Canada's 2.5-km numerical weather prediction system significantly underpredicted the quantity of freezing rain, is examined. The prediction system models precipitation types explicitly, directly from the Milbrandt-Yau microphysics scheme. It was determined that the freezing rain underprediction for this case was due primarily to excessive refreezing of rain, originating from melting snow and graupel, in and under the temperature inversion of the advancing warm front ultimately depleting the supply of rain reaching the surface. The refreezing was caused from excessive collisional freezing between rain and graupel. Sensitivity experiments were conducted to examine the effects of a temperature threshold for collisional freezing and on varying the values of the collection efficiencies between rain and ice-phase hydrometeors. It was shown that by reducing the rain-graupel collection efficiency and by imposing a temperature threshold of -5 degrees C, above which collisional freezing is not permitted, excessive rain-graupel collection and graupel formation can be controlled in the microphysics scheme, leading to an improved simulation of freezing rain at the surface.", "authors": [ "Barszcz, Agnieszka", "Milbrandt, Jason A.", "Theriault, Julie M." ], "keywords": [ "" ], "year": "2018", "source": "WEATHER AND FORECASTING", "publication_type": "J", "point2d": [ -56.700984954833984, -31.36576271057129 ], "cluster": 1.0 }, { "idx": 146, "title": "Recent Very Hot Summers in Northern Hemispheric Land Areas Measured by Wet Bulb Globe Temperature Will Be the Norm Within 20 Years", "abstract": "Wet bulb globe temperature (WBGT) accounts for the effect of environmental temperature and humidity on thermal comfort, and can be directly related to the ability of the human body to dissipate excess metabolic heat and thus avoid heat stress. Using WBGT as a measure of environmental conditions conducive to heat stress, we show that anthropogenic influence has very substantially increased the likelihood of extreme high summer mean WBGT in northern hemispheric land areas relative to the climate that would have prevailed in the absence of anthropogenic forcing. We estimate that the likelihood of summer mean WGBT exceeding the observed historical record value has increased by a factor of at least 70 at regional scales due to anthropogenic influence on the climate. We further estimate that, in most northern hemispheric regions, these changes in the likelihood of extreme summer mean WBGT are roughly an order of magnitude larger than the corresponding changes in the likelihood of extreme hot summers as simply measured by surface air temperature. Projections of future summer mean WBGT under the RCP8.5 emissions scenario that are constrained by observations indicate that by 2030s at least 50% of the summers will have mean WBGT higher than the observed historical record value in all the analyzed regions, and that this frequency of occurrence will increase to 95% by mid-century.", "authors": [ "Li, Chao", "Zhang, Xuebin", "Zwiers, Francis", "Fang, Yuanyuan", "Michalak, Anna M." ], "keywords": [ "Summer Heat Exposure", "Wet Bulb Globe Temperature", "Detection and Attribution", "Observation-constrained change" ], "year": "2017", "source": "EARTHS FUTURE", "publication_type": "J", "point2d": [ -39.06542205810547, -66.07817077636719 ], "cluster": 14.0 }, { "idx": 147, "title": "Revising Return Periods for Record Events in a Climate Event Attribution Context", "abstract": "Both climate and statistical models play an essential role in the process of demonstrating that the distribution of some atmospheric variable has changed over time and in establishing the most likely causes for the detected change. One statistical difficulty in the research field of detection and attribution resides in defining events that can be easily compared and accurately inferred from reasonable sample sizes. As many impacts studies focus on extreme events, the inference of small probabilities and the computation of their associated uncertainties quickly become challenging. In the particular context of event attribution, the authors address the question of how to compare records between the counterfactual world as it might have been'' without anthropogenic forcings and the factual world that is.'' Records are often the most important events in terms of impact and get much media attention. The authors will show how to efficiently estimate the ratio of two small probabilities of records. The inferential gain is particularly substantial when a simple hypothesis-testing procedure is implemented. The theoretical justification of such a proposed scheme can be found in extreme value theory. To illustrate this study's approach, classical indicators in event attribution studies, like the risk ratio or the fraction of attributable risk, are modified and tailored to handle records. The authors illustrate the advantages of their method through theoretical results, simulation studies, temperature records in Paris, and outputs from a numerical climate model.", "authors": [ "Naveau, Philippe", "Ribes, Aurelien", "Zwiers, Francis", "Hannart, Alexis", "Tuel, Alexandre", "Yiou, Pascal" ], "keywords": [ "" ], "year": "2018", "source": "JOURNAL OF CLIMATE", "publication_type": "J", "point2d": [ -30.041271209716797, -70.95755004882812 ], "cluster": 14.0 }, { "idx": 148, "title": "Understanding, modeling and predicting weather and climate extremes: Challenges and opportunities", "abstract": "Weather and climate extremes are identified as major areas necessitating further progress in climate research and have thus been selected as one of the World Climate Research Programme (WCRP) Grand Challenges. Here, we provide an overview of current challenges and opportunities for scientific progress and cross-community collaboration on the topic of understanding, modeling and predicting extreme events based on an expert workshop organized as part of the implementation of the WCRP Grand Challenge on Weather and Climate Extremes. In general, the development of an extreme event depends on a favorable initial state, the presence of large-scale drivers, and positive local feedbacks, as well as stochastic processes. We, therefore, elaborate on the scientific challenges related to large-scale drivers and localto-regional feedback processes leading to extreme events. A better understanding of the drivers and processes will improve the prediction of extremes and will support process-based evaluation of the representation of weather and climate extremes in climate model simulations. Further, we discuss how to address these challenges by focusing on short-duration (less than three days) and long-duration (weeks to months) extreme events, their underlying mechanisms and approaches for their evaluation and prediction.", "authors": [ "Sillmann, Jana", "Thorarinsdottir, Thordis", "Keenlyside, Noel", "Schaller, Nathalie", "Alexander, Lisa V.", "Hegerl, Gabriele", "Seneviratne, Sonia I.", "Vautard, Robert", "Zhang, Xuebin", "Zwiers, Francis W." ], "keywords": [ "" ], "year": "2017", "source": "WEATHER AND CLIMATE EXTREMES", "publication_type": "J", "point2d": [ -34.18901062011719, -65.41051483154297 ], "cluster": 14.0 }, { "idx": 149, "title": "Is the choice of statistical paradigm critical in extreme event attribution studies?", "abstract": "The science of event attribution meets a mounting demand for reliable and timely information about the links between climate change and individual extreme events. Studies have estimated the contribution of human-induced climate change to the magnitude of an event as well as its likelihood, and many types of event have been investigated including heatwaves, floods, and droughts. Despite this progress, such approaches have been criticised for being unreliable and for being overly conservative. We argue that such criticisms are misplaced. Rather, a false dichotomy has arisen between conventional approaches and new alternative framings. We have three points to make about the choice of statistical paradigm for event attribution studies. First, different approaches to event attribution may choose to occupy different places on the conditioning spectrum. Providing this choice of conditioning is communicated clearly, the value of such choices depends ultimately on their utility to the user concerned. Second, event attribution is an estimation problem for which either frequentist or Bayesian paradigms can be used. Third, for hypothesis testing, the choice of null hypothesis is context specific. Thus, the null hypothesis of human influence is not inherently a preferable alternative to the usual null hypothesis of no human influence.", "authors": [ "Stott, Peter A.", "Karoly, David J.", "Zwiers, Francis W." ], "keywords": [ "" ], "year": "2017", "source": "CLIMATIC CHANGE", "publication_type": "J", "point2d": [ -29.570398330688477, -71.19575500488281 ], "cluster": 14.0 }, { "idx": 150, "title": "Transformation of snow isotopic signature along groundwater recharge pathways in the Canadian Prairies", "abstract": "Application of stable isotope methods to evaluate the contribution of different water sources to groundwater recharge relies on the knowledge about isotopic signatures of these sources. The data collected at study sites in the Canadian Prairies show that snowpack isotopic signatures exhibit a high spatial variability over a small scale (<100 m) limiting the usefulness of point samples to estimate an average isotopic composition of snow over a large area. Isotopic signatures of snowmelt runoff can be different from those of pre-melt snowpack, further undermining the applicability of snow isotopic signature to characterisation of snowmelt-driven hydrological processes. Accounting for the actual signature of snow melt runoff has strong effects on its perceived role in recharging groundwater. The data also show that diffuse and depression-focussed components of groundwater recharge have different isotopic signatures, where the latter closely resembles snowmelt runoff. (C) 2017 Elsevier B.V. All rights reserved.", "authors": [ "Pavlovskii, Igor", "Hayashi, Masaki", "Lennon, Matthew R." ], "keywords": [ "Stable isotopes", "Snow", "Snowmelt runoff", "Groundwater recharge", "Canadian Prairies" ], "year": "2018", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -7.925565242767334, 17.000307083129883 ], "cluster": 12.0 }, { "idx": 151, "title": "Prioritizing recovery funding to maximize conservation of endangered species", "abstract": "The absence of a rigorous mechanism for prioritizing investment in endangered species management is a major implementation hurdle affecting recovery. Here, we present a method for prioritizing strategies for endangered species management based on the likelihood of achieving species' recovery goals per dollar invested. We demonstrate our approach for 15 species listed under Canada's Species at Risk Act that co-occur in Southwestern Saskatchewan. Without management, only two species have >50% probability of meeting recovery objectives; whereas, with management, 13 species exceed the >50% threshold with the implementation of just five complementary strategies at a cost of $126m over 20 years. The likelihood of meeting recovery objectives rarely exceeded 70% and two species failed to reach the >50% threshold. Our findings underscore the need to consider the cost, benefit, and feasibility of management strategies when developing recovery plans in order to prioritize implementation in a timely and cost-effective manner.", "authors": [ "Martin, Tara G.", "Kehoe, Laura", "Mantyka-Pringle, Chrystal", "Chades, Iadine", "Wilson, Scott", "Bloom, Robin G.", "Davis, Stephen K.", "Fisher, Ryan", "Keith, Jeff", "Mehl, Katherine", "Diaz, Beatriz Prieto", "Wayland, Mark E.", "Wellicome, Troy, I", "Zimmer, Karl P.", "Smith, Paul A." ], "keywords": [ "complementarity", "cost-effectiveness", "critical habitat", "expert elicitation", "multiobjective optimization", "multispecies conservation", "Priority Threat Management", "priority-setting", "recovery planning", "SARA", "Saskatchewan", "South of the Divide", "species at risk", "structured decision making", "triage" ], "year": "2018", "source": "CONSERVATION LETTERS", "publication_type": "J", "point2d": [ 54.325252532958984, -40.776859283447266 ], "cluster": 11.0 }, { "idx": 152, "title": "Citizen Social Science for More Integrative and Effective Climate Action: A Science-Policy Perspective", "abstract": "Governments are struggling to limit global temperatures below the 2 degrees C Paris target with existing climate change policy approaches. This is because conventional climate policies have been predominantly (inter) nationally top-down, which limits citizen agency in driving policy change and influencing citizen behavior. Here we propose elevating Citizen Social Science (CSS) to a new level across governments as an advanced collaborative approach of accelerating climate action and policies that moves beyond conventional citizen science and participatory approaches. Moving beyond the traditional science-policy model of the democratization of science in enabling more inclusive climate policy change, we present examples of how CSS can potentially transform citizen behavior and enable citizens to become key agents in driving climate policy change. We also discuss the barriers that could impede the implementation of CSS and offer solutions to these. In doing this, we articulate the implications of increased citizen action through CSS in moving forward the broader normative and political program of transdisciplinary and co-productive climate change research and policy.", "authors": [ "Kythreotis, Andrew P.", "Mantyka-Pringle, Chrystal", "Mercer, Theresa G.", "Whitmarsh, Lorraine E.", "Corner, Adam", "Paavola, Jouni", "Chambers, Chris", "Miller, Byron A.", "Castree, Noel" ], "keywords": [ "Citizen Social Science", "climate policy and governance", "science-policy", "citizen agency and behavior", "co-production and co-learning" ], "year": "2019", "source": "FRONTIERS IN ENVIRONMENTAL SCIENCE", "publication_type": "J", "point2d": [ 55.43927764892578, -28.411270141601562 ], "cluster": 4.0 }, { "idx": 153, "title": "Soil and water management: opportunities to mitigate nutrient losses to surface waters in the Northern Great Plains", "abstract": "The Northern Great Plains is a key region to global food production. It is also a region of water stress that includes poor water quality associated with high concentrations of nutrients. Agricultural nitrogen and phosphorus loads to surface waters need to be reduced, yet the unique characteristics of this environment create challenges. The biophysical reality of the Northern Great Plains is one where snowmelt is the major period of nutrient transport, and where nutrients are exported predominantly in dissolved form. This limits the efficacy of many beneficial management practices (BMPs) commonly used in other regions and necessitates place-based solutions. We discuss soil and water management BMPs through a regional lens-first understanding key aspects of hydrology and hydrochemistry affecting BMP efficacy, then discussing the merits of different BMPs for nutrient control. We recommend continued efforts to keep water on the land via wetlands and reservoirs. Adoption and expansion of reduced tillage and perennial forage may have contributed to current nutrient problems, but both practices have other environmental and agronomic benefits. The expansion of tile and surface drainage in the Northern Great Plains raises urgent questions about effects on nutrient export and options to mitigate drainage effects. Riparian vegetation is unlikely to significantly aid in nutrient retention, but when viewed against an alternative of extending cultivation and fertilization to the waters' edge, the continued support of buffer strip management and refinement of best practices (e.g., harvesting vegetation) is merited. While the hydrology of the Northern Great Plains creates many challenges for mitigating nutrient losses, it also creates unique opportunities. For example, relocating winter bale-grazing to areas with low hydrologic connectivity should reduce loadings. Managing nutrient applications must be at the center of efforts to mitigate eutrophication. In this region, ensuring nutrients are not applied during hydrologically sensitive periods such as late autumn, on snow, or when soils are frozen will yield benefits. Working to ensure nutrient inputs are balanced with crop demands is crucial in all landscapes. Ultimately, a targeted approach to BMP implementation is required, and this must consider the agronomic and economic context but also the biophysical reality.", "authors": [ "Baulch, Helen M.", "Elliott, Jane A.", "Cordeiro, Marcos R. C.", "Flaten, Don N.", "Lobb, David A.", "Wilson, Henry F." ], "keywords": [ "beneficial management practice", "agriculture", "nutrient", "Northern Great Plains", "prairie", "water quality" ], "year": "2019", "source": "ENVIRONMENTAL REVIEWS", "publication_type": "J", "point2d": [ 32.88520050048828, 8.188639640808105 ], "cluster": 10.0 }, { "idx": 154, "title": "Influence of seasonal temperature on tree-ring delta C-13 in different-aged temperate pine forests", "abstract": "Tree growth rings from three specimens in two different aged (14- and 77-year old) white pine plantation forests were analyzed for stable carbon isotope ratios to identify both short- and long-term variations in physiological response to changing environmental conditions. Three isotopic (delta C-13(corr)) time series records were constructed from whole wood samples extracted from paths parallel to the growth rings in each forest. These delta C-13(corr) records were corrected for the long-term anthropogenically induced CO2 and compared to historical climate (temperature, precipitation) data from 1935 to 2016. High resolution inter-annual variations in trees in each stand displayed similar intra-annual cycles in delta C-13(corr), demonstrating the seasonal physiological response of these forests to environmental stressors. In both stands, growing season temperature acted as a significant control (p < 0.05) on delta C-13(corr) values and hence carbon uptake through enhanced physiological discrimination against (CO2)-C-13. Wavelet transform methods applied to the carbon isotope composition extracted from tree-rings to investigate Isotope-climate linkages revealed phase relationships linked to changes in stand structure and microclimate due to thinning treatment applied in the older stand in 1983. Cross wavelet transform (XWT) of mean annual temperature with latewood tree-ring isotope time series demonstrated a persistent 12- to 16-year phase-locked relationship, which suggests long-term temperature variations influenced stomatal conductance behavior in the post-thinning period (1983-2012). Overall, air temperature acted as a multi-year control on tree-ring carbon isotope compositions in these different-age forests and variations in delta C-13(corr) time series provided a potential record of past temperature changes in the region.", "authors": [ "McKenzie, Shawn M.", "Slater, Greg", "Kim, Sang-Tae", "Pisaric, Michael F. J.", "Arain, M. Altaf" ], "keywords": [ "Stable carbon isotopes", "Wavelets", "Tree-rings", "Atmospheric carbon", "Managed forest", "Pinus strata White pine", "Afforestation" ], "year": "2018", "source": "FOREST ECOLOGY AND MANAGEMENT", "publication_type": "J", "point2d": [ -45.80074691772461, 68.23822784423828 ], "cluster": 17.0 }, { "idx": 155, "title": "Temporal Dynamics of Aerodynamic Canopy Height Derived From Eddy Covariance Momentum Flux Data Across North American Flux Networks", "abstract": "Aerodynamic canopy height (h(a)) is the effective height of vegetation canopy for its influence on atmospheric fluxes and is a key parameter of surface-atmosphere coupling. However, methods to estimate h(a) from data are limited. This synthesis evaluates the applicability and robustness of the calculation of h(a) from eddy covariance momentum-flux data. At 69 forest sites, annual h(a) robustly predicted site-to-site and year-to-year differences in canopy heights (R-2=0.88, 111site-years). At 23 cropland/grassland sites, weekly h(a) successfully captured the dynamics of vegetation canopies over growing seasons (R-2>0.70 in 74site-years). Our results demonstrate the potential of flux-derived h(a) determination for tracking the seasonal, interannual, and/or decadal dynamics of vegetation canopies including growth, harvest, land use change, and disturbance. The large-scale and time-varying h(a) derived from flux networks worldwide provides a new benchmark for regional and global Earth system models and satellite remote sensing of canopy structure. Plain Language Summary Vegetation canopy height is a key descriptor of the Earth surface and is in use by many modeling and conservation applications. However, large-scale and time-varying data of canopy heights are often unavailable. This synthesis evaluates the applicability and robustness of the calculation of canopy heights from the momentum flux data measured at eddy covariance flux tower sites (i.e., meteorological observation towers with high frequency measurements of wind speed and surface fluxes). We show that the aerodynamic estimation of annual canopy heights robustly predicts the site-to-site and year-to-year differences in canopy heights across a wide variety of forests. The weekly aerodynamic canopy heights successfully capture the dynamics of vegetation canopies over growing seasons at cropland and grassland sites. Our results demonstrate the potential of aerodynamic canopy heights for tracking the seasonal, interannual, and/or decadal dynamics of vegetation canopies including growth, harvest, land use change, and disturbance. Given the amount of data collected and the diversity of vegetation covered by the global networks of eddy covariance flux tower sites, the flux-derived canopy height has great potential for providing a new benchmark for regional and global Earth system models and satellite remote sensing of canopy structure.", "authors": [ "Chu, Housen", "Baldocchi, Dennis D.", "Poindexter, Cristina", "Abraha, Michael", "Desai, Ankur R.", "Bohrer, Gil", "Arain, M. Altaf", "Griffis, Timothy", "Blanken, Peter D.", "O'Halloran, Thomas L.", "Thomas, R. Quinn", "Zhang, Quan", "Burns, Sean P.", "Frank, John M.", "Christian, Dold", "Brown, Shannon", "Black, T. Andrew", "Gough, Christopher M.", "Law, Beverly E.", "Lee, Xuhui", "Chen, Jiquan", "Reed, David E.", "Massman, William J.", "Clark, Kenneth", "Hatfield, Jerry", "Prueger, John", "Bracho, Rosvel", "Baker, John M.", "Martin, Timothy A." ], "keywords": [ "momentum flux", "AmeriFlux", "eddy covariance", "canopy height", "phenology" ], "year": "2018", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -52.11280822753906, 54.20703887939453 ], "cluster": 17.0 }, { "idx": 157, "title": "Comparison of Big-Leaf, Two-Big-Leaf, and Two-Leaf Upscaling Schemes for Evapotranspiration Estimation Using Coupled Carbon-Water Modeling", "abstract": "Evapotranspiration (ET) is commonly estimated using the Penman-Monteith equation, which assumes that the plant canopy is a big leaf (BL) and the water flux from vegetation is regulated by canopy stomatal conductance (G(s)). However, BL has been found to be unsuitable for terrestrial biosphere models built on the carbon-water coupling principle because it fails to capture daily variations of gross primary productivity (GPP). A two-big-leaf scheme (TBL) and a two-leaf scheme (TL) that stratify a canopy into sunlit and shaded leaves have been developed to address this issue. However, there is a lack of comparison of these upscaling schemes for ET estimation, especially on the difference between TBL and TL. We find that TL shows strong performance (r(2)=0.71, root-mean-square error=0.05mm/h) in estimating ET at nine eddy covariance towers in Canada. BL simulates lower annual ET and GPP than TL and TBL. The biases of estimated ET and GPP increase with leaf area index (LAI) in BL and TBL, and the biases of TL show no trends with LAI. BL miscalculates the portions of light-saturated and light-unsaturated leaves in the canopy, incurring negative biases in its flux estimation. TBL and TL showed improved yet different GPP and ET estimations. This difference is attributed to the lower G(s) and intercellular CO2 concentration simulated in TBL compared to their counterparts in TL. We suggest to use TL for ET modeling to avoid the uncertainty propagated from the artificial upscaling of leaf-level processes to the canopy scale in BL and TBL.", "authors": [ "Luo, Xiangzhong", "Chen, Jing M.", "Liu, Jane", "Black, T. Andrew", "Croft, Holly", "Staebler, Ralf", "He, Liming", "Arain, M. Altaf", "Chen, Bin", "Mo, Gang", "Gonsamo, Alemu", "McCaughey, Harry" ], "keywords": [ "evapotranspiration", "big-leaf", "two-leaf", "canopy stomatal conductance", "gross primary productivity", "Penman-Monteith equation" ], "year": "2018", "source": "JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES", "publication_type": "J", "point2d": [ -63.20169448852539, 49.136051177978516 ], "cluster": 3.0 }, { "idx": 158, "title": "Solar-induced chlorophyll fluorescence is strongly correlated with terrestrial photosynthesis for a wide variety of biomes: First global analysis based on OCO-2 and flux tower observations", "abstract": "Solar-induced chlorophyll fluorescence (SIF) has been increasingly used as a proxy for terrestrial gross primary productivity (GPP). Previous work mainly evaluated the relationship between satellite-observed SIF and gridded GPP products both based on coarse spatial resolutions. Finer resolution SIF (1.3kmx2.25km) measured from the Orbiting Carbon Observatory-2 (OCO-2) provides the first opportunity to examine the SIF-GPP relationship at the ecosystem scale using flux tower GPP data. However, it remains unclear how strong the relationship is for each biome and whether a robust, universal relationship exists across a variety of biomes. Here we conducted the first global analysis of the relationship between OCO-2 SIF and tower GPP for a total of 64 flux sites across the globe encompassing eight major biomes. OCO-2 SIF showed strong correlations with tower GPP at both midday and daily timescales, with the strongest relationship observed for daily SIF at the 757nm (R-2=0.72, p<0.0001). Strong linear relationships between SIF and GPP were consistently found for all biomes (R-2=0.57-0.79, p<0.0001) except evergreen broadleaf forests (R-2=0.16, p<0.05) at the daily timescale. A higher slope was found for C-4 grasslands and croplands than for C-3 ecosystems. The generally consistent slope of the relationship among biomes suggests a nearly universal rather than biome-specific SIF-GPP relationship, and this finding is an important distinction and simplification compared to previous results. SIF was mainly driven by absorbed photosynthetically active radiation and was also influenced by environmental stresses (temperature and water stresses) that determine photosynthetic light use efficiency. OCO-2 SIF generally had a better performance for predicting GPP than satellite-derived vegetation indices and a light use efficiency model. The universal SIF-GPP relationship can potentially lead to more accurate GPP estimates regionally or globally. Our findings revealed the remarkable ability of finer resolution SIF observations from OCO-2 and other new or future missions (e.g., TROPOMI, FLEX) for estimating terrestrial photosynthesis across a wide variety of biomes and identified their potential and limitations for ecosystem functioning and carbon cycle studies.", "authors": [ "Li, Xing", "Xiao, Jingfeng", "He, Binbin", "Arain, M. Altaf", "Beringer, Jason", "Desai, Ankur R.", "Emmel, Carmen", "Hollinger, David Y.", "Krasnova, Alisa", "Mammarella, Ivan", "Noe, Steffen M.", "Serrano Ortiz, Penelope", "Rey-Sanchez, A. Camilo", "Rocha, Adrian V.", "Varlagin, Andrej" ], "keywords": [ "carbon cycle", "carbon flux", "chlorophyll fluorescence", "eddy covariance", "gross primary productivity", "MODIS", "OCO-2", "vegetation type" ], "year": "2018", "source": "GLOBAL CHANGE BIOLOGY", "publication_type": "J", "point2d": [ -63.187583923339844, 58.82005310058594 ], "cluster": 17.0 }, { "idx": 159, "title": "Quantifying the effect of forest age in annual net forest carbon balance", "abstract": "Forests dominate carbon (C) exchanges between the terrestrial biosphere and the atmosphere on land. In the long term, the net carbon flux between forests and the atmosphere has been significantly impacted by changes in forest cover area and structure due to ecological disturbances and management activities. Current empirical approaches for estimating net ecosystem productivity (NEP) rarely consider forest age as a predictor, which represents variation in physiological processes that can respond differently to environmental drivers, and regrowth following disturbance. Here, we conduct an observational synthesis to empirically determine to what extent climate, soil properties, nitrogen deposition, forest age and management influence the spatial and interannual variability of forest NEP across 126 forest eddy-covariance flux sites worldwide. The empirical models explained up to 62% and 71% of spatio-temporal and across-site variability of annual NEP, respectively. An investigation of model structures revealed that forest age was adominant factor of NEP spatio-temporal variability in both space and time at the global scale as compared to abiotic factors, such as nutrient availability, soil characteristics and climate. These findings emphasize the importance of forest age in quantifying spatio-temporal variation in NEP using empirical approaches.", "authors": [ "Besnard, Simon", "Carvalhais, Nuno", "Arain, M. Altaf", "Black, Andrew", "de Bruin, Sytze", "Buchmann, Nina", "Cescatti, Alessandro", "Chen, Jiquan", "Clevers, Jan G. P. W.", "Desai, Ankur R.", "Gough, Christopher M.", "Havrankova, Katerina", "Herold, Martin", "Hortnagl, Lukas", "Jung, Martin", "Knohl, Alexander", "Kruijt, Bart", "Krupkova, Lenka", "Law, Beverly E.", "Lindroth, Anders", "Noormets, Asko", "Roupsard, Olivier", "Steinbrecher, Rainer", "Varlagin, Andrej", "Vincke, Caroline", "Reichstein, Markus" ], "keywords": [ "carbon cycle", "eddy covariance", "net ecosystem production", "empirical modelling", "forest age", "climate", "soil properties" ], "year": "2018", "source": "ENVIRONMENTAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -47.430721282958984, 63.579193115234375 ], "cluster": 17.0 }, { "idx": 160, "title": "Experiments on restoring alluvial cover using gravel augmentation in a variable width channel with irregular meanders", "abstract": "In partially-alluvial channels, an understanding of cover formation over a non-alluvial substrate is necessary for effective river management or restoration. Urban rivers, for example, are often sediment starved such that the underlying substrate may be exposed. Few experiments have investigated cover development in meandering channels, particularly where width and meander geometry are irregular as is often the case for partially alluvial channels. The purpose of this work is to support the development of sediment augmentation strategies to mitigate channel degradation and restore alluvial cover. The experiments also provide new insight into the impact of sediment supply rates on alluvial cover dynamics in variable-width channels. Under constant flow discharge and a continuous supply of sediment, sediment disperses downstream of the feed location and cover develops in a fragmented fashion. Cover initiation occurs downstream of bend apexes and develops as a series of discrete fixed bars whose morphology differs as a function of bend geometry and channel width. Cover expands and bars merge with time under steady sediment supply and discharge, eventually thickening to an equilibrium state in which sediment supply and output are approximately balanced. Higher sediment supply rates result in more extensive and thicker cover at equilibrium, including cover expanding into the cross-overs between the main bars. Coarse and fine fractions of the sediment supply are preferentially retained in the cover sediment because of fine particle deposition on bar tops and burial of initial coarse deposits. Models of areal cover with feed rate and cover thickness are proposed and compared with other studies. More experimentation is needed, but augmentation of alluvial gravel cover is a feasible approach to maintaining a sediment balance in partially alluvial channels and for developing mobile alluvial cover in engineered channels. (c) 2020 Elsevier B.V. All rights reserved.", "authors": [ "Peirce, S.", "MacVicar, B. J.", "Papangelakis, E.", "Vervynck, L.", "Ashmore, P." ], "keywords": [ "Alluvial cover", "Partially-alluvial channel", "River restoration", "Physical model", "Gravel augmentation" ], "year": "2021", "source": "GEOMORPHOLOGY", "publication_type": "J", "point2d": [ 11.038500785827637, -7.07070255279541 ], "cluster": 18.0 }, { "idx": 161, "title": "Stream power index for networks (SPIN) toolbox for decision support in urbanizing watersheds", "abstract": "Urbanization typically leads to erosion and instability in rivers, and many management and restoration strategies have been developed to dampen the worst impacts. Stream power, defined as the rate of energy expenditure in a river, is a promising metric for analyzing cumulative effects. In this paper we describe a spatial decision support system called the Stream Power Index for Networks (SPIN) toolbox that can be used to assess urban river stability at a watershed scale. The objectives of the paper are to: a) describe the toolbox algorithms and procedures and b) demonstrate the utility of the approach. SPIN is written in Python and packaged as an ArcGIS toolbox. The toolbox combines existing landscape analysis algorithms with new algorithms to model river confluences, channel sinuosity, and threshold sediment particle sizes. Data can also be ingested from a standard hydraulic model. Two case studies demonstrate use of the toolbox to: i) anticipate current morphology; ii) predict urban morphologic change; and iii) analyze the benefits for stormwater management and channel restoration scenarios on channel stability.", "authors": [ "Ghunowa, K.", "MacVicar, B. J.", "Ashmore, P." ], "keywords": [ "Sediment erosion", "Urban hydrology", "Spatial decision support systems", "Cumulative risk assessment" ], "year": "2021", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 12.218330383300781, -10.474808692932129 ], "cluster": 16.0 }, { "idx": 162, "title": "Process-based assessment of success and failure in a constructed riffle-pool river restoration project", "abstract": "Although there is increasing consensus that river restoration should focus on restoring processes rather than form, proven techniques to design and monitor projects for sediment transport processes are lacking. This study monitors bedload transport and channel morphology in a rural, an urban unrestored, and an urban restored reach. Objectives are to compare bedload transport regimes, assess the stability and self-maintenance of constructed riffle-pool sequences, and evaluate the impact of the project on coarse sediment continuity in the creek. Sediment tracking is done using radio frequency identification tracers and morphologic change is assessed from repeated cross-section surveys. Mean annual velocity is used to quantify the average downstream velocity of tracers, defined as the mean overall tracer travel length divided by the total study duration. The channel reconstruction slows down the downstream velocity of particles in the D-75 and D-90 size classes, but does not significantly change the velocity of particles in the D-50 size class or smaller. Surveys show that riffle features remain stable and that pool depths are maintained or deepened, while tracer paths match with what has been observed in natural riffle-pools. However, the slowdown of coarse sediment and increase in channel slope may lead to future failures related to over-steepening of the banks and a disruption in the continuity of sediment transport in the creek. This study demonstrates how bedload tracking and morphological surveys can be used to assess river restoration projects, and highlights the importance of incorporating coarse sediment connectivity into restoration design and monitoring.", "authors": [ "Papangelakis, Elli", "MacVicar, Bruce" ], "keywords": [ "bedload", "RFID", "riffle-pool", "river restoration", "sediment connectivity", "sediment transport", "tracers" ], "year": "2020", "source": "RIVER RESEARCH AND APPLICATIONS", "publication_type": "J", "point2d": [ 15.102413177490234, -5.494968891143799 ], "cluster": 18.0 }, { "idx": 163, "title": "Bedload Sediment Transport Regimes of Semi-alluvial Rivers Conditioned by Urbanization and Stormwater Management", "abstract": "Watershed urbanization and stormwater management (SWM) alter the hydrologic processes of rivers. Although differences have been documented in channel morphology and sediment yield pre- and posturbanization, little is known about how the modified hydrology affects grain-scale bedload transport dynamics. This study aims to characterize the bedload sediment transport regime of three rivers with different hydrologic settings: rural, urban with no SWM, and urban with peak-shaving SWM. The rivers are semi-alluvial, characterized by an alluvial layer over a cohesive till. Bedload transport was monitored using tracer stones over 3 years. Hydrograph characteristics of the streams fit with what is expected in urban and SWM systems, and the rural stream has an episodic transport regime typical of gravel-bed rivers. Entrainment thresholds are not detectably impacted by the semi-alluvial bed cover, but travel lengths of grains relative to their size are longer than in alluvial gravel-bed streams. Downstream displacement rates of particles up to the D-90 are accelerated in the urban river due to more frequent mobilization rather than increased event-based travel lengths and may explain channel enlargement. SWM decreases the mobility and travel lengths of particles below those in the rural system, which is combined with channel narrowing, and the loss of bed forms suggests a shift toward a competence-limited transport regime. This new regime is a result of reduced shear stresses that are insufficient to transport coarse material. This study presents empirical evidence of the effects of watershed urbanization and SWM on bedload transport and provides recommendations for process-based river management strategies.", "authors": [ "Papangelakis, E.", "MacVicar, B.", "Ashmore, P." ], "keywords": [ "bedload transport", "urbanization", "stormwater management", "tracers", "semi-alluvial", "sediment transport regime" ], "year": "2019", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 14.172085762023926, -8.392190933227539 ], "cluster": 18.0 }, { "idx": 164, "title": "The spatial and temporal distribution of metals in an urban stream: A case study of the Don River in Toronto, Canada", "abstract": "Widespread growth of cities, the association of trace metals with urban runoff, and the potentially deleterious effect of metals on aquatic ecology have made it important to understand the distribution and transport of metals through surface water channel networks. The Don River in Toronto, Canada has been identified as an Area of Concern for pollution to Lake Ontario, with historically high levels of metal contamination. Sampling programs are sparse, therefore a model is needed to understand the spatial and temporal variability of metals in the river network The objectives of the current study are to: i) describe the sampled spatial and temporal variability of metals in the Don River and ii) develop a modelling strategy to describe within flood metal transport dynamics. A model setup tool is developed that links Storm Water Management Model (SWMM) with the Environmental Fluid Dynamics Code (EFDC) to allow a seamless transition from catchment hydrology to in-stream hydraulic and chemical processes. Results show that lead pollution in the Don River is decreasing, likely as a result of policy changes and sediment dredging in the mouth of the river. However, zinc and copper pollution are increasingly problematic, with copper exceeding recommended lower guidelines, particularly during floods. Model results confirm that most of the sediment and metals are transported in relatively short bursts within longer flood durations and are stored in depositional hotspots within the Lower Don River. A better monitoring strategy is needed to understand and more accurately parametrize these processes in an urban river system. (C) 2018 International Association for Great Lakes Research. Published by Elsevier B.V. All rights reserved.", "authors": [ "Mansoor, Sannan Zahid", "Louie, Sana", "Lima, Ana T.", "Van Cappellen, Philippe", "MacVicar, Bruce" ], "keywords": [ "Metals", "Urban stream", "Sediment export", "EFDC hydrodynamic model", "SWMM hydrologic model" ], "year": "2018", "source": "JOURNAL OF GREAT LAKES RESEARCH", "publication_type": "J", "point2d": [ 45.895851135253906, -2.730703830718994 ], "cluster": 18.0 }, { "idx": 165, "title": "Enlargement and evolution of a semi-alluvial creek in response to urbanization", "abstract": "The impact of urbanization on stream channels is of interest due to the growth of cities and the sensitivity of stream morphology and ecology to hydrologic change. Channel enlargement is a commonly observed effect and channel evolution models can help guide management efforts, but the models must be used in the proper geologic and climatic context. Semi-alluvial channels characterized by a relatively thin alluvial layer over clay till and a convex channel profile in a temperate climate are not represented in currently available models. In this study we: (i) assess channel enlargement; and (ii) propose a channel evolution model for an urban semi-alluvial creek in Toronto, Canada. The system is 90% developed with an imperviousness of approximately 47%. Channel enlargement is assessed by comparing 50year old construction surveys, a recent survey of a relic channel, low-precision surveys of channel change over a 15year period, and high-precision surveys over a three year period. The enlargement ratio of the channel since 1958 is 2.6, but could be as high 8.2 in comparison with the pre-urban channel. When the increase in flow capacity is considered, the enlargement ratio is 1.9 since 1958 and up to 6.0 in comparison with the pre-urban channel. Channel enlargement continues in the contemporary channel at an estimated rate of 0.23m(2)/year. A five stage model is presented to describe channel evolution in the lower reaches. In this model the coarse lag material from glacial sources provides a natural resilience to the bed and incision occurs only after the increased flows from urbanization are combined with higher slopes as a result of channel straightening or avulsions. Further research should be done to assess stream behaviour close to an identified geologic control point. Copyright (c) 2018 John Wiley & Sons, Ltd.", "authors": [ "Bevan, Vernon", "MacVicar, Bruce", "Chapuis, Margot", "Ghunowa, Kimisha", "Papangelakis, Elli", "Parish, John", "Snodgrass, William" ], "keywords": [ "sediment transport", "rivers", "urbanization", "channel evolution models", "semi-alluvial" ], "year": "2018", "source": "EARTH SURFACE PROCESSES AND LANDFORMS", "publication_type": "J", "point2d": [ 12.81362247467041, -7.782601833343506 ], "cluster": 18.0 }, { "idx": 166, "title": "Influence of surface water on coarse resolution C-band backscatter: Implications for freeze/thaw retrieval from scatterometer data", "abstract": "The freeze/thaw state of permafrost landscapes is an essential variable for monitoring ecological, hydrological and climate processes. Ground surface state can be obtained from satellite data through time series analysis of C-band backscatter from scatterometer and Synthetic Aperture Radar (SAR) observations. Scatterometer data has been used in a variety of studies concerning freeze/thaw retrieval of the land surface. Coarse spatial resolution scatterometer data has great potential for application in this field due to its high temporal resolution (approx. daily observations). In this study, we investigate the influence of sub-grid cell (12.5 km) surface water (ice free and ice covered) on freeze/thaw retrieval based on ASCAT data using a threshold algorithm. We found discrepancies related to the surface water fraction in the detected timing of thawing and freezing of up to 2 days earlier thawing for spring and 3.5 days earlier freezing for autumn for open water fractions of 40% resulting in an overestimation of the frozen season. Results of this study led to the creation of a method for correction of water fraction impact on freeze/thaw data. Additionally, this study demonstrates the applicability of a new approach to freeze/thaw retrieval which has not so far been tested for SAR, specifically Sentinel-1.", "authors": [ "Bergstedt, Helena", "Bartsch, Annett", "Duguay, Claude R.", "Jones, Benjamin M." ], "keywords": [ "Freeze/thaw", "Surface water", "Lake ice", "ASCAT", "Sentinel-1", "SAR" ], "year": "2020", "source": "REMOTE SENSING OF ENVIRONMENT", "publication_type": "J", "point2d": [ -73.8204574584961, 21.434213638305664 ], "cluster": 2.0 }, { "idx": 167, "title": "Observing Scattering Mechanisms of Bubbled Freshwater Lake Ice Using Polarimetric RADARSAT-2 (C-Band) and UW-Scat (X- and Ku-Bands)", "abstract": "A winter time series of ground-based (X- and Ku-bands) scatterometer and spaceborne synthetic aperture radar (SAR) (C-band) fully polarimetric observations coincident with in situ snow and ice measurements are used to identify the dominant scattering mechanism in bubbled freshwater lake ice in the Hudson Bay Lowlands near Churchill, Manitoba. Scatterometer observations identify two physical sources of backscatter from the ice cover: the snow-ice and ice-water interfaces. Backscatter time series at all frequencies show increases from the ice-water interface prior to the inclusion of tubular bubbles in the ice column based on in situ observations, indicating scattering mechanisms independent of double-bounce scatter. The co-polarized phase difference of interactions at the ice-water interface from both scatterometer and SAR observations is centered at 0 degrees during the time series, also indicating a scattering regime other than double bounce. A Yamaguchi three-component decomposition of the RADARSAT-2 C-band time series is presented, which suggests the dominant scattering mechanism to be single-bounce off the ice-water interface with appreciable surface roughness or preferentially oriented facets, regardless of the presence, absence, or density of tubular bubble inclusions. This paper builds on newly established evidence of single-bounce scattering mechanism for freshwater lake ice and is the first to present a winter time series of ground-based and spaceborne fully polarimetric active microwave observations with polarimetric decompositions for bubbled freshwater lake ice.", "authors": [ "Gunn, Grant E.", "Duguay, Claude R.", "Atwood, Donald K.", "King, Joshua", "Toose, Peter" ], "keywords": [ "Frequency-modulated continuous wave (FMCW)", "lake ice", "polarimetry", "synthetic aperture radar (SAR)" ], "year": "2018", "source": "IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING", "publication_type": "J", "point2d": [ -81.7040023803711, 9.375511169433594 ], "cluster": 2.0 }, { "idx": 168, "title": "A long-term hydrometeorological dataset (1993-2014) of a northern mountain basin: Wolf Creek Research Basin, Yukon Territory, Canada", "abstract": "A set of hydrometeorological data is presented in this paper, which can be used to characterize the hydrometeorology and climate of a subarctic mountain basin and has proven particularly useful for forcing hydrological models and assessing their performance in capturing hydrological processes in subarctic alpine environments. The forcing dataset includes daily precipitation, hourly air temperature, humidity, wind, solar and net radiation, soil temperature, and geographical information system data. The model performance assessment data include snow depth and snow water equivalent, streamflow, soil moisture, and water level in a groundwater well. This dataset was recorded at different elevation bands in Wolf Creek Research Basin, near Whitehorse, Yukon Territory, Canada, representing forest, shrub tundra, and alpine tundra biomes from 1993 through 2014. Measurements continue through 2018 and are planned for the future at this basin and will be updated to the data website. The database presented and described in this article is available for download at https://doi.org/10.20383/101.0113.", "authors": [ "Rasouli, Kabir", "Pomeroy, John W.", "Janowicz, J. Richard", "Williams, Tyler J.", "Carey, Sean K." ], "keywords": [ "" ], "year": "2019", "source": "EARTH SYSTEM SCIENCE DATA", "publication_type": "J", "point2d": [ -30.712596893310547, -7.9719743728637695 ], "cluster": 12.0 }, { "idx": 169, "title": "A long-term hydrometeorological dataset (1993-2014) of a northern mountain basin: Wolf Creek Research Basin, Yukon Territory, Canada", "abstract": "A set of hydrometeorological data is presented in this paper, which can be used to characterize the hydrometeorology and climate of a subarctic mountain basin and has proven particularly useful for forcing hydrological models and assessing their performance in capturing hydrological processes in subarctic alpine environments. The forcing dataset includes daily precipitation, hourly air temperature, humidity, wind, solar and net radiation, soil temperature, and geographical information system data. The model performance assessment data include snow depth and snow water equivalent, streamflow, soil moisture, and water level in a groundwater well. This dataset was recorded at different elevation bands in Wolf Creek Research Basin, near Whitehorse, Yukon Territory, Canada, representing forest, shrub tundra, and alpine tundra biomes from 1993 through 2014. Measurements continue through 2018 and are planned for the future at this basin and will be updated to the data website. The database presented and described in this article is available for download at https://doi.org/10.20383/101.0113.", "authors": [ "Rasouli, Kabir", "Pomeroy, John W.", "Janowicz, J. Richard", "Williams, Tyler J.", "Carey, Sean K." ], "keywords": [ "" ], "year": "2019", "source": "EARTH SYSTEM SCIENCE DATA", "publication_type": "J", "point2d": [ -30.935617446899414, -7.612248420715332 ], "cluster": 12.0 }, { "idx": 170, "title": "Precipitation characteristics and associated weather conditions on the eastern slopes of the Canadian Rockies during March-April 2015", "abstract": "Precipitation events that bring rain and snow to the Banff-Calgary area of Alberta are a critical aspect of the region's water cycle and can lead to major flooding events such as the June 2013 event that was the second most costly natural disaster in Canadian history. Because no special atmospheric-oriented observations of these events have been made, a field experiment was conducted in March and April 2015 in Kananaskis, Alberta, to begin to fill this gap. The goal was to characterize and better understand the formation of the precipitation at the surface during spring 2015 at a specific location in the Kananaskis Valley. Within the experiment, detailed measurements of precipitation and weather conditions were obtained, a vertically pointing Doppler radar was deployed and weather balloons were released. Although 17 precipitation events occurred, this period was associated with much less precipitation than normal (35 %) and above-normal temperatures (2.5 degrees C). Of the 133 h of observed precipitation, solid precipitation occurred 71% of the time, mixed precipitation occurred 9% and rain occurred 20 %. An analysis of 17 504 precipitation particles from 1181 images showed that a wide variety of crystals and aggregates occurred and approximately 63% showed signs of riming. This was largely independent of whether flows aloft were upslope (easterly) or downslope (westerly). In the often sub-saturated surface conditions, hydrometeors containing ice occurred at temperatures as high as 9 degrees C. Radar structures aloft were highly variable with reflectivity sometimes > 30 dBZe and Doppler velocity up to -1 ms(-1), which indicates upward motion of particles within ascending air masses. Precipitation was formed in this region within cloud fields sometimes having variable structures and within which supercooled water at least sometimes existed to produce accreted particles massive enough to reach the surface through the relatively dry sub-cloud region.", "authors": [ "Theriault, Julie M.", "Hung, Ida", "Vaquer, Paul", "Stewart, Ronald E.", "Pomeroy, John W." ], "keywords": [ "" ], "year": "2018", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -48.51927947998047, -23.325714111328125 ], "cluster": 1.0 }, { "idx": 171, "title": "Semi-Automated Classification of Lake Ice Cover Using Dual Polarization RADARSAT-2 Imagery", "abstract": "Lake ice is a significant component of the cryosphere due to its large spatial coverage in high-latitude regions during the winter months. The Laurentian Great Lakes are the world's largest supply of freshwater and their ice cover has a major impact on regional weather and climate, ship navigation, and public safety. Ice experts at the Canadian Ice Service (CIS) have been manually producing operational Great Lakes image analysis charts based on visual interpretation of the synthetic aperture radar (SAR) images. In that regard, we have investigated the performance of the semi-automated segmentation algorithm glocal Iterative Region Growing with Semantics (IRGS) for lake ice classification using dual polarized RADARSAT-2 imagery acquired over Lake Erie. Analysis of various case studies indicated that the glocal IRGS algorithm could provide a reliable ice-water classification using dual polarized images with a high overall accuracy of 90.4%. However, lake ice types that are based on stage of development were not effectively identified due to the ambiguous relation between backscatter and ice types. The slight improvement of using dual-pol as opposed to single-pol images for ice-water discrimination was also demonstrated.", "authors": [ "Wang, Junqian", "Duguay, Claude R.", "Clausi, David A.", "Pinard, Veronique", "Howell, Stephen E. L." ], "keywords": [ "classification", "synthetic aperture radar", "lake ice", "RADARSAT-2" ], "year": "2018", "source": "REMOTE SENSING", "publication_type": "J", "point2d": [ -80.30961608886719, 5.17617130279541 ], "cluster": 2.0 }, { "idx": 172, "title": "Fine-Scale SAR Soil Moisture Estimation in the Subarctic Tundra", "abstract": "In the subarctic tundra, soil moisture information can benefit permafrost monitoring and ecological studies, but fine-scale remote-sensing approaches are lacking. We explore the suitability of C-band SAR, paying attention to two challenges soil moisture retrieval faces. First, the microtopography and the heterogeneous organic soils impart unique microwave scattering properties, even in absence of noteworthy shrub cover. Empirically, we find the polarimetric response is highly random (entropies >0.7). The randomness limits the applicability of purely polarimetric approaches to soil moisture estimation, as it causes a tailor-made decomposition to break down. For comparison, the L-band scattering response is more surfacelike, also in terms of its angular characteristics. The second challenge concerns the large spatial but small temporal variability of soil moisture observed at our site. Accordingly, the Radarsat-2 C-band backscatter has a limited dynamic range (similar to 2 dB). However, contrary to polarimetric indicators, it shows a clear surface soil moisture signal. To account for the small dynamic range while retaining a 100-m spatial resolution, we embed an empirical time-series model in a Bayesian framework. This framework adaptively pools information from neighboring grid cells, thus increasing the precision. The retrieved soil moisture index achieves correlations of 0.3-0.5 with in situ data at 5 cm depth and, upon calibration, root-mean-square errors of <0.04 m(3) m(-3). As this approach is applicable to Sentinel-1 data, it can potentially provide frequent soil moisture estimates across large regions. In the long term, L-band data hold greater promise for operational retrievals.", "authors": [ "Zwieback, Simon", "Berg, Aaron A." ], "keywords": [ "Arctic", "radar polarimetry", "radar remote sensing", "soil moisture", "soil properties", "synthetic aperture radar" ], "year": "2019", "source": "IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING", "publication_type": "J", "point2d": [ -68.24850463867188, 11.744406700134277 ], "cluster": 8.0 }, { "idx": 173, "title": "Improving Permafrost Modeling by Assimilating Remotely Sensed Soil Moisture", "abstract": "Knowledge of soil moisture conditions is important for modeling soil temperatures, as soil moisture influences the thermal dynamics in multiple ways. However, in permafrost regions, soil moisture is highly heterogeneous and difficult to model. Satellite soil moisture data may fill this gap, but the degree to which they can improve permafrost modeling is unknown. To explore their added value for modeling soil temperatures, we assimilate fine-scale satellite surface soil moisture into the CryoGrid-3 permafrost model, which accounts for the soil moisture's influence on the soil thermal properties and the surface energy balance. At our study site in the Canadian Arctic, the assimilation improves the estimates of deeper (>10cm) soil temperatures during summer but not consistently those of the near-surface temperatures. The improvements in the deeper temperatures are strongly contingent on soil type: They are largest for porous organic soils (30%), smaller for thin organic soil covers (20%), and they essentially vanish for mineral soils (only synthetic data available). That the improvements are greatest over organic soils reflects the strong coupling between soil moisture and deeper temperatures. The coupling arises largely from the diminishing soil thermal conductivity with increasing desiccation thanks to which the deeper soil is kept cool. It is this association of dry organic soils being cool at depth that lets the assimilation revise the simulated soil temperatures toward the actually measured ones. In the future, the increasing availability of satellite soil moisture data holds promise for the operational monitoring of soil temperatures, hydrology, and biogeochemistry. Plain Language Summary We explore whether soil moisture data improve the accuracy with which we can predict the soil temperature profile in cold regions. Knowledge of the temperature conditions is important for monitoring the stability of the terrain, for understanding the response of vegetation and microorganisms, and many other applications. Soil moisture data may be useful in this context because soil moisture influences the thermal dynamics of the soil, but so far, such data have been in short supply. Using novel satellite soil moisture data, we show that soil moisture information does indeed help to improve the estimates of deeper temperatures, at least in organic soils. In the future, the increasing availability of satellite soil moisture data holds promise for the operational monitoring of soil temperatures, hydrology, and biogeochemistry.", "authors": [ "Zwieback, S.", "Westermann, S.", "Langer, M.", "Boike, J.", "Marsh, P.", "Berg, A." ], "keywords": [ "permafrost", "soil temperature", "soil moisture", "data assimilation", "remote sensing" ], "year": "2019", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -36.87226486206055, 48.31768035888672 ], "cluster": 17.0 }, { "idx": 175, "title": "Competition for shrinking window of low salinity groundwater", "abstract": "Groundwater resources are being stressed from the top down and bottom up. Declining water tables and near-surface contamination are driving groundwater users to construct deeper wells in many US aquifer systems. This has been a successful short-term mitigation measure where deep groundwater is fresh and free of contaminants. Nevertheless, vertical salinity profiles are not well-constrained at continental-scales. In many regions, oil and gas activities use pore spaces for energy production and waste disposal. Here we quantify depths that aquifer systems transition from fresh-to-brackish and where oil and gas activities are widespread in sedimentary basins across the United States. Fresh-brackish transitions occur at relatively shallow depths of just a few hundred meters, particularly in eastern US basins. We conclude that fresh groundwater is less abundant in several key US basins than previously thought; therefore drilling deeper wells to access fresh groundwater resources is not feasible extensively across the continent. Our findings illustrate that groundwater stores are being depleted not only by excessive withdrawals, but due to injection, and potentially contamination, from the oil and gas industry in areas of deep fresh and brackish groundwater.", "authors": [ "Ferguson, Grant", "McIntosh, Jennifer C.", "Perrone, Debra", "Jasechko, Scott" ], "keywords": [ "groundwater", "salinity", "pore space competition", "hydraulic fracturing", "enhanced oil recovery", "injection wells" ], "year": "2018", "source": "ENVIRONMENTAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ 12.778533935546875, 30.98684310913086 ], "cluster": 18.0 }, { "idx": 176, "title": "Reproductive status of walleye (Sander vitreus) and lake whitefish (Coregonus clupeaformis) in two large, shallow Canadian subarctic lakes", "abstract": "The reproductive status of walleye (Sander vitreus) and lake whitefish (Coregonus clupeaformis) is largely unstudied in the northern extent of their ranges. Tathlina Lake and Kakisa Lake are large, shallow lakes in the Northwest Territories, Canada, supporting important commercial and subsistence fisheries for these species while being threatened by climate change. Fish were sampled in both lakes across multiple years in the spring and autumn to assess differences in reproductive status in the pre- and post-spawning periods for both species. Condition factor (K), gonadosomatic index (GSI), liversomatic index (LSI), and fecundity were calculated, and plasma samples were also taken from each fish to determine levels of reproductive hormones, specifically 17 beta-estradiol in females, and 11-ketotestosterone in males. Significant temporal (intra- and interannual) and spatial (between lakes) variation was found for both species and both sexes for all metrics. Expected differences in hormones and indices of reproductive success between pre- and post- spawning periods were demonstrated. When compared with previously published data, a latitudinal gradient for LSI, GSI and fecundity was evident for walleye, but not for lake whitefish. The differences in the reproductive biology of lake whitefish and walleye in these two neighbouring lakes highlights limitations in the use of a reference lake approach in biomonitoring studies. The data in this study can be used and expanded upon to provide information for the sustainable management of these fish stocks for the future.", "authors": [ "Dixon, Heather J.", "Harrison, Grant", "Lister, Andrea L.", "MacLatchy, Deborah L." ], "keywords": [ "Lake whitefish", "Walleye", "Reproduction", "Northern Canada", "Fecundity" ], "year": "2020", "source": "ENVIRONMENTAL BIOLOGY OF FISHES", "publication_type": "J", "point2d": [ 67.48839569091797, 0.21400736272335052 ], "cluster": 0.0 }, { "idx": 177, "title": "Delineating extent and magnitude of river flooding to lakes across a northern delta using water isotope tracers", "abstract": "Hydrological monitoring in complex, dynamic northern floodplain landscapes is challenging, but increasingly important as a consequence of multiple stressors. The Peace-Athabasca Delta in northern Alberta, Canada, is a Ramsar Wetland of International Importance reliant on episodic river ice-jam flood events to recharge abundant perched lakes and wetlands. Improved and systematic monitoring of landscape-scale hydrological connectivity among freshwater ecosystems (rivers, channels, wetlands, and lakes) is needed to guide stewardship decisions in the face of climate change and upstream industrial development. Here, we use water isotope compositions, supplemented by measurements of specific conductivity and field observations, from 68 lakes and 9 river sites in May 2018 to delineate the extent and magnitude of spring ice-jam induced flooding along the Peace and Athabasca rivers. Lake-specific estimates of input water isotope composition (delta(I)) were modelled after accounting for influence of evaporative isotopic enrichment. Then, using the distinct isotopic signature of input water sources, we develop a set of binary mixing models and estimate the proportion of input to flooded lakes attributable to river floodwater and precipitation (snow or rain). This approach allowed identification of areas and magnitude of flooding that were not captured by other methods, including direct observations from flyovers, and to demarcate flow pathways in the delta. We demonstrate water isotope tracers as an efficient and effective monitoring tool for delineating spatial extent and magnitude of an important hydrological process and elucidating connectivity in the Peace-Athabasca Delta, an approach that can be readily adopted at other floodplain landscapes.", "authors": [ "Remmer, Casey R.", "Owca, Tanner", "Neary, Laura", "Wiklund, Johan A.", "Kay, Mitchell", "Wolfe, Brent B.", "Hall, Roland, I" ], "keywords": [ "floodplain lakes", "freshwater ecosystems", "hydrological connectivity", "hydrological monitoring", "Peace-Athabasca Delta", "river flooding", "water isotope tracers" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 2.7946577072143555, 13.868063926696777 ], "cluster": 18.0 }, { "idx": 178, "title": "Tall Shrubs Mediate Abiotic Conditions and Plant Communities at the Taiga-Tundra Ecotone", "abstract": "Shrub expansion has occurred across much of the arctic tundra over the past century. Increasing dominance of woody vegetation is expected to have global influences on climate patterns and lead to local changes in hydrological function and nutrient cycling. Changing abiotic conditions associated with shrubs will likely alter the relative fitness of neighbouring plants resulting in distinct community composition. Here, we use an extensive set of paired abiotic and biotic data to investigate the capacity for Alnus alnobetula (green alder) patches to modify the habitat of the local plant community at the taiga-tundra ecotone of the Northwest Territories, Canada. Plots were established across topographic positions in ten alder patches and adjacent, alder-free tundra. Habitat corresponded to the strongest gradient of among-site variation in abiotic measures and plant community composition, indicating that alder patch growing conditions were distinct from those of alder-free tundra. Slope position was generally unimportant in determining environmental conditions. Alder patches changed the vertical structure of the understory by increasing the maximum height of birch. Tall shrubs also decreased the richness of tundra specialists, suggesting that these species face competitive pressures from shrub expansion at the southern edge of their ranges. Our findings demonstrate that tall shrub patches can substantially modify their local environment in taiga-tundra ecotone systems, altering available habitat and acting as niche constructors for the local plant community. These habitats will therefore be important to consider in regional predictions of hydrology, nutrient cycling, and biodiversity as shrubs continue to expand across the arctic.", "authors": [ "Wallace, Cory A.", "Baltzer, Jennifer L." ], "keywords": [ "Alnus alnobetula", "biogeography", "community composition", "ecotone", "green alder", "niche construction", "shrub expansion" ], "year": "2020", "source": "ECOSYSTEMS", "publication_type": "J", "point2d": [ -35.99516677856445, 43.69165802001953 ], "cluster": 13.0 }, { "idx": 179, "title": "The influence of snow microstructure on dual-frequency radar measurements in a tundra environment", "abstract": "Recent advancement in the understanding of snow-microwave interactions has helped to isolate the considerable potential for radar-based retrieval of snow water equivalent (SWE). There are however, few datasets available to address spatial uncertainties, such as the influence of snow microstructure, at scales relevant to space-borne application. In this study we introduce measurements from SnowSAR, an airborne, dual-frequency (9.6 and 17.2 GHz) synthetic aperture radar (SAR), to evaluate high resolution (10 m) backscatter within a snow-covered tundra basin. Coincident in situ surveys at two sites characterize a generally thin snowpack (50 cm) interspersed with deeper drift features. Structure of the snowpack is found to be predominantly wind slab (65%) with smaller proportions of depth hoar underlain (35%). Objective estimates of snow microstructure (exponential correlation length; l(ex)), show the slab layers to be 2.8 times smaller than the basal depth hoar. In situ measurements are used to parametrize the Microwave Emission Model of Layered Snowpacks (MEMLS3&a) and compare against collocated SnowSAR backscatter. The evaluation shows a scaling factor (phi) between 1.37 and 1.08, when applied to input of l(ex), minimizes MEMLS root mean squared error to < 1.1 dB. Model sensitivity experiments demonstrate contrasting contributions from wind slab and depth hoar components, where wind rounded microstructures are identified as a strong control on observed backscatter. Weak sensitivity of SnowSAR to spatial variations in SWE is explained by the smaller contributing microstructures of the wind slab.", "authors": [ "King, Joshua", "Derksen, Chris", "Toose, Peter", "Langlois, Alexandre", "Larsen, Chris", "Lemmetyinen, Juha", "Marsh, Phil", "Montpetit, Benoit", "Roy, Alexandre", "Rutter, Nick", "Sturm, Matthew" ], "keywords": [ "Snow", "SWE", "Radar", "SAR", "Tundra", "Arctic" ], "year": "2018", "source": "REMOTE SENSING OF ENVIRONMENT", "publication_type": "J", "point2d": [ -66.65885162353516, 3.3860793113708496 ], "cluster": 8.0 }, { "idx": 180, "title": "Forward and Inverse Radar Modeling of Terrestrial Snow Using SnowSAR Data", "abstract": "In this paper, we develop a radar snow water equivalent (SWE) retrieval algorithm based on a parameterized forward model of bicontinuous dense media radiative transfer (Bic-DMRT). The algorithm is based on retrieving the absorption loss of the snowpack which is directly proportional to the SWE. In the algorithm, Bic-DMRT is first applied to generate a lookup table (LUT) of snowpack backscattering at X- and Ku-band. Regression training is applied to the LUT to transform the dual-frequency backscatter into functions of two parameters: the scattering albedo at X-band and SWE. The background scattering is subtracted from the SnowSAR data to give the volume scattering of snow. Classification of SnowSAR data is applied to provide a priori information. Based on the obtained volume scattering and the priori information, a cost function is established to find SWE. Performance of the retrieval algorithm was tested using three sets of airborne SnowSAR data acquired over mixed areas in Finland and open tundra landscape in Canada. It is shown that the retrieval algorithm has a root-mean-square error below 30 mm of SWE and a correlation coefficient above 0.64.", "authors": [ "Zhu, Jiyue", "Tan, Shurun", "King, Joshua", "Derksen, Chris", "Lemmetyinen, Juha", "Tsang, Leung" ], "keywords": [ "Active microwave remote sensing", "bicontinuous dense media radiative transfer (Bic-DMRT)", "radar retrieval algorithm", "regression training", "snow water equivalent (SWE)", "SnowSAR data" ], "year": "2018", "source": "IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING", "publication_type": "J", "point2d": [ -66.61917877197266, 5.450439453125 ], "cluster": 8.0 }, { "idx": 181, "title": "Carbon release through abrupt permafrost thaw", "abstract": "The permafrost zone is expected to be a substantial carbon source to the atmosphere, yet large-scale models currently only simulate gradual changes in seasonally thawed soil. Abrupt thaw will probably occur in <20% of the permafrost zone but could affect half of permafrost carbon through collapsing ground, rapid erosion and landslides. Here, we synthesize the best available information and develop inventory models to simulate abrupt thaw impacts on permafrost carbon balance. Emissions across 2.5 million km(2) of abrupt thaw could provide a similar climate feedback as gradual thaw emissions from the entire 18 million km(2) permafrost region under the warming projection of Representative Concentration Pathway 8.5. While models forecast that gradual thaw may lead to net ecosystem carbon uptake under projections of Representative Concentration Pathway 4.5, abrupt thaw emissions are likely to offset this potential carbon sink. Active hillslope erosional features will occupy 3% of abrupt thaw terrain by 2300 but emit one-third of abrupt thaw carbon losses. Thaw lakes and wetlands are methane hot spots but their carbon release is partially offset by slowly regrowing vegetation. After considering abrupt thaw stabilization, lake drainage and soil carbon uptake by vegetation regrowth, we conclude that models considering only gradual permafrost thaw are substantially underestimating carbon emissions from thawing permafrost.", "authors": [ "Turetsky, Merritt R.", "Abbott, Benjamin W.", "Jones, Miriam C.", "Anthony, Katey Walter", "Olefeldt, David", "Schuur, Edward A. G.", "Grosse, Guido", "Kuhry, Peter", "Hugelius, Gustaf", "Koven, Charles", "Lawrence, David M.", "Gibson, Carolyn", "Sannel, A. Britta K.", "McGuire, A. David" ], "keywords": [ "" ], "year": "2020", "source": "NATURE GEOSCIENCE", "publication_type": "J", "point2d": [ -29.10879898071289, 46.08720779418945 ], "cluster": 13.0 }, { "idx": 182, "title": "Biological and geophysical feedbacks with fire in the Earth system", "abstract": "Roughly 3% of the Earth's land surface burns annually, representing a critical exchange of energy and matter between the land and atmosphere via combustion. Fires range from slow smouldering peat fires, to low-intensity surface fires, to intense crown fires, depending on vegetation structure, fuel moisture, prevailing climate, and weather conditions. While the links between biogeochemistry, climate and fire are widely studied within Earth system science, these relationships are also mediated by fuels-namely plants and their litter-that are the product of evolutionary and ecological processes. Fire is a powerful selective force and, over their evolutionary history, plants have evolved traits that both tolerate and promote fire numerous times and across diverse clades. Here we outline a conceptual framework of how plant traits determine the flammability of ecosystems and interact with climate and weather to influence fire regimes. We explore how these evolutionary and ecological processes scale to impact biogeochemical and Earth system processes. Finally, we outline several research challenges that, when resolved, will improve our understanding of the role of plant evolution in mediating the fire feedbacks driving Earth system processes. Understanding current patterns of fire and vegetation, as well as patterns of fire over geological time, requires research that incorporates evolutionary biology, ecology, biogeography, and the biogeosciences.", "authors": [ "Archibald, S.", "Lehmann, C. E. R.", "Belcher, C. M.", "Bond, W. J.", "Bradstock, R. A.", "Daniau, A-L", "Dexter, K. G.", "Forrestel, E. J.", "Greve, M.", "He, T.", "Higgins, S. I.", "Hoffmann, W. A.", "Lamont, B. B.", "McGlinn, D. J.", "Moncrieff, G. R.", "Osborne, C. P.", "Pausas, J. G.", "Price, O.", "Ripley, B. S.", "Rogers, B. M.", "Schwilk, D. W.", "Simon, M. F.", "Turetsky, M. R.", "Van der Werf, G. R.", "Zanne, A. E." ], "keywords": [ "flammability", "earth-system feedbacks", "niche-construction", "evolution", "plant traits", "vegetation", "climate" ], "year": "2018", "source": "ENVIRONMENTAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -21.018482208251953, 71.43587493896484 ], "cluster": 15.0 }, { "idx": 183, "title": "Wildfire severity reduces richness and alters composition of soil fungal communities in boreal forests of western Canada", "abstract": "Wildfire is the dominant disturbance in boreal forests and fire activity is increasing in these regions. Soil fungal communities are important for plant growth and nutrient cycling postfire but there is little understanding of how fires impact fungal communities across landscapes, fire severity gradients, and stand types in boreal forests. Understanding relationships between fungal community composition, particularly mycorrhizas, and understory plant composition is therefore important in predicting how future fire regimes may affect vegetation. We used an extreme wildfire event in boreal forests of Canada's Northwest Territories to test drivers of fungal communities and assess relationships with plant communities. We sampled soils from 39 plots 1 year after fire and 8 unburned plots. High-throughput sequencing (MiSeq, ITS) revealed 2,034 fungal operational taxonomic units. We found soil pH and fire severity (proportion soil organic layer combusted), and interactions between these drivers were important for fungal community structure (composition, richness, diversity, functional groups). Where fire severity was low, samples with low pH had higher total fungal, mycorrhizal, and saprotroph richness compared to where severity was high. Increased fire severity caused declines in richness of total fungi, mycorrhizas, and saprotrophs, and declines in diversity of total fungi and mycorrhizas. The importance of stand age (a surrogate for fire return interval) for fungal composition suggests we could detect long-term successional patterns even after fire. Mycorrhizal and plant community composition, richness, and diversity were weakly but significantly correlated. These weak relationships and the distribution of fungi across plots suggest that the underlying driver of fungal community structure is pH, which is modified by fire severity. This study shows the importance of edaphic factors in determining fungal community structure at large scales, but suggests these patterns are mediated by interactions between fire and forest stand composition.", "authors": [ "Day, Nicola J.", "Dunfield, Kari E.", "Johnstone, Jill F.", "Mack, Michelle C.", "Turetsky, Merritt R.", "Walker, Xanthe J.", "White, Alison L.", "Baltzer, Jennifer L." ], "keywords": [ "disturbance", "functional groups", "global change", "mycorrhizas", "saprotrophs", "Taiga Plains", "understory" ], "year": "2019", "source": "GLOBAL CHANGE BIOLOGY", "publication_type": "J", "point2d": [ -20.646020889282227, 76.0232925415039 ], "cluster": 15.0 }, { "idx": 184, "title": "Implementation of human biomonitoring in the Dehcho region of the Northwest Territories, Canada (2016-2017)", "abstract": "BackgroundHuman biomonitoring represents an important tool for health risk assessment, supporting the characterization of contaminant exposure and nutrient status. In communities where country foods (locally harvested foods: land animals, fish, birds, plants) are integrated in the daily diet, as is the case in remote northern regions where food security is a challenge, such foods can potentially be a significant route of contaminant exposure. To assess this issue, a biomonitoring project was implemented among Dene/Metis communities of the Dehcho region of the Northwest Territories, Canada.MethodsParticipants completed dietary surveys (i.e., a food frequency questionnaire and 24-h recall) to estimate food consumption patterns as well as a Health Messages Survey to evaluate the awareness and perception of contaminants and consumption notices. Biological sampling of hair, urine and blood was conducted. Toxic metals (e.g., mercury, lead, cadmium), essential metals (e.g., copper, nickel, zinc), fatty acids, and persistent organic pollutants (POPs) were measured in samples.ResultsThe levels of contaminants in blood, hair and urine for the majority of participants were below the available guidance values for mercury, cadmium, lead and uranium. However, from the 279 participants, approximately 2% were invited to provide follow up samples, mainly for elevated mercury level. Also, at the population level, blood lead (GM: 11g/L) and blood cadmium (GM: 0.53g/L) were slightly above the Canadian Health Measures Survey data. Therefore, although country foods occasionally contain elevated levels of particular contaminants, human exposures to these metals remained similar to those seen in the Canadian general population. In addition, dietary data showed the importance and diversity of country foods across participating communities, with the consumption of an average of 5.1% of total calories from wild-harvested country foods.ConclusionThis project completed in the Mackenzie Valley of the Northwest Territories fills a data gap across other biomonitoring studies in Canada as it integrates community results, will support stakeholders in the development of public health strategies, and will inform environmental health issue prioritization.", "authors": [ "Ratelle, Mylene", "Skinner, Kelly", "Laird, Matthew J.", "Majowicz, Shannon", "Brandow, Danielle", "Packull-McCormick, Sara", "Bouchard, Michele", "Dieme, Denis", "Stark, Ken D.", "Henao, Juan Jose Aristizabal", "Hanning, Rhona", "Laird, Brian D." ], "keywords": [ "Dene", "First nations", "Biomonitoring", "Metals", "Traditional foods", "North", "Biomarker", "Exposure", "Risk assessment" ], "year": "2018", "source": "ARCHIVES OF PUBLIC HEALTH", "publication_type": "J", "point2d": [ 76.81539154052734, -17.21350860595703 ], "cluster": 7.0 }, { "idx": 185, "title": "Cadmium exposure in First Nations communities of the Northwest Territories, Canada: smoking is a greater contributor than consumption of cadmium-accumulating organ meats", "abstract": "Traditional food consumption among northern populations is associated with improved nutrition but occasionally can also increase contaminant exposure. High levels of cadmium in the organs of moose from certain regions of the Northwest Territories, Canada, led to the release of consumption notices. These notices recommended that individuals limit their consumption of kidney and liver from moose harvested from the Southern Mackenzie Mountain. A human biomonitoring project was designed to better characterize exposure and risks from contaminants, including cadmium, among Dene/Metis communities of the Northwest Territories Mackenzie Valley, Canada. The project included a dietary assessment (food frequency questionnaire) to estimate moose and caribou organ (kidney and liver) consumption, as well as urine and blood sampling for the measurement of cadmium concentration using mass spectrometry. For a subset of the samples, urine cotinine was also quantified. The results from this biomonitoring research show that cadmium levels in urine (GM = 0.32 g L-1) and blood (GM = 0.58 g L-1) are similar to those observed in other populations in Canada. For the 38% of participants reporting eating game organs, current traditional food consumption patterns were not associated with cadmium biomarker levels. Instead, smoking appeared to be the main determinant of cadmium exposure. These results are supporting ongoing efforts at the community and territorial level to identify health priorities and design follow up plans in response to environmental monitoring data.", "authors": [ "Ratelle, Mylene", "Li, Xinci", "Laird, Brian D." ], "keywords": [ "" ], "year": "2018", "source": "ENVIRONMENTAL SCIENCE-PROCESSES & IMPACTS", "publication_type": "J", "point2d": [ 78.2704849243164, -18.5594482421875 ], "cluster": 7.0 }, { "idx": 186, "title": "Bi-directional hydrological changes in perched basins of the Athabasca Delta (Canada) in recent decades caused by natural processes", "abstract": "[1] Previous studies of river hydrometric records and Indigenous Knowledge holders claim that floodinduced recharge of ecologically important perched basins decreased across the Peace-Athabasca Delta after 1968 due mainly to hydroelectric regulation of Peace River flow. Natural deltaic processes and climate are acknowledged as additional, lesser contributors, but are challenging to evaluate. We use sediment records spanning similar to 115 years from nine perched basins across the Athabasca Delta to test if unidirectional drying coincides with river regulation. Results show bi-directional hydrological changes since the early 1980s, not 1968, to reduced flooding in areas east of the Embarras River confluence with Cree/Mamawi creeks and increased flooding northward along the Cree/Mamawi distributary. The timing and pattern pinpoint the 1982 Embarras Breakthrough, a natural avulsion that diverted flow northward and away from the Athabasca Delta terminus, as the principal cause. The results demonstrate the need to factor natural deltaic processes into impending decisions on the delta's UNESCO World Heritage status and implementation of a federal Action Plan to mitigate widespread drying.", "authors": [ "Kay, M. L.", "Wiklund, J. A.", "Remmer, C. R.", "Neary, L. K.", "Brown, K.", "Ghosh, A.", "MacDonald, E.", "Thomson, K.", "Vucic, J. M.", "Wesenberg, K.", "Hall, R. I.", "Wolfe, B. B." ], "keywords": [ "paleolimnology", "Peace-Athabasca Delta", "loss-on-ignition", "hydrological change", "natural avulsion", "perched basins", "Wood Buffalo", "National Park Action Plan" ], "year": "2019", "source": "ENVIRONMENTAL RESEARCH COMMUNICATIONS", "publication_type": "J", "point2d": [ 6.98110818862915, 10.83796215057373 ], "cluster": 18.0 }, { "idx": 187, "title": "Extensive land cover change across Arctic-Boreal Northwestern North America from disturbance and climate forcing", "abstract": "A multitude of disturbance agents, such as wildfires, land use, and climate-driven expansion of woody shrubs, is transforming the distribution of plant functional types across Arctic-Boreal ecosystems, which has significant implications for interactions and feedbacks between terrestrial ecosystems and climate in the northern high-latitude. However, because the spatial resolution of existing land cover datasets is too coarse, large-scale land cover changes in the Arctic-Boreal region (ABR) have been poorly characterized. Here, we use 31 years (1984-2014) of moderate spatial resolution (30 m) satellite imagery over a region spanning 4.7 x 10(6) km(2) in Alaska and northwestern Canada to characterize regional-scale ABR land cover changes. We find that 13.6 +/- 1.3% of the domain has changed, primarily via two major modes of transformation: (a) simultaneous disturbance-driven decreases in Evergreen Forest area (-14.7 +/- 3.0% relative to 1984) and increases in Deciduous Forest area (+14.8 +/- 5.2%) in the Boreal biome; and (b) climate-driven expansion of Herbaceous and Shrub vegetation (+7.4 +/- 2.0%) in the Arctic biome. By using time series of 30 m imagery, we characterize dynamics in forest and shrub cover occurring at relatively short spatial scales (hundreds of meters) due to fires, harvest, and climate-induced growth that are not observable in coarse spatial resolution (e.g., 500 m or greater pixel size) imagery. Wildfires caused most of Evergreen Forest Loss and Evergreen Forest Gain and substantial areas of Deciduous Forest Gain. Extensive shifts in the distribution of plant functional types at multiple spatial scales are consistent with observations of increased atmospheric CO2 seasonality and ecosystem productivity at northern high-latitudes and signal continental-scale shifts in the structure and function of northern high-latitude ecosystems in response to climate change.", "authors": [ "Wang, Jonathan A.", "Sulla-Menashe, Damien", "Woodcock, Curtis E.", "Sonnentag, Oliver", "Keeling, Ralph F.", "Friedl, Mark A." ], "keywords": [ "Arctic", "Boreal forest", "deciduous forest", "evergreen", "forest disturbance", "land cover change", "plant functional type", "remote sensing", "shrub encroachment", "wildfire" ], "year": "2020", "source": "GLOBAL CHANGE BIOLOGY", "publication_type": "J", "point2d": [ -39.51351547241211, 51.59817123413086 ], "cluster": 15.0 }, { "idx": 188, "title": "Monthly gridded data product of northern wetland methane emissions based on upscaling eddy covariance observations", "abstract": "Natural wetlands constitute the largest and most uncertain source of methane (CH4) to the atmosphere and a large fraction of them are found in the northern latitudes. These emissions are typically estimated using process (bottom-up) or inversion (top-down) models. However, estimates from these two types of models are not independent of each other since the top-down estimates usually rely on the a priori estimation of these emissions obtained with process models. Hence, independent spatially explicit validation data are needed. Here we utilize a random forest (RF) machine-learning technique to upscale CH4 eddy covariance flux measurements from 25 sites to estimate CH4 wetland emissions from the northern latitudes (north of 45 degrees N). Eddy covariance data from 2005 to 2016 are used for model development. The model is then used to predict emissions during 2013 and 2014. The predictive performance of the RF model is evaluated using a leave-one-site-out cross-validation scheme. The performance (Nash-Sutcliffe model efficiency = 0.47) is comparable to previous studies upscaling net ecosystem exchange of carbon dioxide and studies comparing process model output against site-level CH4 emission data. The global distribution of wetlands is one major source of uncertainty for upscaling CH4. Thus, three wetland distribution maps are utilized in the upscaling. Depending on the wetland distribution map, the annual emissions for the northern wetlands yield 32 (22.3-41.2, 95% confidence interval calculated from a RF model ensemble), 31 (21.4-39.9) or 38 (25.9-49.5) Tg(CH4) yr(-1). To further evaluate the uncertainties of the upscaled CH4 flux data products we also compared them against output from two process models (LPX-Bern and WetCHARTs), and methodological issues related to CH4 flux upscaling are discussed. The monthly upscaled CH4 flux data products are available at https://doi.org/10.5281/zenodo.2560163.", "authors": [ "Peltola, Olli", "Vesala, Timo", "Gao, Yao", "Raty, Olle", "Alekseychik, Pavel", "Aurela, Mika", "Chojnicki, Bogdan", "Desai, Ankur R.", "Dolman, Albertus J.", "Euskirchen, Eugenie S.", "Friborg, Thomas", "Goeckede, Mathias", "Helbig, Manuel", "Humphreys, Elyn", "Jackson, Robert B.", "Jocher, Georg", "Joos, Fortunat", "Klatt, Janina", "Knox, Sara H.", "Kowalska, Natalia", "Kutzbach, Lars", "Lienert, Sebastian", "Lohila, Annalea", "Mammarella, Ivan", "Nadeau, Daniel F.", "Nilsson, Mats B.", "Oechel, Walter C.", "Peichl, Matthias", "Pypker, Thomas", "Quinton, William", "Rinne, Janne", "Sachs, Torsten", "Samson, Mateusz", "Schmid, Hans Peter", "Sonnentag, Oliver", "Wille, Christian", "Zona, Donatella", "Aalto, Tuula" ], "keywords": [ "" ], "year": "2019", "source": "EARTH SYSTEM SCIENCE DATA", "publication_type": "J", "point2d": [ -33.59098434448242, 62.95899963378906 ], "cluster": 17.0 }, { "idx": 189, "title": "Large loss of CO2 in winter observed across the northern permafrost region", "abstract": "Recent warming in the Arctic, which has been amplified during the winter(1-3), greatly enhances microbial decomposition of soil organic matter and subsequent release of carbon dioxide (CO2)(4). However, the amount of CO2 released in winter is not known and has not been well represented by ecosystem models or empirically based estimates(5,6). Here we synthesize regional in situ observations of CO2 flux from Arctic and boreal soils to assess current and future winter carbon losses from the northern permafrost domain. We estimate a contemporary loss of 1,662 TgC per year from the permafrost region during the winter season (October-April). This loss is greater than the average growing season carbon uptake for this region estimated from process models (-1,032 TgC per year). Extending model predictions to warmer conditions up to 2100 indicates that winter CO2 emissions will increase 17% under a moderate mitigation scenario-Representative Concentration Pathway 4.5-and 41% under business-as-usual emissions scenario-Representative Concentration Pathway 8.5. Our results provide a baseline for winter CO2 emissions from northern terrestrial regions and indicate that enhanced soil CO2 loss due to winter warming may offset growing season carbon uptake under future climatic conditions.", "authors": [ "Natali, Susan M.", "Watts, Jennifer D.", "Rogers, Brendan M.", "Potter, Stefano", "Ludwig, Sarah M.", "Selbmann, Anne-Katrin", "Sullivan, Patrick F.", "Abbott, Benjamin W.", "Arndt, Kyle A.", "Birch, Leah", "Bjorkman, Mats P.", "Bloom, A. Anthony", "Celis, Gerardo", "Christensen, Torben R.", "Christiansen, Casper T.", "Commane, Roisin", "Cooper, Elisabeth J.", "Crill, Patrick", "Czimczik, Claudia", "Davydov, Sergey", "Du, Jinyang", "Egan, Jocelyn E.", "Elberling, Bo", "Euskirchen, Eugenie S.", "Friborg, Thomas", "Genet, Helene", "Goeckede, Mathias", "Goodrich, Jordan P.", "Grogan, Paul", "Helbig, Manuel", "Jafarov, Elchin E.", "Jastrow, Julie D.", "Kalhori, Aram A. M.", "Kim, Yongwon", "Kimball, John S.", "Kutzbach, Lars", "Lara, Mark J.", "Larsen, Klaus S.", "Lee, Bang-Yong", "Liu, Zhihua", "Loranty, Michael M.", "Lund, Magnus", "Lupascu, Massimo", "Madani, Nima", "Malhotra, Avni", "Matamala, Roser", "McFarland, Jack", "McGuire, A. David", "Michelsen, Anders", "Minions, Christina", "Oechel, Walter C.", "Olefeldt, David", "Parmentier, Frans-Jan W.", "Pirk, Norbert", "Poulter, Ben", "Quinton, William", "Rezanezhad, Fereidoun", "Risk, David", "Sachs, Torsten", "Schaefer, Kevin", "Schmidt, Niels M.", "Schuur, Edward A. G.", "Semenchuk, Philipp R.", "Shaver, Gaius", "Sonnentag, Oliver", "Starr, Gregory", "Treat, Claire C.", "Waldrop, Mark P.", "Wang, Yihui", "Welker, Jeffrey", "Wille, Christian", "Xu, Xiaofeng", "Zhang, Zhen", "Zhuang, Qianlai", "Zona, Donatella" ], "keywords": [ "" ], "year": "2019", "source": "NATURE CLIMATE CHANGE", "publication_type": "J", "point2d": [ -38.216522216796875, 54.51952362060547 ], "cluster": 17.0 }, { "idx": 190, "title": "FLUXNET-CH4 Synthesis Activity: Objectives, Observations, and Future Directions", "abstract": "This paper describes the formation of, and initial results for, a new FLUXNET coordination network for ecosystem-scale methane (CH4) measurements at 60 sites globally, organized by the Global Carbon Project in partnership with other initiatives and regional flux tower networks. The objectives of the effort are presented along with an overview of the coverage of eddy covariance (EC) CH4 flux measurements globally, initial results comparing CH4 fluxes across the sites, and future research directions and needs. Annual estimates of net CH4 fluxes across sites ranged from -0.2 +/- 0.02 g C m(-2) yr(-1) for an upland forest site to 114.9 +/- 13.4 g C m(-2) yr(-1) for an estuarine freshwater marsh, with fluxes exceeding 40 g C m(-2) yr(-1) at multiple sites. Average annual soil and air temperatures were found to be the strongest predictor of annual CH4 flux across wetland sites globally. Water table position was positively correlated with annual CH4 emissions, although only for wetland sites that were not consistently inundated throughout the year. The ratio of annual CH4 fluxes to ecosystem respiration increased significantly with mean site temperature. Uncertainties in annual CH4 estimates due to gap-filling and random errors were on average +/- 1.6 g C m(-2) yr(-1) at 95% confidence, with the relative error decreasing exponentially with increasing flux magnitude across sites. Through the analysis and synthesis of a growing EC CH4 flux database, the controls on ecosystem CH4 fluxes can be better understood, used to inform and validate Earth system models, and reconcile differences between land surface model- and atmospheric-based estimates of CH4 emissions.", "authors": [ "Knox, Sara H.", "Jackson, Robert B.", "Poulter, Benjamin", "McNicol, Gavin", "Fluet-Chouinard, Etienne", "Zhang, Zhen", "Hugelius, Gustaf", "Bousquet, Philippe", "Canadell, Josep G.", "Saunois, Marielle", "Papale, Dario", "Chu, Housen", "Keenan, Trevor F.", "Baldocchi, Dennis", "Torn, Margaret S.", "Mammarella, Ivan", "Trotta, Carlo", "Aurela, Mika", "Bohrer, Gil", "Campbell, David, I", "Cescatti, Alessandro", "Chamberlain, Samuel", "Chen, Jiquan", "Chen, Weinan", "Dengel, Sigrid", "Desai, Ankur R.", "Euskirchen, Eugenie", "Friborg, Thomas", "Gasbarra, Daniele", "Goded, Ignacio", "Goeckede, Mathias", "Heimann, Martin", "Helbig, Manuel", "Hirano, Takashi", "Hollinger, David Y.", "Iwata, Hiroki", "Kang, Minseok", "Klatt, Janina", "Krauss, Ken W.", "Kutzbach, Lars", "Lohila, Annalea", "Mitra, Bhaskar", "Morin, Timothy H.", "Nilsson, Mats B.", "Niu, Shuli", "Noormets, Asko", "Oechel, Walter C.", "Peichl, Matthias", "Peltola, Olli", "Reba, Michele L.", "Richardson, Andrew D.", "Runkle, Benjamin R. K.", "Ryu, Youngryel", "Sachs, Torsten", "Schaefer, Karina V. R.", "Schmid, Hans Peter", "Shurpali, Narasinha", "Sonnentag, Oliver", "Tang, Angela C., I", "Ueyama, Masahito", "Vargas, Rodrigo", "Vesala, Timo", "Ward, Eric J.", "Windham-Myers, Lisamarie", "Wohlfahrt, Georg", "Zona, Donatella" ], "keywords": [ "" ], "year": "2019", "source": "BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY", "publication_type": "J", "point2d": [ -33.3162956237793, 65.73064422607422 ], "cluster": 17.0 }, { "idx": 191, "title": "Modelling the effects of permafrost loss on discharge from a wetland-dominated, discontinuous permafrost basin", "abstract": "Permafrost degradation in the peat-rich southern fringe of the discontinuous permafrost zone is catalysing substantial changes to land cover with expansion of permafrost-free wetlands (bogs and fens) and shrinkage of forest-dominated permafrost peat plateaux. Predicting discharge from headwater basins in this region depends upon understanding and numerically representing the interactions between storage and discharge within and between the major land cover types and how these interactions are changing. To better understand the implications of advanced permafrost thaw-induced land cover change on wetland discharge, with all landscape features capable of contributing to drainage networks, the hydrological behaviour of a channel fen sub-basin in the headwaters of Scotty Creek, Northwest Territories, Canada, dominated by peat plateau-bog complexes, was modelled using the Cold Regions Hydrological Modelling platform for the period of 2009 to 2015. The model construction was based on field water balance observations, and performance was deemed adequate when evaluated against measured water balance components. A sensitivity analysis was conducted to assess the impact of progressive permafrost loss on discharge from the sub-basin, in which all units of the sub-basin have the potential to contribute to the drainage network, by incrementally reducing the ratio of wetland to plateau in the modelled sub-basin. Simulated reductions in permafrost extent decreased total annual discharge from the channel fen by 2.5% for every 10% decrease in permafrost area due to increased surface storage capacity, reduced run-off efficiency, and increased landscape evapotranspiration. Runoff ratios for the fen hydrological response unit dropped from 0.54 to 0.48 after the simulated 50% permafrost area loss with a substantial reduction of 0.47 to 0.31 during the snowmelt season. The reduction in peat plateau area resulted in decreased seasonal variability in discharge due to changes in the flow path routing, with amplified low flows associated with small increases in subsurface discharge, and decreased peak discharge with large reductions in surface run-off.", "authors": [ "Stone, Lindsay E.", "Fang, Xing", "Haynes, Kristine M.", "Helbig, Manuel", "Pomeroy, John W.", "Sonnentag, Oliver", "Quinton, William L." ], "keywords": [ "Cold Regions Hydrological Modelling platform", "discharge", "discontinuous permafrost", "drainage network", "flow paths", "hydrological connectivity", "land cover change", "peatlands" ], "year": "2019", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -18.906383514404297, 3.8463001251220703 ], "cluster": 13.0 }, { "idx": 192, "title": "A synthesis of three decades of hydrological research at Scotty Creek, NWT, Canada", "abstract": "Scotty Creek, Northwest Territories (NWT), Canada, has been the focus of hydrological research for nearly three decades. Over this period, field and modelling studies have generated new insights into the thermal and physical mechanisms governing the flux and storage of water in the wetland-dominated regions of discontinuous permafrost that characterises much of the Canadian and circumpolar subarctic. Research at Scotty Creek has coincided with a period of unprecedented climate warming, permafrost thaw, and resulting land cover transformations including the expansion of wetland areas and loss of forests. This paper (1) synthesises field and modelling studies at Scotty Creek, (2) highlights the key insights of these studies on the major water flux and storage processes operating within and between the major land cover types, and (3) provides insights into the rate and pattern of the permafrost-thaw-induced land cover change and how such changes will affect the hydrology and water resources of the study region.", "authors": [ "Quinton, William", "Berg, Aaron", "Braverman, Michael", "Carpino, Olivia", "Chasmer, Laura", "Connon, Ryan", "Craig, James", "Devoie, Elise", "Hayashi, Masaki", "Haynes, Kristine", "Olefeldt, David", "Pietroniro, Alain", "Rezanezhad, Fereidoun", "Schincariol, Robert", "Sonnentag, Oliver" ], "keywords": [ "" ], "year": "2019", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -17.296524047851562, 3.1495139598846436 ], "cluster": 13.0 }, { "idx": 193, "title": "Proximal remote sensing of tree physiology at northern treeline: Do late-season changes in the photochemical reflectance index (PRI) respond to climate or photoperiod?", "abstract": "Relatively little is known of how the world's largest vegetation transition zone the Forest Tundra Ecotone (FTE) is responding to climate change. Newly available, satellite-derived time-series of the photochemical reflectance index (PRI) across North America and Europe could provide new insights into the physiological response of evergreen trees to climate change by tracking changes in foliar pigment pools that have been linked to photosynthetic phenology. However, before implementing these data for such purpose at these evergreen dominated systems, it is important to increase our understanding of the fine scale mechanisms driving the connection between PRI and environmental conditions. The goal of this study is thus to gain a more mechanistic understanding of which environmental factors drive changes in PRI during late-season phenological transitions at the FTE including factors that are susceptible to climate change (i.e., air- and soil-temperatures), and those that are not (photoperiod). We hypothesized that late-season phenological changes in foliar pigment pools captured by PRI are largely driven by photoperiod as opposed to less predictable drivers such as air temperature, complicating the utility of PRI time-series for understanding climate change effects on the FTE. Ground-based, time series of PRI were acquired from individual trees in combination with meteorological variables and photoperiod information at six FTE sites in Alaska. A linear mixed-effects modeling approach was used to determine the significance (alpha = 0.001) and effect size (i.e., standardized slope b*) of environmental factors on late-seasonal changes in the PRI signal. Our results indicate that photoperiod had the strongest, significant effect on late season changes in PRI (b* = 0.08, p < 0.001), but environmental variables susceptible to climate change were also significant (i.e., daily mean solar radiation (b* = 0.03, p < 0.001) and daily mean soil temperature (b* = 0.02, p < 0.001)). These results suggest that interpreting PRI time-series of late-season phenological transitions may indeed facilitate our understanding of how northern treeline responds to climate change.", "authors": [ "Eitel, Jan U. H.", "Maguire, Andrew J.", "Boelman, Natalie", "Vierling, Lee A.", "Griffinc, Kevin L.", "Jensen, Johanna", "Magney, Troy S.", "Mahoney, Peter J.", "Meddens, Arjan J. H.", "Silva, Carlos", "Sonnentag, Oliver" ], "keywords": [ "Forest Tundra Ecotone", "Northern treeline", "MODIS", "Photoperiod", "PRI", "Solar radiation", "Climate change", "Photosynthetic phenology" ], "year": "2019", "source": "REMOTE SENSING OF ENVIRONMENT", "publication_type": "J", "point2d": [ -66.79313659667969, 62.86697769165039 ], "cluster": 17.0 }, { "idx": 194, "title": "Data synergy between leaf area index and clumping index Earth Observation products using photon recollision probability theory", "abstract": "Clumping index (CI) is a measure of foliage aggregation relative to a random distribution of leaves in space. The CI can help with estimating fractions of sunlit and shaded leaves for a given leaf area index (LAI) value. Both the CI and LAI can be obtained from global Earth Observation data from sensors such as the Moderate Resolution Imaging Spectrometer (MODIS). Here, the synergy between a MODIS-based CI and a MODIS LAI product is examined using the theory of spectral invariants, also referred to as photon recollision probability ('p-theory'), along with raw LAI-2000/2200 Plant Canopy Analyzer data from 75 sites distributed across a range of plant functional types. The p-theory describes the probability (p-value) that a photon, having intercepted an element in the canopy, will recollide with another canopy element rather than escape the canopy. We show that empirically-based CI maps can be integrated with the MODIS LAI product. Our results indicate that it is feasible to derive approximate p-values for any location solely from Earth Observation data. This approximation is relevant for future applications of the photon recollision probability concept for global and local monitoring of vegetation using Earth Observation data.", "authors": [ "Pisek, Jan", "Buddenbaum, Henning", "Camacho, Fernando", "Hill, Joachim", "Jensen, Jennifer L. R.", "Lange, Holger", "Liu, Zhili", "Piayda, Arndt", "Qu, Yonghua", "Roupsard, Olivier", "Serbin, Shawn P.", "Solberg, Svein", "Sonnentag, Oliver", "Thimonier, Anne", "Vuolo, Francesco" ], "keywords": [ "Photon recollision probability", "Foliage clumping index", "Leaf area index", "Multi-angle remote sensing" ], "year": "2018", "source": "REMOTE SENSING OF ENVIRONMENT", "publication_type": "J", "point2d": [ -62.94108963012695, 64.8637924194336 ], "cluster": 17.0 }, { "idx": 195, "title": "Cross-scale controls on carbon emissions from boreal forest megafires", "abstract": "Climate warming and drying is associated with increased wildfire disturbance and the emergence of megafires in North American boreal forests. Changes to the fire regime are expected to strongly increase combustion emissions of carbon (C) which could alter regional C balance and positively feedback to climate warming. In order to accurately estimate C emissions and thereby better predict future climate feedbacks, there is a need to understand the major sources of heterogeneity that impact C emissions at different scales. Here, we examined 211 field plots in boreal forests dominated by black spruce (Picea mariana) or jack pine (Pinus banksiana) of the Northwest Territories (NWT), Canada after an unprecedentedly large area burned in 2014. We assessed both aboveground and soil organic layer (SOL) combustion, with the goal of determining the major drivers in total C emissions, as well as to develop a high spatial resolution model to scale emissions in a relatively understudied region of the boreal forest. On average, 3.35kgCm(-2) was combusted and almost 90% of this was from SOL combustion. Our results indicate that black spruce stands located at landscape positions with intermediate drainage contribute the most to C emissions. Indices associated with fire weather and date of burn did not impact emissions, which we attribute to the extreme fire weather over a short period of time. Using these results, we estimated a total of 94.3TgC emitted from 2.85Mha of burned area across the entire 2014 NWT fire complex, which offsets almost 50% of mean annual net ecosystem production in terrestrial ecosystems of Canada. Our study also highlights the need for fine-scale estimates of burned area that represent small water bodies and regionally specific calibrations of combustion that account for spatial heterogeneity in order to accurately model emissions at the continental scale.", "authors": [ "Walker, Xanthe J.", "Rogers, Brendan M.", "Baltzer, Jennifer L.", "Cumming, Steven G.", "Day, Nicola J.", "Goetz, Scott J.", "Johnstone, Jill F.", "Schuur, Edward A. G.", "Turetsky, Merritt R.", "Mack, Michelle C." ], "keywords": [ "black spruce", "carbon combustion", "fire severity", "jack pine", "Picea mariana", "Pinus banksiana", "taiga plains", "taiga shield" ], "year": "2018", "source": "GLOBAL CHANGE BIOLOGY", "publication_type": "J", "point2d": [ -27.235034942626953, 74.79646301269531 ], "cluster": 15.0 }, { "idx": 200, "title": "Seasonal thaw and landscape position determine foliar functional traits and whole-plant water use in tall shrubs on the low arctic tundra", "abstract": "Climate warming is driving tundra shrub expansion with implications for ecosystem function and regional climate. Understanding associations between shrub ecophysiological function, distribution and environment is necessary for predicting consequences of expansion. We evaluated the role of topographic gradients on upland shrub productivity to understand potential constraints on shrub expansion. At a low arctic tundra site near Inuvik, Northwest Territories, Canada, we measured sap flow, stem water potential and productivity-related functional traits in green alder, and environmental predictors (water and nutrient availability and seasonal thaw depth) across a toposequence in alder patches. Seasonal thaw reduced stem sap flow whereas topographic position predicted stem water potential and productivity-related functional traits. Upslope shrubs were more water-limited than those downslope. Shrubs in drainage channels had traits associated with greater productivity than those on the tops of slopes. The effect of thaw depth on sap flow has implications for seasonal water-use patterns and warming impacts on tundra ecohydrology. Topographic variation in functional traits corresponds with observed spatial patterns of tundra shrub expansion along floodplains and concave hillslopes rather than in upland areas. Green alder is expanding rapidly across the low arctic tundra in northwestern North America; thus, anticipating the implications of its expansion is essential for predicting tundra function.", "authors": [ "Black, Katherine L.", "Wallace, Cory A.", "Baltzer, Jennifer L." ], "keywords": [ "abiotic limitations", "Alnus alnobetula (green alder)", "Northwest Territories", "plant functional traits", "resource availability", "sap flow", "tundra shrub expansion" ], "year": "2021", "source": "NEW PHYTOLOGIST", "publication_type": "J", "point2d": [ -35.23078918457031, 44.24370193481445 ], "cluster": 13.0 }, { "idx": 201, "title": "Climate-change refugia in boreal North America: what, where, and for how long?", "abstract": "The vast boreal biome plays an important role in the global carbon cycle but is experiencing particularly rapid climate warming, threatening the integrity of valued ecosystems and their component species. We developed a framework and taxonomy to identify climate-change refugia potential in the North American boreal region, summarizing current knowledge regarding mechanisms, geographic distribution, and landscape indicators. While terrain-mediated refugia will mostly be limited to coastal and mountain regions, the ecological inertia (resistance to external fluctuations) contained in some boreal ecosystems may provide more extensive buffering against climate change, resulting in ecosystem-protected refugia. A notable example is boreal peatlands, which can retain high surface soil moisture and water tables even in the face of drought. Refugia from wildfire are also especially important in the boreal region, which is characterized by active disturbance regimes. Our framework will help identify areas of high refugia potential, and inform ecosystem management and conservation planning in light of climate change.", "authors": [ "Stralberg, Diana", "Arseneault, Dominique", "Baltzer, Jennifer L.", "Barber, Quinn E.", "Bayne, Erin M.", "Boulanger, Yan", "Brown, Carissa D.", "Cooke, Hilary A.", "Devito, Kevin", "Edwards, Jason", "Estevo, Cesar A.", "Flynn, Nadele", "Frelich, Lee E.", "Hogg, Edward H.", "Johnston, Mark", "Logan, Travis", "Matsuoka, Steven M.", "Moore, Paul", "Morelli, Toni Lyn", "Morissette, Julienne L.", "Nelson, Elizabeth A.", "Nenzen, Hedvig", "Nielsen, Scott E.", "Parisien, Marc-Andre", "Pedlar, John H.", "Price, David T.", "Schmiegelow, Fiona Ka", "Slattery, Stuart M.", "Sonnentag, Oliver", "Thompson, Daniel K.", "Whitman, Ellen" ], "keywords": [ "" ], "year": "2020", "source": "FRONTIERS IN ECOLOGY AND THE ENVIRONMENT", "publication_type": "J", "point2d": [ -20.870887756347656, 49.62247085571289 ], "cluster": 15.0 }, { "idx": 203, "title": "Tundra shrub expansion may amplify permafrost thaw by advancing snowmelt timing", "abstract": "The overall spatial and temporal influence of shrub expansion on permafrost is largely unknown due to uncertainty in estimating the magnitude of many counteracting processes. For example, shrubs shade the ground during the snow-free season, which can reduce active layer thickness. At the same time, shrubs advance the timing of snowmelt when they protrude through the snow surface, thereby exposing the active layer to thawing earlier in spring. Here, we compare 3056 in situ frost table depth measurements split between mineral earth hummocks and organic inter-hummock zones across four dominant shrub - tundra vegetation types. Snow-free date, snow depth, hummock development, topography, and vegetation cover were compared to frost table depth measurements using a structural equation modeling approach that quantifies the direct and combined interacting influence of these variables. Areas of birch shrubs became snow free earlier regardless of snow depth or hillslope aspect because they protruded through the snow surface, leading to deeper hummock frost table depths. Projected increases in shrub height and extent combined with projected decreases in snowfall would lead to increased shrub protrusion across the Arctic, potentially deepening the active layer in areas where shrub protrusion advances the snow-free date.", "authors": [ "Wilcox, Evan J.", "Keim, Dawn", "de Jong, Tyler", "Walker, Branden", "Sonnentag, Oliver", "Sniderhan, Anastasia E.", "Mann, Philip", "Marsh, Philip" ], "keywords": [ "frost table", "active layer", "shrubs", "snowmelt", "hummocks" ], "year": "2019", "source": "ARCTIC SCIENCE", "publication_type": "J", "point2d": [ -33.741329193115234, 45.24332046508789 ], "cluster": 13.0 }, { "idx": 204, "title": "In situ microbiota distinguished primary anthropogenic stressor in freshwater sediments", "abstract": "Conventional assessment and evaluation of sediment quality are based on laboratory-based ecotoxicological and chemical measurements with lack of concern for ecological relevance. Microbiotas in sediment are responsive to pollutants and can be used as alternative ecological indicators of sediment pollutants; however, the linkage between the microbial ecology and ecotoxicological endpoints in response to sediment contamination has been poorly evaluated. Here, in situ microbiotas from the Three Gorges Reservoir (TGR) area of the Yangtze River were characterized by DNA metabarcoding approaches, and then, changes of in situ microbiotas were compared with the ecotoxicological endpoint, aryl hydrocarbon receptor (AhR) mediated activity, and level of polycyclic aromatic hydrocarbons (PAHs) in sediments. PAHs and organic pollutant mixtures mediating AhR activity had different effects on the structures of microbiotas. Specifically, Shannon indices of protistan communities were negatively correlated with the levels of AhR mediated activity and PAHs. The sediment AhR activity was positively correlated with the relative abundance of prokaryotic Acetobacteraceae, but had a negative correlation with protistan Oxytrichidae. Furthermore, a quantitative classification model was built to predict the level of AhR activity based on the relative abundances of Acetobacteraceae and Oxytrichidae. These results suggested that in situ Protista communities could provide a useful tool for monitoring and assessing ecological stressors. The observed responses of microbial community provided supplementary evidence to support that the AhR-active pollutants, such as PAHs, were the primary stressors of the aquatic community in TGR area. (C) 2018 Elsevier Ltd. All rights reserved.", "authors": [ "Xie, Yuwei", "Floehr, Tilman", "Zhang, Xiaowei", "Xiao, Hongxia", "Yang, Jianghua", "Xia, Pu", "Burton, G. Allen, Jr.", "Hollert, Henner" ], "keywords": [ "Bacteria", "Protista", "PAHs", "Bioindicators", "Xenobiotics", "AhR" ], "year": "2018", "source": "ENVIRONMENTAL POLLUTION", "publication_type": "J", "point2d": [ 75.86091613769531, 12.62276840209961 ], "cluster": 0.0 }, { "idx": 205, "title": "Acid mine drainage affects the diversity and metal resistance gene profile of sediment bacterial community along a river", "abstract": "Acid mine drainage (AMD) is one of the most hazardous byproducts of some types of mining. However, research on how AMD affects the bacterial community structure of downstream riverine ecosystems and the distribution of metal resistance genes (MRGs) along pollution gradient is limited. Comprehensive geochemical and high-throughput next-generation sequencing analyses can be integrated to characterize spatial distributions and MRG profiles of sediment bacteria communities along the AMD-contaminated Hengshi River. We found that (1) diversities of bacterial communities significantly and gradually increased along the river with decreasing contamination, suggesting community composition reflected changes in geochemical conditions; (2) relative abundances of phyla Proteobacteria and genus Halomonas and Planococcaceae that function in metal reduction decreased along the AMD gradient; (3) low levels of sediment salinity, sulfate, aquatic lead (Pb), and cadmium (Cd) were negatively correlated with bacterial diversity despite pH was in a positive manner with diversity; and (4) arsenic (As) and copper (Cu) resistance genes corresponded to sediment concentrations of As and Cu, respectively. Altogether, our findings offer initial insight into the distribution patterns of sediment bacterial community structure, diversity and MRGs along a lotic ecosystem contaminated by AMD, and the factors that affect them. (C) 2018 Elsevier Ltd. All rights reserved.", "authors": [ "Zhang, Xiaohui", "Tang, Song", "Wang, Mao", "Sun, Weimin", "Xie, Yuwei", "Peng, Hui", "Zhong, Aimin", "Liu, Hongling", "Zhang, Xiaowei", "Yu, Hongxia", "Giesy, John P.", "Hecker, Markus" ], "keywords": [ "AMD gradient", "Daobaoshan mine", "16S rDNA sequencing", "Comparative metagenomics", "Electrical conductivity", "pH" ], "year": "2019", "source": "CHEMOSPHERE", "publication_type": "J", "point2d": [ 74.29936218261719, 14.254830360412598 ], "cluster": 19.0 }, { "idx": 206, "title": "Acid mine drainage affects the diversity and metal resistance gene profile of sediment bacterial community along a river", "abstract": "Acid mine drainage (AMD) is one of the most hazardous byproducts of some types of mining. However, research on how AMD affects the bacterial community structure of downstream riverine ecosystems and the distribution of metal resistance genes (MRGs) along pollution gradient is limited. Comprehensive geochemical and high-throughput next-generation sequencing analyses can be integrated to characterize spatial distributions and MRG profiles of sediment bacteria communities along the AMD-contaminated Hengshi River. We found that (1) diversities of bacterial communities significantly and gradually increased along the river with decreasing contamination, suggesting community composition reflected changes in geochemical conditions; (2) relative abundances of phyla Proteobacteria and genus Halomonas and Planococcaceae that function in metal reduction decreased along the AMD gradient; (3) low levels of sediment salinity, sulfate, aquatic lead (Pb), and cadmium (Cd) were negatively correlated with bacterial diversity despite pH was in a positive manner with diversity; and (4) arsenic (As) and copper (Cu) resistance genes corresponded to sediment concentrations of As and Cu, respectively. Altogether, our findings offer initial insight into the distribution patterns of sediment bacterial community structure, diversity and MRGs along a lotic ecosystem contaminated by AMD, and the factors that affect them. (C) 2018 Elsevier Ltd. All rights reserved.", "authors": [ "Zhang, Xiaohui", "Tang, Song", "Wang, Mao", "Sun, Weimin", "Xie, Yuwei", "Peng, Hui", "Zhong, Aimin", "Liu, Hongling", "Zhang, Xiaowei", "Yu, Hongxia", "Giesy, John P.", "Hecker, Markus" ], "keywords": [ "AMD gradient", "Daobaoshan mine", "16S rDNA sequencing", "Comparative metagenomics", "Electrical conductivity", "pH" ], "year": "2019", "source": "CHEMOSPHERE", "publication_type": "J", "point2d": [ 73.91716003417969, 14.648578643798828 ], "cluster": 19.0 }, { "idx": 207, "title": "Application of Environmental DNA Metabarcoding for Predicting Anthropogenic Pollution in Rivers", "abstract": "Rivers are among the most threatened freshwater ecosystems, and anthropogenic activities are affecting both river structures and water quality. While assessing the organisms can provide a comprehensive measure of a river's ecological status, it is limited by the traditional morphotaxonomy-based biomonitoring. Recent advances in environmental DNA (eDNA) metabarcoding allow to identify prokaryotes and eukaryotes in one sequencing run, and could thus allow unprecedented resolution. Whether such eDNA-based data can be used directly to predict the pollution status of rivers as a complementation of environmental data remains unknown. Here we used eDNA metabarcoding to explore the main stressors of rivers along which community structure changes, and to identify the method's potential for predicting pollution status based on eDNA data. We showed that a broad range of taxa in bacterial, protistan, and metazoan communities could be profiled with eDNA. Nutrients were the main driving stressor affecting communities' structure, alpha diversity, and the ecological network. We specifically observed that the relative abundance of indicative OTUs was significantly correlated with nutrient levels. These OTUs data could be used to predict the nutrient status up to 79% accuracy on testing data sets. Thus, our study gives a novel approach to predicting the pollution status of rivers by eDNA data.", "authors": [ "Li, Feilong", "Peng, Ying", "Fang, Wendi", "Altermatt, Florian", "Xie, Yuwei", "Yang, Jianghua", "Zhang, Xiaowei" ], "keywords": [ "" ], "year": "2018", "source": "ENVIRONMENTAL SCIENCE & TECHNOLOGY", "publication_type": "J", "point2d": [ 74.29378509521484, 11.482004165649414 ], "cluster": 0.0 }, { "idx": 208, "title": "Temporal variation in zooplankton and phytoplankton community species composition and the affecting factors in Lake Taihu-a large freshwater lake in China", "abstract": "Monitoring diverse components of aquatic ecosystems is vital for elucidation of diversity dynamics and processes, which alter freshwater ecosystems, but such studies are seldom conducted. Phytoplankton and zooplankton are integral components which play indispensable parts in the structure and ecological service function of water bodies. However, few studies were made on how zooplankton and phytoplankton community may respond simultaneously to change of circumstance and their mutual relationship. Therefore, we researched synchronously the phytoplankton communities as well as zooplankton communities based on monthly monitoring data from September 2011 to August 2012 in heavily polluted areas and researched their responses to variation in environmental parameters and their mutual relationship. As indicated by Time-lag analysis (TLA), the long-term dynamics of phytoplankton and zooplankton were undergoing directional variations, what's more, there exists significant seasonal variations of phytoplankton and zooplankton communities as indicated by Non-Metric Multidimensional scaling (NMDS) methods. Also, Redundancy Analysis (RDA) demonstrated that environmental indicators together accounted for 25.6% and 50.1% variance of phytoplankton and zooplankton, respectively, indicating that environmental variations affected significantly on the temporal dynamics of phytoplankton as well as zooplankton communities. What's more, variance partioning suggested that the major environmental factors influencing variation structures of zooplankton communities were water temperature, concentration of nitrogen, revealing the dominating driving mechanism which shaped the communities of zooplankton. It was also found that there was significant synchronization between zooplankton biomass and phytoplankton biomass (expressed as Chl-a concentration), which suggested that zooplankton respond to changes in dynamic structure of phytoplankton community and can initiate a decrease in phytoplankton biomass through grazing in a few months. (C) 2018 Elsevier Ltd. All rights reserved.", "authors": [ "Li, Cuicui", "Feng, Weiying", "Chen, Haiyan", "Li, Xiaofeng", "Song, Fanhao", "Guo, Wenjing", "Giesy, John P.", "Sun, Fuhong" ], "keywords": [ "Phytoplankton", "Zooplanicton", "Environmental indicators", "Relationship" ], "year": "2019", "source": "ENVIRONMENTAL POLLUTION", "publication_type": "J", "point2d": [ 56.85569381713867, 18.99517250061035 ], "cluster": 19.0 }, { "idx": 209, "title": "Role of sublimation and riming in the precipitation distribution in the Kananaskis Valley, Alberta, Canada", "abstract": "The phase of precipitation and its distribution at the surface can affect water resources and the regional water cycle of a region. A field project was held in March-April 2015 on the eastern slope of the Canadian Rockies to document precipitation characteristics and associated atmospheric conditions. During the project, 60 % of the particles documented were rimed in relatively warm and dry conditions. Rain-snow transitions also occurred aloft and at the surface in sub-saturated conditions. Ice-phase precipitation falling through a saturated atmospheric layer with temperatures > 0 degrees C will start melting. In contrast, if the melting layer is sub-saturated, the ice-phase precipitation undergoes sublimation, which increases the depth of the rain-snow transition. In this context, this study investigates the role of sublimation and riming in precipitation intensity and type reaching the surface in the Kananaskis Valley, Alberta, during March-April 2015. To address this, a set of numerical simulations of an event of mixed precipitation observed at the surface was conducted. This event on 31 March 2015 was documented with a set of devices at the main observation site (Kananaskis Emergency Services, KES), including a precipitation gauge, disdrometer, and micro rain radar. Sensitivity experiments were performed to assess the impacts of temperature changes from sublimation and the role of the production of graupel (riming) aloft in the surface precipitation evolution. A warmer environment associated with no temperature changes from sublimation leads to a peak in the intensity of graupel at the surface. When the formation of graupel is not considered, the maximum snowfall rate occurred at later times. Results suggest that unrimed snow reaching the surface is formed on the western flank and is advected east-ward. In contrast, graupel would form aloft in the Kananaskis Valley. The cooling from sublimation and melting by rimed particles increases the vertical shear near KES. Overall, this study illustrated that the presence of graupel influenced the surface evolution of precipitation type in the valley due to the horizontal transport of precipitation particles.", "authors": [ "Poirier, Emilie", "Theriault, Julie M.", "Leriche, Maud" ], "keywords": [ "" ], "year": "2019", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -47.765724182128906, -23.21179962158203 ], "cluster": 12.0 }, { "idx": 211, "title": "The Cariboo Alpine Mesonet: sub-hourly hydrometeorological observations of British Columbia's Cariboo Mountains and surrounding area since 2006", "abstract": "This article presents the development of a sub-hourly database of hydrometeorological conditions collected in British Columbia's (BC's) Cariboo Mountains and surrounding area extending from 2006 to present. The Cariboo Alpine Mesonet (CAMnet) forms a network of 11 active hydrometeorological stations positioned at strategic locations across mid- to high elevations of the Cariboo Mountains. This mountain region spans 44 150 km(2), forming the northern extension of the Columbia Mountains. Deep fjord lakes along with old-growth western redcedar and hemlock forests reside in the lower valleys, montane forests of Engelmann spruce, lodge-pole pine and subalpine fir permeate the mid-elevations, while alpine tundra, glaciers and several large ice fields cover the higher elevations. The automatic weather stations typically measure air and soil temperature, relative humidity, atmospheric pressure, wind speed and direction, rainfall and snow depth at 15 min intervals. Additional measurements at some stations include shortwave and longwave radiation, near-surface air, skin, snow, or water temperature, and soil moisture, among others. Details on deployment sites, the instrumentation used and its precision, the collection and quality control process are provided. Instructions on how to access the database at Zenodo, an online public data repository, are also furnished (https://doi.org/10.5281/zenodo.1195043). Information on some of the challenges and opportunities encountered in maintaining continuous and homogeneous time series of hydrometeorological variables and remote field sites is provided. The paper also summarizes ongoing plans to expand CAMnet to better monitor atmospheric conditions in BC's mountainous terrain, efforts to push data online in (near-)real time, availability of ancillary data and lessons learned thus far in developing this mesoscale network of hydrometeorological stations in the data-sparse Cariboo Mountains.", "authors": [ "Hernandez-Henriquez, Marco A.", "Sharma, Aseem R.", "Taylor, Mark", "Thompson, Hadleigh D.", "Dery, Stephen J." ], "keywords": [ "" ], "year": "2018", "source": "EARTH SYSTEM SCIENCE DATA", "publication_type": "J", "point2d": [ -28.7200870513916, -7.329661846160889 ], "cluster": 8.0 }, { "idx": 212, "title": "Assessing Recovery of In Vitro Steroid Production in Male Rainbow Darter (Etheostoma caeruleum) in Response to Municipal Wastewater Treatment Plant Infrastructure Changes", "abstract": "The present study examined in vitro 11-ketotestosterone and testosterone production by the testes of rainbow darter (Etheostoma caeruleum) collected from selected reference sites and downstream of 2 municipal wastewater treatment plants (MWWTPs; Waterloo and Kitchener) on the central Grand River (Ontario, Canada), over a 6-yr period (2011-2016). The main objective was to investigate if infrastructure upgrades at the Kitchener MWWTP in 2012 resulted in a recovery of this response in the post-upgrade period (2013-2016). Two supporting studies showed that the fall season is appropriate for measuring in vitro sex steroid production because it provides stable detection of steroid patterns, and that the sample handling practiced in the present study did not introduce a bias. Infrastructure upgrades of the Kitchener MWWTP resulted in significant reductions in ammonia and estrogenicity. After the upgrades, 11-ketotestosterone production by MWWTP-exposed fish increased in 2013 and it continued to recover throughout the study period of 2014 through 2016, returning to levels measured in reference fish. Testosterone production was less sensitive and it lacked consistency. The Waterloo MWWTP underwent some minor upgrades but the level of ammonia and estrogenicity remained variable over time. The production of 11-ketotestosterone and testosterone in rainbow darter below the Waterloo MWWTP was variable and without a clear recovery pattern over the course of the present study. The results of the present study demonstrated that measuring production of sex steroids (especially 11-ketotestosterone) over multiple years can be relevant for assessing responses in fish to environmental changes such as those resulting from major infrastructure upgrades. (C) 2017 SETAC", "authors": [ "Marjan, Patricija", "Van der Kraak, Glen J.", "MacLatchy, Deborah L.", "Fuzzen, Meghan L. M.", "Bragg, Leslie M.", "McMaster, Mark E.", "Tetreault, Gerald R.", "Servos, Mark R." ], "keywords": [ "Municipal effluents", "Androgens", "Freshwater toxicology", "In vitro sex steroid production" ], "year": "2018", "source": "ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY", "publication_type": "J", "point2d": [ 72.4131088256836, -2.949859857559204 ], "cluster": 0.0 }, { "idx": 213, "title": "Agricultural Edge-of-Field Phosphorus Losses in Ontario, Canada: Importance of the Nongrowing Season in Cold Regions", "abstract": "Agricultural P losses are a global economic and water quality concern. Much of the current understanding of P dynamics in agricultural systems has been obtained from rainfall-driven runoff, and less is known about cold-season processes. An improved understanding of the magnitude, form, and transport flow paths of P losses from agricultural croplands year round, and the climatic drivers of these processes, is needed to prioritize and evaluate appropriate best management practices (BMPs) to protect soil-water quality in cold regions. This study examines multiyear, year-round, high-frequency edge-of-field P losses (soluble reactive P and total P [TP]) in overland flow and tile drainage from three croplands in southern Ontario, Canada. Annual and seasonal budgets for water, P, and estimates of field P budgets (including fertilizer inputs, crop uptake, and runoff) were calculated for each site. Annual edge-of-field TP loads ranged from 0.18 to 1.93 kg ha(-1) yr(-1) (mean = 0.59 kg ha(-1) yr(-1)) across the region, including years with fertilizer application. Tile drainage dominated runoff across sites, whereas the contribution of tiles and overland flow to P loss differed regionally, likely related to site-specific topography, soil type, and microclimate. The nongrowing season was the dominant period for runoff and P loss across sites, where TP loss during this period was often associated with overland flow during snowmelt. These results indicate that emphasis should be placed on BMPs that are effective during both the growing and nongrowing season in cold regions, but that the suitability of various BMPs may vary for different sites.", "authors": [ "Plach, Janina", "Pluer, Will", "Macrae, Merrin", "Kompanizare, Mazda", "McKague, Kevin", "Carlow, Ryan", "Brunke, Richard" ], "keywords": [ "" ], "year": "2019", "source": "JOURNAL OF ENVIRONMENTAL QUALITY", "publication_type": "J", "point2d": [ 37.03089904785156, 17.730371475219727 ], "cluster": 10.0 }, { "idx": 214, "title": "The Latitudes, Attitudes, and Platitudes of Watershed Phosphorus Management in North America", "abstract": "Phosphorus (P) plays a crucial role in agriculture as a primary fertilizer nutrient-and as a cause of the eutrophication of surface waters. Despite decades of efforts to keep P on agricultural fields and reduce losses to waterways, frequent algal blooms persist, triggering not only ecological disruption but also economic, social, and political consequences. We investigate historical and persistent factors affecting agricultural P mitigation in a transect of major watersheds across North America: Lake Winnipeg, Lake Erie, the Chesapeake Bay, and Lake Okeechobee/Everglades. These water bodies span 26 degrees of latitude, from the cold climate of central Canada to the subtropics of the southeastern United States. These water bodies and their associated watersheds have tracked trajectories of P mitigation that manifest remarkable similarities, and all have faced challenges in the application of science to agricultural management that continue to this day. An evolution of knowledge and experience in watershed P mitigation calls into question uniform solutions as well as efforts to transfer strategies from other arenas. As a result, there is a need to admit to shortcomings of past approaches, plotting a future for watershed P mitigation that accepts the sometimes two-sided nature of Hennig Brandt's Devil's Element.", "authors": [ "Smith, D. R.", "Macrae, M. L.", "Kleinman, P. J. A.", "Jarvie, H. P.", "King, K. W.", "Bryant, R. B." ], "keywords": [ "" ], "year": "2019", "source": "JOURNAL OF ENVIRONMENTAL QUALITY", "publication_type": "J", "point2d": [ 45.62423324584961, 7.314222812652588 ], "cluster": 10.0 }, { "idx": 215, "title": "Impacts of Cover Crops and Crop Residues on Phosphorus Losses in Cold Climates: A Review", "abstract": "The use of cover crops and crop residues is a common strategy to mitigate sediment and nutrient losses from land to water. In cold climates, elevated dissolved P losses can occur associated with freeze-thaw of plant materials. Here, we review the impacts of cover crops and crop residues on dissolved P and total P loss in cold climates across similar to 41 studies, exploring linkages between water-extractable P (WEP) in plant materials and P loss in surface runoff and subsurface drainage. Water-extractable P concentrations are influenced by plant type and freezing regimes. For example, WEP was greater in brassica cover crops than in non- brassicas, and increased with repeated freeze-thaw cycles. However, total P losses in surface runoff and subsurface drainage from cropped fields under cold climates were much lower than plant WEP, owing to retention of 45 to > 99% of released P by soil. In cold climatic regions, cover crops and crop residues generally prevented soil erosion and loss of particle-bound P during nongrowing seasons in erodible landscapes but tended to elevate dissolved P loss in nonerodible soils. Their impact on total P loss was inconsistent across studies and complicated by soil, climate, and management factors. More research is needed to understand interactions between these factors and plant type that influence P loss, and to improve the assessment of crop contributions to P loss in field settings in cold climates. Further, tradeoffs between P loss and the control of sediment loss and N leaching by plants should be acknowledged.", "authors": [ "Liu, Jian", "Macrae, Merrin L.", "Elliott, Jane A.", "Baulch, Helen M.", "Wilson, Henry F.", "Kleinman, Peter J. A." ], "keywords": [ "" ], "year": "2019", "source": "JOURNAL OF ENVIRONMENTAL QUALITY", "publication_type": "J", "point2d": [ 30.132802963256836, 20.019094467163086 ], "cluster": 10.0 }, { "idx": 216, "title": "Temporal Dynamics of Snowmelt Nutrient Release from Snow-Plant Residue Mixtures: An Experimental Analysis and Mathematical Model Development", "abstract": "Reducing eutrophication in surface water is a major environmental challenge in many countries around the world. In cold Canadian prairie agricultural regions, part of the eutrophication challenge arises during spring snowmelt when a significant portion of the total annual nutrient export occurs, and plant residues can act as a nutrient source instead of a sink. Although the total mass of nutrients released from various crop residues has been studied before, little research has been conducted to capture finetimescale temporal dynamics of nutrient leaching from plant residues, and the processes have not been represented in water quality models. In this study, we measured the dynamics of P and N release from a cold-hardy perennial plant species, alfalfa (Medicago sativa L.), to meltwater after freeze-thaw through a controlled snowmelt experiment. Various winter conditions were simulated by exposing alfalfa residues to different numbers of freeze-thaw cycles (FTCs) of uniform magnitude prior to snowmelt. The monitored P and N dynamics showed that most nutrients were released during the initial stages of snowmelt (first 5 h) and that the magnitude of nutrient release was affected by the number of FTCs. A threshold of five FTCs was identified for a greater nutrient release, with plant residue contributing between 0.29 (NO3) and 9 (PO4) times more nutrients than snow. The monitored temporal dynamics of nutrient release were used to develop the first process-based predictive model controlled by three potentially measurable parameters that can be integrated into catchment water quality models to improve nutrient transport simulations during snowmelt.", "authors": [ "Costa, Diogo", "Liu, Jian", "Roste, Jennifer", "Elliott, Jane" ], "keywords": [ "" ], "year": "2019", "source": "JOURNAL OF ENVIRONMENTAL QUALITY", "publication_type": "J", "point2d": [ 26.345701217651367, 16.066030502319336 ], "cluster": 10.0 }, { "idx": 218, "title": "Differences in preferential flow with antecedent moisture conditions and soil texture: Implications for subsurface P transport", "abstract": "Preferential flowpaths transport phosphorus (P) to agricultural tile drains. However, if and to what extent this may vary with soil texture, moisture conditions, and P placement is poorly understood. This study investigated (a) interactions between soil texture, antecedent moisture conditions, and the relative contributions of matrix and preferential flow and (b) associated P distributions through the soil profile when fertilizers were applied to the surface or subsurface. Brilliant blue dye was used to stain subsurface flowpaths in clay and silt loam plots during simulated rainfall events under wet and dry conditions. Fertilizer P was applied to the surface or via subsurface placement to plots of different soil texture and moisture condition. Photographs of dye stains were analysed to classify the flow patterns as matrix dominated or macropore dominated, and soils within plots were analysed for their water-extractable P (WEP) content. Preferential flow occurred under all soil texture and moisture conditions. Dye penetrated deeper into clay soils via macropores and had lower interaction with the soil matrix, compared with silt loam soil. Moisture conditions influenced preferential flowpaths in clay, with dry clay having deeper infiltration (92 +/- 7.6 cm) and less dye-matrix interaction than wet clay (77 +/- 4.7 cm). Depth of staining did not differ between wet (56 +/- 7.2 cm) and dry (50 +/- 6.6 cm) silt loam, nor did dominant flowpaths. WEP distribution in the top 10 cm of the soil profile differed with fertilizer placement, but no differences in soil WEP were observed at depth. These results demonstrate that large rainfall events following drought conditions in clay soil may be prone to rapid P transport to tile drains due to increased preferential flow, whereas flow in silt loams is less affected by antecedent moisture. Subsurface placement of fertilizer may minimize the risk of subsurface P transport, particularily in clay.", "authors": [ "Grant, Kirsten N.", "Macrae, Merrin L.", "Ali, Genevieve A." ], "keywords": [ "preferential flow", "antecedent moisture conditions", "soil texture", "phosphorus", "fertilizer placement", "vadose zone", "dye tracer", "agriculture" ], "year": "2019", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 39.20608901977539, 21.800512313842773 ], "cluster": 10.0 }, { "idx": 219, "title": "Nutrient Leaching in Soil Affected by Fertilizer Application and Frozen Ground", "abstract": "Agricultural runoff containing P and N from drainage tiles contributes to nutrient loading in waterways, leading to downstream eutrophication. Recent studies suggest that nutrient losses through tile drains can be reduced if nutrients are applied in the subsurface. This study explored interactions between nutrient supply and infiltrating water during a simulated nongrowing season using a laboratory experiment to understand how water and nutrients move through partially frozen and unfrozen soil and if fertilizer placement influences NO3- and dissolved reactive P (DRP) leaching. Intact silt loam and clay soil monoliths (28 by 30 by 30 cm) were fertilized with P and N via subsurface placement or surface broadcast and subjected to simulated rainfall under unfrozen (10 degrees C) and partially frozen (similar to 0 degrees C) conditions. Conservative tracers (Br-, Cl-, and D2O) applied to characterize subsurface flow paths throughout a subset of events indicated that matrix flow dominated in unfrozen silt loam soil. However, preferential flow paths dominated in unfrozen clay and in both soil types under partially frozen conditions, transporting applied nutrients while minimizing contact with the soil matrix. The subsurface placement of inorganic fertilizer relative to surface broadcast reduced both NO3- (by 26.85 kg ha(-1) [23%] in silt loam and 65.73 kg ha(-1) [61%] in clay) and DRP losses (by 2.33 kg ha(-1) [60%] in silt loam and 4.25 kg ha(-1) [64%] in clay). This study demonstrates the advantage of subsurface placement of fertilizer in the reduction of nutrient leaching by limiting the interaction of the nutrient supply with preferential flow pathways.", "authors": [ "Grant, Kirsten N.", "Macrae, Merrin L.", "Rezanezhad, Fereidoun", "Lam, W. Vito" ], "keywords": [ "" ], "year": "2019", "source": "VADOSE ZONE JOURNAL", "publication_type": "J", "point2d": [ 37.98235321044922, 22.685495376586914 ], "cluster": 10.0 }, { "idx": 220, "title": "Effect of climate change and mining on hydrological connectivity of surficial layers in the Athabasca Oil Sands Region", "abstract": "This research analyses the impact of climate change and surface mining activities on the hydrologic connectivity of surficial (soil and geological) layers located in a watershed in the Athabasca Oil Sands Region. Surface water and groundwater flow are simulated for the period 2014-2080 under four climate scenarios: median (M), double precipitation (DP), no change in precipitation (NP), and double temperature (DT) and with the assumption of no change in the extent of mine activities after 2013. The results demonstrate that the annual growing season duration is longer and snowmelt happens earlier in the year 2080. During the growing season, the daily proportion of connected hydrologic units (DPCUs) remains approximately the same in the future under the different climate scenarios. It appears that around 68% of watershed area, mostly in western and central eastern portions, will be frequently connected (annual proportion of connected days [APCD] >= 20%) in the future. This area remains hydro-logically connected for more than 20-50% of the year. Results also show that mining areas are located in infrequently connected areas (APCD < 20%), where DPCU values are significantly lower than other areas. DPCUs in forestlands are more stable with a growing season, that is, similar to 15 days longer than in wetlands. Comparisons between hydrologic responses in 2016 and 2080 show that, in 2080, maximum snow depths are about 0.7 times smaller, evapotranspiration is similar to 0.05 mm higher, capillary soil moisture in DT and NP scenarios are 1.01-1.52 mm lower, and the ratio of precipitation to potential evapotranspiration is almost the same during the growing season. However, at the end of growing season, the ratio is similar to 1 unit less in 2080 in DT and NP scenarios. Results also demonstrate that thinner surficial geological layers in the mining areas (located mostly in downstream part of the watershed) lead to their lower hydrologic connectivities. Therefore, these areas are more vulnerable to mining activity impacts, and their hydrologic response under a changing climate should be considered in reclamation planning.", "authors": [ "Kompanizare, Mazda", "Petrone, Richard M.", "Shafii, Mahyar", "Robinson, Derek T.", "Rooney, Rebecca C." ], "keywords": [ "climate change", "hydrological connectivity", "mining activities", "oil sands region" ], "year": "2018", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -22.786941528320312, 3.0395331382751465 ], "cluster": 13.0 }, { "idx": 221, "title": "Hydroclimatic controls on runoff activation in an artificially drained, near-level vertisolic clay landscape in a Prairie climate", "abstract": "Water quality problems are frequently influenced by hydrological processes, particularly in landscapes in which land drainage has been modified. The expansion of agricultural tile drainage in the Northern Great Plains of North America is occurring, yet is controversial due to persistent water quality problems such as eutrophication. Runoff-generating mechanisms in North American tile-drained landscapes in vertisolic soils have not been investigated but are important for understanding the impacts of tile drainage on water quantity and quality. This study evaluated the role of climate drivers on the activation of overland (OF) and tile (TF) flow and groundwater flow responses (GWT) on tile-drained and nontile-drained farm fields in Southern Manitoba, Canada. The response times of different flow paths (OF, TF, and GWT) were compared for 23 hydrological events (April-September 2015, 2016) to infer dominant runoff generation processes. Runoff responses (all pathways) were more rapid following higher intensity rainfall. Subsurface responses were hastened by wetter antecedent conditions in spring and delayed by the seasonal soil-ice layer. The activation of OF did not differ between the tiled and nontiled fields, suggesting that tile drains do little to reduce the occurrence of OF in this landscape. Rapid vertical preferential flow into tiles via preferential flow pathways was uncommon at our site, and the soil profile instead wet up from the top down. These conclusions have implications for the expansion of tile drainage and the impact of such an expansion on hydrological and biogeochemical processes in agricultural landscapes.", "authors": [ "Kokulan, Vivekananthan", "Macrae, Merrin L.", "Ali, Genevieve A.", "Lobb, David A." ], "keywords": [ "antecedent moisture", "groundwater", "macropores", "preferential flow", "rainfall intensity", "Red River Valley", "runoff activation", "tile drainage" ], "year": "2019", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 31.033082962036133, 10.770840644836426 ], "cluster": 10.0 }, { "idx": 222, "title": "Dominant glacial landforms of the lower Great Lakes region exhibit different soil phosphorus chemistry and potential risk for phosphorus loss", "abstract": "Phosphorus (P) losses from agricultural soils are a growing economic and water-quality concern in the Lake Erie watershed. While recent studies have explored edge-of-field and watershed P losses related to land-use and agricultural management, the potential for soils developed from contrasting parent materials to retain or release P to runoff has not been examined. A field-based study comparing eight agricultural fields in contrasting glacial landscapes (hummocky coarse-textured till-plain, lacustrine and fine-textured till-plain) showed distinct physical and geochemical soil properties influencing inorganic P (P-i) partitioning throughout the soil profile between the two regions. Fields located on the coarse-textured till-plain in mid-western Ontario, Canada had alkaline calcareous soils with the highest Total-P-i concentrations and the majority of soil P-i stored in an acid-soluble pool (up to 91%). In contrast, loosely to moderately soluble P-i concentrations were higher in soils of the lacustrine and fine textured till-plain in southwestern Ontario, northeast Indiana and northwestern Ohio, US. Overall, soils on the lacustrine and fine-textured till-plain had a greater shrink swell-capacity, likely creating preferential flow to minimize P-i interaction with the more acidic, lower carbonate and lower sorption capacity soils. These differences in soil P-i retention and transport pathways demonstrate that in addition to management, the natural landscape may exert a significant control on how P-i is mobilized throughout the lake Erie watershed. Further, results indicate that careful consideration of region-specific hydrology and soil biogeochemistry may be required when designing appropriate management strategies to minimize P-i losses across the lower Great Lakes region. (C) 2018 International Association for Great Lakes Research. Published by Elsevier B.V. All rights reserved.", "authors": [ "Plach, Janina M.", "Macrae, Merrin L.", "Williams, Mark R.", "Lee, Brad D.", "King, Kevin W." ], "keywords": [ "Great Lakes", "Water quality", "Agriculture", "Phosphorus", "Soil geochemistry" ], "year": "2018", "source": "JOURNAL OF GREAT LAKES RESEARCH", "publication_type": "J", "point2d": [ 41.377784729003906, 12.59398078918457 ], "cluster": 10.0 }, { "idx": 223, "title": "Evaluation of convection-permitting WRF CONUS simulation on the relationship between soil moisture and heatwaves", "abstract": "Soil moisture plays an important role in modulating regional climate from sub-seasonal to seasonal timescales. Particularly important, soil moisture deficits can amplify summer heatwaves (HWs) through soil moisture-temperature feedback which has critical impacts on society, economy and human health. In this study, we evaluate decade-long convection-permitting Weather Research and Forecast (WRF) model simulations over the contiguous US on simulating heatwaves and their relationship with antecedent soil moisture using a dense observational network. We showed that the WRF model is capable of capturing the spatial patten of temperature threshold to define HWs, though the simulation shows a warm bias in the Midwest and cold bias in western mountainous regions. Two HW indices, based on frequency (HWF) and magnitude (HWM), are evaluated. Significant anti-correlations between antecedent soil moisture and both HW indices have been found in most parts of the domain except the South Pacific Coast. A detailed study has been conducted for the Midwest and South Great Plains regions, where two heatwaves had occurred in the last decade. In both regions, the high quantile of the HWF distribution shows a strong dependence on antecedent soil moisture: drier soil leads to much larger increase on the upper quantile of HWF than it does on the lower quantile. Soil moisture effects on the higher end of HWM are not as strong as on the lower end: wetter antecedent soil corresponds to a larger decrease on the lower quantile of HWM. WRF captures the heterogeneous responses to dry soil on HWF distribution in both regions, but overestimates these HWM responses in the Midwest and underestimates them in the South Great Plains. Our results show confidence in WRF's ability to simulate HW characteristics and the impacts of antecedent soil moisture on HWs. These are also important implications for using high-resolution convection-permitting mode to study the coupling between land and atmosphere.", "authors": [ "Zhang, Zhe", "Li, Yanping", "Chen, Fei", "Barlage, Michael", "Li, Zhenhua" ], "keywords": [ "Soil moisture", "Heatwave", "Regional climate", "Land-atmosphere interaction", "Soil moisture-temperature feedback", "WRF" ], "year": "2020", "source": "CLIMATE DYNAMICS", "publication_type": "J", "point2d": [ -48.93939208984375, -61.78934097290039 ], "cluster": 14.0 }, { "idx": 224, "title": "Evaluation of convection-permitting WRF CONUS simulation on the relationship between soil moisture and heatwaves", "abstract": "Soil moisture plays an important role in modulating regional climate from sub-seasonal to seasonal timescales. Particularly important, soil moisture deficits can amplify summer heatwaves (HWs) through soil moisture-temperature feedback which has critical impacts on society, economy and human health. In this study, we evaluate decade-long convection-permitting Weather Research and Forecast (WRF) model simulations over the contiguous US on simulating heatwaves and their relationship with antecedent soil moisture using a dense observational network. We showed that the WRF model is capable of capturing the spatial patten of temperature threshold to define HWs, though the simulation shows a warm bias in the Midwest and cold bias in western mountainous regions. Two HW indices, based on frequency (HWF) and magnitude (HWM), are evaluated. Significant anti-correlations between antecedent soil moisture and both HW indices have been found in most parts of the domain except the South Pacific Coast. A detailed study has been conducted for the Midwest and South Great Plains regions, where two heatwaves had occurred in the last decade. In both regions, the high quantile of the HWF distribution shows a strong dependence on antecedent soil moisture: drier soil leads to much larger increase on the upper quantile of HWF than it does on the lower quantile. Soil moisture effects on the higher end of HWM are not as strong as on the lower end: wetter antecedent soil corresponds to a larger decrease on the lower quantile of HWM. WRF captures the heterogeneous responses to dry soil on HWF distribution in both regions, but overestimates these HWM responses in the Midwest and underestimates them in the South Great Plains. Our results show confidence in WRF's ability to simulate HW characteristics and the impacts of antecedent soil moisture on HWs. These are also important implications for using high-resolution convection-permitting mode to study the coupling between land and atmosphere.", "authors": [ "Zhang, Zhe", "Li, Yanping", "Chen, Fei", "Barlage, Michael", "Li, Zhenhua" ], "keywords": [ "Soil moisture", "Heatwave", "Regional climate", "Land-atmosphere interaction", "Soil moisture-temperature feedback", "WRF" ], "year": "2020", "source": "CLIMATE DYNAMICS", "publication_type": "J", "point2d": [ -48.66640853881836, -61.446685791015625 ], "cluster": 14.0 }, { "idx": 225, "title": "Combined impacts of ENSO and MJO on the 2015 growing season drought on the Canadian Prairies", "abstract": "Warm-season precipitation on the Canadian Prairies plays a crucial role in agricultural production. This research investigates how the early summer 2015 drought across the Canadian Prairies is related to the tropical Pacific forcing. The significant deficit of precipitation in May and June 2015 coincided with a warm phase of the El Nino-Southern Oscillation (ENSO) and a negative phase of Madden-Julian Oscillation (MJO)-4 index, which favour a positive geopotential height (GPH) anomaly in western Canada. Our further investigation during the instrumental record (1979-2016) shows that warm-season precipitation in the Canadian Prairies and the corresponding atmospheric circulation anomalies over western Canada teleconnected with the lower boundary conditions in the tropical western Pacific. Our results indicate that MJO can play a crucial role in determining the summer precipitation anomaly in the western Canadian Prairies when the equatorial central Pacific is warmer than normal (NINO4 > 0) and MJO is more active. This teleconnection is due to the propagation of a stationary Rossby wave that is generated in the MJO-4 index region. When the tropical convection around MJO-4 index region (western tropical Pacific, centred over 140 degrees E) is more active than normal (NINO4 > 0), Rossby wave trains originate from the western Pacific with wavenumbers determined by the background mean wind and meridional absolute vorticity gradient. Under warm NINO4 conditions waves are generated with smaller wavenumbers compared to cold NINO4 conditions. These waves under warm NINO4 can propagate into the mid-latitudes over North America, causing a persistent anomalous ridge in the upper level over western Canada, which favours dry conditions over the region.", "authors": [ "Li, Zhenhua", "Li, Yanping", "Bonsal, Barrie", "Manson, Alan H.", "Scaff, Lucia" ], "keywords": [ "" ], "year": "2018", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -37.53483963012695, -36.87149429321289 ], "cluster": 1.0 }, { "idx": 226, "title": "Preferential meltwater flowpaths as a driver of preferential elution of chemicals from melting snowpacks", "abstract": "Seasonal snowcovers release nutrients accumulated over the winter during spring snowmelt and this can be an important part of the annual biogeochemical cycling of chemicals and their loading to soils and water bodies. The characteristics of this load are controlled by snowmelt dynamics and the physical and chemical properties of the snowpack, which are affected by overwinter and snowmelt metamorphism, refreezing of meltwater, and ion exclusion from snow crystals. Rain-on-snow (ROS) events can accelerate and modify the snowpack discharge process. The interplay of these processes can cause microscale flow heterogeneity and preferential flow pathways (PFP). Previous experimental work has examined PFP and ion elution processes in snowpacks, but their combined effect on the spatial and temporal characteristics of snowmelt ion elution remains uncertain. In this research, two controlled laboratory experiments were performed to investigate the role of PFP and ROS in controlling snow ion release to runoff. These involved the high frequency monitoring of flow and meltwater concentrations during snowmelt induced by radiation-convection (RC) processes and rain-on-snow (ROS). Results showed that when ROS was included, PFP was responsible for the transport of 68% and 73% of the total NO3 and PO4 load discharged during the early snowmelt phase recorded by the experiment. However, this initial load increased to 95% and 75% when ROS was removed, causing the release of more than 20% of the total snowpack NO3 and PO4 during the first 1.5% of melt. Small intensity ROS may refreeze in the snowpack, which may affect the ability of lateral flow to deliver snow ions located beyond the leading edge of PFP. (C) 2019 Published by Elsevier B.V.", "authors": [ "Costa, Diogo", "Pomeroy, John W." ], "keywords": [ "Snow hydrochemistry", "Cold regions hydrology", "Nutrient exports", "Ion exclusion", "Ion preferential elution", "Acid snow" ], "year": "2019", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ -25.321393966674805, 20.37738609313965 ], "cluster": 12.0 }, { "idx": 227, "title": "Prairie water: a global water futures project to enhance the resilience of prairie communities through sustainable water management", "abstract": "", "authors": [ "Spence, Christopher", "Wolfe, Jared D.", "Whitfield, Colin J.", "Baulch, Helen Margaret", "Basu, Nandita B.", "Bedard-Haughn, Angela K.", "Belcher, Ken W.", "Clark, Robert G.", "Ferguson, Grant A.", "Hayashi, Masaki", "Liber, Karsten", "McDonnell, Jeff J.", "Morrissey, Christy A.", "Pomeroy, John W.", "Reed, Maureen G.", "Strickert, Graham" ], "keywords": [ "" ], "year": "2019", "source": "CANADIAN WATER RESOURCES JOURNAL", "publication_type": "J", "point2d": [ 42.25211715698242, -30.49310874938965 ], "cluster": 4.0 }, { "idx": 228, "title": "Prairie water: a global water futures project to enhance the resilience of prairie communities through sustainable water management", "abstract": "", "authors": [ "Spence, Christopher", "Wolfe, Jared D.", "Whitfield, Colin J.", "Baulch, Helen Margaret", "Basu, Nandita B.", "Bedard-Haughn, Angela K.", "Belcher, Ken W.", "Clark, Robert G.", "Ferguson, Grant A.", "Hayashi, Masaki", "Liber, Karsten", "McDonnell, Jeff J.", "Morrissey, Christy A.", "Pomeroy, John W.", "Reed, Maureen G.", "Strickert, Graham" ], "keywords": [ "" ], "year": "2019", "source": "CANADIAN WATER RESOURCES JOURNAL", "publication_type": "J", "point2d": [ 42.30177688598633, -30.92784881591797 ], "cluster": 4.0 }, { "idx": 229, "title": "ESM-SnowMIP: assessing snow models and quantifying snow-related climate feedbacks", "abstract": "This paper describes ESM-SnowMIP, an international coordinated modelling effort to evaluate current snow schemes, including snow schemes that are included in Earth system models, in a wide variety of settings against local and global observations. The project aims to identify crucial processes and characteristics that need to be improved in snow models in the context of local-and global-scale modelling. A further objective of ESM-SnowMIP is to better quantify snow-related feedbacks in the Earth system. Although it is not part of the sixth phase of the Coupled Model Intercomparison Project (CMIP6), ESM-SnowMIP is tightly linked to the CMIP6-endorsed Land Surface, Snow and Soil Moisture Model Intercomparison (LS3MIP).", "authors": [ "Krinner, Gerhard", "Derksen, Chris", "Essery, Richard", "Flanner, Mark", "Hagemann, Stefan", "Clark, Martyn", "Hall, Alex", "Rott, Helmut", "Brutel-Vuilmet, Claire", "Kim, Hyungjun", "Menard, Cecile B.", "Mudryk, Lawrence", "Thackeray, Chad", "Wang, Libo", "Arduini, Gabriele", "Balsamo, Gianpaolo", "Bartlett, Paul", "Boike, Julia", "Boone, Aaron", "Cheruy, Frederique", "Colin, Jeanne", "Cuntz, Matthias", "Dai, Yongjiu", "Decharme, Bertrand", "Derry, Jeff", "Ducharne, Agnes", "Dutra, Emanuel", "Fang, Xing", "Fierz, Charles", "Ghattas, Josephine", "Gusev, Yeugeniy", "Haverd, Vanessa", "Kontu, Anna", "Lafaysse, Matthieu", "Law, Rachel", "Lawrence, Dave", "Li, Weiping", "Marke, Thomas", "Marks, Danny", "Menegoz, Martin", "Nasonova, Olga", "Nitta, Tomoko", "Niwano, Masashi", "Pomeroy, John", "Raleigh, Mark S.", "Schaedler, Gerd", "Semenov, Vladimir", "Smirnova, Tanya G.", "Stacke, Tobias", "Strasser, Ulrich", "Svenson, Sean", "Turkov, Dmitry", "Wang, Tao", "Wever, Nander", "Yuan, Hua", "Zhou, Wenyan", "Zhu, Dan" ], "keywords": [ "" ], "year": "2018", "source": "GEOSCIENTIFIC MODEL DEVELOPMENT", "publication_type": "J", "point2d": [ -45.35549545288086, -11.77337646484375 ], "cluster": 8.0 }, { "idx": 230, "title": "A global meta-analysis of groundwater quality valuation studies", "abstract": "A global meta-analysis consisting of almost three decades of groundwater quality valuation studies is presented. New in this study is the focus on the uncertainties surrounding different groundwater quality levels and the control included for groundwater contaminants originating from agriculture and other sources. Separate meta-regression models are estimated for the USA, Europe and the World, detecting sensitivity to scope and reference dependence. Public willingness to pay appears more sensitive to uncertainty in the baseline scenario than in the policy scenario. The high explanatory power of the estimated meta-regression models and low prediction errors provide confidence in their usefulness for reliable benefits transfer.", "authors": [ "Brouwer, Roy", "Neverre, Noemie" ], "keywords": [ "groundwater", "meta-analysis", "non-market valuation" ], "year": "2020", "source": "EUROPEAN REVIEW OF AGRICULTURAL ECONOMICS", "publication_type": "J", "point2d": [ 54.53317642211914, -50.2996711730957 ], "cluster": 11.0 }, { "idx": 231, "title": "Economic valuation of groundwater protection using a groundwater quality ladder based on chemical threshold levels", "abstract": "Improving groundwater quality is expected to yield direct use benefits to society (e.g. clean and safe drinking water) and groundwater dependent ecosystems. Ten years after the adoption of the European Groundwater Directive (GWD), policymaker and public understanding of the societal value of groundwater protection is still rather limited. This is partly due to the invisible and intangible nature of groundwater resources and the sheer lack of valuation studies. This study contributes to the limited number of groundwater valuation studies in Europe by estimating the public benefits from improved groundwater quality in the Aveiro Quaternary Aquifer (AQA) in Portugal. This is the first and only economic valuation study of groundwater in Portugal. In order to communicate the various benefits provided by groundwater resources in easy understandable terms to lay people, and to assess public perception and willingness to pay (WTP) for groundwater protection, a groundwater quality ladder was developed based on the threshold values proposed in the GWD. The ladder reflects the different use and non-use values of groundwater quality improvements and accounts for natural background levels of chemicals in groundwater. The large-scale survey targets a representative sample of residents in the AQA. Split samples are used to assess the impact of framing groundwater protection in a broader regional water resources management context, giving part of the sample furthermore time to think about their WTP for. the different groundwater threshold levels. Although use values dominate public WTP for the different groundwater threshold values, substantial non-use values are also found. Public WTP is considerable, varying between 20 and 30% over and above the current water bill residents pay for safe drinking water quality and natural background levels, respectively. Giving respondents time to think and framing groundwater protection as part of the improvement of all water resources in the region results in a more conservative WTP estimate. Public WTP is higher for better informed private well owners in rural areas. Aggregated across the entire aquifer the estimated total economic value is 1.5 million euros annually for safe drinking water quality and 3.5 million euros annually for groundwater containing natural background levels only.", "authors": [ "Brouwer, Roy", "Ordens, Carlos Miraldo", "Pinto, Rute", "Teresa Condesso de Melo, M." ], "keywords": [ "Groundwater quality ladder", "Natural background levels", "Contingent valuation", "European Groundwater Directive" ], "year": "2018", "source": "ECOLOGICAL INDICATORS", "publication_type": "J", "point2d": [ 55.1712760925293, -50.1230354309082 ], "cluster": 11.0 }, { "idx": 232, "title": "Modelling farmer choices for water security measures in the Litani river basin in Lebanon", "abstract": "Lebanon is facing an increasing water supply deficit due to the increasing demand for freshwater, decreasing surface and groundwater resources and malfunctioning water governance structures. Technological and policy changes are needed to alleviate the impact of water scarcity and secure water in the future. This paper investigates farmers' preferences and willingness to pay (WTP) in a choice experiment for a series of water saving measures at plot and irrigation district level, including more timely information of water delivery. These measures are expected to strengthen water security and use water more efficiently. Farmers are willing to pay higher water prices of $0.32/m(3) and $0.22/m(3) to support the implementation of water saving measures at plot level and the installation of water metering devices across the irrigation district, respectively. They are not willing to pay extra for obtaining information related to their water delivery earlier in time if this means that they will also have to pay earlier in the year for the water. Farmers with higher income and education levels who decide on their cropping pattern based on expected rainfall data are more interested in taking action than farmers whose cropping decisions are primarily based on last year's sales prices. The study shows that when aiming to design more effective sustainable water management strategies, accounting for farmers' needs and preferences, their age also has to be considered: younger farmers (<40 years) are on average more interested in and willing to pay more for new water saving measures than older farmers (>40 years). (C) 2018 Elsevier B.V. All rights reserved.", "authors": [ "Alcon, F.", "Tapsuwan, S.", "Brouwer, R.", "Yunes, M.", "Mounzer, O.", "de-Miguel, M. D." ], "keywords": [ "Choice experiment", "Water security", "Irrigation", "Lebanon", "Water saving", "Water pricing", "Willingness to pay" ], "year": "2019", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 44.319950103759766, -39.73236846923828 ], "cluster": 11.0 }, { "idx": 233, "title": "Using an inverse modelling approach with equifinality control to investigate the dominant controls on snowmelt nutrient export", "abstract": "There is great interest in modelling the export of nitrogen (N) and phosphorus (P) from agricultural fields because of ongoing challenges of eutrophication. However, the use of existing hydrochemistry models can be problematic in cold regions because models frequently employ incomplete or conceptually incorrect representations of the dominant cold regions hydrological processes and are overparameterized, often with insufficient data for validation. Here, a process-based N model, WINTRA, which is coupled to a physically based cold regions hydrological model, was expanded to simulate P and account for overwinter soil nutrient biochemical cycling. An inverse modelling approach, using this model with consideration of parameter equifinality, was applied to an intensively monitored agricultural basin in Manitoba, Canada, to help identify the main climate, soil, and anthropogenic controls on nutrient export. Consistent with observations, the model results suggest that snow water equivalent, melt rate, snow cover depletion rate, and contributing area for run-off generation determine the opportunity time and surface area for run-off-soil interaction. These physical controls have not been addressed in existing models. Results also show that the time lag between the start of snowmelt and the arrival of peak nutrient concentration in run-off increased with decreasing antecedent soil moisture content, highlighting potential implications of frozen soils on run-off processes and hydrochemistry. The simulations showed TDP concentration peaks generally arriving earlier than NO3 but also decreasing faster afterwards, which suggests a significant contribution of plant residue Total dissolved Phosphorus (TDP) to early snowmelt run-off. Antecedent fall tillage and fertilizer application increased TDP concentrations in spring snowmelt run-off but did not consistently affect NO3 run-off. In this case, the antecedent soil moisture content seemed to have had a dominant effect on overwinter soil N biogeochemical processes such as mineralization, which are often ignored in models. This work demonstrates both the need for better representation of cold regions processes in hydrochemical models and the model improvements that are possible if these are included.", "authors": [ "Costa, Diogo", "Pomeroy, John", "Baulch, Helen", "Elliott, Jane", "Wheater, Howard" ], "keywords": [ "agriculture", "cold climates", "nitrogen", "nutrient exports", "phosphorus", "snowmelt" ], "year": "2019", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 27.095584869384766, 13.671557426452637 ], "cluster": 10.0 }, { "idx": 234, "title": "Impacts of Soil Phosphorus Drawdown on Snowmelt and Rainfall Runoff Water Quality", "abstract": "Managing P export from agricultural land is critical to address freshwater eutrophication. However, soil P management, and options to draw down soil P have received little attention in snowmelt-dominated regions because of limited interaction between soil and snowmelt. Here, we assessed the impacts of soil P drawdown (reducing fertilizer P inputs combined with harvest removal) on soil Olsen P dynamics, runoff P concentrations, and crop yields from 1997 to 2014 in paired fields in Manitoba, Canada. We observed that Olsen P concentrations in the 0-to 5-cm soil layer were negatively correlated with the cumulative P depletion and declined rapidly at the onset of the drawdown practice (3.1 to 5.4 mg kg(-1)yr(-1) during 2007-2010). In both snowmelt runoff and rainfall runoff, concentrations of total dissolved P (TDP) were positively correlated with the concentrations of soil Olsen P. Soil P drawdown to low to moderate fertility levels significantly decreased mean annual flow-weighted TDP concentrations in snowmelt runoff from 0.60 to 0.30 mg L-1 in the field with high initial soil P and from 1.17 to 0.42 mg L-1 in the field with very high initial soil P. Declines in TDP concentration in rainfall runoff were greater. Critically, yields of wheat (Triticum spp.) and canola (Brassica napus L.) were not affected by soil P depletion. In conclusion, we demonstrate that relatively rapid reductions in P loads are achievable at the field scale via managing P inputs and soil P pools, highlighting a management opportunity that can maintain food security while improving water security in cold regions.", "authors": [ "Liu, Jian", "Elliott, Jane A.", "Wilson, Henry F.", "Baulch, Helen M." ], "keywords": [ "" ], "year": "2019", "source": "JOURNAL OF ENVIRONMENTAL QUALITY", "publication_type": "J", "point2d": [ 35.32111740112305, 16.53551483154297 ], "cluster": 10.0 }, { "idx": 235, "title": "Nutrient Loss in Snowmelt Runoff: Results from a Long-term Study in a Dryland Cropping System", "abstract": "Snowmelt runoff often comprises the majority of annual runoff in the Canadian Prairies and a significant proportion of total nutrient loss from agricultural land to surface water. Our objective was to determine the effect of agroecosystem management on snowmelt runoff and nutrient losses from a long-term field experiment at Swift Current, SK. Runoff quantity, nutrient concentrations, and loads were estimated after a change in management from conventionally tilled wheat (Triticum aestivum L.)-fallow (Conv W-F) to no-till wheat-fallow and subsequently no-till wheat-pulse (NT W-F/LP) and to an organic system with a wheat-green manure rotation (Org W-GM). The conversion from conventional tillage practices to no-till increased snowmelt runoff likely due to snow trapping by standing stubble after summer fallow. Relatedly, runoff after no-till summer fallow had higher dissolved P losses (0.07 kg P ha(-1)). Replacing summer fallow with a pulse crop in the no-till rotation decreased snowmelt runoff losses and nutrient concentrations. The Org W-GM treatment had the lowest P loss after stubble (0.02 kg P ha(-1)) but had high dissolved P concentrations in snowmelt following the green manure (0.55 mg P L-1), suggesting a contribution from incorporated crop residues. In this semiarid climate with little runoff, dissolved reactive P and NO3-N loads in snowmelt runoff were smaller than those reported elsewhere on the prairies (averaging < 0.05 kg P ha(-1) yr(-1), and < 0.2 kg NO3 -N ha(-1) yr(-1)); however, the nutrient concentrations we observed, in particular for P, even without P fertilizer addition for organic production, question the practicality of agricultural management systems in this region meeting water quality guidelines.", "authors": [ "Schneider, Kimberley D.", "McConkey, Brian G.", "Thiagarajan, Arumugam", "Elliott, Jane A.", "Reid, D. Keith" ], "keywords": [ "" ], "year": "2019", "source": "JOURNAL OF ENVIRONMENTAL QUALITY", "publication_type": "J", "point2d": [ 34.178749084472656, 17.703824996948242 ], "cluster": 10.0 }, { "idx": 236, "title": "Characterizing the Phytotoxic Effects of Hydrogen Peroxide on Common Microgreen Species and Lettuce Cultivars", "abstract": "Hydrogen peroxide (H2O2) is an oxidizing agent used to disinfect recirculated irrigation water during the production of organic crops under controlled environmental systems (e.g., greenhouses). To characterize the phytotoxic effects and define a concentration threshold for H2O2, three microgreen species [arugula (Brassica eruca ssp. sativa), radish (Raphanus sativus), and sunflower (Helianthus annuus 'Black Oil')], and three lettuce (Lactuca sativa) cultivars, Othilie, Xandra, and Rouxai, were foliar sprayed once daily with water containing 0, 25, 50, 75, 100, 125, 150, or 200 mg.L-1 of H2O2 from seed to harvest under greenhouse conditions. Leaf damage was assessed at harvest using two distinct methods: 1) the percentage of damaged leaves per tray and 2) a damage index (DI). Applied H2O2 concentrations, starting from 25 mg.L-1, increased the percentage of damaged leaves in every species except 'Black Oil' sunflower, which remained unaffected by any applied concentration. Symptoms of leaf damage manifested in similar patterns on the surface of microgreen cotyledons and lettuce leaves, while mean DI values and extent of damage were unique to each crop. Fresh weight, dry weight, and leaf area of all crops were not significantly affected by daily H2O2 spray. Identifying how foliar H2O2 damage manifests throughout the crop, as well at individual cotyledon or leaf surfaces, is necessary to establish an upper concentration threshold for H2O2 use. On the basis of the aforementioned metrics, maximum recommended concentrations were 150 mg.L-1 (radish), 100 mg.L-1 (arugula) for microgreens and 125 mg.L-1 ('Othilie'), 75 mg.L-1 ('Rouxai'), and 125 mg.L-1 ('Xandra') lettuce.", "authors": [ "Eicher-Sodo, Mitchell", "Gordon, Robert", "Zheng, Youbin" ], "keywords": [ "arugula", "damage index", "greenhouse", "irrigation", "radish", "sunflower" ], "year": "2019", "source": "HORTTECHNOLOGY", "publication_type": "J", "point2d": [ 57.10633087158203, -18.519901275634766 ], "cluster": 6.0 }, { "idx": 237, "title": "Simulation of Nitrate-N Leaching in No-Till Fields with DRAINMOD-N II in a Cold-Humid Region", "abstract": "Conservation agriculture, especially no-tillage, has proven to become sustainable farming in many agricultural environments globally. In spite of advantages of no-till systems, this practice may result in excess infiltration into the soil and can enhance the movement of mobile nutrients and some pesticides to subsurface drains and groundwater along preferential pathways. The goal of this study was to evaluate the capacity of DRAINMOD-N II to simulate subsurface nitrate-N leaching in no-till fields in Truro, Nova Scotia, Canada, from 2003 to 2006. The model performance was first evaluated by comparing observed and simulated drain outflow data that is an essential prerequisite for the model to obtain a proper prediction of NO3-N movement, and then by comparing observed and simulated NO3-N concentration in no-till fields using three statistical indices, relative root mean square error (RRMSE), average absolute deviation (AAD) and the correlation coefficient (R-2). The RRMSE, AAD and R-2 for the validation period were determined to be 1.09, 1.85 and 0.83mm for drain outflow, and 1.43, 0.51 and 0.79mg l(-1) for NO3-N concentration respectively. The results showed that DRAINMOD-N II predicted NO3-N leaching reasonably well in drainage outflow of no-till fields over the whole period. Copyright (c) 2018 John Wiley & Sons, Ltd. Resume L'agriculture de conservation, en particulier le semis direct, s'est revelee etre une agriculture durable dans de nombreux milieux agricoles a l'echelle mondiale. En depit de certains avantages des systemes sans labour, cette pratique peut entrainer une infiltration excessive dans le sol et peut ameliorer le mouvement des nutriments mobiles et certains pesticides vers les drains souterrains et les eaux souterraines le long des voies preferentielles. L'objectif de cette etude etait d'evaluer la capacite de DRAINMOD-N II a simuler la lixiviation au nitrate-N dans des parcelles sans labour a Truro, Nouvelle-Ecosse, Canada, de 2003 a 2006. La performance du modele a d'abord ete evaluee en comparant les donnees de sortie de vidange observees et simulees qui constituent une condition prealable essentielle pour que le modele obtienne une prediction appropriee du mouvement du NO3-N, puis en comparant la concentration observee et simulee de NO3-N avec/sans labour en utilisant trois indices statistiques, erreur carree moyenne relative (RRMSE), ecart absolu moyen (AAD) et coefficient de correlation (R-2). Le RRMSE, AAD et R-2 pour la periode de validation ont ete determines de 1.09, 1.85 et 0.83mm pour l'ecoulement du drain, et 1.43, 0.51 et 0.79mg l(-1) pour la concentration de NO3-N respectivement. Les resultats ont montre que DRAINMOD-N II prevoyait une lixiviation NO3-N raisonnablement bonne dans les debits de drainage des champs sans labour sur l'ensemble des annees. Copyright (c) 2018 John Wiley & Sons, Ltd.", "authors": [ "Garmdareh, Seyyed Ebrahim Hashemi", "Malekian, Raheleh", "Madani, Ali", "Gordon, Robert" ], "keywords": [ "DRAINMOD-N II", "leachingt", "Nitrate", "no-till" ], "year": "2018", "source": "IRRIGATION AND DRAINAGE", "publication_type": "J", "point2d": [ 23.807451248168945, 7.899949550628662 ], "cluster": 10.0 }, { "idx": 238, "title": "Current inventory approach overestimates the effect of irrigated crop management on soil-derived greenhouse gas emissions in the semi-arid Canadian Prairies", "abstract": "Greenhouse gas (GHG) emissions from agricultural soils in the Canadian Prairie region are generally low and, due to dry, well aerated soil conditions, can be quite variable. Compared to dryland (rainfed) crop production, irrigated cropping has potential to contribute greater quantities of soil derived nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) to the atmosphere as producers target higher yields by minimizing soil moisture limitations and applying greater amounts of nitrogen fertilizers. However, the actual GHG dynamics from irrigated soils in this region are not well understood as there have been few field-based studies in the semi-arid prairies of western Canada. The goal of this study was to identify how emissions of soil derived N2O, CO2, and CH4 are influenced by changes in soil temperature, water status, and nitrogen rates brought about by irrigated crop management. This was achieved through continuous, in-situ monitoring of soil conditions and chamber-based measurements of soil GHG flux. The most notable change in soil conditions brought about by irrigation was elevated moisture levels, which appeared to influence the flux dynamics of all three agricultural greenhouse-gases specifically, a reduction in CH4 uptake and periodic increases in CO2 and N2O emissions. Despite the reduced soil moisture limitation, annual N2O emissions from the irrigated cropping system were much lower than those calculated using the current Canadian National GHG Inventory Reporting. This suggests that annual emissions are limited more by N availability rather than moisture deficits, as the current method for emissions accounting assumes. Consequently, our results indicate that emissions from irrigated cropping systems in the semi-arid Canadian Prairies are overestimated by the current inventory approach. Moreover, because irrigated crop production involves more than just the application of water, our results demonstrate that a more systems-oriented approach to GHG accounting is required to capture the combined effects of water-soil-crop management on GHG emissions from irrigated cropping systems.", "authors": [ "David, Cody", "Lemke, Reynald", "Helgason, Warren", "Farrell, Richard E." ], "keywords": [ "Irrigated cropping", "Dryland cropping", "Nitrous oxide", "Carbon dioxide", "Methane" ], "year": "2018", "source": "AGRICULTURAL WATER MANAGEMENT", "publication_type": "J", "point2d": [ -57.02922821044922, 34.72361373901367 ], "cluster": 10.0 }, { "idx": 239, "title": "Potential impacts of climate change on the habitat of boreal woodland caribou", "abstract": "Boreal woodland caribou (Rangifer tarandus caribou) are currently listed as threatened in Canada, with populations in the province of Alberta expected to decline as much as 50 percent over the next 8-15 yr. We assessed the future of caribou habitat across a region of northeast Alberta using a model of habitat-quality and projections of future climate from three general circulation models. We used mapped climatic and topo-edaphic properties to project future upland vegetation cover and a fire simulation model to project the frequency and extent of wildfires. Based on those projections, we quantified the future habitat of caribou according to estimates of nutritional resources and predation risk derived from vegetation cover type and stand age. Grassland vegetation covered up to half of the study area by the 2080s, expanding from <1% in the present and contributing to a significant contraction in mixedwood and coniferous forests. This change in vegetation would increase the risk of predation and disease, as habitat becomes more suitable for white-tailed deer (Odocoileus virginianus) and, consequently, gray wolves (Canis lupus). Borne out, these changes would severely compromise the long-term persistence of caribou in the boreal forest of Alberta.", "authors": [ "Barber, Quinn E.", "Parisien, Marc-Andre", "Whitman, Ellen", "Stralberg, Diana", "Johnson, Chris J.", "St-Laurent, Martin-Hugues", "DeLancey, Evan R.", "Price, David T.", "Arseneault, Dominique", "Wang, Xianli", "Flannigan, Mike D." ], "keywords": [ "climate change", "disturbance modeling", "predation risk", "wildland fire", "woodland caribou" ], "year": "2018", "source": "ECOSPHERE", "publication_type": "J", "point2d": [ -7.621535301208496, 51.136962890625 ], "cluster": 15.0 }, { "idx": 240, "title": "Increases in salinity following a shift in hydrologic regime in a constructed wetland watershed in a post-mining oil sands landscape", "abstract": "Bitumen extraction via surface mining in the Athabasca Oil Sands Region results in permanent alteration of boreal forests and wetlands. As part of their legal requirements, oil companies must reclaim disturbed landscapes into functioning ecosystems. Despite considerable work establishing upland forests, only two pilot wetlandpeatland systems integratedwithin a watershed have been constructed to date. Peatland reclamation is challenging as it requires complete reconstruction with few guidelines or previous work in this region. Furthermore, the variable sub-humid climate and salinity of tailings materials present additional challenges. In 2012, Syncrude Canada Ltd. constructed a 52-ha pilot upland-wetland system, the Sandhill FenWatershed, which was designed with a pump and underdrain system to provide freshwater and enhance drainage to limit salinization from underlying soft tailings materials that have elevated electrical conductivity (EC) and Na+. The objective of this research is to evaluate the hydrochemical response of a constructed wetland to variations in hydrology and water management with respect to water sources, flow pathways and major chemical transformations in the three years following commissioning. Results suggest that active water management practices in 2013 kept EC relatively low, with mostwetland sites <1000 mu S/cmwith Na+ concentrations <250mg/L. With limitedmanagement in 2014 and 2015, the EC increased in the wetland to N1000 mu S/cm in 2014 and >2000 mu S/cm in 2015. The most notable changewas the emergence of several Na+ enriched zones in the margins. Here, Na+ concentrations were two to three times higher than other sites. Stable isotopes of water support that the Na+ enriched areas arise from underlying process-affected water in the tailings, providing evidence of its upward transport and seepage under a natural hydrologic regime. In future years, salinity is expected to evolve in its flow pathways and diffusion, yet the timeline and extent of these changes are uncertain. (c) 2018 Elsevier B. V. All rights reserved.", "authors": [ "Biagi, K. M.", "Oswald, C. J.", "Nicholls, E. M.", "Carey, S. K." ], "keywords": [ "Athabasca Oil Sands Region", "Constructed wetland", "Hydrochemistry", "Peatland", "Reclamation", "Sodium" ], "year": "2019", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 8.555551528930664, 32.608421325683594 ], "cluster": 18.0 }, { "idx": 241, "title": "Monitoring ecosystem reclamation recovery using optical remote sensing: Comparison with field measurements and eddy covariance", "abstract": "Time series remote sensing vegetation indices derived from SPOT 5 data are compared with vegetation structure and eddy covariance flux data at 15 dry to wet reclamation and reference sites within the Oil Sands region of Alberta, Canada. This comprehensive analysis examines the linkages between indicators of ecosystem function and change trajectories observed both at the plot level and within pixels. Using SPOT imagery, we find that higher spatial resolution datasets (e.g. 10 m) improves the relationship between vegetation indices and structural measurements compared with interpolated (lower resolution) pixels. The simple ratio (SR) vegetation index performs best when compared with stem density-based indicators (R-2 = 0.65; p < 0.00), while the normalised difference vegetation index (NDVI) and soil adjusted vegetation index (SAVI) are most comparable to foliage indicators (leaf area index (LAI) and canopy cover (R-2 = 0.52-0.78; p > 0.02). Fluxes (net ecosystem production (NEP) and gross ecosystem production (GEP)) are most related to NDVI and SAVI when these are interpolated to larger 20 m x 20 m pixels (R-2 = 0.44-0.50; p < 0.00). As expected, decreased sensitivity of NDVI is problematic for sites with LAI > 3 m(2)m(-2),making this index more appropriate for newly regenerating reclamation areas. For sites with LAI < 3 m(2)m(-2), trajectories of vegetation change can be mapped over time and are within 2.7% and 33% of annual measured LAI changes observed at most sites. This study demonstrates the utility of remote sensing in combination with field and eddy covariance data for monitoring and scaling of reclaimed and reference site productivity within and beyond the Oil Sands Region of western Canada. (C) 2018 Elsevier B.V. All rights reserved.", "authors": [ "Chasmer, L.", "Baker, T.", "Carey, S. K.", "Straker, J.", "Strilesky, S.", "Petrone, R." ], "keywords": [ "Oil sands reclamation", "Trajectory", "Net ecosystem exchange", "LAI", "Remote sensing", "Biomass" ], "year": "2018", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ -62.7880859375, 17.396018981933594 ], "cluster": 15.0 }, { "idx": 242, "title": "Evaluation of Gridded Precipitation Data and Interpolation Methods for Forest Fire Danger Rating in Alberta, Canada", "abstract": "The Canadian Forest Fire Weather Index System is the primary measurement of wildfire danger in Canada. Interpolating daily precipitation, one of the inputs for the Fire Weather Index System is a key challenge in areas without sufficient weather stations. This work evaluates the performance of gridded precipitation from the Canadian Precipitation Analysis (CaPA) System and six interpolation methods to achieve the best fire danger rating in Alberta, Canada. Results show that the CaPA System has only average performance due to limited radar coverage (10%) in the forested region; however, using the CaPA System as a covariate with regression kriging generates significantly better precipitation estimates. Ordinary kriging, regression kriging with elevation as a covariate, and the thin-plate smoothed spline are methods with similar performance. Fuel moisture codes of the Fire Weather Index System respond differently to precipitation amounts due to differences in their time constants for drying. Fine fuels with a short drying time (Fine Fuel Moisture Code) are best estimated by the CaPA System because of its enhanced skill in estimating small precipitation events. Compacted organic fuels with longer drying times (Duff Moisture Code and Drought Code) are best estimated by regression kriging with CaPA because it better predicts significant precipitation events. The dense fire weather station network in our study area (similar to 3.0 stations/10,000km(2)) allows us to perform a sensitivity analysis, and we find that a threshold of >0.5 stations/10,000km(2) is needed for regression kriging with CaPA to become", "authors": [ "Cai, Xinli", "Wang, Xianli", "Jain, Piyush", "Flannigan, Mike D." ], "keywords": [ "forest fires", "Fire Weather Index System", "Canadian Precipitation Analysis System", "spatial interpolation", "regression kriging", "weather station density" ], "year": "2019", "source": "JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES", "publication_type": "J", "point2d": [ -5.858959674835205, 42.49278259277344 ], "cluster": 1.0 }, { "idx": 243, "title": "Temporal Patterns of Wildfire Activity in Areas of Contrasting Human Influence in the Canadian Boreal Forest", "abstract": "The influence of humans on the boreal forest has altered the temporal and spatial patterns of wildfire activity through modification of the physical environment and through fire management for the protection of human and economic values. Wildfires are actively suppressed in areas with higher human influence, but, paradoxically, these areas have more numerous ignitions than low-impact ones because of the high rates of human-ignited fires, especially during the springtime. The aim of this study is to evaluate how humans have altered the temporal patterns of wildfire activity in the Canadian boreal forest by comparing two adjacent areas of low and high human influence, respectively: Wood Buffalo National Park (WBNP) and the Lower Athabasca Plains (LAP). We carried out Singular Spectrum Analysis to identify trends and cycles in wildfires from 1970 to 2015 for the two areas and examined their association with climate conditions. We found human influence to be reflected in wildfire activity in multiple ways: (1) by dampening (i.e., for area burned)-and even reversing (i.e., for the number of fires)-the increasing trends of fire activity usually associated with drier and warmer conditions; (2) by shifting the peak of fire activity from the summer to the spring; (3) by altering the fire-climate association; and (4) by exhibiting more recurrent (<8 year periodicities) cyclical patterns of fire activity than WBNP (>9 years).", "authors": [ "Campos-Ruiz, Rodrigo", "Parisien, Marc-Andre", "Flannigan, Mike D." ], "keywords": [ "Wildfire", "Wildland fire", "forest fire", "boreal forest", "fire management", "human influence", "climate" ], "year": "2018", "source": "FORESTS", "publication_type": "J", "point2d": [ -4.29653263092041, 47.215904235839844 ], "cluster": 15.0 }, { "idx": 244, "title": "Remote sensing of ecosystem trajectories as a proxy indicator for watershed water balance", "abstract": "Ecosystem trajectories are inextricably linked to hydrology; however, water availability is not easily observed within the landscape. The response of vegetation to soil water availability may provide an indicator of local hydrology and the resilience or sensitivity of ecosystems to long-term changes in water balance. In this study, vegetation trajectories derived from Landsat Modified Soil Adjusted Vegetation Index over a 22-year period are used as an indicator of spatio-temporal changes of watershed water balance and surface water storage within 6 proximal watersheds of the Boreal Plains ecozone of Alberta, Canada. The interactions between hydrology, topography, geology, and land cover type are examined as they relate to vegetation change. In this study, we find that run-off ratio (run-off/precipitation) is greater within watersheds with greater variability of relief, compared within subhumid, wetland-dominated watersheds (average = 0.35, 0.20, respectively), which experience lagged run-off response. A 2-year drought had a greater impact on vegetation trajectories within variable relief watersheds containing a high proportion of coarse-grain surficial geology, compared with peatland-dominated watersheds. The drought extended for an additional 1 to 2 years within 3 subhumid watersheds, reducing watershed run-off to less than 50 mm per water year (November to October) in 2 watersheds. However, proportional area of decline of Modified Soil Adjusted Vegetation Index was significantly less within these watersheds. The results of this study indicate that wetlands play an important role for local water balance and ecosystem maintenance during periods of water stress and should be considered within land use planning and reclamation strategies of the Boreal Plains.", "authors": [ "Chasmer, L. E.", "Devito, K. J.", "Hopkinson, C. D.", "Petrone, R. M." ], "keywords": [ "Boreal", "drought", "hydrology", "Landsat", "remote sensing", "vegetation change", "water balance", "watershed" ], "year": "2018", "source": "ECOHYDROLOGY", "publication_type": "J", "point2d": [ -16.799806594848633, -10.262771606445312 ], "cluster": 13.0 }, { "idx": 245, "title": "The initial three years of carbon dioxide exchange between the atmosphere and a reclaimed oil sand wetland", "abstract": "Northern peatlands contain up to 20% of the similar to 3000 Pg of global soil organic carbon. Carbon-rich peatlands cover upwards of 65% of the landscape in northern Canada where resource extraction activities disturb both the carbon pools and the future carbon sequestration capacity of the landscape. Previous estimates of the carbon losses from this disturbance predict a complete loss of the region's peatland carbon pool. Mining industries operating in these sensitive environments have recently begun constructing closure landscapes which are intended to develop carbon cycle processes similar to undisturbed northern peatlands. This study investigates eddy covariance fluxes of carbon dioxide (CO2) at one of Canada's first fully constructed boreal plains watersheds, the Sandhill Fen Watershed. During the first three years since inception, only the lowland region had an annual net ecosystem exchange of CO2 (NEE) indicative of increasing CO2 sink potential. The lowland region was characterized by saturated salvaged peat soils, standing water, thriving communities of Typha and Carex spp. and was a net CO2 sink of 77 g C m(-2) in the third year. At the same time the upland and the midland regions characterized by moist salvaged peat soils and a mix of herbaceous, shrub and planted Picea glauca and Pinus banksiana remained net sources of CO2. Despite similar rates of gross primary production, ecosystem and plot-level respiration rates in the lowland were significantly lower than in the midland region, likely due to very low reduction potentials within the lowland's saturated soils. With no other significant outflows of carbon, the lowland of the Sandhill Fen Watershed may be in the early stages of organic matter accumulation. Due to limited oxidation of the salvaged peat substrate in the lowland region, wetland reclamation employing these techniques may reduce the disturbance loss of the carbon pool in the boreal plains.", "authors": [ "Clark, M. Graham", "Humphreys, Elyn", "Carey, Sean K." ], "keywords": [ "Eddy covariance", "Net ecosystem exchange (NEE)", "Respiration", "Reclamation", "Wetland", "Peat" ], "year": "2019", "source": "ECOLOGICAL ENGINEERING", "publication_type": "J", "point2d": [ 0.6890631318092346, 63.79682540893555 ], "cluster": 9.0 }, { "idx": 246, "title": "Challenges in Modeling Turbulent Heat Fluxes to Snowpacks in Forest Clearings", "abstract": "Forest clearings are common features of evergreen forests and produce snowpack accumulation and melt differing from that in adjacent forests and open terrain. This study has investigated the challenges in specifying the turbulent fluxes of sensible and latent heat to snowpacks in forest clearings. The snowpack in two forest clearings in the Canadian Rockies was simulated using a one-dimensional (1D) snowpack model. A trade-off was found between optimizing against measured snow surface temperature or snowmelt when choosing how to specify the turbulent fluxes. Schemes using the Monin-Obukhov similarity theory tended to produce negatively biased surface temperature, while schemes that enhanced turbulent fluxes, to reduce the surface temperature bias, resulted in too much melt. Uncertainty estimates from Monte Carlo experiments showed that no realistic parameter set could successfully remove biases in both surface temperature and melt. A simple scheme that excludes atmospheric stability correction was required to successfully simulate surface temperature under low wind speed conditions. Nonturbulent advective fluxes and/or nonlocal sources of turbulence are thought to account for the maintenance of heat exchange in low-wind conditions. The simulation of snowmelt was improved by allowing enhanced latent heat fluxes during low-wind conditions. Caution is warranted when snowpack models are optimized on surface temperature, as model tuning may compensate for deficiencies in conceptual and numerical models of radiative, conductive, and turbulent heat exchange at the snow surface and within the snowpack. Such model tuning could have large impacts on the melt rate and timing of the snow-free transition in simulations of forest clearings within hydrological and meteorological models.", "authors": [ "Conway, Jonathan P.", "Pomeroy, John W.", "Helgason, Warren D.", "Kinar, Nicholas J." ], "keywords": [ "" ], "year": "2018", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -49.16628646850586, -7.074547290802002 ], "cluster": 12.0 }, { "idx": 247, "title": "Challenges in Modeling Turbulent Heat Fluxes to Snowpacks in Forest Clearings", "abstract": "Forest clearings are common features of evergreen forests and produce snowpack accumulation and melt differing from that in adjacent forests and open terrain. This study has investigated the challenges in specifying the turbulent fluxes of sensible and latent heat to snowpacks in forest clearings. The snowpack in two forest clearings in the Canadian Rockies was simulated using a one-dimensional (1D) snowpack model. A trade-off was found between optimizing against measured snow surface temperature or snowmelt when choosing how to specify the turbulent fluxes. Schemes using the Monin-Obukhov similarity theory tended to produce negatively biased surface temperature, while schemes that enhanced turbulent fluxes, to reduce the surface temperature bias, resulted in too much melt. Uncertainty estimates from Monte Carlo experiments showed that no realistic parameter set could successfully remove biases in both surface temperature and melt. A simple scheme that excludes atmospheric stability correction was required to successfully simulate surface temperature under low wind speed conditions. Nonturbulent advective fluxes and/or nonlocal sources of turbulence are thought to account for the maintenance of heat exchange in low-wind conditions. The simulation of snowmelt was improved by allowing enhanced latent heat fluxes during low-wind conditions. Caution is warranted when snowpack models are optimized on surface temperature, as model tuning may compensate for deficiencies in conceptual and numerical models of radiative, conductive, and turbulent heat exchange at the snow surface and within the snowpack. Such model tuning could have large impacts on the melt rate and timing of the snow-free transition in simulations of forest clearings within hydrological and meteorological models.", "authors": [ "Conway, Jonathan P.", "Pomeroy, John W.", "Helgason, Warren D.", "Kinar, Nicholas J." ], "keywords": [ "" ], "year": "2018", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -49.0082893371582, -6.645210266113281 ], "cluster": 12.0 }, { "idx": 248, "title": "Potential influence of nutrient availability along a hillslope: Peatland gradient on aspen recovery following fire", "abstract": "The Boreal Plains (BP) of Western Canada have been exposed to increasing disturbance by wildfire and host a mixture of upland-wetland-pond complexes with substantial quantities of trembling aspen (Populus tremuloides Michx.) throughout the terrestrial areas. The ability of these tree species to regenerate within both upland and wetland areas of the BP following wildfire is unclear. The purpose of this study was to investigate the influence of fire on nutrient dynamics in soil and water in peatlands and forested landscapes in the BP and relate this to aspen regeneration. Nutrient concentrations, nutrient supply rates, and net nutrient mineralization rates were determined in burned and unburned sections of a peatland and forest and compared with the regeneration of aspen. NO3-, NH4+, and P varied spatially throughout the landscape, and differences were observed between peatland and upland areas. In general, differences in nutrient dynamics were not observed between burned and unburned areas, with the exception of P. Nutrient and growth data suggest that aspen do not require nutrient-rich conditions for regeneration and instead relied on forest litter to satisfy nutrient demands. Although the peatlands contained high nutrients, aspen did not flourish in the combination of anoxic and aerobic organic-rich soils present in this area. Although aspen may use peat water and nutrients through their rooting zones, peatlands are unsuitable for aspen re-establishment in the long-term. However, the combination of abundant nutrients in surface mineral soils in peat margins may indicate the vulnerability of margins to upland transformations in later successional stages.", "authors": [ "Depante, M.", "Petrone, R. M.", "Devito, K. J.", "Kettridge, N.", "Macrae, M. L.", "Mendoza, C.", "Waddington, J. . M." ], "keywords": [ "aspen", "boreal", "forests", "nutrients", "peatlands", "succession", "wildfire" ], "year": "2018", "source": "ECOHYDROLOGY", "publication_type": "J", "point2d": [ -8.100092887878418, 74.48251342773438 ], "cluster": 9.0 }, { "idx": 249, "title": "Wildfire as a major driver of recent permafrost thaw in boreal peatlands", "abstract": "Permafrost vulnerability to climate change may be underestimated unless effects of wildfire are considered. Here we assess impacts of wildfire on soil thermal regime and rate of thermokarst bog expansion resulting from complete permafrost thaw in western Canadian permafrost peatlands. Effects of wildfire on permafrost peatlands last for 30 years and include a warmer and deeper active layer, and spatial expansion of continuously thawed soil layers (taliks). These impacts on the soil thermal regime are associated with a tripled rate of thermokarst bog expansion along permafrost edges. Our results suggest that wildfire is directly responsible for 2200 +/- 1500 km(2) (95% CI) of thermokarst bog development in the study region over the last 30 years, representing similar to 25% of all thermokarst bog expansion during this period. With increasing fire frequency under a warming climate, this study emphasizes the need to consider wildfires when projecting future circumpolar permafrost thaw.", "authors": [ "Gibson, Carolyn M.", "Chasmer, Laura E.", "Thompson, Dan K.", "Quinton, William L.", "Flannigan, Mike D.", "Olefeldt, David" ], "keywords": [ "" ], "year": "2018", "source": "NATURE COMMUNICATIONS", "publication_type": "J", "point2d": [ -26.88718605041504, 47.9679069519043 ], "cluster": 15.0 }, { "idx": 250, "title": "Ecohydrological functioning of an upland undergoing reclamation on post-mining landscape of the Athabasca oil sands region, Canada", "abstract": "Ecohydrological functioning of natural Boreal forest in Canada's Boreal Plains is a product of interactions between soil hydrophysical characteristics and hydrogeochemical processes. These interactions create a moisture-nutrient gradient within the surface soils, increasing along low-relief transitions from upland to riparian zone, and in turn influence the distribution of vegetation communities. It is not yet known if/when analogous ecohydrological functions can be achieved in constructed uplands following industrial disturbance, such as that following oil sands development. Hence, to assess this, we studied interactions between hydrogeochemical processes and vegetation colonization in a constructed upland relative to hydrophysical properties of 2 reclamation cover substrates during a typical continental climate's growing season. Our results indicated that in 3years of postconstruction, the establishment of a moisture-nutrient gradient that supports vegetation colonization along slope positions was still limited by heterogeneity of cover substrates. Portions of the upland under peat-mineral mix were characterized by lower nutrient availability, high moisture content, and establishment of planted shrubs and trees. In contrast, forest floor materials plots were characterized by poor soil quality, but higher nutrient availability and greater colonization of invasive grasses and native shrubs. We suggest that the colonization of underdeveloped soils by invasive grasses may facilitate pedogenic processes and thus should be accepted by reclamation managers as a successional milestone in the recovery of ecohydrological functioning of constructed uplands. Poor soil structure under forest floor materials could not support edaphic conditions required by plants to efficiently utilize fertilizer, making this practise futile at the early stage of soil development.", "authors": [ "Gingras-Hill, Tristan", "Nwaishi, Felix C.", "Macrae, Merrin L.", "Price, Jonathan S.", "Petrone, Richard M." ], "keywords": [ "Athabasca oil sands region", "ecohydrology", "forest floor material", "hydrogeochemistry", "peat-mineral mix", "reclamation", "upland" ], "year": "2018", "source": "ECOHYDROLOGY", "publication_type": "J", "point2d": [ 1.3175197839736938, 65.1828842163086 ], "cluster": 9.0 }, { "idx": 251, "title": "Reframing the Challenge of Global Wildfire Threats to Water Supplies", "abstract": "The timing, extent, and severity of forest wildfires have increased in many parts of the world in recent decades. These wildfires can have substantial and devastating impacts on water supply, ecohydrological systems, and sociohydrosystems. Existing frameworks to assess the magnitude and spatial extent of these effects generally focus on local processes or services and are not readily transferable to other regions. However, there is a growing need for regional, continental, and global scale indices to assess the potential effect of wildfires on freshwater availability and water supply resilience. Such indices must consider both the individual and compound effects of wildfires. In so doing, this will enable comprehensive insights on the water security paradigm and the value of hydrological services in fire-affected areas around the globe. Plain Language Summary The number of large forest fires and the length of the wildfire season have both increased globally in the past few decades. Wildfire trends are expected to continue due to increasing occurrence of drought and denser forests associated with historical forest management and fire suppression. This development has raised concerns for water supplies because most water used for irrigation, industry, hydropower, recreation, and community drinking water comes from rivers draining watersheds that are prone to wildfires. As such, it is critical to improve our understanding of the capacity of watersheds and downstream communities to absorb or mitigate fire impacts. In this commentary, we emphasize the need for new continental and global scale indices to assess the full range of wildfire hazards to water supply and society. This will ultimately contribute to sustainable policies and land management plans for safeguarding water supplies and community health.", "authors": [ "Hallema, Dennis W.", "Robinne, Francois-Nicolas", "Bladon, Kevin D." ], "keywords": [ "wildfire", "climate change", "water supply", "water resources", "hydrology", "sociohydrology" ], "year": "2018", "source": "EARTHS FUTURE", "publication_type": "J", "point2d": [ 21.07924461364746, -27.128225326538086 ], "cluster": 11.0 }, { "idx": 252, "title": "Fire-regime changes in Canada over the last half century", "abstract": "Contemporary fire regimes of Canadian forests have been well documented based on forest fire records between the late 1950s to 1990s. Due to known limitations of fire datasets, an analysis of changes in fire-regime characteristics could not be easily undertaken. This paper presents fire-regime trends nationally and within two zonation systems, the homogeneous fire-regime zones and ecozones, for two time periods, 1959-2015 and 1980-2015. Nationally, trends in both area burned and number of large fires (>= 200 ha) have increased significantly since 1959, which might be due to increases in lightning-caused fires. Human-caused fires, in contrast, have shown a decline. Results suggest that large fires have been getting larger over the last 57 years and that the fire season has been starting approximately one week earlier and ending one week later. At the regional level, trends in fire regimes are variable across the country, with fewer significant trends. Area burned, number of large fires, and lightning-caused fires are increasing in most of western Canada, whereas human-caused fires are either stable or declining throughout the country. Overall, Canadian forests appear to have been engaged in a trajectory towards more active fire regimes over the last half century.", "authors": [ "Hanes, Chelene C.", "Wang, Xianli", "Jain, Piyush", "Parisien, Marc-Andre", "Little, John M.", "Flannigan, Mike D." ], "keywords": [ "fire regime", "wildfire", "trend analysis", "Canadian forests" ], "year": "2019", "source": "CANADIAN JOURNAL OF FOREST RESEARCH", "publication_type": "J", "point2d": [ -3.770662784576416, 46.602996826171875 ], "cluster": 15.0 }, { "idx": 253, "title": "A hydrogeological landscape framework to identify peatland wildfire smouldering hot spots", "abstract": "Northern peatlands are important global carbon stores, but there is concern that these boreal peat reserves are at risk due to increased fire frequency and severity as predicted by climate change models. In a subhumid climate, hydrogeological position is an important control on peatland hydrology and wildfire vulnerability. Consequently, we hypothesized that in a coarse-textured glaciofluvial outwash, isolated peatlands lacking the moderating effect of large-scale groundwater flow would have greater water table (WT) variability and would also be more vulnerable to deep WT drawdown and wildfire during dry climate cycles. A holistic approach was taken to evaluate 3 well-accepted factors that are associated with smouldering in boreal peatlands: hollow microform coverage, peatland margin morphometry, and gravimetric water content. Using a combination of field measurements (bulk density, humification, WT position, hummock-hollow distribution, and margin width) and modelling (1-D vertical unsaturated flow coupled with a simple peat-fuel energy balance equation), we assessed the vulnerability of peat to smouldering. We found that a peatland in the regionally intermediate topographic position is the most vulnerable to smouldering due to the interaction of variable connectivity to large-scale groundwater flow and the absence of mineral stratigraphy for limiting WT declines during dry conditions. Our findings represent a novel assessment framework and tool for fire managers by providing a priori knowledge of potential peat smouldering hot spot locations in the landscape to efficiently allocate resources and reduce emergency response time to smouldering events.", "authors": [ "Hokanson, K. J.", "Moore, P. A.", "Lukenbach, M. C.", "Devito, K. J.", "Kettridge, N.", "Petrone, R. M.", "Mendoza, C. A.", "Waddington, J. M." ], "keywords": [ "boreal", "carbon", "hydrogeology", "organic soil", "peatland", "wildfire" ], "year": "2018", "source": "ECOHYDROLOGY", "publication_type": "J", "point2d": [ -12.11715316772461, 66.4629898071289 ], "cluster": 9.0 }, { "idx": 254, "title": "Postfire Soil Carbon Accumulation Does Not Recover Boreal Peatland Combustion Loss in Some Hydrogeological Settings", "abstract": "Deep peat burning at the interface between subhumid Boreal Plains (BP) peatlands and forestlands (margin ecotones) in some hydrogeological settings has brought into question the long-term stability of these peatlands under current and future predicted climate. Small peatlands located at midtopographic positions on coarse sediments have been identified as hot spots for severe burning, as these peatland margins are not regularly connected to regional groundwater flow. The ability of these peatland systems to recover carbon lost from both the interior and margin within the fire return interval, however, has not yet been investigated. Here we examine peatland soil carbon accumulation along a chronosequence of time since fire for 26 BP ombrotrophic bogs located across a range of hydrogeological settings. Soil organic carbon accumulation following wildfire does not appear to be influenced by hydrogeological setting; however, the ability of a peatland to recover the quantity of carbon lost within the fire return interval is dependent on the amount of carbon that was released through smoldering, which is influenced by hydrogeological setting for peatland margins. Based on published measurements of organic soil carbon loss during wildfire and our soil carbon accumulation rates, we suggest that peatlands located at topographic lows on coarse-grained glaciofluvial outwash sediments or on low-relief, fine-grained sediment deposits from glaciolacustrine or subglacial paleoenvironments are currently resilient to wildfire on the BP landscape. Peatlands that experience severe smoldering at the margins, such as ephemerally perched systems on glaciofluvial outwash sediments, will likely undergo permanent loss of legacy carbon stores.", "authors": [ "Ingram, R. C.", "Moore, P. A.", "Wilkinson, S.", "Petrone, R. M.", "Waddington, J. M." ], "keywords": [ "" ], "year": "2019", "source": "JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES", "publication_type": "J", "point2d": [ -15.068239212036133, 68.59832000732422 ], "cluster": 9.0 }, { "idx": 255, "title": "Severe wildfire exposes remnant peat carbon stocks to increased post-fire drying", "abstract": "The potential of high severity wildfires to increase global terrestrial carbon emissions and exacerbate future climatic warming is of international concern. Nowhere is this more prevalent than within high latitude regions where peatlands have, over millennia, accumulated legacy carbon stocks comparable to all human CO2 emissions since the beginning of the industrial revolution. Drying increases rates of peat decomposition and associated atmospheric and aquatic carbon emissions. The degree to which severe wildfires enhance drying under future climates and induce instability in peatland ecological communities and carbon stocks is unknown. Here we show that high burn severities increased post-fire evapotranspiration by 410% within a feather moss peatland by burning through the protective capping layer that restricts evaporative drying in response to low severity burns. High burn severities projected under future climates will therefore leave peatlands that dominate dry sub-humid regions across the boreal, on the edge of their climatic envelopes, more vulnerable to intense post-fire drying, inducing high rates of carbon loss to the atmosphere that amplify the direct combustion emissions.", "authors": [ "Kettridge, N.", "Lukenbach, M. C.", "Hokanson, K. J.", "Devito, K. J.", "Petrone, R. M.", "Mendoza, C. A.", "Waddington, J. M." ], "keywords": [ "" ], "year": "2019", "source": "SCIENTIFIC REPORTS", "publication_type": "J", "point2d": [ -11.826480865478516, 69.17818450927734 ], "cluster": 9.0 }, { "idx": 256, "title": "An Assessment of Surface and Atmospheric Conditions Associated with the Extreme 2014 Wildfire Season in Canada's Northwest Territories", "abstract": "Weather and climate are major factors influencing worldwide wildfire activity. This study assesses surface and atmospheric conditions associated with the 2014 extreme wildfires in the Northwest Territories (NWT) of Canada. Hot and dry conditions led to the NWT experiencing the most severe wildfire season in its recorded history. The season included a record number of cloud-to-ground lightning flashes and set a record for area burned. Lightning was the dominant ignition source and accounted for about 95% of the wildfires. Prolonged periods of smoke led to dramatic reductions in visibility, frequent road closures, and reduced air quality resulting in numerous health alerts. Temporal and spatial patterns of lightning characteristics in 2014, derived from Canadian Lightning Detection Network data, were different from those in other years with, for example, far more positive flashes from 0600 to 1200 utc (midnight to 6:00 am local time). The highest fraction of positive cloud-to-ground flashes (43.1%) occurred in the smoke-dominated North Slave region, which was more than in the Dehcho, South Slave, or Sahtu regions. Mid-tropospheric atmospheric circulation over a large region that included the NWT was classified into the six most common summer patterns. Results showed that ridging and ridge displacements occurred more frequently during 2014 although lightning was associated with all circulation patterns. This study has advanced the understanding of the roles of weather, lightning, and mid-tropospheric circulation patterns associated with extreme wildfires in northwestern Canada.", "authors": [ "Kochtubajda, Bohdan", "Stewart, Ronald E.", "Flannigan, Mike D.", "Bonsal, Barrie R.", "Cuell, Charles", "Mooney, Curtis J." ], "keywords": [ "lightning", "wildfires", "smoke", "Northwest Territories", "500 hPa circulation", "extremes" ], "year": "2019", "source": "ATMOSPHERE-OCEAN", "publication_type": "J", "point2d": [ -3.407972812652588, 45.53281784057617 ], "cluster": 15.0 }, { "idx": 257, "title": "Recent changes to the hydrological cycle of an Arctic basin at the tundra-taiga transition", "abstract": "The impact of transient changes in climate and vegetation on the hydrology of small Arctic headwater basins has not been investigated before, particularly in the tundra-taiga transition region. This study uses weather and land cover observations and a hydrological model suitable for cold regions to investigate historical changes in modelled hydrological processes driving the streamflow response of a small Arctic basin at the treeline. The physical processes found in this environment and explicit changes in vegetation extent and density were simulated and validated against observations of streamflow discharge, snow water equivalent and active layer thickness. Mean air temperature and all-wave irradiance have increased by 3.7 degrees C and 8.4 W m(-2), respectively, while precipitation has decreased 48 mm (10 %) since 1960. Two modelling scenarios were created to separate the effects of changing climate and vegetation on hydrological processes. Results show that over 1960-2016 most hydrological changes were driven by climate changes, such as decreasing snowfall, evapotranspiration, deepening active layer thickness, earlier snow cover depletion and diminishing annual sublimation and soil moisture. However, changing vegetation has a significant impact on decreasing blowing snow redistribution and sublimation, counteracting the impact of decreasing precipitation on streamflow, demonstrating the importance of including transient changes in vegetation in long-term hydrological studies. Streamflow dropped by 38 mm as a response to the 48 mm decrease in precipitation, suggesting a small degree of hydrological resiliency. These results represent the first detailed estimate of hydrological changes occurring in small Arctic basins, and can be used as a reference to inform other studies of Arctic climate change impacts.", "authors": [ "Krogh, Sebastian A.", "Pomeroy, John W." ], "keywords": [ "" ], "year": "2018", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -36.21809768676758, 4.9763312339782715 ], "cluster": 13.0 }, { "idx": 258, "title": "Recent changes to the hydrological cycle of an Arctic basin at the tundra-taiga transition", "abstract": "The impact of transient changes in climate and vegetation on the hydrology of small Arctic headwater basins has not been investigated before, particularly in the tundra-taiga transition region. This study uses weather and land cover observations and a hydrological model suitable for cold regions to investigate historical changes in modelled hydrological processes driving the streamflow response of a small Arctic basin at the treeline. The physical processes found in this environment and explicit changes in vegetation extent and density were simulated and validated against observations of streamflow discharge, snow water equivalent and active layer thickness. Mean air temperature and all-wave irradiance have increased by 3.7 degrees C and 8.4 W m(-2), respectively, while precipitation has decreased 48 mm (10 %) since 1960. Two modelling scenarios were created to separate the effects of changing climate and vegetation on hydrological processes. Results show that over 1960-2016 most hydrological changes were driven by climate changes, such as decreasing snowfall, evapotranspiration, deepening active layer thickness, earlier snow cover depletion and diminishing annual sublimation and soil moisture. However, changing vegetation has a significant impact on decreasing blowing snow redistribution and sublimation, counteracting the impact of decreasing precipitation on streamflow, demonstrating the importance of including transient changes in vegetation in long-term hydrological studies. Streamflow dropped by 38 mm as a response to the 48 mm decrease in precipitation, suggesting a small degree of hydrological resiliency. These results represent the first detailed estimate of hydrological changes occurring in small Arctic basins, and can be used as a reference to inform other studies of Arctic climate change impacts.", "authors": [ "Krogh, Sebastian A.", "Pomeroy, John W." ], "keywords": [ "" ], "year": "2018", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -36.57789993286133, 4.498246669769287 ], "cluster": 13.0 }, { "idx": 259, "title": "Impact of Future Climate and Vegetation on the Hydrology of an Arctic Headwater Basin at the Tundra-Taiga Transition", "abstract": "The rapidly warming Arctic is experiencing permafrost degradation and shrub expansion. Future climate projections show a clear increase in mean annual temperature and increasing precipitation in the Arctic; however, the impact of these changes on hydrological cycling in Arctic headwater basins is poorly understood. This study investigates the impact of climate change, as represented by simulations using a high-resolution atmospheric model under a pseudo-global-warming configuration, and projected changes in vegetation, using a spatially distributed and physically based Arctic hydrological model, on a small headwater basin at the tundra-taiga transition in northwestern Canada. Climate projections under the RCP8.5 emission scenario show a 6.1 degrees C warming, a 38% increase in annual precipitation, and a 19 W m(-2) increase in all-wave annual irradiance over the twenty-first century. Hydrological modeling results suggest a shift in hydrological processes with maximum peak snow accumulation increasing by 70%, snow-cover duration shortening by 26 days, active layer deepening by 0.25 m, evapotranspiration increasing by 18%, and sublimation decreasing by 9%. This results in an intensification of the hydrological regime by doubling discharge volume, a 130% increase in spring runoff, and earlier and larger peak streamflow. Most hydrological changes were found to be driven by climate change; however, increasing vegetation cover and density reduced blowing snow redistribution and sublimation, and increased evaporation from intercepted rainfall. This study provides the first detailed investigation of projected changes in climate and vegetation on the hydrology of an Arctic headwater basin, and so it is expected to help inform larger-scale climate impact studies in the Arctic.", "authors": [ "Krogh, Sebastian A.", "Pomeroy, John W." ], "keywords": [ "Arctic", "Watersheds", "Hydrology", "Climate models", "Hydrologic models" ], "year": "2019", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -35.36594772338867, 3.9402124881744385 ], "cluster": 13.0 }, { "idx": 260, "title": "Disturbance Impacts on Thermal Hot Spots and Hot Moments at the Peatland-Atmosphere Interface", "abstract": "Soil-surface temperature acts as a master variable driving nonlinear terrestrial ecohydrological, biogeochemical, and micrometeorological processes, inducing short-lived or spatially isolated extremes across heterogeneous landscape surfaces. However, subcanopy soil-surface temperatures have been, to date, characterized through isolated, spatially discrete measurements. Using spatially complex forested northern peatlands as an exemplar ecosystem, we explore the high-resolution spatiotemporal thermal behavior of this critical interface and its response to disturbances by using Fiber-Optic Distributed Temperature Sensing. Soil-surface thermal patterning was identified from 1.9 million temperature measurements under undisturbed, trees removed and vascular subcanopy removed conditions. Removing layers of the structurally diverse vegetation canopy not only increased mean temperatures but it shifted the spatial and temporal distribution, range, and longevity of thermal hot spots and hot moments. We argue that linking hot spots and/or hot moments with spatially variable ecosystem processes and feedbacks is key for predicting ecosystem function and resilience.", "authors": [ "Leonard, R. M.", "Kettridge, N.", "Devito, K. J.", "Petrone, R. M.", "Mendoza, C. A.", "Waddington, J. M.", "Krause, S." ], "keywords": [ "soil temperature", "thermal hot spots", "hot moments", "ecosystem structure", "ecosystem functioning" ], "year": "2018", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -14.19074821472168, 63.58159637451172 ], "cluster": 9.0 }, { "idx": 261, "title": "Delineating boreal plains bog margin ecotones across hydrogeological settings for wildfire risk management", "abstract": "Canada's Boreal Plains peatland vegetation species assemblages are characterized by their functional ecosystem roles and feedbacks, which are important for carbon and water storage in a sub-humid climate. The vegetation communities at the peatland-upland interface, or the peatland margin ecotone, have not been extensively delineated or characterized as a distinct ecotone. Because these ecotones constitute a smouldering hotspot during wildfire, with carbon loss from these margins accounting for 50-90% of total peatland carbon loss, their delineation is critical. Post-fire, areas of severe peat smouldering have previously been shown to undergo shifts in vegetation community composition, resulting in a loss of key peatland ecohydrological functions. The aim of this study was to delineate Boreal Plains peatland margin ecotones and assess their prevalence across the landscape. Using split moving window analysis on vegetation transect data from a chronosequence of study sites, the margin ecotones were delineated at sites having different times since fire. No significant differences were identified in margin width over time or margin peat depths across hydrogeological settings. However, with peat depths of up to 2.46m in small peatlands characteristic of moraine and glaciofluvial deposits, vulnerable margin peat has been demonstrated to represent a significant carbon store. Fire managers employing peatland fuel treatments for wildfire abatement and community protection should consider these confined peatlands more carefully to mitigate catastrophic carbon losses. Further, we suggest that a greater understanding is needed of the roles of peatland margin ecotones in sustaining peatland autogenic feedback mechanisms that promote paludification and recovery following wildfire.", "authors": [ "Mayner, Kristyn M.", "Moore, Paul A.", "Wilkinson, Sophie L.", "Petrone, Richard M.", "Waddington, James M." ], "keywords": [ "Peatland", "Ecotone", "Interface", "Sphagnum", "Feathermoss", "Wildfire" ], "year": "2018", "source": "WETLANDS ECOLOGY AND MANAGEMENT", "publication_type": "J", "point2d": [ -13.960976600646973, 67.97308349609375 ], "cluster": 9.0 }, { "idx": 262, "title": "Scenarios of probability and potential power of vegetation fires in the department of Landes, France", "abstract": "Although the southwestern region of France has not experienced a major wildfire in several decades, the wildfire potential of this area remains high. This threat not only represents a matter of human safety, especially given the substantial influx of tourists during the summer season, but also endangers the important forest resources of this region. Widely used in North America, modelling wildfire probability at the landscape level is now a proven method for wildfire risk mapping. The aim of this study is to adapt Burn-P3, a Canadian simulation model for burn probability mapping, to the geographic context of the Landes department, France, in order to calculate wildfire probability and potential fire intensity (considered together as the two main components of wildfire hazard) for several weather scenarios. This exercise involved a conversion of the vegetation of the Landes region to the forest fuel types derived from the Canadian method. Results reveal a highly heterogeneous wildfire probability and head fire intensity across the study landscape, with the two modelled components exhibiting divergent spatial configurations. They also show a rapid and nonlinear increase in wildfire risk according to the severity of weather conditions. These findings represent the first detailed mapping of wildfire risk in southwestern France using a probabilistic simulation model. This product can be readily integrated in risk analysis and guide targeted mitigation actions to improve human safety and optimize the protection of forest resources.", "authors": [ "Parisien, Marc-Andre", "Robinne, Francois-Nicolas", "Perez, Jean-Yves", "Denave, Bruno", "DeLancey, Evan R.", "Doche, Clement" ], "keywords": [ "wildfire probability", "fire intensity", "fire meteorology", "ignitions", "simulation model", "Landes department" ], "year": "2018", "source": "CANADIAN JOURNAL OF FOREST RESEARCH", "publication_type": "J", "point2d": [ -4.483224868774414, 50.106101989746094 ], "cluster": 15.0 }, { "idx": 263, "title": "Hydrological Responses of Headwater Basins to Monthly Perturbed Climate in the North American Cordillera", "abstract": "How mountain hydrology at different elevations will respond to climate change is a challenging question of great importance to assessing changing water resources. Here, three North American Cordilleran snow-dominated basins-Wolf Creek, Yukon; Marmot Creek, Alberta; and Reynolds Mountain East, Idaho-each with good meteorological and hydrological records, were modeled using the physically based, spatially distributed Cold Regions Hydrological Model. Model performance was verified using field observations and found adequate for diagnostic analysis. To diagnose the effects of future climate, the monthly temperature and precipitation changes projected for the future by 11 regional climate models for the mid-twenty-first century were added to the observed meteorological time series. The modeled future was warmer and wetter, increasing the rainfall fraction of precipitation and shifting all three basins toward rainfall-runoff hydrology. This shift was largest at lower elevations and in the relatively warmer Reynolds Mountain East. In the warmer future, there was decreased blowing snow transport, snow interception and sublimation, peak snow accumulation, and melt rates, and increased evapotranspiration and the duration of the snow-free season. Annual runoff in these basins did not change despite precipitation increases, warming, and an increased prominence of rainfall over snowfall. Reduced snow sublimation offset reduced snowfall amounts, and increased evapotranspiration offset increased rainfall amounts. The hydrological uncertainty due to variation among climate models was greater than the predicted hydrological changes. While the results of this study can be used to assess the vulnerability and resiliency of water resources that are dependent on mountain snow, stakeholders and water managers must make decisions under considerable uncertainty, which this paper illustrates.", "authors": [ "Rasouli, Kabir", "Pomeroy, John W.", "Whitfield, Paul H." ], "keywords": [ "" ], "year": "2019", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -33.720272064208984, -14.727179527282715 ], "cluster": 12.0 }, { "idx": 264, "title": "Hydrological Responses of Headwater Basins to Monthly Perturbed Climate in the North American Cordillera", "abstract": "How mountain hydrology at different elevations will respond to climate change is a challenging question of great importance to assessing changing water resources. Here, three North American Cordilleran snow-dominated basins-Wolf Creek, Yukon; Marmot Creek, Alberta; and Reynolds Mountain East, Idaho-each with good meteorological and hydrological records, were modeled using the physically based, spatially distributed Cold Regions Hydrological Model. Model performance was verified using field observations and found adequate for diagnostic analysis. To diagnose the effects of future climate, the monthly temperature and precipitation changes projected for the future by 11 regional climate models for the mid-twenty-first century were added to the observed meteorological time series. The modeled future was warmer and wetter, increasing the rainfall fraction of precipitation and shifting all three basins toward rainfall-runoff hydrology. This shift was largest at lower elevations and in the relatively warmer Reynolds Mountain East. In the warmer future, there was decreased blowing snow transport, snow interception and sublimation, peak snow accumulation, and melt rates, and increased evapotranspiration and the duration of the snow-free season. Annual runoff in these basins did not change despite precipitation increases, warming, and an increased prominence of rainfall over snowfall. Reduced snow sublimation offset reduced snowfall amounts, and increased evapotranspiration offset increased rainfall amounts. The hydrological uncertainty due to variation among climate models was greater than the predicted hydrological changes. While the results of this study can be used to assess the vulnerability and resiliency of water resources that are dependent on mountain snow, stakeholders and water managers must make decisions under considerable uncertainty, which this paper illustrates.", "authors": [ "Rasouli, Kabir", "Pomeroy, John W.", "Whitfield, Paul H." ], "keywords": [ "" ], "year": "2019", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -33.395076751708984, -14.408567428588867 ], "cluster": 12.0 }, { "idx": 265, "title": "A novel tool for measuring the penetration of the ecosystem service concept into public policy", "abstract": "The ecosystem services (ES) concept has gained traction amongst stakeholders involved in environmental regulation, yet little is known about the extent to which the ES concept has been translated into public policy. Here, we present a new online database of policy documents related to ES: GlobaLDES (https://tinyurl.com/GlobalDES). The database was created in 2016 and compiled through a crowdsourced process. Learners involved in a Massive Open Online Course (MOOC) were invited to submit documents that explicitly refer to ES. We included in our analysis documents related to laws, regulations, ordonnances, tax incentives, certification, and strategic planning. By early 2018 the database contained 136 relevant entries from 46 countries. Most examples (60%) were in a language other than English. More than 50% of entries addressed multiple ES or the link between biodiversity and ES. There was also a positive temporal trend towards inclusion of multiple ecosystem services. The GlobaLDES database represents the first known snapshot of the mainstreaming of the ES concept at a global scale. Our analysis suggests an accelerating adoption of the ES concept into policy. As the number of entries improves, GlobaLDES will serve as a useful benchmarking tool for monitoring the diffusion of the ES concept into policy-making.", "authors": [ "Robinne, Francois-Nicolas", "Gallagher, Louise", "Brethaut, Christian", "Schlaepfer, Martin A." ], "keywords": [ "GlobaLDES", "Ecosystem services", "Environmental mainstreaming", "Massive Open Online Course", "Citizen science" ], "year": "2019", "source": "ECOSYSTEM SERVICES", "publication_type": "J", "point2d": [ 58.367637634277344, -41.095481872558594 ], "cluster": 4.0 }, { "idx": 266, "title": "Determination of fire risk to assist fire management for insular areas: the case of a small Greek island", "abstract": "Forest fire risk estimation constitutes an essential process to prevent high-intensity fires which are associated with severe implications to the natural and cultural environment. The primary aim of this research was to determine fire risk levels based on the local features of an island, namely, the impact of fuel structures, slope, aspects, as well as the impact of the road network and inhabited regions. The contribution of all the involved factors to forest fires ignition and behavior highlight certain regions which are highly vulnerable. In addition, the influence of both natural and anthropogenic factors to forest fire phenomena is explored. In this study, natural factors play a dominant role compared to anthropogenic factors. Hence essential preventative measures must focus on specific areas and established immediately. Indicative measures may include: the optimal allocation of watchtowers as well as the spatial optimization of mobile firefighting vehicles; and, forest fuel treatments in areas characterized by extremely high fire risk. The added value of this fire prediction tool is that it is highly flexible and could be adopted elsewhere with the necessary adjustments to local characteristics.", "authors": [ "Sakellariou, S.", "Tampekis, S.", "Samara, F.", "Flannigan, M.", "Jaeger, D.", "Christopoulou, O.", "Sfougaris, A." ], "keywords": [ "Forest fires", "Fire risk", "Multi-criteria analysis", "Fire prevention", "GIS", "Greece" ], "year": "2019", "source": "JOURNAL OF FORESTRY RESEARCH", "publication_type": "J", "point2d": [ -3.0529215335845947, 50.77122116088867 ], "cluster": 15.0 }, { "idx": 267, "title": "Water table dynamics in a constructed wetland, Fort McMurray, Alberta", "abstract": "Surface mining in northern Alberta transforms wetlands and forests into open pits, tailings ponds, and overburden. As part of their license to operate, mine operators are required to reclaim this altered landscape to a predisturbance capacity. In 2012, Syncrude Canada Limited constructed one of the first of two reclaimed wetlands, the Sandhill Fen Watershed (SFW), to evaluate wetland reclamation strategies. SFW is a 52-ha system atop soft-tailings that includes an inflow/outflow pump system, underdrains, upland hummocks, and a fen lowland. In this study, water table dynamics of the fen lowland were evaluated in the 2 years following commissioning (2014-2015) to assess whether this newly constructed watershed has hydrological conditions that facilitate hydric soils with water table regimes similar to reference systems. Results indicate that the location and hydrophysical properties of placed materials control water table responses to both water management and precipitation. This differential water table response in the SFW lowland drove lateral fluxes between adjacent landforms, suggesting periods of intermittent water supply from uplands to wetlands along hummock margins. As in natural systems, the lowland fen exhibited several lateral flow reversals over the 2 years depending upon water level. Water tables on-average were greater than those observed in natural analogues. Comparison during these first 2 years following commissioning contribute to the increasing insight as to how construction and management practices support reclamation postmining.", "authors": [ "Spennato, Haley M.", "Ketcheson, Scott J.", "Mendoza, Carl A.", "Carey, Sean K." ], "keywords": [ "hydrology", "oil sands", "peatland", "reclamation", "water table", "wetland" ], "year": "2018", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 10.151369094848633, 4.085524559020996 ], "cluster": 18.0 }, { "idx": 268, "title": "Could restoration of a landscape to a pre-European historical vegetation condition reduce burn probability?", "abstract": "Montane regions throughout western North America have experienced increases in forest canopy closure and forest encroachment into grasslands over the past century; this has been attributed to climate change and fire suppression/exclusion. These changes threaten ecological values and potentially increase probabilities of intense wildfire. Restoration of landscapes to historical conditions has been proposed as a potential solution. We used historical oblique photographs of an area in the Rocky Mountains of Alberta, Canada, to determine the vegetation composition in 1909 and then asked whether restoration to a historical vegetation condition would: (1) reduce the overall burn probability of fire; (2) reduce the probability of high-intensity fires; and (3) change the spatial pattern of burn probabilities, as compared to current conditions. We used the Burn-P3 model to calculate the overall and high-intensity burn probabilities in two scenarios: (1) the baseline (current (2014) vegetation composition) and (2) historical restoration (vegetation in the study area as of 1909 with the surrounding landscape in its current condition). In the baseline, the landscape had 50% less grassland and more coniferous forest than 100 yr ago. Except for the fuel grids, we ensured all input parameters (number and locations of ignitions, weather conditions, etc.) were identical between the two scenarios; therefore, any differences in outputs are solely attributable to the changed fuels. The historical restoration scenario reduced the overall burn probability by only 1.3%, but the probability of high-intensity wildfires was reduced by nearly half (44.2%), as compared to the baseline scenario. There were also differences in the spatial pattern of overall burn probabilities between the two scenarios. While 6.7% of the landscape burned with half (or less) the probability in the restoration scenario (compared to the baseline), other areas (3.2%) had burn probabilities two to five times higher. More than 21.5% had high-intensity burn probabilities that were 20% or less of those in the baseline scenario. Differences in burn probabilities between the two scenarios were largely attributable to the effects of the vegetation difference on rate of fire spread. Restoration to historical vegetation structure significantly lowered wildfire risk to the landscape.", "authors": [ "Stockdale, Christopher A.", "McLoughlin, Neal", "Flannigan, Mike", "MacDonald, S. Ellen" ], "keywords": [ "burn probability", "burn-P3 model", "ecological restoration", "forest encroachment", "historical ecology", "indicator kriging", "landscape change", "repeat photography", "vegetation change", "wildfire intensity" ], "year": "2019", "source": "ECOSPHERE", "publication_type": "J", "point2d": [ -5.779609203338623, 50.33143997192383 ], "cluster": 15.0 }, { "idx": 269, "title": "Topoedaphic and Forest Controls on Post-Fire Vegetation Assemblies Are Modified by Fire History and Burn Severity in the Northwestern Canadian Boreal Forest", "abstract": "Wildfires, which constitute the most extensive natural disturbance of the boreal biome, produce a broad range of ecological impacts to vegetation and soils that may influence post-fire vegetation assemblies and seedling recruitment. We inventoried post-fire understory vascular plant communities and tree seedling recruitment in the northwestern Canadian boreal forest and characterized the relative importance of fire effects and fire history, as well as non-fire drivers (i.e., the topoedaphic context and climate), to post-fire vegetation assemblies. Topoedaphic context, pre-fire forest structure and composition, and climate primarily controlled the understory plant communities and shifts in the ranked dominance of tree species (***8% and **13% of variance explained, respectively); however, fire and fire-affected soils were significant secondary drivers of post-fire vegetation. Wildfire had a significant indirect effect on understory vegetation communities through post-fire soil properties (**5%), and fire history and burn severity explained the dominance shifts of tree species (*7%). Fire-related variables were important explanatory variables in classification and regression tree models explaining the dominance shifts of four tree species (R-2 = 0.43-0.65). The dominance of jack pine (Pinus banksiana Lamb.) and trembling aspen (Populus tremuloides Michx.) increased following fires, whereas that of black spruce (Picea mariana (Mill.) BSP.) and white spruce (Picea glauca (Moench) Voss) declined. The overriding importance of site and climate to post-fire vegetation assemblies may confer some resilience to disturbed forests; however, if projected increases in fire activity in the northwestern boreal forest are borne out, secondary pathways of burn severity, fire frequency, and fire effects on soils are likely to accelerate ongoing climate-driven shifts in species compositions.", "authors": [ "Whitman, Ellen", "Parisien, Marc-Andre", "Thompson, Dan K.", "Flannigan, Mike D." ], "keywords": [ "boreal forest", "burn severity", "disturbance", "fire effects", "fire history", "forest fire", "regeneration", "species richness" ], "year": "2018", "source": "FORESTS", "publication_type": "J", "point2d": [ -20.00492286682129, 74.2886734008789 ], "cluster": 15.0 }, { "idx": 271, "title": "The effects of black spruce fuel management on surface fuel condition and peat burn severity in an experimental fire", "abstract": "In the boreal plains ecozone, black spruce (Picea mariana (Mill.) Britton, Sterns & Poggenb.) peatlands can represent large parts of the expanding wildland-urban interface (WUI) and wildland-industry interface (WII). The boreal plains wildfire regime is predicted to increase in areal extent and intensity, amplifying the need for wildfire management to protect the WUI and WII. Forested peatland ecosystems can burn at high intensity and present challenges for wildfire managers such as severe smouldering combustion and large carbon loss. Fuel management techniques such as mulching treatments (converting surface and canopy fuel to a masticated fuelbed) can be applied to black spruce peatlands, yet the impact on fuel load, condition, and peat burn severity is unclear. Using observations from an experimental fire, we found that a mulch-thinning fuel treatment could reduce peat depth of burn. However, where peat bulk density was increased by compaction, this led to an increased peat combustion carbon loss relative to the control. Furthermore, near-total combustion of the mulch layer resulted in significantly more surface fuel carbon emission from thinned and stripped fuel-treated areas compared with the control. We argue that although fuel treatment may benefit smouldering combustion suppression efforts, surface fuel carbon loss should be considered before treatments are implemented on a large scale.", "authors": [ "Wilkinson, S. L.", "Moore, P. A.", "Thompson, D. K.", "Wotton, B. M.", "Hvenegaard, S.", "Schroeder, D.", "Waddington, J. M." ], "keywords": [ "prescribed fire", "mulch", "wildfire", "peat", "burn severity" ], "year": "2018", "source": "CANADIAN JOURNAL OF FOREST RESEARCH", "publication_type": "J", "point2d": [ -13.874019622802734, 71.89234924316406 ], "cluster": 9.0 }, { "idx": 272, "title": "Validity of managing peatlands with fire", "abstract": "", "authors": [ "Baird, A. J.", "Evans, C. D.", "Mills, R.", "Morris, P. J.", "Page, S. E.", "Peacock, M.", "Reed, M.", "Robroek, B. J. M.", "Stoneman, R.", "Swindles, G. T.", "Thom, T.", "Waddington, J. M.", "Young, D. M." ], "keywords": [ "" ], "year": "2019", "source": "NATURE GEOSCIENCE", "publication_type": "J", "point2d": [ -17.988229751586914, 65.48538208007812 ], "cluster": 9.0 }, { "idx": 273, "title": "Scientists' warning on wildfire - a Canadian perspective", "abstract": "Recently, the World Scientists' Warning to Humanity: a Second Notice was issued in response to ongoing and largely unabated environmental degradation due to anthropogenic activities. In the warning, humanity is urged to practice more environmentally sustainable alternatives to business as usual to avoid potentially catastrophic outcomes. Following the success of their warning, the Alliance of World Scientists called for discipline-specific follow-up papers. This paper is an answer to that call for the topic of wildland fire. Across much of Canada and the world, wildfires are anticipated to increase in severity and frequency in response to anthropogenic activities. The world scientists' second warning provides the opportunity for wildland fire researchers to raise the profile of the potential impacts that anthropogenic activities are likely to have on future fire regimes and, in return, what impacts future fire regimes may have on humanity. We discuss how wildfire is related to several issues of concern raised in the world scientists' second warning, including climate change, human population growth, biodiversity and forests, and freshwater availability. Furthermore, we touch on the potential future health impacts and challenges to wildfire suppression and management in Canada. In essence, our wildfire scientists' warning to humanity is that we, as a society, will have to learn to live with more fire on the landscape. We provide some recommendations on how we might move forward to prepare for and adapt to future wildfire regimes in Canada. Although this paper is primarily Canadian in focus, the concepts and information herein also draw from international examples and are of relevance globally.", "authors": [ "Coogan, Sean C. P.", "Robinne, Francois-Nicolas", "Jain, Piyush", "Flannigan, Mike D." ], "keywords": [ "climate change", "wildfire", "wildland fire", "world scientists' warning" ], "year": "2019", "source": "CANADIAN JOURNAL OF FOREST RESEARCH", "publication_type": "J", "point2d": [ -1.9337434768676758, 46.52155303955078 ], "cluster": 15.0 }, { "idx": 274, "title": "Hydrogeologic setting overrides any influence of wildfire on pore water dissolved organic carbon concentration and quality at a boreal fen", "abstract": "Western Boreal Canada could experience drier hydrometeorological conditions under future climatic changes, and the drying of nonpermafrost peatlands can lead to higher frequency and extent of wildfires. Despite increasing pressures, our understanding of the impact of fire on dissolved organic carbon (DOC) concentration and quality across boreal peatlands is not consistent. This study capitalizes on the rare opportunity of having 3 years of prefire and 3 years of postfire DOC data at a treed, moderate-rich fen in the Western Boreal Plain, northern Alberta, to investigate wildfire effects on peatland DOC dynamics. We investigated whether a wildfire facilitated any changes in the pore water DOC concentration and quality. There was very little impact of the fire directly, with no significant changes in DOC concentrations postfire. We highlight that DOC patterns are more likely to be controlled by local hydrogeological factors than any effect of fire. Fall hydrological conditions and subsequent winter storage processes impose a strong control on DOC concentrations the following year. We suggest that the presence or absence of concrete ground frost in the fen (determined by fall water table position) influences overwinter storage changes, controlling the effect that DOC-poor snowmelt may have on pore water concentrations. However, an increase in SUVA(254) was found 2 years postfire, indicating an increase in aromaticity. These results highlight the need for careful consideration of the local hydrogeologic setting and hydrological regime when predicting and analysing trends in DOC concentrations and quality.", "authors": [ "Davidson, Scott J.", "Elmes, Matthew C.", "Rogers, Hayley", "van Beest, Christine", "Petrone, Richard", "Price, Jonathan S.", "Strack, Maria" ], "keywords": [ "boreal peatlands", "dissolved organic carbon", "water table dynamics", "wildfire" ], "year": "2019", "source": "ECOHYDROLOGY", "publication_type": "J", "point2d": [ 29.5498104095459, 38.80421447753906 ], "cluster": 9.0 }, { "idx": 275, "title": "Hydraulic redistribution and hydrological controls on aspen transpiration and establishment in peatlands following wildfire", "abstract": "In the sub-humid Western Boreal Plains of Alberta, where evapotranspiration often exceeds precipitation, trembling aspen (Populus tremuloides Michx.) uplands often depend on adjacent peatlands for water supply through hydraulic redistribution. Wildfire is common in the Boreal Plains, so the resilience of the transfer of water from peatlands to uplands through roots immediately following wildfire may have implications for aspen succession. The objective of this research was to characterize post-fire peatland-upland hydraulic connectivity and assess controls on aspen transpiration (as a measure of stress and productivity) among landscape topographic positions. In May 2011, a wildfire affected 90,000 ha of north central Alberta, including the Utikuma Region Study Area (URSA). Portions of an URSA glacio-fluval outwash lake catchment were burned, which included forests and a small peatland. Within 1 year after the fire, aspen were found to be growing in both the interior and margins of this peatland. Across recovering land units, transpiration varied along a topographic gradient of upland midslope (0.42 mm hr(-1)) > upland hilltop (0.29 mm hr(-1)) > margin (0.23 mm hr(-1)) > peatland (0.10 mm hr(-1)); similar trends were observed with leaf area and stem heights. Although volumetric water content was below field capacity, P. tremuloides were sustained through roots present, likely before fire, in peatland margins through hydraulic redistribution. Evidence for this was observed through the analysis of oxygen (delta O-18) and hydrogen (delta H-2) isotopes where upland xylem and peat core signatures were -10.0 parts per thousand and -117.8 parts per thousand and -9.2 parts per thousand and -114.0 parts per thousand, respectively. This research highlights the potential importance of hydraulic redistribution to forest sustainability and recovery, in which the continued delivery of water may result in the encroachment of aspen into peatlands. As such, we suggest that through altering ecosystem services, peatland margins following fire may be at risk to aspen colonization during succession.", "authors": [ "Depante, Midori", "Morison, Matthew Q.", "Petrone, Richard M.", "Devito, Kevin J.", "Kettridge, Nicholas", "Waddington, James M." ], "keywords": [ "Aspen", "boreal", "forest recovery", "hydraulic redistribution", "peatland-upland interface", "transpiration", "Western Boreal Plains", "wildfire" ], "year": "2019", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -8.423192024230957, 72.44995880126953 ], "cluster": 9.0 }, { "idx": 276, "title": "Post-fire peatland vegetation recovery: a case study in open rich fens of the Canadian boreal forest", "abstract": "Fire plays a major role in the structuring and functioning of boreal ecosystems. As peatlands are important components of boreal forests, the impact of fire upon these wetter ecosystems is increasingly studied, but with the focus on treed peatlands and Sphagnum-dominated bogs so far. Important fires occurring more frequently in the past decade in southern Northwest Territories (Canada) provide the opportunity to assess early post-fire vegetation regeneration in open rich fens (one, two, and five years post-fire) and to better understand early recovery succession. We aimed to (i) evaluate whether and how open rich fens are affected by fire, and (ii) describe short-term vegetation regeneration for both bryophytes and vascular species. A shift was observed between pioneer bryophytes and brown mosses between the second and fifth year post-fire. Vascular plants, especially slow-growing species and the ones reproducing mainly by seeds, recovered partially. The first bryophyte species recovering were pioneer species adapted to colonize burned environments such as Marchantia polymorpha L. or Ceratodon purpureus (Hedw.) Brid. For vascular plant species, the ones previously present and able to regrow rapidly from unburned plant structures (base of tussocks, rhizomes, roots) were represented by species like Betula glandulosa Michx. or Carex aquatilis Wahlenb. The wetter conditions and lower fuel availability of fen depressional biotopes were important factors controlling the resistance and regeneration of species associated with them.", "authors": [ "Guene-Nanchen, Melina", "LeBlanc, Marie-Claire", "Rochefort, Line" ], "keywords": [ "peatland", "fen", "fire", "regeneration", "vegetation", "succession" ], "year": "2022", "source": "BOTANY", "publication_type": "J", "point2d": [ -16.937524795532227, 74.93206024169922 ], "cluster": 9.0 }, { "idx": 277, "title": "Assessing the peatland hummock-hollow classification framework using high-resolution elevation models: implications for appropriate complexity ecosystem modeling", "abstract": "The hummock-hollow classification framework used to categorize peatland ecosystem microtopography is pervasive throughout peatland experimental designs and current peatland ecosystem modeling approaches. However, identifying what constitutes a representative hummock-hollow pair within a site and characterizing hummock-hollow variability within or between peatlands remains largely unassessed. Using structure from motion (SfM), high-resolution digital elevation models (DEMs) of hummock-hollow microtopography were used to (1) examine how much area needs to be sampled to characterize site-level microtopographic variation; and (2) examine the potential role of microtopographic shape/structure on biogeochemical fluxes using plot-level data from nine northern peatlands. To capture 95% of site-level microtopographic variability, on average, an aggregate sampling area of 32 m(2) composed of 10 randomly located plots was required. Both site(i.e. transect data) and plot-level (i.e. SfM-derived DEM) results show that microtopographic variability can be described as a fractal at the submeter scale, where contributions to total variance are very small below a 0.5 m length scale. Microtopography at the plot level was often found to be non-bimodal, as assessed using a Gaussian mixture model (GMM). Our findings suggest that the non-bimodal distribution of microtopography at the plot level may result in an undersampling of intermediate topographic positions. Extended to the modeling domain, an underrepresentation of intermediate microtopographic positions is shown to lead to potentially large flux biases over a wide range of water table positions for ecosystem processes which are non-linearly related to water and energy availability at the moss surface. Moreover, our simple modeling results suggest that much of the bias can be eliminated by representing microtopography with several classes rather than the traditional two (i.e. hummock/hollow). A range of tools examined herein can be used to easily parameterize peatland models, from GMMs used as simple transfer functions to spatially explicit fractal landscapes based on simple power-law relations between microtopographic variability and scale.", "authors": [ "Moore, Paul A.", "Lukenbach, Maxwell C.", "Thompson, Dan K.", "Kettridge, Nick", "Granath, Gustaf", "Waddington, James M." ], "keywords": [ "" ], "year": "2019", "source": "BIOGEOSCIENCES", "publication_type": "J", "point2d": [ -10.500311851501465, 64.38351440429688 ], "cluster": 9.0 }, { "idx": 278, "title": "A Regional-Scale Index for Assessing the Exposure of Drinking-Water Sources to Wildfires", "abstract": "Recent human-interface wildfires around the world have raised concerns regarding the reliability of freshwater supply flowing from severely burned watersheds. Degraded source water quality can often be expected after severe wildfire and can pose challenges to drinking water facilities by straining treatment response capacities, increasing operating costs, and jeopardizing their ability to supply consumers. Identifying source watersheds that are dangerously exposed to post-wildfire hydrologic changes is important for protecting community drinking-water supplies from contamination risks that may lead to service disruptions. This study presents a spatial index of watershed exposure to wildfires in the province of Alberta, Canada, where growing water demands coupled with increasing fire activity threaten municipal drinking-water supplies. Using a multi-criteria analysis design, we integrated information regarding provincial forest cover, fire danger, source water volume, source-water origin (i.e., forested/un-forested), and population served. We found that (1) >2/3 of the population of the province relies on drinking-water supplies originating in forested watersheds, (2) forest cover is the most important variable controlling final exposure scores, and (3) watersheds supplying small drinking water treatment plants are particularly exposed, especially in central Alberta. The index can help regional authorities prioritize the allocation of risk management resources to mitigate adverse impacts from wildfire. The flexible design of this tool readily allows its deployment at larger national and continental scales to inform broader water security frameworks.", "authors": [ "Robinne, Francois-Nicolas", "Bladon, Kevin D.", "Silins, Uldis", "Emelko, Monica B.", "Flannigan, Mike D.", "Parisien, Marc-Andre", "Wang, Xianli", "Kienzle, Stefan W.", "Dupont, Diane P." ], "keywords": [ "post-fire hydrology", "source water protection", "drinking-water security", "multi-criteria analysis", "Forests to Faucets", "community drinking-water", "compound wildfire-water risk" ], "year": "2019", "source": "FORESTS", "publication_type": "J", "point2d": [ 21.862760543823242, -25.10193634033203 ], "cluster": 11.0 }, { "idx": 279, "title": "Wildfire impacts on hydrologic ecosystem services in North American high-latitude forests: A scoping review", "abstract": "High-latitude forests of North America are characterized by their natural dependence on large and severe wildfires. However, these wildfires also pose a range of social, economic, and environmental risks, with growing concern regarding persistent effects on stream flow volume, seasonal timing of flow, water quality, aquatic ecosystem health, and downstream community drinking water treatment. Here, we present the outcomes of a comprehensive scoping review of post-fire hydrologic studies in high-latitude forests of North America (Canada and Alaska). Our objectives were to (1) create an inventory of studies on post-fire hydrologic effects on surface water; (2) analyze those studies in terms of watershed characteristics and the type and duration of hydrologic effects; (3) identify and evaluate the link between upstream hydrologic effects with hydrologic ecosystem services; and (4) propose a research agenda addressing the link between wildfire science and hydrologic ecosystem services. We screened 2935 peer-reviewed articles and selected 82 studies to include based on their relevance according to a systematic, multi-step selection process. Next, we classified the papers into five themes: (a) runoff volume and flow regimes, (b) erosion and sediment transport, (c) water chemistry, (d) hydromorphology, and (e) aquatic food webs. For each study, we documented location, fire regime, watershed characteristics, and ecosystem services. The annual number of published studies on post-fire hydrology in high-latitude forests and, in particular, those addressing hydrologic ecosystem services, has increased steadily in recent years. Descriptions of wildfire characteristics, watershed characteristics, and effects on hydrologic ecosystem services were highly variable across studies, hindering cross-study comparisons. Moreover, there were limited efforts to extend study results to implications for forest or water management decisions regarding ecosystem services from source watersheds. Most studies focused on fire impacts on aquatic habitats and water chemistry while services of direct concern to communities, such as drinking water, were rarely addressed. We contend that study standardization, further use of geospatial technologies, and more studies directly addressing ecosystem services will help mitigate the increasing risks to water resources in northern forests.", "authors": [ "Robinne, Francois-Nicolas", "Hallema, Dennis W.", "Bladon, Kevin D.", "Buttle, James M." ], "keywords": [ "Forest fires", "Water security", "Source watersheds", "Post-fire hydrology" ], "year": "2020", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ 20.2185001373291, -25.50351905822754 ], "cluster": 13.0 }, { "idx": 280, "title": "Cellulose nanocrystal zero-valent iron nanocomposites for groundwater remediation", "abstract": "Zero-valent iron nanoparticles (nano-ZVIs) have been widely studied for in situ remediation of groundwater and other environmental matrices. Nano-ZVI particle mobility and reactivity are still the main impediments in achieving efficient in situ groundwater remediation. Compared to the nano-ZVI coating strategy, nano-ZVI stabilization on supporting material allows direct contact with the contaminant, reduces the electron path from the nano-ZVI to the target contaminant and increases nano-ZVI reactivity. Herein, we report the synthesis of nano-ZVI stabilized by cellulose nanocrystal (CNC) rigid nanomaterials (CNC-nano-ZVI; Fe/CNC = 1 w/w) with two different CNC functional surfaces (-OH and -COOH) using a classic sodium borohydride synthesis pathway. The final nanocomposites were thoroughly characterized and the reactivity of CNC-nano-ZVIs was assessed by their methyl orange (MO) dye degradation potential. The mobility of nanocomposites was determined in (sand/glass bead) porous media by utilizing a series of flowthrough transport column experiments. The synthesized CNC-nano-ZVI provided a stable colloidal suspension and demonstrated high mobility in porous media with an attachment efficiency (a) value of less than 0.23. In addition, reactivity toward MO increased up to 25% compared to bare ZVI. The use of CNC as a delivery vehicle shows promising potential to further improve the capability and applicability of nano-ZVI for in situ groundwater remediation and can spur advancements in CNC-based nanocomposites for their application in environmental remediation.", "authors": [ "Bossa, Nathan", "Carpenter, Alexis Wells", "Kumar, Naresh", "de lannoy, Charles-Francois", "Wiesner, Mark" ], "keywords": [ "" ], "year": "2017", "source": "ENVIRONMENTAL SCIENCE-NANO", "publication_type": "J", "point2d": [ 77.89668273925781, 38.578163146972656 ], "cluster": 6.0 }, { "idx": 281, "title": "Hydrological effects of resource-access road crossings on boreal forested peatlands", "abstract": "Resource-access road crossings are expected to alter peatland hydrological properties by obstructing surface and sub-surface water flows. We conducted a multi-year study at two boreal peatlands - a forested bog and a shrubby rich fen near Peace River, Alberta - to study the impacts of resource access roads on the hydrology of adjacent peatland. Field measurements (bi-weekly depth to water table and hydraulic head, one-time hydraulic conductivity) during the growing seasons (May-August) of 2016 and 2017 were taken from sampling plots representing: 1) sides of the road (upstream and downstream); 2) distance from the road (obstruction); and 3) distance from culverts. Compared to the growing season average precipitation for the region of 1.8 mm d(-1), the study period had very wet conditions in 2016 (3.7 mm d(-1)) and dry conditions in 2017 (1.1 mm d(-1)). In contrast to our assumptions, resource access road disturbed the surface and sub-surface water flow at the bog, but the effect was minimal at the fen as the road orientation was nearly parallel to the flow direction at the latter. At the bog, the shallowest depth to water table position was observed at upstream areas closer to the road, when culverts were located > 20m distance from transects. In contrast, when culverts were present < 2m from the transects, variation in hydrological conditions between upstream and downstream areas were greatly reduced. Our work shows road effects on peatland hydrology could be minimized by aligning roads parallel to the water flow direction when possible. If water flow is perpendicular to the road, adequate spacing and installation of culverts could help to reduce flow obstruction.", "authors": [ "Saraswati, Saraswati", "Petrone, Richard M.", "Rahman, Mir Mustafizur", "McDermid, Gregory J.", "Xu, Bin", "Strack, Maria" ], "keywords": [ "Hydrological variation", "Access road", "Boreal peatland", "Hydraulic head", "Water table", "Linear disturbance" ], "year": "2020", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ 9.048413276672363, 2.8203141689300537 ], "cluster": 13.0 }, { "idx": 282, "title": "Increased Peatland Nutrient Availability Following the Fort McMurray Horse River Wildfire", "abstract": "Northern peatlands are experiencing increased wildfire disturbance, threatening peatland biogeochemical function and ability to remain major stores of carbon (C) and macronutrients (nitrogen-N, and phosphorus-P). The impacts of climate change-driven drying on peatland nutrient dynamics have been explored previously; however, the impacts of wildfire on nutrient dynamics have not been examined when comparing burned and unburned areas in a post-fire fen. This study assessed the impact of wildfire on N and P bioavailability, change in CNP stoichiometric balance and feedback on plant nutrient limitation patterns in a fen peatland, one-year post-wildfire, by comparing Burned and Unburned areas. Water extractable P increased up to 200 times in shallow leachate, 125 times in groundwater and 5 times in peat. Surface ash leachate had increased concentrations in Ammonium (NH4+) and Nitrate (NO3-), and through groundwater mobility, increased extractable N concentrations were observed in peat throughout the entire fen. The net mineralization of N and P were minimal at the Burned areas relative to Unburned areas. Fire affected plant nutrient limitation patterns, switching from dominantly N-limited to NP co-limited and P-limitation in moss and vascular species respectively. The top 20 cm of the Burned area C concentrations was higher relative to the Unburned area, with increased CN and CP ratios also being found in the Burned area. These findings suggest that the long-term effects of elevated C, N, and P concentrations on plant productivity and decomposition must be re-evaluated for fire disturbance to understand the resiliency of peatland biogeochemistry post-wildfire.", "authors": [ "van Beest, Christine", "Petrone, Richard", "Nwaishi, Felix", "Waddington, James Michael", "Macrae, Merrin" ], "keywords": [ "wildfire", "peatland", "nitrogen", "phosphorus", "nutrients" ], "year": "2019", "source": "DIVERSITY-BASEL", "publication_type": "J", "point2d": [ -9.450139045715332, 74.3434066772461 ], "cluster": 9.0 }, { "idx": 283, "title": "Seasonal ground ice impacts on spring ecohydrological conditions in a western boreal plains peatland", "abstract": "Peatlands in the Western Boreal Plains act as important water sources in the landscape. Their persistence, despite potential evapotranspiration (PET) often exceeding annual precipitation, is attributed to various water storage mechanisms. One storage element that has been understudied is seasonal ground ice (SGI). This study characterized spring SGI conditions and explored its impacts on available energy, actual evapotranspiration, water table, and near surface soil moisture in a western boreal plains peatland. The majority of SGI melt took place over May 2017. Microtopography had limited impact on melt rates due to wet conditions. SGI melt released 139mm in ice water equivalent (IWE) within the top 30cm of the peat, and weak significant relationships with water table and surface moisture suggest that SGI could be important for maintaining vegetation transpiration during dry springs. Melting SGI decreased available energy causing small reductions in PET (<10mm over the melt period) and appeared to reduce actual evapotranspiration variability but not mean rates, likely due to slow melt rates. This suggests that melting SGI supplies water, allowing evapotranspiration to occur at near potential rates, but reduces the overall rate at which evapotranspiration could occur (PET). The role of SGI may help peatlands in headwater catchments act as a conveyor of water to downstream landscapes during the spring while acting as a supply of water for the peatland. Future work should investigate SGI influences on evapotranspiration under differing peatland types, wet and dry spring conditions, and if the spatial variability of SGI melt leads to spatial variability in evapotranspiration.", "authors": [ "Van Huizen, Brandon", "Petrone, Richard M.", "Price, Jonathan S.", "Quinton, William L.", "Pomeroy, John W." ], "keywords": [ "evapotranspiration", "ground heat flux", "microtopography", "peatlands", "seasonal ground ice", "western boreal plain" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -16.142229080200195, 56.78525924682617 ], "cluster": 13.0 }, { "idx": 284, "title": "Quantifying the spatial variability of melting seasonal ground ice and its influence on potential evapotranspiration spatial variability in a boreal peatland", "abstract": "Melting seasonal ground ice (SGI) in western Boreal Plains (WBP) peatlands can reduce the available energy at the surface by reducing potential evapotranspiration (PET). PET often exceeds annual precipitation in the WBP. Including this effect in hydrological models may be important in assessing water deficits. However, SGI melt and the timing of ice-free conditions vary spatially, which suggests PET spatial variability could be influenced by SGI. Understanding this potential linkage can help improve site scale PET in peatland hydrological models. The objectives of this paper were (a) to quantify the effect of ice thickness and melt rate on peatland PET; (b) quantify the spatial variability of SGI thickness and melt rate across spatial scales; and (c) assess how/if spatial variability in SGI thickness/melt rate affects site scale PET. Results from the sensitivity analysis indicated that SGI thickness had a bigger impact on reducing PET compared with the melt rate. Two SGI thickness values were used that were observed on site: 0.32 m, which was measured in a more treed area, and 0.18 m, which was in a more open area. The 0.32 m had an average PET reduction of 14 mm (+/- 0.7), over the month of May, compared with 9 mm (+/- 1 mm) when there was 0.18 m of SGI, which are 13.7 and 8.8% reductions, respectively. SGI thickness and melt rate, both exhibited large- and small-scale spatial variability. At the large scale, spatial patterns in SGI thickness appeared to be influenced by extensive shading from the adjacent hillslopes. Small scale, SGI thickness may be a function of tree proximity and the snowpack. Finally, net radiation, rather than SGI, appeared to be the main driver behind PET spatial variability. This work enhances our conceptual understanding of the role of SGI in WBP peatlands. Future work can use the findings to better inform peatland hydrological models, allowing for better representation of peatlands in regional-scale models.", "authors": [ "Van Huizen, Brandon", "Petrone, Richard M." ], "keywords": [ "ground heat flux", "peatlands", "potential evapotranspiration", "seasonal ground ice", "spatial variability" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -15.710670471191406, 57.076595306396484 ], "cluster": 13.0 }, { "idx": 285, "title": "Hydrophobicity of peat soils: Characterization of organic compound changes associated with heat-induced water repellency", "abstract": "Boreal peatlands provide critical global and regional ecosystem functions including climate regulation and nutrient and water retention. Wildfire represents the largest disturbance to these ecosystems. Peatland resilience depends greatly on the extent of post-fire peat soil hydrophobicity. Climate change is altering wildfire intensity and severity and consequently impacting post-fire peat soil chemistry and structure. However, research on fire-impacted peatlands has rarely considered the influence of peat soil chemistry and structure on peatland resilience. Here we characterized the geochemical and physical properties of natural peat soils under laboratory heating conditions. The general trend observed is that hydrophilic peat soils become hydrophobic under moderate heating and then become hydrophilic again after heating for longer, or at higher, temperatures. The loss of peat soil hydrophilicity initially occurs due to evaporative water loss (250 degrees C and 300 degrees C for <5 min). Gently but thoroughly dried peat soils (105 degrees C for 24 h) also show mass losses after heating, indicating the loss of organic compounds through thermal degradation. Gas chromatography-mass spectrometry (GC-MS) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the chemistry of unburned and 300 degrees C burned peat soils, and various fatty acids, polycyclic compounds, saccharides, aromatic acids, short-chain molecules, lignin and carbohydrates were identified. We determined that the heat-induced degradation of polycyclic compounds and aliphatic hydrocarbons, especially fatty acids, caused dried, hydrophobic peat soils to become hydrophilic after only 20 min of heating at 300 degrees C. Furthermore, peat soils became hydrophilic more quickly (20 min vs 6 h) with an increase in heat from 250 degrees C et to 300 degrees C. Minimal structural changes occurred, as characterized by BET and SEM analyses, confirming that surface chemistry, in particular fatty add content, rather than structure govern changes in peat soil hydrophobicity. (C) 2020 Elsevier B.V. All rights reserved.", "authors": [ "Wu, Yichen", "Zhang, Nan", "Slater, Greg", "Waddington, James Michael", "de Lannoy, Charles-Francois" ], "keywords": [ "Feather moss", "Hydrophilicity", "Wildfire", "Moisture content", "GC-MS analysis", "Chemical characterization" ], "year": "2020", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ -3.575302839279175, 70.9629135131836 ], "cluster": 9.0 }, { "idx": 286, "title": "Hydrophobicity of peat soils: Characterization of organic compound changes associated with heat-induced water repellency", "abstract": "Boreal peatlands provide critical global and regional ecosystem functions including climate regulation and nutrient and water retention. Wildfire represents the largest disturbance to these ecosystems. Peatland resilience depends greatly on the extent of post-fire peat soil hydrophobicity. Climate change is altering wildfire intensity and severity and consequently impacting post-fire peat soil chemistry and structure. However, research on fire-impacted peatlands has rarely considered the influence of peat soil chemistry and structure on peatland resilience. Here we characterized the geochemical and physical properties of natural peat soils under laboratory heating conditions. The general trend observed is that hydrophilic peat soils become hydrophobic under moderate heating and then become hydrophilic again after heating for longer, or at higher, temperatures. The loss of peat soil hydrophilicity initially occurs due to evaporative water loss (250 degrees C and 300 degrees C for <5 min). Gently but thoroughly dried peat soils (105 degrees C for 24 h) also show mass losses after heating, indicating the loss of organic compounds through thermal degradation. Gas chromatography-mass spectrometry (GC-MS) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the chemistry of unburned and 300 degrees C burned peat soils, and various fatty acids, polycyclic compounds, saccharides, aromatic acids, short-chain molecules, lignin and carbohydrates were identified. We determined that the heat-induced degradation of polycyclic compounds and aliphatic hydrocarbons, especially fatty acids, caused dried, hydrophobic peat soils to become hydrophilic after only 20 min of heating at 300 degrees C. Furthermore, peat soils became hydrophilic more quickly (20 min vs 6 h) with an increase in heat from 250 degrees C et to 300 degrees C. Minimal structural changes occurred, as characterized by BET and SEM analyses, confirming that surface chemistry, in particular fatty add content, rather than structure govern changes in peat soil hydrophobicity. (C) 2020 Elsevier B.V. All rights reserved.", "authors": [ "Wu, Yichen", "Zhang, Nan", "Slater, Greg", "Waddington, James Michael", "de Lannoy, Charles-Francois" ], "keywords": [ "Feather moss", "Hydrophilicity", "Wildfire", "Moisture content", "GC-MS analysis", "Chemical characterization" ], "year": "2020", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ -3.575302839279175, 70.9629135131836 ], "cluster": 9.0 }, { "idx": 287, "title": "Integrated modelling of the impacts of hydropower projects on the water-food-energy nexus in a transboundary Himalayan river basin", "abstract": "The sustainable development goals (SDGs) and the Paris agreement target a global cleaner energy transition with wider adaptation, poverty reduction and climate resilience benefits. Hydropower development in the trans boundary Koshi river basin in the Himalayan region presents an intervention that can support the SDGs whilst meeting the regional commitments to the Paris agreement. This study aims to quantify the benefits of proposed water resource development projects in the transboundary basin (4 storage and 7 run-of-the-river hydropower dams) in terms of hydroelectric power generation, crop production and flood damage reduction. A hydro-economic model is constructed by soft coupling hydrological and crop growth simulation models to an economic optimization model. The model assesses the potential of the interventions to break the vicious cycle of poverty and water, food, and energy insecurity. Unlike previous studies, the model (a) incorporates the possibility of using hydropower to pump groundwater for irrigation as well as flood regulation and (b) quantifies the resilience of the estimated benefits under future climate scenarios from downscaled general circulation models affecting both river flows and crop growth. The results show significant potential economic benefits generated from electricity production, increased agricultural production, and flood damage control at the transboundary basin scale. The estimated annual benefits are around USD 2.3 billion under the baseline scenario and USD 2.4 billion under a future (RCP 4.5) climate scenario, compared to an estimated annual investment cost of USD 0.7 billion. The robustness of the estimated benefits illustrates the climate resilience of the water resource development projects. Contrary to the commonly held view that the benefits of these proposed projects are limited to hydropower, the irrigation and flood regulation benefits account for 40 percent of the total benefits. The simulated scenarios also show substantial irrigation gains from the construction of the ROR schemes, provided the generated power is also used for groundwater irrigation. The integrated modelling framework and results provide useful policy insights for evidence-based decision-making in transboundary river basins around the globe facing the challenges posed by the water-food-energy nexus.", "authors": [ "Amjath-Babu, T. S.", "Sharma, Bikash", "Brouwer, Roy", "Rasul, Golam", "Wahid, Shahriar M.", "Neupane, Nilhari", "Bhattarai, Utsav", "Sieber, Stefan" ], "keywords": [ "Water-food-energy nexus", "Hydro-economic modelling", "Koshi river basin", "Climate change" ], "year": "2019", "source": "APPLIED ENERGY", "publication_type": "J", "point2d": [ 40.943058013916016, -49.72779083251953 ], "cluster": 11.0 }, { "idx": 288, "title": "Comparative valuation of potential and realized ecosystem services in Southern Ontario, Canada", "abstract": "The full production of a given ecosystem service is called the potential ecosystem service; the fraction of the potential ecosystem service that is actually used by society is referred to as the realized ecosystem service. Because they are directly contributing to human well-being, the realized ecosystem services are of particular socio-economic importance. A key challenge faced by the economic valuation of ecosystem services is how to differentiate between realized and potential ecosystem services. Here, we address this challenge for Southern Ontario, which is the most densely populated region of Canada. We apply the CoSting Nature model to generate the combined spatial distribution and use intensity of a bundle of six ecosystem services: water provisioning and supply, water quality, carbon sequestration, carbon storage, flood regulation, and nature-based tourism. The relative distribution of the potential ecosystem services is then combined with region-specific unit values for the land covers supplying the ecosystem services. The unit values are expressed in 2017 Canadian dollars per hectare and per year. Our analysis yields a total potential value of the bundled ecosystem services of $19 billion per year for Southern Ontario. To estimate the value of the realized ecosystem services, the potential values are scaled by the corresponding relative use indices. The resulting value of the realized ecosystem services is $9.7 billion per year, that is, about 50% of the value of the potential ecosystem services. The importance of accounting for the use intensity of ecosystem services is illustrated for the Greenbelt, a protected area of about 7600 km(2) surrounding the Greater Toronto-Hamilton conurbation, which is home to more than nine million people. Within the Greenbelt, 61% of the value of potential ecosystem services is realized, significantly higher than the regional average. Of particular importance is flood regulation by the Greenbelt, given the growing threat of urban flooding in the Toronto area.", "authors": [ "Aziz, Tariq", "Van Cappellen, Philippe" ], "keywords": [ "Potential ecosystem services", "Realized ecosystem services", "Economic valuation", "CoSting nature", "Southern Ontario", "Greenbelt" ], "year": "2019", "source": "ENVIRONMENTAL SCIENCE & POLICY", "publication_type": "J", "point2d": [ 51.291107177734375, -43.74799346923828 ], "cluster": 11.0 }, { "idx": 289, "title": "On the Role of a Large Shallow Lake (Lake St. Clair, USA-Canada) in Modulating Phosphorus Loads to Lake Erie", "abstract": "It is often assumed that large shallow water bodies are net sediment nondepositional annually and that if they have nutrient loads from multiple sources, those loads are quickly homogenized before exiting the water bodies. Where this is not the case, it impacts understanding and predicting consequences of nutrient load reductions, both for the water body and for those downstream of it. We applied a three-dimensional ecological model to a large shallow lake, Lake St. Clair (US/Canada), to quantify the total and dissolved reactive phosphorus (TP and DRP) transport and retention, and construct tributary-specific relationships between phosphorus load to the lake and the amount of phosphorus that leaves the lake for the three major tributaries. Lake St. Clair is situated between the St. Clair and Detroit rivers, the latter enters Lake Erie. Efforts to reduce Lake Erie's re-eutrophication requires an understanding of nutrient transport and retention in each of its subwatersheds including those that feed indirectly via Lake St. Clair. We found that over the simulation period, the lake retained a significant portion of TP (17%) and DRP (35%) load and that TP and DRP retention was spatially variable and largely controlled by a combination of lake depth, resuspension, and plankton uptake. Compared to the Clinton and Sydenham rivers, the Thames River contributed a larger proportion of its load to the lake's outflow. However, because the lake's load is dominated by the St. Clair River, 40% reductions of nutrients from those subwatersheds will result in less than a 5% reduction in the load to Lake Erie.", "authors": [ "Bocaniov, Serghei A.", "Van Cappellen, Philippe", "Scavia, Donald" ], "keywords": [ "Lake St", "Clair", "Nutrients", "Retention", "Settling", "Tributary", "Resuspension" ], "year": "2019", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 51.22147750854492, 5.803239822387695 ], "cluster": 19.0 }, { "idx": 290, "title": "Nutrient Loss Rates in Relation to Transport Time Scales in a Large Shallow Lake (Lake St. Clair, USA-Canada): Insights From a Three-Dimensional Model", "abstract": "A nutrient mass balance and a three-dimensional, coupled hydrodynamic-ecological model, calibrated and validated for Lake St. Clair with observations from 2009 and 2010, were integrated to estimate monthly lake-scale nutrient loss rates, and to calculate 3 monthly transport time scales: flushing time, water age, and water residence time. While nutrient loss rates had statistically significant relationships with all transport time scale measures, water age had the strongest explanatory power, with water age and nutrient loss rates both smaller in spring and fall and larger in summer. We show that Lake St. Clair is seasonally divided into two discrete regions of contrasting water age and productivity. The north-western region is dominated by oligotrophic waters from the St. Clair River, and south-eastern region is dominated by the nutrient enriched, more productive waters from the Thames-Sydenham River complex. The spatial and temporal variations in local transport scales and nutrient loss rates, coupled with strong seasonal variations in discharge and nutrient loads from the major tributaries, suggest the need for different load reduction strategies for different tributaries.", "authors": [ "Bocaniov, Serghei A.", "Scavia, Donald" ], "keywords": [ "phosphorus", "water age", "ecosystem modeling", "nutrient mass balance", "ELCOM-CAEDYM" ], "year": "2018", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 51.91828155517578, 5.360506057739258 ], "cluster": 19.0 }, { "idx": 291, "title": "Subwatershed-based lake and river routing products for hydrologic and land surface models applied over Canada", "abstract": "Lakes and reservoirs have critical impacts on hydrological, biogeochemical, and ecological processes, and they should be an essential component of regional-scale hydrological and eco-hydrological models. This is particularly important in Canada with its tens of thousands of lakes. Past large-scale hydrologic modelling efforts tend to either ignore the impacts of all lakes or explicitly simulate the behaviour of only the largest lakes in a watershed. This research derives a suite of Pan-Canadian subwatershed-based lake and river routing GIS products at multiple spatial resolutions (average catchment size ranges from 60 to 306 km(2)while the number of lakes explicitly represented ranges from 11,000 to 87,000). These publicly available data products supply all the necessary hydrologic routing model inputs, including network topology, subwatershed geometry, channel characteristics (slope, length, roughness, and geometry), and lake characteristics (area, volume, and outlet description), and were derived primarily from the HydroLAKES, HydroBASINS and HydroSHEDS databases. All Water Survey of Canada streamflow gauging stations are used to define subwatershed outlets in the products. The routing product is used to inform a hydrologic routing model in the Raven hydrologic modelling framework. This is the first demonstration of Raven in routing-only mode. As a case study, the Hudson Bay drainage basin (similar to 40% of Canada) is simulated using GEM-Surf land surface model gridded runoff and recharge as inputs and includes more than 20,000 river reaches and more than 10,000 lakes explicitly represented at an hourly timestep. Uncalibrated streamflows compare reasonably well to measured streamflows at select locations. The sensitivity of the routing model prediction quality to the discretization level for represented lakes is evaluated and shows, for example, that ignoring multiple smaller lakes can have a significant impact on predictions.", "authors": [ "Han, Ming", "Mai, Juliane", "Tolson, Bryan A.", "Craig, James R.", "Gaborit, Etienne", "Liu, Hongli", "Lee, Konhee" ], "keywords": [ "Routing", "lakes", "pan-Canadian", "HydroSHEDS", "HydroLAKES" ], "year": "2020", "source": "CANADIAN WATER RESOURCES JOURNAL", "publication_type": "J", "point2d": [ 0.8319798111915588, -15.393881797790527 ], "cluster": 10.0 }, { "idx": 292, "title": "Criteria-based ranking (CBR): A comprehensive process for selecting and prioritizing monitoring indicators", "abstract": "Resources allocated to natural resource management often fluctuate, requiring the types and numbers of parameters used in monitoring programs (e.g., indicators of ecosystem health) to be frequently reassessed. Conventional approaches to selecting monitoring indicators are often biased and non-inclusive. A new Criteria-based Ranking (CBR) process for selecting and/or prioritizing indicators was tested in the Muskoka River Watershed (Ontario, Canada). The CBR process is based on two environmental assessment tools, Simple Weighted and Leopold matrices. It incorporates environmental components and criteria for assessing each indicator, which generate a score per indicator. The process tested in this study was concluded to be an effective way to prioritize and/or select environmental monitoring indicators. A different set of indicators emerged when a common set of criteria was used to assess monitoring indicators. Benefits of the CBR process include: Standardization of indicator selection process with less bias and lower cost (e.g., time and human resources). Indicators that are representative of the community and more relevant for decision-making (e.g., more resilient to socio-political change). Adaptability: (1) to other goals, e.g., selecting from a list of Valued Ecosystem Components (VECs), and (2) to any context through localized scoring criteria. Easily integrated into existing practice. (C) 2018 The Author(s). Published by Elsevier B.V.", "authors": [ "Ho, Elaine" ], "keywords": [ "Valued ecosystem components (VECs)", "Indicators", "Monitoring", "Watershed monitoring", "Water monitoring", "Indicator selection process" ], "year": "2018", "source": "METHODSX", "publication_type": "J", "point2d": [ 56.479576110839844, -22.439672470092773 ], "cluster": 11.0 }, { "idx": 293, "title": "Assessing current monitoring indicators and reporting for cumulative effects integration: A case study in Muskoka, Ontario, Canada", "abstract": "Climate is changing at an unprecedented rate with impacts being felt in social and ecological systems around the world. Opportunities for building climate resilience of the social-ecological system surrounding freshwater areas are assessed using the aquatic monitoring and reporting programs of Muskoka River Watershed (Ontario, Canada) as a case study. A three-step study design was used: establishment of a knowledge baseline (i.e., what has been done), confirmation of the baseline to ensure perspectives that emerged were inclusive of multiple stakeholders (i.e., broadly applicable) and an exploratory workshop to disseminate recommendations and discuss implementation with key stakeholders. Two themes are discussed: the strengthening of watershed-scale monitoring approaches, and improved communication with stakeholders (e.g., through 'state of the watershed' reporting). This study offers an evaluation of watershed-scale aquatic monitoring and reporting and provides concrete examples from the case study. We test a new process for refining, selecting, or prioritizing indicators for aquatic monitoring. Cumulative effects assessment and monitoring (CEAM) is considered as the suggested monitoring approach at a watershed-scale. Recommendations for developing CEAM in the Muskoka River Watershed include considerations for selection of monitoring indicators, consistent communication of indicators, and implementing a metadatabase. Ways to enhance education of, and engagement with, local stakeholders through improved 'state of the watershed' report cards are highlighted. Resilience is strengthened by addressing two goals in the case study: engaging with the community and improving knowledge of stressor-effect relationships in the watershed via stronger aquatic monitoring.", "authors": [ "Ho, Elaine", "Eger, Sondra", "Courtenay, Simon C." ], "keywords": [ "Social-ecological resilience", "Climate change", "Cumulative effects", "Monitoring indicators", "Watershed monitoring", "Watershed reporting" ], "year": "2018", "source": "ECOLOGICAL INDICATORS", "publication_type": "J", "point2d": [ 56.68428039550781, -24.7276611328125 ], "cluster": 4.0 }, { "idx": 294, "title": "A Race Against Time: Modeling Time Lags in Watershed Response", "abstract": "Land use change and agricultural intensification have increased food production but at the cost of polluting surface and groundwater. Best management practices implemented to improve water quality have met with limited success. Such lack of success is increasingly attributed to legacy nutrient stores in the subsurface that may act as sources after reduction of external inputs. However, current water-quality models lack a framework to capture these legacy effects. Here we have modified the SWAT (Soil Water Assessment Tool) model to capture the effects of nitrogen (N) legacies on water quality under multiple land-management scenarios. Our new SWAT-LAG model includes (1) a modified carbon-nitrogen cycling module to capture the dynamics of soil N accumulation, and (2) a groundwater travel time distribution module to capture a range of subsurface travel times. Using a 502-km(2) Iowa watershed as a case study, we found that between 1950 and 2016, 25% of the total watershed N surplus (N Deposition + Fertilizer + Manure + N Fixation - Crop N uptake) had accumulated within the root zone, 14% had accumulated in groundwater, while 27% was lost as riverine output, and 34% was denitrified. In future scenarios, a 100% reduction in fertilizer application led to a 79% reduction in stream N load, but the SWAT-LAG results suggest that it would take 84years to achieve this reduction, in contrast to the 2years predicted in the original SWAT model. The framework proposed here constitutes a first step toward modifying a widely used modeling approach to assess the effects of legacy N on the time required to achieve water-quality goals. Plain Language Summary For nearly a century, we have used nitrogen fertilizers to boost crop yields. However, the environmental effects of fertilizer use have been severe. Drinking water with high nitrate levels threatens human health, and high nitrogen loads in rivers lead to the creation of dead zones in coastal waters that make it impossible for fish or underwater plants to survive. Although we have tried for decades to reduce nitrogen levels in our waterways, the results have been disappointing. Scientists now believe that improvements may be slow to come because there are large amounts of nitrogen that have accumulated in soil and groundwater-legacy nitrogen-that continue to pollute our rivers even after farmers have reduced fertilizer use or improved management. However, policymakers still struggle to predict how long it will take to improve water quality. In our work, we have created a new model, Soil Water Assessment Tool-LAG, that allows us to predict the time lags caused by legacy nitrogen. Using an agricultural watershed in Iowa as a case study, we show that it can take as long as 80years to see the full effects of new management practices and that these time lags must be considered when setting policy goals.", "authors": [ "Ilampooranan, Idhayachandhiran", "Van Meter, K. J.", "Basu, Nandita B." ], "keywords": [ "" ], "year": "2019", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 30.797210693359375, 3.09132719039917 ], "cluster": 10.0 }, { "idx": 295, "title": "Scientists' Warning to Humanity: Rapid degradation of the world's large lakes", "abstract": "Large lakes of the world are habitats for diverse species, including endemic taxa, and are valuable resources that provide humanity with many ecosystem services. They are also sentinels of global and local change, and recent studies in limnology and paleolimnology have demonstrated disturbing evidence of their collective degradation in terms of depletion of resources (water and food), rapid warming and loss of ice, destruction of habitats and ecosystems, loss of species, and accelerating pollution. Large lakes are particularly exposed to anthropogenic and climatic stressors. The Second Warning to Humanity provides a framework to assess the dangers now threatening the world's large lake ecosystems and to evaluate pathways of sustainable development that are more respectful of their ongoing provision of services. Here we review current and emerging threats to the large lakes of the world, including iconic examples of lake management failures and successes, from which we identify priorities and approaches for future conservation efforts. The review underscores the extent of lake resource degradation, which is a result of cumulative perturbation through time by long-term human impacts combined with other emerging stressors. Decades of degradation of large lakes have resulted in major challenges for restoration and management and a legacy of ecological and economic costs for future generations. Large lakes will require more intense conservation efforts in a warmer, increasingly populated world to achieve sustainable, high-quality waters. This Warning to Humanity is also an opportunity to highlight the value of a long-term lake observatory network to monitor and report on environmental changes in large lake ecosystems. (C) 2020 The Authors. Published by Elsevier B.V. on behalf of International Association for Great Lakes Research.", "authors": [ "Jenny, Jean-Philippe", "Anneville, Orlane", "Arnaud, Fabien", "Baulaz, Yoann", "Bouffard, Damien", "Domaizon, Isabelle", "Bocaniov, Serghei A.", "Chevre, Nathalie", "Dittrich, Maria", "Dorioz, Jean-Marcel", "Dunlop, Erin S.", "Dur, Gael", "Guillard, Jean", "Guinaldo, Thibault", "Jacquet, Stephan", "Jamoneau, Aurelien", "Jawed, Zobia", "Jeppesen, Erik", "Krantzberg, Gail", "Lenters, John", "Leoni, Barbara", "Meybeck, Michel", "Nava, Veronica", "Noges, Tiina", "Noges, Peeter", "Patelli, Martina", "Pebbles, Victoria", "Perga, Marie-Elodie", "Rasconi, Serena", "Ruetz, Carl R., III", "Rudstam, Lars", "Salmaso, Nico", "Sapna, Sharma", "Straile, Dietmar", "Tammeorg, Olga", "Twiss, Michael R.", "Uzarski, Donald G.", "Ventela, Anne-Mari", "Vincent, Warwick F.", "Wilhelm, Steven W.", "Wangberg, Sten-Ake", "Weyhenmeyer, Gesa A." ], "keywords": [ "Second Warning to Humanity", "Large lakes", "Global change", "Biodiversity loss", "Ecosystem services", "Eutrophication" ], "year": "2020", "source": "JOURNAL OF GREAT LAKES RESEARCH", "publication_type": "J", "point2d": [ 56.62987518310547, -1.669952154159546 ], "cluster": 19.0 }, { "idx": 296, "title": "The Transboundary Impacts of Trade Liberalization and Climate Change on the Nile Basin Economies and Water Resource Availability", "abstract": "A multi-country, multi-sector computable general equilibrium (CGE) model is used for the first time to evaluate the economic and water resource availability effects of trade liberalization (removal of import tariffs) and facilitation (reducing non-tariff barriers) under climate change in the Nile Basin. The analysis uses the GTAP 9 Database and the GTAP-W model that distinguishes between rainfed and irrigated agriculture and implements water as a factor of production directly substitutable in the production process of irrigated agriculture. A full trade liberalization and improved trade facilitation scenario is considered with and without climate change. The study reveals that trade liberalization and facilitation generates substantial economic benefits and enhances economic growth and welfare in the Nile basin. The effect of instituting a free trade policy on water savings is found to be limited, while climate change improves water supply and hence irrigation water use, enhancing economic growth and welfare in the basin.", "authors": [ "Kahsay, Tewodros Negash", "Kuik, Onno", "Brouwer, Roy", "van der Zaag, Pieter" ], "keywords": [ "Computable general equilibriummodel", "Climate change", "Trade liberalization", "Nile River Basin" ], "year": "2018", "source": "WATER RESOURCES MANAGEMENT", "publication_type": "J", "point2d": [ 39.10344696044922, -52.09225845336914 ], "cluster": 11.0 }, { "idx": 297, "title": "A hybrid partial and general equilibrium modeling approach to assess the hydro-economic impacts of large dams - The case of the Grand Ethiopian Renaissance Dam in the Eastern Nile River basin", "abstract": "A novel integrated hydro-economic modeling framework that links a bottom-up partial equilibrium (engineering) model with a top-down (economic) general equilibrium model is developed for assessing the regional economic impacts of water resources management and infrastructure development decisions in a transboundary river basin. The engineering model is employed first to solve the water allocation problem for a river system in a partial equilibrium setting. The resulting system-wide changes in optimal water allocation are subsequently fed into the general equilibrium model to provide an economy-wide perspective. This integrated hydro-economic modeling framework is illustrated using the Eastern Nile River basin as a case study. The engineering-based stochastic dual dynamic programming (SDDP) model of the Eastern Nile basin is coupled with the computable general equilibrium (CGE) model GTAP-W to assess the economy-wide impacts of the Grand Ethiopian Renaissance Dam (GERD) on the Eastern Nile economies.", "authors": [ "Kahsay, Tewodros Negash", "Arjoon, Diane", "Kuik, Onno", "Brouwer, Roy", "Tilmant, Amaury", "van der Zaag, Pieter" ], "keywords": [ "Computable general equilibrium modeling", "Stochastic dual dynamic programming", "Grand Ethiopian Renaissance dam", "Eastern Nile countries" ], "year": "2019", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 41.45686340332031, -51.196449279785156 ], "cluster": 11.0 }, { "idx": 298, "title": "Contributions of catchment and in-stream processes to suspended sediment transport in a dominantly groundwater-fed catchment", "abstract": "Suspended sediments impact stream water quality by increasing the turbidity and acting as a vector for strongly sorbing pollutants. Understanding their sources is of great importance to developing appropriate river management strategies. In this study, we present an integrated sediment transport model composed of a catchment-scale hydrological model to predict river discharge, a river-hydraulics model to obtain shear stresses in the channel, a sediment-generating model, and a river sediment-transport model. We use this framework to investigate the sediment contributions from catchment and in-stream processes in the Ammer catchment close to Tubingen in southwestern Germany. The model is calibrated to stream flow and suspended-sediment concentrations. We use the monthly mean suspended-sediment load to analyze seasonal variations of different processes. The contributions of catchment and in-stream processes to the total loads are demonstrated by model simulations under different flow conditions. The evaluation of shear stresses by the river-hydraulics model allows the identification of hotspots and hot moments of bed erosion for the main stem of the Ammer River. The results suggest that the contributions of suspended-sediment loads from urban areas and in-stream processes are higher in the summer months, while deposition has small variations with a slight increase in summer months. The sediment input from agricultural land and urban areas as well as bed and bank erosion increase with an increase in flow rates. Bed and bank erosion are negligible when flow is smaller than the corresponding thresholds of 1.5 and 2.5 times the mean discharge, respectively. The bed-erosion rate is higher during the summer months and varies along the main stem. Over the simulated time period, net sediment trapping is observed in the Ammer River. The present work is the basis to study particle-facilitated transport of pollutants in the system, helping to understand the fate and transport of sediments and sediment-bound pollutants.", "authors": [ "Liu, Yan", "Zarfl, Christiane", "Basu, Nandita B.", "Schwientek, Marc", "Cirpka, Olaf A." ], "keywords": [ "" ], "year": "2018", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ 47.77080535888672, 33.739845275878906 ], "cluster": 18.0 }, { "idx": 299, "title": "Do the societal benefits of river restoration outweigh their costs? A cost-benefit analysis", "abstract": "Switzerland plans to restore 4000 km of rivers by 2090. Despite the immense investment costs, river restoration benefits have not been valued in monetary terms, and a cost-benefit analysis (CBA) does not exist for any river restoration project in Switzerland. We apply stated preference methods to elicit public preferences and willingness to pay for restoring two specific but representative river sites. The benefits of restoration are compared with its costs. Upscaling the results to the national level shows that the government budget allocated for river restoration (CHF 1200/m) is insufficient to cover the costs of local restoration projects. However, the surveyed local populations are willing to pay substantially more for restoring rivers in their area of residence than they are legally obliged to do. The CBA results demonstrate that the benefits outweigh the costs in the two case studies, and hence that restoration efforts are justified from an economic point of view. A sensitivity analysis shows that the main results and conclusions do not change when we change some of the key assumptions underlying the CBA.", "authors": [ "Logar, Ivana", "Brouwer, Roy", "Paillex, Amael" ], "keywords": [ "Ecosystem services", "Willingness to pay", "Choice experiment", "Economic valuation", "Stated preferences", "Switzerland" ], "year": "2019", "source": "JOURNAL OF ENVIRONMENTAL MANAGEMENT", "publication_type": "J", "point2d": [ 59.263465881347656, -47.54844284057617 ], "cluster": 11.0 }, { "idx": 300, "title": "Coupling Water Column and Sediment Biogeochemical Dynamics: Modeling Internal Phosphorus Loading, Climate Change Responses, and Mitigation Measures in Lake Vansjo, Norway", "abstract": "We expanded the existing one-dimensional MyLake model by incorporating a vertically resolved sediment diagenesis module and developing a reaction network that seamlessly couples the water column and sediment biogeochemistry. The application of the MyLake-Sediment model to boreal Lake Vansjo illustrates the model's ability to reproduce daily water quality variables and predict sediment-water column exchange fluxes over a long historical period. In prognostic scenarios, we assessed the importance of sediment processes and the effects of various climatic and anthropogenic drivers on the lake's biogeochemistry and phytoplankton dynamics. First, MyLake-Sediment was used to simulate the potential impacts of increasing air temperature on algal growth and water quality. Second, the key role of ice cover in controlling water column mixing and biogeochemical cycles was analyzed in a series of scenarios that included a fully ice-free end-member. Third, in another end-member scenario P loading from the watershed to the lake was abruptly halted. The model results suggest that remobilization of legacy P stored in the bottom sediments could sustain the lake's primary productivity on a time scale of several centuries. Finally, while the majority of management practices to reduce excessive algal growth in lakes focus on reducing external P loads, other efforts rely on the addition of reactive materials that sequester P in the sediment. Therefore, we investigated the effectiveness of ferric iron additions in decreasing the dissolved phosphate efflux from the sediment and, consequently, limit phytoplankton growth in Lake Vansjo.", "authors": [ "Markelov, Igor", "Couture, Raoul-Marie", "Fischer, Rachele", "Haande, Sigrid", "Van Cappellen, Philippe" ], "keywords": [ "eutrophication", "early diagenesis", "internal load", "lake model", "phosphorus", "MyLake" ], "year": "2019", "source": "JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES", "publication_type": "J", "point2d": [ 55.32966995239258, 12.609867095947266 ], "cluster": 19.0 }, { "idx": 301, "title": "A review of economic approaches modeling the complex interactions between forest management and watershed services", "abstract": "This paper provides a comprehensive review of two decades of published research that applies different economic approaches to address forested watershed management decisions. The review takes stock of the applied integrated economic and ecohydrological modeling approaches and assesses the way these approaches capture the complexities involved when linking ecohydrological and economic systems. The implications of integrating watershed services into forest management decisions are discussed, lessons are drawn from existing approaches and future research needs identified. Existing modeling approaches are categorized from independent modular models with a unidirectional flow of information to fully coupled holistic models, and are analyzed, among others, in terms of the efficiency improvement that forest-based investments achieve in watershed services provision. The review shows that the number of studies investigating the relationship between forest management and watershed services in economic decision-support models is very limited. Only 14 studies that were identified examine these relationships for water supply, while 9 studies were found to focus on the impact on water quality, 2 of which addressed water quality in combination with water supply. A shortcoming is that about half of the studies do not clearly specify baseline conditions to test the incremental value of the evaluated forest management actions in terms of watershed services provision, which undermines evaluating their cost-effectiveness or economic efficiency. A promising finding is nevertheless that in 8 of the 10 studies where these relationships were evaluated in terms of their costs and benefits compared to a specified baseline alternative, forest conservation or forest management is shown to be an economically efficient nature-based solution to supply the watershed services of interest. The limited availability of geo-referenced data and information, including the often complex and confidential nature of cost and price data, and the high data demands of more advanced spatial econometric models are among the main barriers to address relevant forest and water economic interactions. Important future extensions of existing integrated approaches include the further coupling of more detailed ecohydrological models and multi-sectoral hydro-economic models that are able to account for the different risks (floods, droughts, wildfires) and uncertainties under climate change and their impact on watershed services and water security.", "authors": [ "Ovando, Paola", "Brouwer, Roy" ], "keywords": [ "Hydro-economic models", "Forest management", "Forest conservation", "Decision-making", "Watershed services" ], "year": "2019", "source": "FOREST POLICY AND ECONOMICS", "publication_type": "J", "point2d": [ 43.367252349853516, -47.8318977355957 ], "cluster": 11.0 }, { "idx": 302, "title": "St. Clair-Detroit River system: Phosphorus mass balance and implications for Lake Erie load reduction, monitoring, and climate change", "abstract": "To support the 2012 Great Lakes Water Quality Agreement on reducing Lake Erie's phosphorus inputs, we integrated US and Canadian data to update and extend total phosphorus (TP) loads into and out of the St. Clair-Detroit River System for 1998-2016. The most significant changes were decreased loads from Lake Huron caused by mussel-induced oligotrophication of the lake, and decreased loads from upgraded Great lakes Water Authority sewage treatment facilities in Detroit. By comparing lake St. Clair inputs and outputs, we demonstrated that on average the lake retains 20% of its TP inputs. We also identified for the first time that loads from resuspended Lake Huron sediment were likely not always detected in US and Canadian monitoring programs due to mismatches in sampling and resuspension event frequencies, substantially underestimating the load. This additional load increased over time due to climate-induced decreases in Lake Huron ice cover and increases in winter storm frequencies. Given this more complete load inventory, we estimated that to reach a 40% reduction in the Detroit River TP load to Lake Erie, accounting for the missed load, point and non-point sources other than that coming from Lake Huron and the atmosphere would have to be reduced by at least 50%. We also discuss the implications of discontinuous monitoring efforts. (C) 2018 The Author(s). Published by Elsevier B.V. on behalf of International Association for Great lakes Research.", "authors": [ "Scavia, Donald", "Bocaniov, Serghei A.", "Dagnew, Awoke", "Long, Colleen", "Wang, Yu-Chen" ], "keywords": [ "Detroit River", "Phosphorus load targets", "Lake St. Clair retention", "Sediment load", "Climate change", "Monitoring" ], "year": "2019", "source": "JOURNAL OF GREAT LAKES RESEARCH", "publication_type": "J", "point2d": [ 49.984127044677734, 7.829482078552246 ], "cluster": 19.0 }, { "idx": 303, "title": "Can Improved Flow Partitioning in Hydrologic Models Increase Biogeochemical Predictability?", "abstract": "Hydrologic models partition flows into surface and subsurface pathways, but their calibration is typically conducted only against streamflow. Here we argue that unless model outcomes are constrained using flow pathway data, multiple partitioning schemes can lead to the same streamflow. This point becomes critical for biogeochemical modeling as individual flow paths may yield unique chemical signatures. We show how information on flow pathways can be used to constrain hydrologic flow partitioning and how improved partitioning can lead to better water quality predictions. As a case study, an agricultural basin in Ontario is used to demonstrate that using tile discharge data could increase the performance of both the hydrology and the nitrogen transport models. Watershed-scale tile discharge was estimated based on sparse tile data collected at some tiles using a novel regression-based approach. Through a series of calibration experiments, we show that utilizing tile flow signatures as calibration criteria improves model performance in the prediction of nitrate loads in both the calibration and validation periods. Predictability of nitrate loads is improved even with no tile flow data and by model calibration only against an approximate understanding of annual tile flow percent. However, despite high values of goodness-of-fit metrics in this case, temporal dynamics of predictions are inconsistent with reality. For instance, the model predicts significant tile discharge in summer with no tile flow occurrence in the field. Hence, the proposed tile flow upscaling approach and the partitioning-constrained model calibration are vital steps toward improving the predictability of biogeochemical models in tiled landscapes.", "authors": [ "Shafii, Mahyar", "Craig, James R.", "Macrae, Merrin L.", "English, Michael C.", "Schiff, Sherry L.", "Van Cappellen, Philippe", "Basu, Nandita B." ], "keywords": [ "" ], "year": "2019", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 26.316164016723633, 4.305659294128418 ], "cluster": 10.0 }, { "idx": 304, "title": "Biogeochemical asynchrony: Ecosystem drivers of seasonal concentration regimes across the Great Lakes Basin", "abstract": "Changes in seasonal nutrient dynamics are occurring across a range of climates and land use types. Although it is known that seasonal patterns in nutrient availability are key drivers of both stream metabolism and eutrophication, there has been little success in developing a comprehensive understanding of seasonal variations in nutrient export across watersheds or of the relationship between nutrient seasonality and watershed characteristics. In the present study, we have used concentration and discharge data from more than 200 stations across U.S. and Canadian watersheds to identify (1) archetypal seasonal concentration regimes for nitrate, soluble reactive phosphorus (SRP), and total phosphorus, and (2) dominant watershed controls on these regimes across a gradient of climate, land use, and topography. Our analysis shows that less impacted watersheds, with more forested and wetland area, most commonly exhibit concentration regimes that are in phase with discharge, with concentration lows occurring during summer low-flow periods. Agricultural watersheds also commonly exhibit in-phase behavior, though the seasonality is usually muted compared to that seen in less impacted areas. With increasing urban area, however, nutrient concentrations frequently become essentially aseasonal or even exhibit clearly out-of-phase behavior. In addition, our data indicate that seasonal SRP concentration patterns may be strongly influenced by proximal controls such as the presence of dams and reservoirs. In all, these results suggest that human activity is significantly altering nutrient concentration regimes, with large potential consequences for both in-stream metabolism and eutrophication risk in downstream waterbodies.", "authors": [ "Van Meter, Kim J.", "Chowdhury, Shadman", "Byrnes, Danyka K.", "Basu, Nandita B." ], "keywords": [ "" ], "year": "2020", "source": "LIMNOLOGY AND OCEANOGRAPHY", "publication_type": "J", "point2d": [ 38.58407974243164, 10.427389144897461 ], "cluster": 10.0 }, { "idx": 305, "title": "From principles to practice in paying for nature's services", "abstract": "Payments for Environmental Services (PES) constitute an innovative economic intervention to counteract the global loss of biodiversity and ecosystem functions. In theory, some appealing features should enable PES to perform well in achieving conservation and welfare goals. In practice, outcomes depend on the interplay between context, design and implementation. Inspecting a new global dataset, we find that some PES design principles pre-identified in the social-science literature as desirable, such as spatial targeting and payment differentiation, are only partially being applied in practice. More importantly, the PES-defining principle of conditionality-monitoring compliance and sanctioning detected non-compliance-is seldom being implemented. Administrative ease, multiple non-environmental side objectives and social equity concerns may jointly help explain the reluctance to adopt more sophisticated, theoretically informed practices. However, by taking simplifying shortcuts in design and implementation, PES programmes may become less environmentally effective and efficient as economic incentives, thus under-performing their conservation potential.", "authors": [ "Wunder, S.", "Brouwer, R.", "Engel, S.", "Ezzine-De-Blas, D.", "Muradian, R.", "Pascual, U.", "Pinto, R." ], "keywords": [ "" ], "year": "2018", "source": "NATURE SUSTAINABILITY", "publication_type": "J", "point2d": [ 57.94506072998047, -41.837059020996094 ], "cluster": 11.0 }, { "idx": 307, "title": "When a Water Problem Is More Than a Water Problem: Fragmentation, Framing, and the Case of Agricultural Wetland Drainage", "abstract": "Complex interactions between water, society, the economy, and the environment necessitate attention to how water issues are framed, and the limitations of a water-centric framework for analyzing or solving problems. We explore this complexity through an example of an existing complex, or wicked, policy problem-the case of agricultural wetland drainage in the Canadian Prairies. Agricultural wetland drainage expands the amount of productive agricultural land, increasing agricultural efficiency and productivity. Drainage is also one of the primary drivers of the loss of Canada's wetlands and is a hotly contentious issue between actors with divergent views and values in the Canadian Prairies. Using the nuances of drainage as an exemplar, we discuss how fragmented framings of water foster perspectives and solutions that fail to consider the full range of aspects and interactions, and contribute to the enduring conflicts that accompany drainage debates inmany regions. First, we discuss agricultural wetland drainage as practiced in the province of Saskatchewan, where significant regulatory and governance changes are in progress. Next, we discuss the challenges of policy and governance fragmentation, both specific to water and to the surrounding system. Finally, we note potential alternative framings that, while specific to prairie water governance, provide guidance for how other complex social-ecological challenges might be approached.", "authors": [ "Breen, Sarah-Patricia W.", "Loring, Philip A.", "Baulch, Helen" ], "keywords": [ "water governance", "agricultural wetland drainage", "fragmentation", "water policy", "framing" ], "year": "2018", "source": "FRONTIERS IN ENVIRONMENTAL SCIENCE", "publication_type": "J", "point2d": [ 53.554264068603516, -33.98273849487305 ], "cluster": 4.0 }, { "idx": 308, "title": "When a Water Problem Is More Than a Water Problem: Fragmentation, Framing, and the Case of Agricultural Wetland Drainage", "abstract": "Complex interactions between water, society, the economy, and the environment necessitate attention to how water issues are framed, and the limitations of a water-centric framework for analyzing or solving problems. We explore this complexity through an example of an existing complex, or wicked, policy problem-the case of agricultural wetland drainage in the Canadian Prairies. Agricultural wetland drainage expands the amount of productive agricultural land, increasing agricultural efficiency and productivity. Drainage is also one of the primary drivers of the loss of Canada's wetlands and is a hotly contentious issue between actors with divergent views and values in the Canadian Prairies. Using the nuances of drainage as an exemplar, we discuss how fragmented framings of water foster perspectives and solutions that fail to consider the full range of aspects and interactions, and contribute to the enduring conflicts that accompany drainage debates inmany regions. First, we discuss agricultural wetland drainage as practiced in the province of Saskatchewan, where significant regulatory and governance changes are in progress. Next, we discuss the challenges of policy and governance fragmentation, both specific to water and to the surrounding system. Finally, we note potential alternative framings that, while specific to prairie water governance, provide guidance for how other complex social-ecological challenges might be approached.", "authors": [ "Breen, Sarah-Patricia W.", "Loring, Philip A.", "Baulch, Helen" ], "keywords": [ "water governance", "agricultural wetland drainage", "fragmentation", "water policy", "framing" ], "year": "2018", "source": "FRONTIERS IN ENVIRONMENTAL SCIENCE", "publication_type": "J", "point2d": [ 53.510379791259766, -33.544918060302734 ], "cluster": 4.0 }, { "idx": 309, "title": "Co-design of water services and infrastructure for Indigenous Canada: A scoping review", "abstract": "There is movement in engineering fields and in Indigenous communities for enhancement of local participation in the design of community infrastructure. Inclusion of community priorities and unique cultural, spiritual, and traditional values harmonize the appearance, location, and functionality of developments with the social and cultural context in which they are built and contribute to holistic wellness. However, co-design processes that align community values and the technical needs of water facilities are difficult to find. A scoping review was conducted to explore the state of knowledge on co-design of water infrastructure in Indigenous Canada to build a knowledge base from which practices and processes could emerge. The scoping results revealed that articles and reports emerged only in recent years, contained case studies and meta-reviews with primary (qualitative) data, and involved community members in various capacities. Overall, 13 articles were reviewed that contributed to understanding co-design for water infrastructure in Indigenous Canada. Barriers to co-design included funding models for Indigenous community infrastructure, difficulties in engineers and designers understanding Indigenous worldviews and paradigms, and a lack of cooperation among stakeholders that contribute to ongoing design failures. A working definition of co-design for Indigenous water infrastructure is presented.", "authors": [ "Bradford, Lori E. A.", "Vogel, Tim", "Lindenschmidt, Karl-Erich", "McPhedran, Kerry", "Strickert, Graham E. H.", "Fonstad, Terrence A.", "Bharadwaj, Lalita A." ], "keywords": [ "co-design", "water infrastructure", "Indigenous", "First Nations", "Canada", "water" ], "year": "2018", "source": "FACETS", "publication_type": "J", "point2d": [ 63.7552490234375, -26.14673614501953 ], "cluster": 4.0 }, { "idx": 310, "title": "Snowmelt Infiltration and Macropore Flow in Frozen Soils: Overview, Knowledge Gaps, and a Conceptual Framework", "abstract": "Macropore flow in frozen soils plays a critical role in partitioning snowmelt at the land surface and modulating snowmelt-driven hydrological processes. Previous descriptions of macropore flow processes in frozen soil do not explicitly represent the physics of water and heat transfer between macropores and the soil matrix, and there is a need to adapt recent conceptual and numerical models of unfrozen macropore flow to account for frozen ground. Macropores remain air filled under partially saturated conditions, allowing preferential flow and meltwater infiltration prior to ground thaw. Nonequilibrium gravity-driven flow can rapidly transport snowmelt to depths below the frost zone or, alternatively, infiltrated water may refreeze in macropores and restrict preferential flow. As with unfrozen soils, models of water movement in frozen soil that rely solely on diffuse flow concepts cannot adequately represent unsaturated macropore hydraulics. Dual-domain descriptions of unsaturated flow that explicitly define macropore hydraulic characteristics have been successful under unfrozen conditions but need refinement for frozen soils. In particular, because pore connectivity and hydraulic conductivity are influenced by ice content, modeling schemes specifying macropore-matrix interactions and refreezing of infiltrating water are critical. This review discusses the need for research on the interacting effects of macropore flow and soil freeze-thaw and the integration of these concepts into a framework of coupled heat and water transfer. As a result, it proposes a conceptual model of unsaturated flow in frozen macroporous soils that assumes two interacting domains (macropore and matrix) with distinct water and heat transfer regimes.", "authors": [ "Mohammed, Aaron A.", "Kurylyk, Barret L.", "Cey, Edwin E.", "Hayashi, Masaki" ], "keywords": [ "" ], "year": "2018", "source": "VADOSE ZONE JOURNAL", "publication_type": "J", "point2d": [ -36.440155029296875, 22.559001922607422 ], "cluster": 12.0 }, { "idx": 311, "title": "A Coupled Soil Water Balance Model for Simulating Depression-Focused Groundwater Recharge", "abstract": "In arid and semiarid environments, focused infiltration of rain and snowmelt water under topographic depressions is an important mechanism of ground-water recharge. Quantifying the aggregated recharge from numerous small depressions is a major challenge in water resource management. Building on field-based investigations into the surface water-groundwater interaction of individual depressions and their catchments (i.e., uplands) in the Canadian Prairies, we have developed a simple water balance model to simulate groundwater recharge considering the hydrological coupling of a depression-upland system. The model is based on the Versatile Soil Moisture Budget (VSMB), which has been widely used in the Canadian Prairies to simulate soil moisture conditions. We evaluated the new model, VSMB Depression-Upland System (VSMB-DUS), using field data consisting of an artificial flooding experiment and long-term monitoring of a depression in Alberta, Canada. The model captured surface water level, soil moisture, and groundwater responses to the artificial flooding with reasonable accuracy and represented the interannual variability of recharge fluxes during a 5-yr period (2007-2011), including dry and wet years. Simulated annual recharge varied between 12 and 45 mm, and annual precipitation varied between 453 and 597 mm during the 5-yr period. The VSMB-DUS tends to over-or underestimate snowmelt runoff in individual years; however, simulated recharge was only slightly affected by the errors in snowmelt runoff estimation. Due to its computational efficiency and robust algorithms, the VSMB-DUS will provide a useful tool for estimating aggregated recharge in a large-scale model grid cell containing hundreds of depression-upland systems.", "authors": [ "Noorduijn, Saskia L.", "Hayashi, Masaki", "Mohammed, Getachew A.", "Mohammed, Aaron A." ], "keywords": [ "" ], "year": "2018", "source": "VADOSE ZONE JOURNAL", "publication_type": "J", "point2d": [ -7.672279357910156, -20.50880241394043 ], "cluster": 10.0 }, { "idx": 314, "title": "The effect of freeze-thaw cycles on phosphorus release from riparian macrophytes in cold regions", "abstract": "Storage and removal of nutrients by wetlands and riparian areas is an important process in understanding catchment nutrient fluxes and in helping to mitigate current issues of eutrophication in many regions. In cold climates, strong seasonality affects natural wetlands and those constructed for water treatment alike, raising important questions about how ecosystems can be managed to maximize nutrient retention in the landscape, particularly in light of rapid and ongoing wetland loss. This study assessed how freeze-thaw cycles (FTCs) affect the release of phosphorus (P) from common riparian macrophytes (Typha spp). The goal was to understand whether the freeze-thaw processes could drive enhanced nutrient release as has been shown for agricultural residues, but which has not previously been assessed in riparian vegetation. Given the rapid expansion of Phragmites australis in parts of the study area, this study also tested the effects of FTC on P release from Phragmites tissue. A common experimental protocol was used across 11 wetlands in three regions of Canada. These results demonstrate the potential for FTCs to induce P release from macrophyte tissue, although this is not observed in all cases. The impact of FTCs on P release was greatest and most consistent when samples were collected earlier in the growing season. Release rates were positively correlated with plant P content. This suggests that the degree of plant senescence may play a role in determining the response to FTCs. Typha and Phragmites showed similar responses to FTCs, suggesting that the importance of this process does not depend on the dominant taxon. Sequential FTCs led to further enhancement of P release from macrophyte tissue. The results from this study suggest that specific management such as harvesting Typha during the growing season, may mitigate the potential for P release due to FTCs.", "authors": [ "Whitfield, Colin J.", "Casson, Nora J.", "North, Rebecca L.", "Venkiteswaran, Jason J.", "Ahmed, Osama", "Leathers, Jeremy", "Nugent, Katy J.", "Prentice, Tyler", "Bauch, Helen M." ], "keywords": [ "Freeze-thaw cycles", "nutrient release", "nutrient release", "nutrient retention", "Phragmites", "Typha", "wetlands" ], "year": "2019", "source": "CANADIAN WATER RESOURCES JOURNAL", "publication_type": "J", "point2d": [ 27.713674545288086, 19.25439453125 ], "cluster": 13.0 }, { "idx": 316, "title": "Antagonistic, synergistic and direct effects of land use and climate on Prairie wetland ecosystems: Ghosts of the past or present?", "abstract": "Aim Wetland loss and degradation threaten biodiversity to an extent greater than most ecosystems. Science-supported responses require understanding of interacting effects of land use and climate change on wetland biodiversity. Location Alberta, Canada. Methods We evaluated how current climate, climate change (as a ghost of the past), land use and wetland water quality relate to aquatic macroinvertebrates and birds. Results Climatic relationships and climate-land use interactions were observed on chironomid abundance, but not macroinvertebrate taxa richness (MTR) or odonate abundance, which responded to land use and water chemistry. Chironomid abundance was positively associated with cropland and negatively associated with total precipitation. Higher cropland cover and dissolved organic carbon synergistically interacted with total precipitation to affect chironomids. MTR was negatively related to salinity, yet greater area of non-woody riparian vegetation attenuated salinity effects on MTR. Odonate abundance was negatively related to total phosphorus. Higher grassland cover also increased the negative relationship of total phosphorous to odonate abundance. Climatic relationships and climate-land use interactions were observed on bird species richness (BSR) and abundance of several bird functional groups. Higher BSR and abundances of several bird groups were positively related to average rainfall and greater warming temperatures over time. Area of non-crop cover and wetlands was positively associated with most bird groups and BSR. Warming temperatures over time ameliorated the negative relationship of higher cropland or less shrubland on aerial insectivores and other bird groups. Main conclusions Climate patterns and climate change are as important as land use pressures with stronger impacts on birds. Climate change was more influential than current climate and provided novel empirical evidence that progressively warmer, wetter conditions is benefiting some bird groups, including aerial insectivores, a group of conservation concern. Riparian vegetation ameliorated the negative impacts of climate and water quality gradients on MTR and could mitigate global change impacts in agricultural systems.", "authors": [ "Mantyka-Pringle, Chrystal", "Leston, Lionel", "Messmer, Dave", "Asong, Elvis", "Bayne, Erin M.", "Bortolotti, Lauren E.", "Sekulic, Gregory", "Wheater, Howard", "Howerter, David W.", "Clark, Robert G." ], "keywords": [ "agriculture", "antagonistic", "aquatic macroinvertebrates", "birds", "climate change", "functional group", "interaction", "synergistic", "water quality", "wetlands" ], "year": "2019", "source": "DIVERSITY AND DISTRIBUTIONS", "publication_type": "J", "point2d": [ -13.474761009216309, -7.918105125427246 ], "cluster": 13.0 }, { "idx": 317, "title": "Evaluating ecosystem services for agricultural wetlands: a systematic review and meta-analysis", "abstract": "Globally, the extent of inland wetlands has declined by approximately 70% since the start of the twentieth century, resulting in the loss of important wetland-associated ecosystem services. We evaluate the drivers of wetland values in agricultural landscapes to increase the effectiveness and reliability of benefit transfer tools to assign values to local wetland services. We reviewed 668 studies that analyzed wetland ecosystem services within agricultural environments and identified 45 studies across 22 countries that provided sufficient economic information to be included in a quantitative meta-analysis. We developed meta-regression models to represent provisioning and regulating wetland ecosystem services and identify the main drivers of these ecosystem service categories. Provisioning wetland ecosystem service values were best explained (direction of effects in parenthesis) by high-income variable (+), peer-reviewed journal publications (+), agricultural total factor productivity index (-) and population density (+), while agricultural total factor productivity index (-), income level ( +) and wetland area (-) had significant effects on regulating wetland ecosystem service values. Our models can help estimate wetland values more reliably across similar regions because they have significantly lower transfer errors (66 and 185% absolute percentage error for the provisioning and regulating models, respectively) than the errors from unit value transfers. Model predicted wetland values ($/Ha/Year) range from $0.62 to $11,216 for regulating services and $0.95 to $2,122 for provisioning services and vary based on the differences in the levels of the variables (in the wetland locations) that best explained the estimated models.", "authors": [ "Eric, Asare", "Chrystal, Mantyka-Pringle", "Erik, Anderson", "Kenneth, Belcher", "Robert, Clark" ], "keywords": [ "Agricultural landscapes", "Benefit transfer", "Provisioning ecosystem services", "Regulating ecosystem services", "Meta-regression", "Wetlands" ], "year": "2022", "source": "WETLANDS ECOLOGY AND MANAGEMENT", "publication_type": "J", "point2d": [ 48.344688415527344, -45.36899185180664 ], "cluster": 11.0 }, { "idx": 318, "title": "Instantaneous Iodine-Assisted DNAzyme Cleavage of Phosphorothioate RNA", "abstract": "Metal ions play a critical role in the RNA-cleavage reaction by interacting with the scissile phosphate and stabilizing the highly negatively charged transition state. Many metal-dependent DNAzymes have been selected for RNA cleavage. Herein, we report that the Ce13d DNAzyme can use nonmetallic iodine (I-2) to cleave a phosphorothioate (PS)-modified substrate. The cleavage yield exceeded 60% for both the R-p and S-p stereoisomers in 10 s, while the yield without the enzyme strand was only similar to 10%. The Ce13d cleavage with I-2 also required Na+, consistent with the property of Ce13d and confirming the similar role of I-2 as a metal ion. Ce13d had the highest yield among eight tested DNAzymes, with the second highest DNAzyme showing only 20% cleavage. The incomplete cleavage was due to competition from desulfurization and isomerization reactions. This DNAzyme was engineered for fluorescence-based I-2 detection. With EDTA for masking metal ions, I-2 was selectively detected down to 4.7 nM. Oxidation of I- with Fe3+ produced I-2 in situ, allowing detection of Fe3+ down to 78 nM. By harnessing nonelectrostatic interactions, such as the I-2/sulfur interaction observed here, more nonmetal species might be discovered to assist DNAzyme-based RNA cleavage.", "authors": [ "Huang, Po-Jung Jimmy", "Moon, Woohyun J.", "Liu, Juewen" ], "keywords": [ "" ], "year": "2019", "source": "BIOCHEMISTRY", "publication_type": "J", "point2d": [ 90.57862854003906, 36.650970458984375 ], "cluster": 6.0 }, { "idx": 319, "title": "Polyamide 6.6 separates oil/water due to its dual underwater oleophobicity/underoil hydrophobicity: Role of 2D and 3D porous structures", "abstract": "Porous polyamide functionalized by plasma or various coatings has been investigated for oil/water separation. In literature, polyamide has rarely been studied for oil removal, and this work investigated the performance of bare polyamide 6.6 (nylon 6.6) in terms of the oil/water separation efficiency and the intrusion pressure, inspiring cost-effective solutions for large-scale oil removal in the industry. Both polyamide meshes possessing two-dimensional (2D) one-layer pores and nonwoven fabrics with three-dimensional (3D) irregular pores were found to be able to separate oil/water with a high efficiency above 98.5%. This finding was attributed to the dual underwater oleophobicity and underoil hydrophobicity of these polyamide samples. The roles of 2D and 3D structures in oil/water separation were illustrated, to provide a new insight into filter designing. Due to its greater intrusion pressure, the 3D netting structure was suggested as being more beneficial for oil/water separation than the 2D structure.", "authors": [ "Zhao, Pei", "Qin, Ning", "Ren, Carolyn L.", "Wen, John Z." ], "keywords": [ "Polyamide 6.6", "Meshes and nonwoven fabrics", "Oil/water separation", "Intrusion pressure and contact angle", "Dual underwater oleophobicity and underoil hydrophobicity" ], "year": "2019", "source": "APPLIED SURFACE SCIENCE", "publication_type": "J", "point2d": [ 65.2716064453125, 51.17299270629883 ], "cluster": 6.0 }, { "idx": 320, "title": "Surface modification of polyamide meshes and nonwoven fabrics by plasma etching and a PDA/cellulose coating for oil/water separation", "abstract": "This work investigated a two-step surface modification of polyamide meshes and nonwoven fabrics for oil/water separation and looked into the durability of such modified polyamide. The two-step modification included 1) pre-etching the polyamide surface using plasma treatment and 2) coating the pre-etched surface by eco-friendly polydopamine (PDA)/cellulose. The pre-etching increased the surface roughness, which further improved the underwater superoleophobicity of the coating. Therefore, the modified polyamide was able to separate various oil/water mixtures and showed a higher intrusion pressure than the original sample and the samples which were only etched or only coated. The grooves on the surface that resulted from the pre-etching prevented the coating from peeling off. In durability tests, after 6 repeated uses, the modified nonwoven sample lost its underwater oleophobicity due to severe oil fouling, coming to a complete failure in oil/water separation. After 19 cycles, the modified mesh was still able to separate a certain amount of oil/water but showed reduced intrusion pressure because of slight oil contamination. Filters with different structures, like meshes with one layer of pores and nonwoven fabrics with complex three dimensional pores, had different oil fouling levels that affected oil/water separation. The recoverability of filters from oil contamination should be considered for practical applications.", "authors": [ "Zhao, Pei", "Qin, Ning", "Ren, Carolyn L.", "Wen, John Z." ], "keywords": [ "A hybrid coating of PDA/cellulose", "Plasma etching", "Oil/water separation", "Meshes and nonwoven fabrics", "Underwater oleophobicity", "Durability" ], "year": "2019", "source": "APPLIED SURFACE SCIENCE", "publication_type": "J", "point2d": [ 65.84415435791016, 51.09798049926758 ], "cluster": 6.0 }, { "idx": 321, "title": "Integrated water quality monitoring system with pH, free chlorine, and temperature sensors", "abstract": "Accurate, efficient, inexpensive, and multi-parameter monitoring of water quality parameters is critical for continued water safety from developed urban regions to resource-limited or sparsely populated areas. This study describes an integrated sensing system with solution-processed pH, free chlorine, and temperature sensors on a common glass substrate. The pH and temperature sensors are fabricated by low-cost inkjet printing of palladium/palladium oxide and silver. The potentiometric pH sensor has a high sensitivity of 60.6 mV/pH and a fast response of 15 s. The Wheatstone-bridge-based temperature sensor shows an immediate response of 3.35 mv/degrees C towards temperature change. The free chlorine sensor is based on an electrochemically modified pencil lead, which exhibits a stable and reproducible sensitivity of 342 nA/ppm for hypochlorous acid. Such a free chlorine sensor is potentiostat-free and calibration free, so it is easy-to-use. The three sensors are connected to a field-programmable gate array board for data collection, analysis and display, with real-time pH and temperature compensation for free chlorine sensing. The developed sensing system is user-friendly, cost-effective, and can monitor water samples in real-time with an accuracy of >82%. This platform enables water quality monitoring by nonprofessionals in a simple manner. (C) 2017 Elsevier B.V. All rights reserved.", "authors": [ "Qin, Yiheng", "Alam, Arif U.", "Pan, Si", "Howlader, Matiar M. R.", "Ghosh, Raja", "Hu, Nan-Xing", "Jin, Hao", "Dong, Shurong", "Chen, Chih-Hung", "Deen, M. Jamal" ], "keywords": [ "Inkjet printing", "Integration", "pH", "Free chlorine", "Temperature", "Water quality monitoring", "Sensor" ], "year": "2018", "source": "SENSORS AND ACTUATORS B-CHEMICAL", "publication_type": "J", "point2d": [ 78.51359558105469, 44.24555969238281 ], "cluster": 6.0 }, { "idx": 322, "title": "Using two-eyed seeing to bridge Western science and Indigenous knowledge systems and understand long-term change in the Saskatchewan River Delta, Canada", "abstract": "Although researchers now recognize that Indigenous knowledge can strengthen environmental planning and assessment, little research has empirically demonstrated how to bring together Indigenous knowledge and Western science to form a more complete picture of social-ecological change. This study attempts to fill this gap by using 'two-eyed seeing' - an approach that brings together Indigenous and Western perspectives on an equal basis - to collect and analyze changes in the Saskatchewan River Delta since upstream dams were built in the 1960s. Results found corroboration across the knowledge systems that operation of dams has lowered summer flows and created unnaturally high winter flows. The knowledge systems, however, diverged in some areas, such as the production of northern pike, where local residents observed abundant pike but records showed the pike commercial harvest declining to near zero. Indigenous knowledge alone provided information about berries and berry seasons. This two-eyed seeing approach can enhance environmental assessment and planning by providing a more accurate and coherent narrative of long-term social-ecological change.", "authors": [ "Abu, Razak", "Reed, Maureen G.", "Jardine, Timothy D." ], "keywords": [ "Indigenous knowledge", "Saskatchewan River Delta", "social-ecological system", "two-eyed seeing", "Western science" ], "year": "2020", "source": "INTERNATIONAL JOURNAL OF WATER RESOURCES DEVELOPMENT", "publication_type": "J", "point2d": [ 60.54177474975586, -25.413089752197266 ], "cluster": 4.0 }, { "idx": 323, "title": "Historical drought patterns over Canada and their teleconnections with large-scale climate signals", "abstract": "Drought is a recurring extreme climate event and among the most costly natural disasters in the world. This is particularly true over Canada, where drought is both a frequent and damaging phenomenon with impacts on regional water resources, agriculture, industry, aquatic ecosystems, and health. However, nationwide drought assessments are currently lacking and impacted by limited ground-based observations. This study provides a comprehensive analysis of historical droughts over the whole of Canada, including the role of large-scale teleconnections. Drought events are characterized by the Standardized Precipitation Evapotranspiration Index (SPEI) over various temporal scales (1, 3, 6, and 12 consecutive months, 6 months from April to September, and 12 months from October to September) applied to different gridded monthly data sets for the period 1950-2013. The Mann-Kendall test, rotated empirical orthogonal function, continuous wavelet transform, and wavelet coherence analyses are used, respectively, to investigate the trend, spatio-temporal patterns, periodicity, and teleconnectivity of drought events. Results indicate that southern (northern) parts of the country experienced significant trends towards drier (wetter) conditions although substantial variability exists. Two spatially well-defined regions with different temporal evolution of droughts were identified - the Canadian Prairies and northern central Canada. The analyses also revealed the presence of a dominant periodicity of between 8 and 32 months in the Prairie region and between 8 and 40 months in the northern central region. These cycles of low-frequency variability are found to be associated principally with the Pacific-North American (PNA) and Multivariate El Nino/Southern Oscillation Index (MEI) relative to other considered large-scale climate indices. This study is the first of its kind to identify dominant periodicities in drought variability over the whole of Canada in terms of when the drought events occur, their duration, and how often they occur.", "authors": [ "Asong, Zilefac Elvis", "Wheater, Howard Simon", "Bonsal, Barrie", "Razavi, Saman", "Kurkute, Sopan" ], "keywords": [ "" ], "year": "2018", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -36.116477966308594, -37.63737869262695 ], "cluster": 1.0 }, { "idx": 324, "title": "Correlation Effects? A Major but Often Neglected Component in Sensitivity and Uncertainty Analysis", "abstract": "Global sensitivity analysis (GSA) provides essential insights into the behavior of Earth and environmental systems models and identifies dominant controls of output uncertainty. Previous work on GSA, however, has typically been under the assumption that the controlling factors such as model inputs and parameters are independent, whereas, in many cases, they are correlated and their joint distribution follows a variety of forms. Although this assumption can limit the credibility of GSA and its results, very few studies in the field of water and environmental modeling address this issue. In this paper, we first discuss the significance of correlation effects in GSA and then propose a new GSA framework for properly accounting for correlations in input/parameter spaces. To this end, we extend the variogram-based theory of GSA, called variogram analysis of response surfaces (VARS), and develop a new generalized star sampling technique (called gSTAR) to accommodate correlated multivariate distributions. We test the new gSTAR-VARS method on two test functions, against a state-of-the-art GSA method that handles correlation effects. We then apply gSTAR-VARS to the HBV-SASK model, calibrated via a Bayesian, Markov chain Monte Carlo approach, for design flood estimation in the Oldman River Basin in Canada. Results demonstrate that accounting for correlation effects can be critically important in GSA, especially in the presence of nonlinearity and interaction effects in the underlying response surfaces. The proposed method can efficiently handle correlations and different distribution types and simultaneously generate a range of sensitivity indices, such as total-variogram effects, variance-based total-order effects, and derivative-based elementary effects.", "authors": [ "Do, Nhu Cuong", "Razavi, Saman" ], "keywords": [ "" ], "year": "2020", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 4.607396602630615, -72.55792236328125 ], "cluster": 16.0 }, { "idx": 325, "title": "The economic impacts of water supply restrictions due to climate and policy change: A transboundary river basin supply-side input-output analysis", "abstract": "Finding sustainable pathways to efficiently allocate limited available water resources among increasingly competing water uses has become crucial due to climate-change-induced water shortages and increasing water demand. This has led to an urgent need for the inclusion of economic principles, models, and methods in water resources management. Although several studies have developed macro-economic models to evaluate the economic impacts of alternative water allocation strategies, many if not most ignore the hydrological boundaries of transboundary river basins. Furthermore, of those using input-output (IO) models, only a handful have applied supply-side IO models. In this paper, we present one of the first attempts to develop an inter-regional, supply-side IO modelling framework for a multi-jurisdictional, transboundary river basin to assess the direct and indirect economic impacts of water supply restrictions due to climate and policy change. Applying this framework to the Saskatchewan River Basin in Canada encompassing three provinces, we investigate the economic impacts of two different water supply restriction scenarios on the entire river basin and its sub-basins individually. We find that in the face of climate-change-induced water shortage, economic losses can be reduced by almost 50% by adopting appropriate management practices, including prioritization of water allocation, using alternative water sources, and water re-use technologies.", "authors": [ "Eamen, Leila", "Brouwer, Roy", "Razavi, Saman" ], "keywords": [ "Supply-side input-output model", "Transboundary river basin", "Water supply restriction", "Climate change", "Economic impacts", "Water policy" ], "year": "2020", "source": "ECOLOGICAL ECONOMICS", "publication_type": "J", "point2d": [ 42.022308349609375, -54.702388763427734 ], "cluster": 11.0 }, { "idx": 326, "title": "The economic impacts of water supply restrictions due to climate and policy change: A transboundary river basin supply-side input-output analysis", "abstract": "Finding sustainable pathways to efficiently allocate limited available water resources among increasingly competing water uses has become crucial due to climate-change-induced water shortages and increasing water demand. This has led to an urgent need for the inclusion of economic principles, models, and methods in water resources management. Although several studies have developed macro-economic models to evaluate the economic impacts of alternative water allocation strategies, many if not most ignore the hydrological boundaries of transboundary river basins. Furthermore, of those using input-output (IO) models, only a handful have applied supply-side IO models. In this paper, we present one of the first attempts to develop an inter-regional, supply-side IO modelling framework for a multi-jurisdictional, transboundary river basin to assess the direct and indirect economic impacts of water supply restrictions due to climate and policy change. Applying this framework to the Saskatchewan River Basin in Canada encompassing three provinces, we investigate the economic impacts of two different water supply restriction scenarios on the entire river basin and its sub-basins individually. We find that in the face of climate-change-induced water shortage, economic losses can be reduced by almost 50% by adopting appropriate management practices, including prioritization of water allocation, using alternative water sources, and water re-use technologies.", "authors": [ "Eamen, Leila", "Brouwer, Roy", "Razavi, Saman" ], "keywords": [ "Supply-side input-output model", "Transboundary river basin", "Water supply restriction", "Climate change", "Economic impacts", "Water policy" ], "year": "2020", "source": "ECOLOGICAL ECONOMICS", "publication_type": "J", "point2d": [ 41.5425910949707, -54.43281173706055 ], "cluster": 11.0 }, { "idx": 327, "title": "Introductory overview of identifiability analysis: A guide to evaluating whether you have the right type of data for your modeling purpose", "abstract": "Identifiability is a fundamental concept in parameter estimation, and therefore key to the large majority of environmental modeling applications. Parameter identifiability analysis assesses whether it is theoretically possible to estimate unique parameter values from data, given the quantities measured, conditions present in the forcing data, model structure (and objective function), and properties of errors in the model and observations. In other words, it tackles the problem of whether the right type of data is available to estimate the desired parameter values. Identifiability analysis is therefore an essential technique that should be adopted more routinely in practice, alongside complementary methods such as uncertainty analysis and evaluation of model performance. This article provides an introductory overview to the topic. We recommend that any modeling study should document whether a model is non-identifiable, the source of potential non-identifiability, and how this affects intended project outcomes.", "authors": [ "Guillaume, Joseph H. A.", "Jakeman, John D.", "Marsili-Libelli, Stefano", "Asher, Michael", "Brunner, Philip", "Croke, Barry", "Hill, Mary C.", "Jakeman, Anthony J.", "Keesman, Karel J.", "Razavi, Saman", "Stigter, Johannes D." ], "keywords": [ "Identifiability", "Response surface", "Non-uniqueness", "Derivative based methods", "Hessian", "Emulation", "Uncertainty" ], "year": "2019", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 4.121247291564941, -78.36901092529297 ], "cluster": 16.0 }, { "idx": 328, "title": "A framework for engaging stakeholders in water quality modeling and management: Application to the Qu'Appelle River Basin, Canada", "abstract": "Water quality is increasingly at risk due to nutrient pollution entering river systems from cities, industrial zones and agricultural areas. Agricultural activities are typically the largest non-point source of water pollution. The dynamics of agricultural impacts on water quality are complex and stem from the decisions and activities of multiple stakeholders, often with diverse business plans, values, and attitudes towards practices that can improve water quality. This study proposes a framework to understand and incorporate stakeholders' viewpoints into water quality modeling and management. The framework was applied to the Qu'Appelle River Basin, Saskatchewan, Canada. Q-methodology was used to understand viewpoints of stakeholders, namely agricultural producers (annual croppers, cattle producers, mixed farmers) and cottage owners, regarding a range of agricultural Beneficial Management Practices (BMPs) that can improve water quality, and to identify their preferred BMPs. A System Dynamics (SD) approach was employed to develop a transparent and user-friendly water quality model, SD-Qu'Appelle, to simulate nutrient loads in the region before and after implementation of stakeholder identified BMPs. The SD-Qu'Appelle was used in real-time engagement of stakeholders in model simulations to demonstrate and explore the potential effects of different BMPs in mitigating water pollution. Stakeholder perspectives were explored to understand the functionality and value of the SD-Qu'Appelle, preferred policies and potential barriers to BMP implementation on their land. Results show that although there are differences between viewpoints of stakeholders, they identified wetland restoration/retention, flow and erosion control, and relocation of corrals near creeks to sites more distant from waterways as the most effective BMPs for improving water quality. Economics was identified as a primary factor that causes agricultural producers to either accept or refuse the implementation of BMPs. Agricultural producers believe that incentives rather than regulations are the best policies for increasing the adoption of BMPs. Overall, stakeholders indicated the SD-Qu'Appelle had considerable value for water quality management and provided a set of recommendations to improve the model.", "authors": [ "Hassanzadeh, Elmira", "Strickert, Graham", "Morales-Marin, Luis", "Noble, Bram", "Baulch, Helen", "Shupena-Soulodre, Etienne", "Lindenschmidt, Karl-Erich" ], "keywords": [ "Water quality modeling and management", "Nutrient pollution", "Stakeholder engagement", "Agricultural Beneficial Management Practices (BMPs)", "Q-methodology", "System dynamics" ], "year": "2019", "source": "JOURNAL OF ENVIRONMENTAL MANAGEMENT", "publication_type": "J", "point2d": [ 47.47307586669922, -36.796504974365234 ], "cluster": 11.0 }, { "idx": 329, "title": "Radar Scatter Decomposition to Differentiate between Running Ice Accumulations and Intact Ice Covers along Rivers", "abstract": "For ice-jam flood forecasting it is important to differentiate between intact ice covers and ice runs. Ice runs consist of long accumulations of rubble ice that stem from broken up ice covers or ice-jams that have released. A water wave generally travels ahead of the ice run at a faster celerity, arriving at the potentially high flood-risk area much sooner than the ice accumulation. Hence, a rapid detection of the ice run is necessary to lengthen response times for flood mitigation. Intact ice covers are stationary and hence are not an immediate threat to a downstream flood situation, allowing more time for flood preparedness. However, once ice accumulations are moving and potentially pose imminent impacts to flooding, flood response may have to switch from a mitigation to an evacuation mode of the flood management plan. Ice runs are generally observed, often by chance, through ground observations or airborne surveys. In this technical note, we introduce a novel method of differentiating ice runs from intact ice covers using imagery acquired from space-borne radar backscatter signals. The signals are decomposed into different scatter componentssurface scattering, volume scattering and double-bouncethe ratios of one to another allow differentiation between intact and running ice. The method is demonstrated for the breakup season of spring 2018 along the Athabasca River, when an ice run shoved into an intact ice cover which led to some flooding in Fort McMurray, Alberta, Canada.", "authors": [ "Lindenschmidt, Karl-Erich", "Li, Zhaoqin" ], "keywords": [ "Athabasca River", "decomposition", "Fort McMurray", "ice run", "MODIS", "RADARSAT-2" ], "year": "2019", "source": "REMOTE SENSING", "publication_type": "J", "point2d": [ -78.44485473632812, 9.201891899108887 ], "cluster": 2.0 }, { "idx": 330, "title": "Development of an Ice Jam Flood Forecasting System for the Lower Oder RiverRequirements for Real-Time Predictions of Water, Ice and Sediment Transport", "abstract": "Despite ubiquitous warming, the lower Oder River typically freezes over almost every year. Ice jams may occur during freeze-up and ice cover breakup phases, particularly in the middle and lower reaches of the river, with weirs and piers. The slush ice and ice blocks may accumulate to form ice jams, leading to backwater effects and substantial water level rise. The small bottom slope of the lower Oder and the tidal backflow from the Baltic Sea enhance the formation of ice jams during cold weather conditions, jeopardizing the dikes. Therefore, development of an ice jam flood forecasting system for the Oder River is much needed. This commentary presents selected results from an international workshop that took place in Wrocaw (Poland) on 26-27 November 2018 that brought together an international team of experts to explore the requirements and research opportunities in the field of ice jam flood forecasting and risk assessment for the Oder River section along the German-Polish border. The workshop launched a platform for collaboration amongst Canadian, German and Polish scientists, government officials and water managers to pave a way forward for joint research focused on achieving the long-term goal of forecasting, assessing and mitigating ice jam impacts along the lower Oder. German and Polish government agencies are in need of new tools to forecast ice jams and assess their subsequent consequences and risks to communities and ship navigation along a river. Addressing these issues will also help research and ice flood management in a Canadian context. A research program would aim to develop a modelling system by addressing fundamental issues that impede the prediction of ice jam events and their consequences in cold regions.", "authors": [ "Lindenschmidt, Karl-Erich", "Carstensen, Dirk", "Froehlich, Wolfgang", "Hentschel, Bernd", "Iwicki, Stefan", "Koegel, Michael", "Kubicki, Michal", "Kundzewicz, Zbigniew W.", "Lauschke, Cornelia", "Lazarow, Adam", "Los, Helena", "Marszelewski, Wlodzimierz", "Niedzielski, Tomasz", "Nowak, Marcin", "Pawlowski, Boguslaw", "Roers, Michael", "Schlaffer, Stefan", "Weintrit, Beata" ], "keywords": [ "flood forecasting system", "ice breaking", "ice jam flooding", "river ice monitoring", "Oder River", "remote sensing" ], "year": "2019", "source": "WATER", "publication_type": "J", "point2d": [ -4.998460292816162, -38.4555549621582 ], "cluster": 2.0 }, { "idx": 331, "title": "Development of an Ice Jam Flood Forecasting System for the Lower Oder RiverRequirements for Real-Time Predictions of Water, Ice and Sediment Transport", "abstract": "Despite ubiquitous warming, the lower Oder River typically freezes over almost every year. Ice jams may occur during freeze-up and ice cover breakup phases, particularly in the middle and lower reaches of the river, with weirs and piers. The slush ice and ice blocks may accumulate to form ice jams, leading to backwater effects and substantial water level rise. The small bottom slope of the lower Oder and the tidal backflow from the Baltic Sea enhance the formation of ice jams during cold weather conditions, jeopardizing the dikes. Therefore, development of an ice jam flood forecasting system for the Oder River is much needed. This commentary presents selected results from an international workshop that took place in Wrocaw (Poland) on 26-27 November 2018 that brought together an international team of experts to explore the requirements and research opportunities in the field of ice jam flood forecasting and risk assessment for the Oder River section along the German-Polish border. The workshop launched a platform for collaboration amongst Canadian, German and Polish scientists, government officials and water managers to pave a way forward for joint research focused on achieving the long-term goal of forecasting, assessing and mitigating ice jam impacts along the lower Oder. German and Polish government agencies are in need of new tools to forecast ice jams and assess their subsequent consequences and risks to communities and ship navigation along a river. Addressing these issues will also help research and ice flood management in a Canadian context. A research program would aim to develop a modelling system by addressing fundamental issues that impede the prediction of ice jam events and their consequences in cold regions.", "authors": [ "Lindenschmidt, Karl-Erich", "Carstensen, Dirk", "Froehlich, Wolfgang", "Hentschel, Bernd", "Iwicki, Stefan", "Koegel, Michael", "Kubicki, Michal", "Kundzewicz, Zbigniew W.", "Lauschke, Cornelia", "Lazarow, Adam", "Los, Helena", "Marszelewski, Wlodzimierz", "Niedzielski, Tomasz", "Nowak, Marcin", "Pawlowski, Boguslaw", "Roers, Michael", "Schlaffer, Stefan", "Weintrit, Beata" ], "keywords": [ "flood forecasting system", "ice breaking", "ice jam flooding", "river ice monitoring", "Oder River", "remote sensing" ], "year": "2019", "source": "WATER", "publication_type": "J", "point2d": [ -4.637780666351318, -38.741355895996094 ], "cluster": 2.0 }, { "idx": 332, "title": "Introductory overview: Optimization using evolutionary algorithms and other metaheuristics", "abstract": "Environmental models are used extensively to evaluate the effectiveness of a range of design, planning, operational, management and policy options. However, the number of options that can be evaluated manually is generally limited, making it difficult to identify the most suitable options to consider in decision-making processes. By linking environmental models with evolutionary and other metaheuristic optimization algorithms, the decision options that make best use of scarce resources, achieve the best environmental outcomes for a given budget or provide the best trade-offs between competing objectives can be identified. This Introductory Overview presents reasons for embedding formal optimization approaches in environmental decision-making processes, details how environmental problems are formulated as optimization problems and outlines how single- and multi-objective optimization approaches find good solutions to environmental problems. Practical guidance and potential challenges are also provided.", "authors": [ "Maier, H. R.", "Razavi, S.", "Kapelan, Z.", "Matott, L. S.", "Kasprzyk, J.", "Tolson, B. A." ], "keywords": [ "" ], "year": "2019", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 8.019424438476562, -79.76495361328125 ], "cluster": 11.0 }, { "idx": 335, "title": "Potential Changes of Annual-Averaged Nutrient Export in the South Saskatchewan River Basin under Climate and Land-Use Change Scenarios", "abstract": "Climate and land-use changes modify the physical functioning of river basins and, in particular, influence the transport of nutrients from land to water. In large-scale basins, where a variety of climates, topographies, soil types and land uses co-exist to form a highly heterogeneous environment, a more complex nutrient dynamic is imposed by climate and land-use changes. This is the case of the South Saskatchewan River (SSR) that, along with the North Saskatchewan River, forms one of the largest river systems in western Canada. The SPAtially Referenced Regression On Watershed (SPARROW) model is therefore implemented to assess water quality in the basin, in order to describe spatial and temporal patterns and identify those factors and processes that affect water quality. Forty-five climate and land-use change scenarios comprehended by five General Circulation Models (GCMs) and three Representative Concentration Pathways (RCPs) were incorporated into the model to explain how total nitrogen (TN) and total phosphorus (TP) export could vary across the basin in 30, 60 and 90 years from now. According to model results, annual averages of TN and TP export in the SSR are going to increase in the range 0.9-1.28 kg km(2) year(-1) and 0.12-0.17 kg km(2) year(-1), respectively, by the end of the century, due to climate and land-use changes. Higher increases of TP compared to TN are expected since TP and TN are going to increase similar to 36% and similar to 21%, respectively, by the end of the century. This research will support management plans in order to mitigate nutrient export under future changes of climate and land use.", "authors": [ "Morales-Marin, Luis", "Wheater, Howard", "Lindenschmidt, Karl-Erich" ], "keywords": [ "climate change", "land-use change", "nutrient export", "SPARROW", "river basin" ], "year": "2018", "source": "WATER", "publication_type": "J", "point2d": [ 37.48225784301758, -11.342693328857422 ], "cluster": 10.0 }, { "idx": 336, "title": "A hydrological and water temperature modelling framework to simulate the timing of river freeze-up and ice-cover breakup in large-scale catchments", "abstract": "Ice phenology, defined as the timing of freeze-up and ice-cover breakup, plays a key role in streamflow regimes in cold-region river catchments. River freeze-up and ice-cover breakup events are controlled by meteorological and hydrological variables. In this study, we present a modelling framework consisting of a physically-based semi-distributed hydrological model and the integration of a 1D stream temperature model that can predict the ice duration in cold region rivers. The hydrological model provides streamflow and hydraulic parameters for the stream temperature model to obtain instream water temperature. The model was successfully applied in the Athabasca River basin in western Canada. Calibration was carried out using the water temperature recorded in the stations at the towns of Hinton, Athabasca and Fort McMurray. Model results show consistent correspondence between simulated freeze-up and breakup dates and the hydrometric station data. In the main tributaries of the basin, freeze-up timing spans from the last week of September to the second week of November and ice-cover breakup occurs from the second week of March to the last week of May. The model presents an application of water temperature and ice phenology simulation which can be incorporated in ice-jam flood forecasting and future climate change studies.", "authors": [ "Morales-Marin, L. A.", "Sanyal, P. R.", "Kadowaki, H.", "Li, Z.", "Rokaya, P.", "Lindenschmidt, K. E." ], "keywords": [ "Stream temperature", "Simulation", "Freeze-up", "Breakup", "Athabasca river basin" ], "year": "2019", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ -10.481881141662598, -41.37562942504883 ], "cluster": 12.0 }, { "idx": 338, "title": "VARS-TOOL: A toolbox for comprehensive, efficient, and robust sensitivity and uncertainty analysis", "abstract": "VARS-TOOL is a software toolbox for sensitivity and uncertainty analysis. Developed primarily around the Variogram Analysis of Response Surfaces framework, VARS-TOOL adopts a multi-method approach that enables simultaneous generation of a range of sensitivity indices, including ones based on derivative, variance, and variogram concepts, from a single sample. Other special features of VARS-TOOL include (1) novel tools for time varying and time-aggregate sensitivity analysis of dynamical systems models, (2) highly efficient sampling techniques, such as Progressive Latin Hypercube Sampling (PLHS), that maximize robustness and rapid convergence to stable sensitivity estimates, (3) factor grouping for dealing with high-dimensional problems, (4) visualization for monitoring stability and convergence, (5) model emulation for handling model crashes, and (6) an interface that allows working with any model in any programming language and operating system. As a test bed for training and research, VARS-TOOL provides a set of mathematical test functions and the (dynamical) HBV-SASK hydrologic model.", "authors": [ "Razavi, Saman", "Sheikholeslami, Razi", "Gupta, Hoshin V.", "Haghnegahdar, Amin" ], "keywords": [ "Global sensitivity analysis", "Uncertainty analysis", "Variogram analysis of response surface (VARS)", "Sobol'", "Morris", "Progressive Latin hypercube sampling (PLHS)", "Dynamical systems models", "Sensitivity indices", "Performance metrics" ], "year": "2019", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 5.3288140296936035, -74.37506866455078 ], "cluster": 16.0 }, { "idx": 339, "title": "Ice-jam flood research: a scoping review", "abstract": "Almost 60% of the rivers in the northern hemisphere experience significant seasonal effects of river ice. In many of these northern rivers, ice-jam floods (IJFs) pose serious threats to riverine communities. Since the inundation elevations associated with ice-jam events can be several meters higher than open-water floods for the same or even lower discharges, IJFs can be more disastrous to local communities and economies, especially as their occurrence isoften very sudden and difficult to anticipate. In the last several decades, there have been many important advances in river ice hydrology, resulting in improved knowledge and capacity to deal with IJFs. This paper presents a review of IJF literature available on the Web of Science. Nature and scope of scholarly research on IJF are analysed, and an agenda for research that better integrates IJF challenges with research and mitigation opportunities is suggested.", "authors": [ "Rokaya, Prabin", "Budhathoki, Sujata", "Lindenschmidt, Karl-Erich" ], "keywords": [ "Ice-jam flood", "Cold regions", "River ice", "Natural hazards", "Scoping review" ], "year": "2018", "source": "NATURAL HAZARDS", "publication_type": "J", "point2d": [ -6.013116359710693, -36.72504425048828 ], "cluster": 2.0 }, { "idx": 340, "title": "Promoting Sustainable Ice-Jam Flood Management along the Peace River and Peace-Athabasca Delta", "abstract": "The regulation of rivers has always been a controversial issue, with potential benefits but also environmental impacts. In western Canada, the construction of W.A.C. Bennett Dam in the headwaters of the Peace River has raised concerns over the ecological health of the Peace-Athabasca Delta (PAD), a socioeconomically and ecologically important delta with national and international significance. The major concern is the reduced frequency of ice-jam floods, which are particularly effective in replenishing the high-elevation basins of the PAD. Previous studies have suggested that releasing water at opportune times from the dam could promote ice-jam flooding of the delta; however, ice-jam flood events can also be severe and devastating to riverside communities and economies. Thus, a critical and challenging question is how to promote flooding in the downstream deltaic ecosystem where it is essential without necessarily increasing the flood risk in upstream communities of the Peace River. This study reviews previous approaches and explores possible reservoir operation schemes with an integrated hydrologic and hydraulic river ice modeling framework to minimize flood risk and maximize flood potential at desired locations. It is demonstrated that by increasing reservoir release in the breakup period, it is possible to increase the likelihood of ice-jam flooding in the PAD without necessarily causing ice-jam floods in the upstream communities. However, the timing of the flow release, taking into account the receding ice front and local hydrometeorological conditions, is critical.", "authors": [ "Rokaya, Prabin", "Wheater, Howard", "Lindenschmidt, Karl-Erich" ], "keywords": [ "Regulation", "Deltaic ecosystem", "Peace-Athabasca Delta", "Ice-jam flood", "Reservoir operation", "Sustainability" ], "year": "2019", "source": "JOURNAL OF WATER RESOURCES PLANNING AND MANAGEMENT", "publication_type": "J", "point2d": [ -8.92320728302002, -32.95742416381836 ], "cluster": 11.0 }, { "idx": 341, "title": "Global sensitivity analysis for high-dimensional problems: How to objectively group factors and measure robustness and convergence while reducing computational cost", "abstract": "Dynamical earth and environmental systems models are typically computationally intensive and highly parameterized with many uncertain parameters. Together, these characteristics severely limit the applicability of Global Sensitivity Analysis (GSA) to high-dimensional models because very large numbers of model runs are typically required to achieve convergence and provide a robust assessment. Paradoxically, only 30 percent of GSA applications in the environmental modelling literature have investigated models with more than 20 parameters, suggesting that GSA is under-utilized on problems for which it should prove most useful. We develop a novel grouping strategy, based on bootstrap-based clustering, that enables efficient application of GSA to high-dimensional models. We also provide a new measure of robustness that assesses GSA stability and convergence. For two models, having 50 and 111 parameters, we show that grouping-enabled GSA provides results that are highly robust to sampling variability, while converging with a much smaller number of model runs.", "authors": [ "Sheikholeslami, Razi", "Razavi, Saman", "Gupta, Hoshin V.", "Becker, William", "Haghnegahdar, Amin" ], "keywords": [ "Global sensitivity analysis", "Curse of dimensionality", "Computationally intensive simulations", "Factor grouping", "Robustness", "Convergence" ], "year": "2019", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 7.703485012054443, -75.81745910644531 ], "cluster": 16.0 }, { "idx": 342, "title": "What should we do when a model crashes? Recommendations for global sensitivity analysis of Earth and environmental systems models", "abstract": "Complex, software-intensive, technically advanced, and computationally demanding models, presumably with ever-growing realism and fidelity, have been widely used to simulate and predict the dynamics of the Earth and environmental systems. The parameter-induced simulation crash (failure) problem is typical across most of these models despite considerable efforts that modellers have directed at model development and implementation over the last few decades. A simulation failure mainly occurs due to the violation of numerical stability conditions, non-robust numerical implementations, or errors in programming. However, the existing sampling-based analysis techniques such as global sensitivity analysis (GSA) methods, which require running these models under many configurations of parameter values, are ill equipped to effectively deal with model failures. To tackle this problem, we propose a new approach that allows users to cope with failed designs (samples) when performing GSA without rerunning the entire experiment. This approach deems model crashes as missing data and uses strategies such as median substitution, single nearest-neighbor, or response surface modeling to fill in for model crashes. We test the proposed approach on a 10-parameter HBV-SASK (Hydrologiska Byrans Vattenbalansavdelning modified by the second author for educational purposes) rainfall-runoff model and a 111-parameter Modelisation Environmentale-Surface et Hydrologie (MESH) land surface-hydrology model. Our results show that response surface modeling is a superior strategy, out of the data-filling strategies tested, and can comply with the dimensionality of the model, sample size, and the ratio of the number of failures to the sample size. Further, we conduct a failure analysis and discuss some possible causes of the MESH model failure that can be used for future model improvement.", "authors": [ "Sheikholeslami, Razi", "Razavi, Saman", "Haghnegandar, Amin" ], "keywords": [ "" ], "year": "2019", "source": "GEOSCIENTIFIC MODEL DEVELOPMENT", "publication_type": "J", "point2d": [ 7.035207748413086, -71.47735595703125 ], "cluster": 16.0 }, { "idx": 343, "title": "Paleo-hydrologic reconstruction of 400 years of past flows at a weekly time step for major rivers of Western Canada", "abstract": "The assumption of stationarity in water resources no longer holds, particularly within the context of future climate change. Plausible scenarios of flows that fluctuate outside the envelope of variability of the gauging data are required to assess the robustness of water resource systems to future conditions. This study presents a novel method of generating weekly time step flows based on tree-ring chronology data. Specifically, this method addresses two long-standing challenges with paleo-reconstruction: (i) the typically limited predictive power of tree-ring data at the annual and sub-annual scale and (ii) the inflated short-term persistence in tree-ring time series and improper use of pre-whitening. Unlike the conventional approach, this method establishes relationships between tree-ring chronologies and naturalized flow at a biennial scale to preserve persistence properties and variability of hydrological time series. Biennial flow reconstructions are further disaggregated to weekly flow reconstructions, according to the weekly flow distribution of reference 2-year instrumental periods, identified as periods with broadly similar tree-ring properties to those of every 2-year paleo-period. The Saskatchewan River basin (SaskRB) in Western Canada is selected as a study area, and weekly flows in its four major tributaries are extended back to the year 1600. The study shows that the reconstructed flows properly preserve the statistical properties of the reference flows, particularly in terms of short- to long-term persistence and the structure of variability across timescales. An ensemble approach is presented to represent the uncertainty inherent in the statistical relationships and disaggregation method.", "authors": [ "Slaughter, Andrew R.", "Razavi, Saman" ], "keywords": [ "" ], "year": "2020", "source": "EARTH SYSTEM SCIENCE DATA", "publication_type": "J", "point2d": [ -28.817344665527344, -26.416982650756836 ], "cluster": 1.0 }, { "idx": 346, "title": "Precipitation transition regions over the southern Canadian Cordillera during January-April 2010 and under a pseudo-global-warming assumption", "abstract": "The occurrence of various types of winter precipitation is an important issue over the southern Canadian Cordillera. This issue is examined from January to April of 2010 by exploiting the high-resolution Weather Research and Forecasting (WRF) model Version 3.4.1 dataset that was used to simulate both a historical reanalysis-driven (control - CTRL) and a pseudo-global-warming (PGW) experiment (Liu et al., 2016). Transition regions, consisting of both liquid and solid precipitation or liquid precipitation below 0 degrees C, occurred on 93 % and 94 % of the days in the present and PGW future, respectively. This led to accumulated precipitation within the transition region increasing by 27 % and was associated with a rise in its average elevation by 374 m over the Coast Mountains and Insular Mountains and by 240 m over the Rocky Mountains and consequently to an eastward shift towards the higher terrain of the Rocky Mountains. Transition regions comprised of only rain and snow were most common under both the CTRL and PGW simulations, although all seven transition region categories occurred. Transition region changes would enhance some of the factors leading to avalanches and would also impact ski resort operations.", "authors": [ "Almonte, Juris D.", "Stewart, Ronald E." ], "keywords": [ "" ], "year": "2019", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -47.84113693237305, -28.873132705688477 ], "cluster": 1.0 }, { "idx": 347, "title": "Precipitation transition regions over the southern Canadian Cordillera during January-April 2010 and under a pseudo-global-warming assumption", "abstract": "The occurrence of various types of winter precipitation is an important issue over the southern Canadian Cordillera. This issue is examined from January to April of 2010 by exploiting the high-resolution Weather Research and Forecasting (WRF) model Version 3.4.1 dataset that was used to simulate both a historical reanalysis-driven (control - CTRL) and a pseudo-global-warming (PGW) experiment (Liu et al., 2016). Transition regions, consisting of both liquid and solid precipitation or liquid precipitation below 0 degrees C, occurred on 93 % and 94 % of the days in the present and PGW future, respectively. This led to accumulated precipitation within the transition region increasing by 27 % and was associated with a rise in its average elevation by 374 m over the Coast Mountains and Insular Mountains and by 240 m over the Rocky Mountains and consequently to an eastward shift towards the higher terrain of the Rocky Mountains. Transition regions comprised of only rain and snow were most common under both the CTRL and PGW simulations, although all seven transition region categories occurred. Transition region changes would enhance some of the factors leading to avalanches and would also impact ski resort operations.", "authors": [ "Almonte, Juris D.", "Stewart, Ronald E." ], "keywords": [ "" ], "year": "2019", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -47.79954528808594, -29.32082176208496 ], "cluster": 1.0 }, { "idx": 348, "title": "Atmospheric Rivers Increase Future Flood Risk in Western Canada's Largest Pacific River", "abstract": "Snow-dominated watersheds are bellwethers of climate change. Hydroclimate projections in such basins often find reductions in annual peak runoff due to decreased snowpack under global warming. British Columbia's Fraser River Basin (FRB) is a large, nival basin with exposure to moisture-laden atmospheric rivers originating in the Pacific Ocean. Landfalling atmospheric rivers over the region in winter are projected to increase in both strength and frequency in Coupled Model Intercomparison Project Phase 5 climate models. We investigate future changes in hydrology and annual peak daily streamflow in the FRB using a hydrologic model driven by a bias-corrected Coupled Model Intercomparison Project Phase 5 ensemble. Under Representative Concentration Pathway (8.5), the FRB evolves toward a nival-pluvial regime featuring an increasing association of extreme rainfall with annual peak daily flow, a doubling in cold season peak discharge, and a decrease in the return period of the largest historical flow, from a 1-in-200-year to 1-in-50-year event by the late 21st century. Plain Language Summary Snow-covered areas of the globe are particularly sensitive to global warming. Future projections using global climate models generally show that as the ratio of snow to rain declines, river flows peak earlier in the year with reduced volume. These models also capture the phenomenon of atmospheric rivers: long, meandering plumes of water vapor often originating over the tropical oceans that bring sustained, heavy precipitation to the west coasts of North America and northern Europe. The present-day frequency of landfalling atmospheric rivers on the Canadian west coast is projected to increase nearly fourfold by the late 21st century, with a proportionate increase in extreme rainfall events. Our work is the first to directly investigate the impact of these rivers in the sky on rivers on the land using climate model projections. Focusing on the Fraser River Basin, Canada's largest Pacific watershed, and using a business-as-usual industrial emissions scenario, we show that the basin transitions from one where peak flow results from spring snowmelt to one where peak flow is often caused by extreme rainfall. Our modeling suggests that extreme rainfall events resulting from atmospheric rivers may lead to peak annual floods of historic proportions, and of unprecedented frequency, by the late 21st century in the Fraser River Basin.", "authors": [ "Curry, C. L.", "Islam, S. U.", "Zwiers, F. W.", "Dery, S. J." ], "keywords": [ "" ], "year": "2019", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -20.360586166381836, -29.032567977905273 ], "cluster": 1.0 }, { "idx": 349, "title": "Groundwater flow and storage processes in an inactive rock glacier", "abstract": "Groundwater flow through coarse blocky landforms contributes to streamflow in mountain watersheds, yet its role in the alpine hydrologic cycle has received relatively little attention. This study examines the internal structure and hydrogeological characteristics of an inactive rock glacier in the Canadian Rockies using geophysical imaging techniques, analysis of the discharge hydrograph of the spring draining the rock glacier, and chemical and stable isotopic compositions of source waters. The results show that the coarse blocky sediments forming the rock glacier allow the rapid infiltration of snowmelt and rain water to an unconfined aquifer above the bedrock surface. The water flowing through the aquifer is eventually routed via an internal channel parallel to the front of the rock glacier to a spring, which provides baseflow to a headwater stream designated as a critical habitat for an at-risk cold-water fish species. Discharge from the rock glacier spring contributes up to 50% of basin streamflow during summer baseflow periods and up to 100% of basin streamflow over winter, despite draining less than 20% of the watershed area. The rock glacier contains patches of ground ice even though it may have been inactive for thousands of years, suggesting the resiliency of the ground thermal regime under a warming climate.", "authors": [ "Harrington, Jordan S.", "Mozil, Alexandra", "Hayashi, Masaki", "Bentley, Laurence R." ], "keywords": [ "alpine hydrology", "geophysical imaging", "hydrogeology", "mountain permafrost", "periglacial", "spring" ], "year": "2018", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -5.276909351348877, -0.9677400588989258 ], "cluster": 18.0 }, { "idx": 350, "title": "Lake O'Hara alpine hydrological observatory: hydrological and meteorological dataset, 2004-2017", "abstract": "The Lake O'Hara watershed in the Canadian Rockies has been the site of several hydrological investigations. It has been instrumented to a degree uncommon for many alpine study watersheds. Air temperature, relative humidity, wind, precipitation, radiation, and snow depth are measured at two meteorological stations near Lake O'Hara and in the higher elevation Opabin Plateau. Water levels at Lake O'Hara, Opabin Lake, and several stream gauging stations are recorded using pressure transducers and validated against manual measurements. Stage-discharge rating curves were determined at gauging stations and used to calculate discharge from stream stage. The database includes additional data such as water chemistry (temperature, electrical conductivity, and stable isotope abundance) and snow survey (snow depth and density) for select years, as well as geospatial data (elevation and land cover). This dataset will be useful for the future study of alpine regions, where substantial and long-term hydrological datasets are scarce due to difficult field conditions.", "authors": [ "He, Jesse", "Hayashi, Masaki" ], "keywords": [ "" ], "year": "2019", "source": "EARTH SYSTEM SCIENCE DATA", "publication_type": "J", "point2d": [ 0.006624438334256411, -10.155244827270508 ], "cluster": 12.0 }, { "idx": 351, "title": "Heterogeneous Changes in Western North American Glaciers Linked to Decadal Variability in Zonal Wind Strength", "abstract": "Western North American (WNA) glaciers outside of Alaska cover 14,384km(2) of mountainous terrain. No comprehensive analysis of recent mass change exists for this region. We generated over 15,000 multisensor digital elevation models from spaceborne optical imagery to provide an assessment of mass change for WNA over the period 2000-2018. These glaciers lost 11742gigatons (Gt) of mass, which accounts for up to 0.320.11mm of sea level rise over the full period of study. We observe a fourfold increase in mass loss rates between 2000-2009 [-2.93.1Gt yr(-1)] and 2009-2018 [-12.34.6Gt yr(-1)], and we attribute this change to a shift in regional meteorological conditions driven by the location and strength of upper level zonal wind. Our results document decadal-scale climate variability over WNA that will likely modulate glacier mass change in the future. Plain Language Summary Glaciers in western North America provide important thermal and flow buffering to streams when seasonal snowpack is depleted. We used spaceborne optical satellite imagery to produce thousands of digital elevation models to assess recent mass loss for glaciers in western North America outside of Alaska. Our analysis shows that glacier loss over the period 2009-2018 increased fourfold relative to the period 2000-2009. This mass change over the last 18years is partly explained by changes in atmospheric circulation. Our results can be used for future modeling studies to understand the fate of glaciers under future climate change scenarios.", "authors": [ "Menounos, B.", "Hugonnet, R.", "Shean, D.", "Gardner, A.", "Howat, I.", "Berthier, E.", "Pelto, B.", "Tennant, C.", "Shea, J.", "Noh, Myoung-Jong", "Brun, F.", "Dehecq, A." ], "keywords": [ "glacier change", "mass balance", "zonal wind" ], "year": "2019", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -43.35968780517578, 10.405183792114258 ], "cluster": 8.0 }, { "idx": 352, "title": "Heterogeneous Changes in Western North American Glaciers Linked to Decadal Variability in Zonal Wind Strength", "abstract": "Western North American (WNA) glaciers outside of Alaska cover 14,384km(2) of mountainous terrain. No comprehensive analysis of recent mass change exists for this region. We generated over 15,000 multisensor digital elevation models from spaceborne optical imagery to provide an assessment of mass change for WNA over the period 2000-2018. These glaciers lost 11742gigatons (Gt) of mass, which accounts for up to 0.320.11mm of sea level rise over the full period of study. We observe a fourfold increase in mass loss rates between 2000-2009 [-2.93.1Gt yr(-1)] and 2009-2018 [-12.34.6Gt yr(-1)], and we attribute this change to a shift in regional meteorological conditions driven by the location and strength of upper level zonal wind. Our results document decadal-scale climate variability over WNA that will likely modulate glacier mass change in the future. Plain Language Summary Glaciers in western North America provide important thermal and flow buffering to streams when seasonal snowpack is depleted. We used spaceborne optical satellite imagery to produce thousands of digital elevation models to assess recent mass loss for glaciers in western North America outside of Alaska. Our analysis shows that glacier loss over the period 2009-2018 increased fourfold relative to the period 2000-2009. This mass change over the last 18years is partly explained by changes in atmospheric circulation. Our results can be used for future modeling studies to understand the fate of glaciers under future climate change scenarios.", "authors": [ "Menounos, B.", "Hugonnet, R.", "Shean, D.", "Gardner, A.", "Howat, I.", "Berthier, E.", "Pelto, B.", "Tennant, C.", "Shea, J.", "Noh, Myoung-Jong", "Brun, F.", "Dehecq, A." ], "keywords": [ "glacier change", "mass balance", "zonal wind" ], "year": "2019", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -43.5867919921875, 10.104644775390625 ], "cluster": 8.0 }, { "idx": 356, "title": "Beaver Dams Induce Hyporheic and Biogeochemical Changes in Riparian Areas in a Mountain Peatland", "abstract": "Hyporheic exchange is important in increasing stream water transit time through basins and enhancing redox-sensitive biogeochemical reactions influencing downstream water quality. Such exchange may be enhanced by beaver dams which are common throughout low order streams including those originating in peatlands. To understand the influence of beaver dams on hyporheic flows and biogeochemical properties, nitrogen (N), dissolved organic nitrogen (DOC) and N cycling rates were observed along a beaver dammed, third-order stream draining Canadian Rocky Mountain peatland. Beaver dams enlarged the hyporheric zone from 1.5 to 7.5m. The looping hyporheic flow path created a zone of N and DOC depletion adjacent to the dams. As a result, nitrification rates were lowest in this zone. Where hyporheic flows exited the riparian area and flowed back to the stream channel downstream of a dam, the adjacent riparian area served as a source of N and DOC to the stream. Enhanced nutrient influx to streams owing to beaver dam modified hyporheic flow paths has implications for stream biogeochemical cycling and ecological integrity, which need further exploration.", "authors": [ "Wang, Xiaoyue", "Shaw, Erin L.", "Westbrook, Cherie J.", "Bedard-Haughn, Angela" ], "keywords": [ "Hyporheic exchange", "Nitrogen mineralization", "Nitrogen dynamics", "Peatlands", "Riparian", "Nutrient flushing" ], "year": "2018", "source": "WETLANDS", "publication_type": "J", "point2d": [ 13.808244705200195, 1.8349387645721436 ], "cluster": 13.0 }, { "idx": 357, "title": "Climate-phenology-hydrology interactions in northern high latitudes: Assessing the value of remote sensing data in catchment ecohydrological studies", "abstract": "We assessed the hydrological implications of climate effects on vegetation phenology in northern environments by fusion of data from remote-sensing and local catchment monitoring. Studies using satellite data have shown earlier and later dates for the start (SOS) and end of growing seasons (EOS), respectively, in the Northern Hemisphere over the last 3 decades. However, estimates of the change greatly depend on the satellite data utilized. Validation with experimental data on climate-vegetation-hydrology interactions requires long-term observations of multiple variables which are rare and usually restricted to small catchments. In this study, we used two NDVI (normalized difference vegetation index) products (at similar to 25 & 0.5 km spatial resolutions) to infer SOS and EOS for six northern catchments, and then investigated the likely climate impacts on phenology change and consequent effects on catchment water yield, using both assimilated data (GLDAS: global land data assimilation system) and direct catchment observations. The major findings are: (1) The assimilated air temperature compared well with catchment observations (regression slopes and R-2 close to 1), whereas underestimations of summer rainstorms resulted in overall underestimations of precipitation (regression slopes of 0.3-0.7, R-2 >= 0.46). (2) The two NDVI products inferred different vegetation phenology characteristics. (3) Increased mean pre-season temperature significantly influenced the advance of SOS and delay of EOS. The precipitation influence was weaker, but delayed SOS corresponding to increased pre-season precipitation at most sites can be related to later snow melting. (4) Decreased catchment streamflow over the last 15 years could be related to the advance in SOS and extension of growing seasons. Greater streamflow reductions in the cold sites than the warm ones imply stronger climate warming impacts on vegetation and hydrology in colder northerly environments. The methods used in this study have potential for better understanding interactions between vegetation, climate and hydrology in observation-scarce regions. (C) 2018 Elsevier B.V. All rights reserved.", "authors": [ "Wang, Hailong", "Tetzlaff, Doerthe", "Buttle, James", "Carey, Sean K.", "Laudon, Hjalmar", "McNamara, James P.", "Spence, Christopher", "Soulsby, Chris" ], "keywords": [ "Vegetation phenology", "Climate", "Hydrology", "Temperature", "Precipitation", "Streamflow" ], "year": "2019", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ -56.686832427978516, 41.650428771972656 ], "cluster": 14.0 }, { "idx": 359, "title": "A Comparison of Intra-Annual and Long-Term Trend Scaling of Extreme Precipitation with Temperature in a Large-Ensemble Regional Climate Simulation", "abstract": "Long-term changes in extreme daily and subdaily precipitation simulated by climate models are often compared with corresponding temperature changes to estimate the sensitivity of extreme precipitation to warming. Such trend scaling'' rates are difficult to estimate from observations, however, because of limited data availability and high background variability. Intra-annual temperature scaling (here called binning scaling), which relates extreme precipitation to temperature at or near the time of occurrence, has been suggested as a possible substitute for trend scaling. Weuse a large ensemble simulation of the Canadian regional climate model (CanRCM4) to assess this possibility, considering both daily near-surface air temperature and daily dewpoint temperature as scaling variables. Wefind that binning curves that are based on precipitation data for the whole year generally look like the composite of binning curves for winter and summer, with the lower temperature portion similar to winter and the higher temperature portion similar to summer, indicating that binning curves reflect seasonal changes in the relationship between temperature and extreme precipitation. The magnitude and spatial pattern of binning and trend scaling rates are also quantitatively different, with little spatial correlation between them, regardless of precipitation duration or choice of temperature variable. The evidence therefore suggests that binning scaling with temperature is not a reliable predictor for future changes in precipitation extremes in the climate simulated by CanRCM4. Nevertheless, external forcing does have a discernable influence on binning curves, which are seen to shift upward and to the right in some regions, consistent with a general increase in extreme precipitation.", "authors": [ "Sun, Qiaohong", "Zwiers, Francis", "Zhang, Xuebin", "Li, Guilong" ], "keywords": [ "Precipitation", "Temperature", "Statistical techniques", "Ensembles", "Trends" ], "year": "2020", "source": "JOURNAL OF CLIMATE", "publication_type": "J", "point2d": [ -32.9445686340332, -46.78777313232422 ], "cluster": 14.0 }, { "idx": 360, "title": "Larger Increases in More Extreme Local Precipitation Events as Climate Warms", "abstract": "Climate models project that extreme precipitation events will intensify in proportion to their intensity during the 21st century at large spatial scales. The identification of the causes of this phenomenon nevertheless remains tenuous. Using a large ensemble of North American regional climate simulations, we show that the more rapid intensification of more extreme events also appears as a robust feature at finer regional scales. The larger increases in more extreme events than in less extreme events are found to be primarily due to atmospheric circulation changes. Thermodynamically induced changes have relatively uniform effects across extreme events and regions. In contrast, circulation changes weaken moderate events over western interior regions of North America and enhance them elsewhere. The weakening effect decreases and even reverses for more extreme events, whereas there is further intensification over other parts of North America, creating an intense gets intenser pattern over most of the continent.", "authors": [ "Li, Chao", "Zwiers, Francis", "Zhang, Xuebin", "Chen, Gang", "Lu, Jian", "Li, Guilong", "Norris, Jesse", "Tan, Yaheng", "Sun, Ying", "Liu, Min" ], "keywords": [ "extreme precipitation events", "impact-relevant spatial scales", "atmospheric dynamics", "climate change" ], "year": "2019", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -50.3653678894043, -72.13761901855469 ], "cluster": 14.0 }, { "idx": 361, "title": "Larger Increases in More Extreme Local Precipitation Events as Climate Warms", "abstract": "Climate models project that extreme precipitation events will intensify in proportion to their intensity during the 21st century at large spatial scales. The identification of the causes of this phenomenon nevertheless remains tenuous. Using a large ensemble of North American regional climate simulations, we show that the more rapid intensification of more extreme events also appears as a robust feature at finer regional scales. The larger increases in more extreme events than in less extreme events are found to be primarily due to atmospheric circulation changes. Thermodynamically induced changes have relatively uniform effects across extreme events and regions. In contrast, circulation changes weaken moderate events over western interior regions of North America and enhance them elsewhere. The weakening effect decreases and even reverses for more extreme events, whereas there is further intensification over other parts of North America, creating an intense gets intenser pattern over most of the continent.", "authors": [ "Li, Chao", "Zwiers, Francis", "Zhang, Xuebin", "Chen, Gang", "Lu, Jian", "Li, Guilong", "Norris, Jesse", "Tan, Yaheng", "Sun, Ying", "Liu, Min" ], "keywords": [ "extreme precipitation events", "impact-relevant spatial scales", "atmospheric dynamics", "climate change" ], "year": "2019", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -50.460174560546875, -72.58963775634766 ], "cluster": 14.0 }, { "idx": 362, "title": "Parameterization of the Bulk Liquid Fraction on Mixed-Phase Particles in the Predicted Particle Properties (P3) Scheme: Description and Idealized Simulations", "abstract": "Bulk microphysics parameterizations that are used to represent clouds and precipitation usually allow only solid and liquid hydrometeors. Predicting the bulk liquid fraction on ice allows an explicit representation of mixed-phase particles and various precipitation types, such as wet snow and ice pellets. In this paper, an approach for the representation of the bulk liquid fraction into the predicted particle properties (P3) microphysics scheme is proposed and described. Solid-phase microphysical processes, such as melting and sublimation, have been modified to account for the liquid component. New processes, such as refreezing and condensation of the liquid portion of mixed-phase particles, have been added to the parameterization. Idealized simulations using a one-dimensional framework illustrate the overall behavior of the modified scheme. The proposed approach compares well to a Lagrangian benchmark model. Temperatures required for populations of ice crystals to melt completely also agree well with previous studies. The new processes of refreezing and condensation impact both the surface precipitation type and feedback between the temperature and the phase changes. Overall, prediction of the bulk liquid fraction allows an explicit description of new precipitation types, such as wet snow and ice pellets, and improves the representation of hydrometeor properties when the temperature is near 0 degrees C.", "authors": [ "Cholette, Melissa", "Morrison, Hugh", "Milbrandt, Jason A.", "Theriault, Julie M." ], "keywords": [ "" ], "year": "2019", "source": "JOURNAL OF THE ATMOSPHERIC SCIENCES", "publication_type": "J", "point2d": [ -65.19232940673828, -31.62464714050293 ], "cluster": 12.0 }, { "idx": 364, "title": "Influence of the Model Horizontal Resolution on Atmospheric Conditions Leading to Freezing Rain in Regional Climate Simulations", "abstract": "Freezing rain occurs in complex atmospheric conditions when the temperature is close to 0 degrees C. To better understand how its occurrence will change in the future, there is a need to assess how well regional climate models can reproduce those conditions. The goal of the present study is to investigate the influence of horizontal resolution on the simulation of freezing rain using the fifth generation of the Canadian Regional Climate Model (CRCM5). Three CRCM5 simulations driven by the European Centre for Medium-range Weather Forecasts interim reanalysis (ERA-Interim) over eastern North America at resolutions of 0.11 degrees, 0.22 degrees, and 0.44 degrees were conducted over a period of 36 years (1979-2014). Freezing rain is diagnosed using an in-line diagnostic method for precipitation partitioning. A climatological study of annual and seasonal accumulated freezing rain was conducted. In addition, the ability of the three simulations to reproduce individual freezing rain events was evaluated. Our analyses include frequency and partitioning of different precipitation types and comparisons with observations. All simulations reproduced the climatology of freezing rain sufficiently well and show similar large-scale patterns. The number of freezing rain events tends to be overestimated at higher resolution and underestimated at lower resolution. Despite the overestimation, detailed maxima associated with freezing rain are well defined and located at higher resolution, notably in regions of the St. Lawrence River Valley. Overall, this study is consistent with other added-value studies, generally showing a mix of improvement and deterioration in the precipitation fields by the higher resolution simulations. Resume[Traduit par la redaction] La pluie verglacante se produit dans des conditions atmospheriques complexes avec des temperatures se maintenant de part et d'autre de 0 degrees C. Pour bien comprendre les changements futurs de ce phenomene, il faut evaluer a quel point les modeles climatiques regionaux en reproduisent les conditions sous-jacentes. Nous etudions ici l'influence de la resolution horizontale sur la simulation de pluie verglacante, et ce, a l'aide de la cinquieme generation du Modele regional canadien du climat (MRCC5). Nous avons produit, pour l'est de l'Amerique du Nord et a partir du MRCC5, trois simulations pilotees par les donnees de reanalyses du Centre europeen pour les previsions meteorologiques a moyen terme (ERA-Interim), et ce, a des resolutions de 0,11 degrees, 0,22 degrees et 0,44 degrees, sur une periode de 36 ans (de 1979 a 2014). Nous diagnostiquons la presence de pluie verglacante selon une methode de calcul directe permettant de determiner le type de precipitations. Nous examinons les accumulations annuelles et saisonnieres de pluie verglacante. De plus, nous evaluons la capacite des trois simulations a reproduire des episodes individuels de pluie verglacante. Nous determinons les differents types de precipitations simulees et leur frequence, puis les comparons avec les observations. Toutes les simulations reproduisent suffisamment bien la climatologie de la pluie verglacante et montrent des configurations similaires a grande echelle. haute resolution, le modele tend a surestimer le nombre d'episodes de pluie verglacante; a basse resolution, le contraire se produit. Malgre la surestimation, a haute resolution, les maximums associes a la pluie verglacante restent bien definis et positionnes, notamment dans la vallee du Saint-Laurent. Dans l'ensemble, cette etude concorde avec d'autres etudes de valeur ajoutee, qui montrent a la fois une amelioration et une deterioration des champs de precipitations dans les simulations basees sur une resolution superieure.", "authors": [ "St-Pierre, Mederic", "Theriault, Julie M.", "Paquin, Dominique" ], "keywords": [ "freezing rain", "regional climate models", "spatial resolution", "climatology" ], "year": "2019", "source": "ATMOSPHERE-OCEAN", "publication_type": "J", "point2d": [ -55.028926849365234, -30.53314208984375 ], "cluster": 1.0 }, { "idx": 366, "title": "Meaningful engagement with Indigenous peoples: a case study of Ontario's Great Lakes Protection Act", "abstract": "While governments in Canada have a duty to act honourably in the development of legislative actions that may affect Aboriginal or treaty rights, Indigenous peoples' input and knowledge have largely been excluded from the process. The Ontario provincial government recently sought to remedy this failure by engaging with Indigenous groups in the development and implementation of the Great Lakes Protection Act. Using qualitative data, this article explores the successes, challenges and lessons learned during Crown-Indigenous engagement in the development of this Act. The article concludes with recommendations on ways to strengthen processes of engagement between government and Indigenous groups.", "authors": [ "Lukawiecki, Jessica", "Gagnon, Rhonda", "Dokis, Carly", "Walters, Dan", "Molot, Lewis" ], "keywords": [ "Duty to act honourably", "meaningful engagement", "collaborative water governance", "Great Lakes Protection Act", "integrated watershed management" ], "year": "2021", "source": "INTERNATIONAL JOURNAL OF WATER RESOURCES DEVELOPMENT", "publication_type": "J", "point2d": [ 67.1078872680664, -26.30424690246582 ], "cluster": 4.0 }, { "idx": 369, "title": "Drivers of water quality changes within the Laurentian Great Lakes region over the past 40 years", "abstract": "Water quality of freshwater lakes within the Laurentian Great Lakes region is vulnerable to degradation owing to multiple environmental stressors including climate change, alterations in land use, and the introduction of invasive species. Our research questions were two-fold: (1) What are the temporal patterns and trends in water quality? (2) Are climate, invasive species and lake morphology associated with changes in water quality? Our study incorporated timeseries data for at least 20 years from 36 lakes in Ontario and Wisconsin sampled between 1976 and 2016. We evaluated patterns in water quality (total phosphorus [TP], total nitrogen, dissolved organic carbon [DOC], and chlorophylla[Chla]) using segmented regression analysis which identified significant breakpoints in Chlaand TP in the 1900s to mid-2000s after which Chlaand TP began to increase, whereas breakpoints in DOC exhibited increasing trends prior to the year 2000 with levels declining afterward. Next, we examined linear trends in water quality and climate (temperature and precipitation) using Sen slope analysis where, generally, over the past 40 years, lake TP and Chlahave significantly declined, whereas DOC has increased. Lastly, we conducted a redundancy analysis (RDA) to identify how climate, lake morphology, and the presence of invasive dreissenid mussels contributed to changes in water quality. The RDA revealed that precipitation, air temperature, and morphology explained 73.1% of the variation in water quality trends for the Great Lakes whereas precipitation, temperature, morphology, and occurrence of mussels explained 45.6% of the variation for smaller inland lakes.", "authors": [ "Mahdiyan, Octavia", "Filazzola, Alessandro", "Molot, Lewis A.", "Gray, Derek", "Sharma, Sapna" ], "keywords": [ "" ], "year": "2021", "source": "LIMNOLOGY AND OCEANOGRAPHY", "publication_type": "J", "point2d": [ 50.82918167114258, 9.202678680419922 ], "cluster": 19.0 }, { "idx": 370, "title": "Understanding rivers and their social relations: A critical step to advance environmental water management", "abstract": "River flows connect people, places, and other forms of life, inspiring and sustaining diverse cultural beliefs, values, and ways of life. The concept of environmental flows provides a framework for improving understanding of relationships between river flows and people, and for supporting those that are mutually beneficial. Nevertheless, most approaches to determining environmental flows remain grounded in the biophysical sciences. The newly revised Brisbane Declaration and Global Action Agenda on Environmental Flows (2018) represents a new phase in environmental flow science and an opportunity to better consider the co-constitution of river flows, ecosystems, and society, and to more explicitly incorporate these relationships into river management. We synthesize understanding of relationships between people and rivers as conceived under the renewed definition of environmental flows. We present case studies from Honduras, India, Canada, New Zealand, and Australia that illustrate multidisciplinary, collaborative efforts where recognizing and meeting diverse flow needs of human populations was central to establishing environmental flow recommendations. We also review a small body of literature to highlight examples of the diversity and interdependencies of human-flow relationships-such as the linkages between river flow and human well-being, spiritual needs, cultural identity, and sense of place-that are typically overlooked when environmental flows are assessed and negotiated. Finally, we call for scientists and water managers to recognize the diversity of ways of knowing, relating to, and utilizing rivers, and to place this recognition at the center of future environmental flow assessments. This article is categorized under: Water and Life > Conservation, Management, and Awareness Human Water > Water Governance Human Water > Water as Imagined and Represented", "authors": [ "Anderson, Elizabeth P.", "Jackson, Sue", "Tharme, Rebecca E.", "Douglas, Michael", "Flotemersch, Joseph E.", "Zwarteveen, Margreet", "Lokgariwar, Chicu", "Montoya, Mariana", "Wali, Alaka", "Tipa, Gail T.", "Jardine, Timothy D.", "Olden, Julian D.", "Cheng, Lin", "Conallin, John", "Cosens, Barbara", "Dickens, Chris", "Garrick, Dustin", "Groenfeldt, David", "Kabogo, Jane", "Roux, Dirk J.", "Ruhi, Albert", "Arthington, Angela H." ], "keywords": [ "environmental flows", "environmental water allocations", "freshwater", "rivers", "social-ecological systems" ], "year": "2019", "source": "WILEY INTERDISCIPLINARY REVIEWS-WATER", "publication_type": "J", "point2d": [ 49.468589782714844, -21.387004852294922 ], "cluster": 4.0 }, { "idx": 371, "title": "Spatial variability of mean daily estimates of actual evaporation from remotely sensed imagery and surface reference data", "abstract": "Land surface evaporation has considerable spatial variability that is not captured by point-scale estimates calculated from meteorological data alone. Knowing how evaporation varies spatially remains an important issue for improving parameterisations of land surface schemes and hydrological models and various land management practices. Satellite-based and aerial remote sensing has been crucial for capturing moderate- to larger-scale surface variables to indirectly estimate evaporative fluxes. However, more recent advances for field research via unmanned aerial vehicles (UAVs) now allow for the acquisition of more highly detailed surface data. Integrating models that can estimate actual evaporation from higher-resolution imagery and surface reference data would be valuable to better examine potential impacts of local variations in evaporation on upscaled estimates. This study introduces a novel approach for computing a normalised ratiometric index from surface variables that can be used to obtain more-realistic distributed estimates of actual evaporation. For demonstration purposes the Granger-Gray evaporation model (Granger and Gray, 1989) was applied at a rolling prairie agricultural site in central Saskatchewan, Canada. Visible and thermal images and meteorological reference data required to parameterise the model were obtained at midday. Ratiometric indexes were computed for the key surface variables albedo and net radiation at midday. This allowed point observations of albedo and mean daily net radiation to be scaled across high-resolution images over a large study region. Albedo and net radiation estimates were within 5 %-10 % of measured values. A daily evaporation estimate for a grassed surface was 0 5 mm (23 %) larger than eddy covari- ance measurements. Spatial variations in key factors driving evaporation and their impacts on upscaled evaporation estimates are also discussed. The methods applied have two key advantages for estimating evaporation over previous remotesensing approaches: (1) detailed daily estimates of actual evaporation can be directly obtained using a physically based evaporation model, and (2) analysis of more-detailed and more-reliable evaporation estimates may lead to improved methods for upscaling evaporative fluxes to larger areas.", "authors": [ "Armstrong, Robert N.", "Pomeroy, John W.", "Martz, Lawrence W." ], "keywords": [ "" ], "year": "2019", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -62.66888427734375, 45.903648376464844 ], "cluster": 8.0 }, { "idx": 372, "title": "High-resolution meteorological forcing data for hydrological modelling and climate change impact analysis in the Mackenzie River Basin", "abstract": "Cold region hydrology is very sensitive to the impacts of climate warming. Impacts of warming over recent decades in western Canada include glacier retreat, permafrost thaw, and changing patterns of precipitation, with an increased proportion of winter precipitation falling as rainfall and shorter durations of snow cover, as well as consequent changes in flow regimes. Future warming is expected to continue along these lines. Physically realistic and sophisticated hydrological models driven by reliable climate forcing can provide the capability to assess hydrological responses to climate change. However, the provision of reliable forcing data remains problematic, particularly in data-sparse regions. Hydrological processes in cold regions involve complex phase changes and so are very sensitive to small biases in the driving meteorology, particularly in temperature and precipitation, including precipitation phase. Cold regions often have sparse surface observations, particularly at high elevations that generate a large amount of runoff. This paper aims to provide an improved set of forcing data for large-scale hydrological models for climate change impact assessment. The best available gridded data in Canada are from the high-resolution forecasts of the Global Environmental Multiscale (GEM) atmospheric model and outputs of the Canadian Precipitation Analysis (CaPA), but these datasets have a short historical record. The EU WATCH ERA-Interim reanalysis (WFDEI) has a longer historical record but has often been found to be biased relative to observations over Canada. The aim of this study, therefore, is to blend the strengths of both datasets (GEM-CaPA and WFDEI) to produce a less-biased long-record product (WFDEI-GEM-CaPA) for hydrological modelling and climate change impact assessment over the Mackenzie River Basin. First, a multivariate generalization of the quantile mapping technique was implemented to bias-correct WFDEI against GEM-CaPA at 3 h x 0.125 degrees resolution during the 2005-2016 overlap period, followed by a hindcast of WFDEI-GEM-CaPA from 1979. The derived WFDEI-GEM-CaPA data are validated against station observations as a preliminary step to assess their added value. This product is then used to bias-correct climate projections from the Canadian Centre for Climate Modelling and Analysis Canadian Regional Climate Model (CanRCM4) between 1950 and 2100 under RCP8.5, and an analysis of the datasets shows that the biases in the original WFDEI product have been removed and the climate change signals in CanRCM4 are preserved. The resulting biascorrected datasets are a consistent set of historical and climate projection data suitable for large-scale modelling and future climate scenario analysis. The final historical product (WFDEI-GEM-CaPA, 1979-2016) is freely available at the Federated Research Data Repository at https://doi.org/10.20383/101.0111 (Asong et al., 2018), while the original and corrected CanRCM4 data are available at https://doi.org/10.20383/101.0162 (Asong et al., 2019).", "authors": [ "Asong, Zilefac Elvis", "Elshamy, Mohamed Ezzat", "Princz, Daniel", "Wheater, Howard Simon", "Pomeroy, John Willard", "Pietroniro, Alain", "Cannon, Alex" ], "keywords": [ "" ], "year": "2020", "source": "EARTH SYSTEM SCIENCE DATA", "publication_type": "J", "point2d": [ -31.346393585205078, -29.702577590942383 ], "cluster": 1.0 }, { "idx": 373, "title": "A multi-objective calibration approach using in-situ soil moisture data for improved hydrological simulation of the Prairies", "abstract": "Traditionally, hydrological models are only calibrated to reproduce streamflow regime without considering other hydrological state variables, such as soil moisture and evapotranspiration. Limited studies have been performed on constraining the model parameters, despite the fact that the presence of a large number of parameters may provide large degree of freedom, resulting in equifinality and poor model performance. In this study, a multi-objective optimization approach is adopted, and both streamflow and soil moisture data are calibrated simultaneously for an experimental study basin in the Saskatchewan Prairies in western Canada. The results of this study show that the multi-objective calibration improves model fidelity compared to the single objective calibration. Moreover, the study demonstrates that single objective calibration performed against only streamflow can fairly mimic the streamflow hydrograph but does not yield realistic estimation of other fluxes such as evapotranspiration and soil moisture (especially in deeper soil layers).", "authors": [ "Budhathoki, Sujata", "Rokaya, Prabin", "Lindenschmidt, Karl-Erich", "Davison, Bruce" ], "keywords": [ "hydrological modelling", "model fidelity", "multi-objective calibration", "soil moisture", "evapotranspiration", "Prairies" ], "year": "2020", "source": "HYDROLOGICAL SCIENCES JOURNAL", "publication_type": "J", "point2d": [ 16.70290184020996, -54.47308349609375 ], "cluster": 16.0 }, { "idx": 374, "title": "Impacts of Varying Dam Outflow Elevations on Water Temperature, Dissolved Oxygen, and Nutrient Distributions in a Large Prairie Reservoir", "abstract": "Dam operations are known to have significant impacts on reservoir hydrodynamics and solute transport processes. The Gardiner Dam, one of the structures that forms the Lake Diefenbaker reservoir located in the Canadian Prairies, is managed for hydropower generation and agricultural irrigation and is known to have widely altering temperature regimes and nutrient circulations. This study applies the hydrodynamic and nutrient CE-QUAL-W2 model to explore how various withdrawal depths (5, 15, 25, 35, 45, and 55 m) influence the concentrations and distribution of nutrients, temperature, and dissolved oxygen (DO) within the Lake Diefenbaker reservoir. As expected, the highest dissolved nutrient (phosphate, and nitrate) concentrations were associated with hypoxic depth horizons in both studied years. During summer high flow period spillway operations impact the distribution of nutrients, water temperatures, and DO as increased epilimnion flow velocities route the incoming water through the surface of the reservoir and reduce mixing and surface warming. This reduces reservoir concentrations but can lead to increased outflow nitrogen (N) and phosphorus (P) concentrations. Lower withdrawal elevations pull warmer surface water deeper within the reservoir and decrease reservoir DO during summer stratification. During fall turnover low outflow elevations increase water column mixing and draws warmer water deeper, leading to slightly higher temperatures and nutrient concentrations than shallow withdrawal elevations. The 15 m depth (540 m above sea level) outflow generally provided the best compromise for overall reservoir and outflow nutrient reduction.", "authors": [ "Carr, Meghan K.", "Sadeghian, Amir", "Lindenschmidt, Karl-Erich", "Rinke, Karsten", "Morales-Marin, Luis" ], "keywords": [ "dam withdrawal", "dissolved oxygen", "nutrients", "reservoir", "temperature", "water quality" ], "year": "2020", "source": "ENVIRONMENTAL ENGINEERING SCIENCE", "publication_type": "J", "point2d": [ 34.997806549072266, -7.572873592376709 ], "cluster": 10.0 }, { "idx": 376, "title": "On the configuration and initialization of a large-scale hydrological land surface model to represent permafrost", "abstract": "Permafrost is an important feature of cold-region hydrology, particularly in river basins such as the Mackenzie River basin (MRB), and it needs to be properly represented in hydrological and land surface models (H-LSMs) built into existing Earth system models (ESMs), especially under the unprecedented climate warming trends that have been observed. Higher rates of warming have been reported in high latitudes compared to the global average, resulting in permafrost thaw with wide-ranging implications for hydrology and feedbacks to climate. The current generation of H-LSMs is being improved to simulate permafrost dynamics by allowing deep soil profiles and incorporating organic soils explicitly. Deeper soil profiles have larger hydraulic and thermal memories that require more effort to initialize. This study aims to devise a robust, yet computationally efficient, initialization and parameterization approach applicable to regions where data are scarce and simulations typically require large computational resources. The study further demonstrates an upscaling approach to inform large-scale ESM simulations based on the insights gained by modelling at small scales. We used permafrost observations from three sites along the Mackenzie River valley spanning different permafrost classes to test the validity of the approach. Results show generally good performance in reproducing present-climate permafrost properties at the three sites. The results also emphasize the sensitivity of the simulations to the soil layering scheme used, the depth to bedrock, and the organic soil properties.", "authors": [ "Elshamy, Mohamed E.", "Princz, Daniel", "Sapriza-Azuri, Gonzalo", "Abdelhamed, Mohamed S.", "Pietroniro, Al", "Wheater, Howard S.", "Razavi, Saman" ], "keywords": [ "" ], "year": "2020", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -28.748872756958008, 0.9842610359191895 ], "cluster": 13.0 }, { "idx": 377, "title": "Hydrometeorological data from Marmot Creek Research Basin, Canadian Rockies", "abstract": "Meteorological, snow survey, streamflow, and groundwater data are presented from Marmot Creek Research Basin, Alberta, Canada. The basin is a 9.4 km(2), alpine-montane forest headwater catchment of the Saskatchewan River basin that provides vital water supplies to the Prairie Provinces of Canada. It was heavily instrumented, experimented upon, and operated by several federal government agencies between 1962 and 1986, during which time its main and sub-basin streams were gauged, automated meteorological stations at multiple elevations were installed, groundwater observation wells were dug and automated, and frequent manual measurements of snow accumulation and ablation and other weather and water variables were made. Over this period, mature evergreen forests were harvested in two sub-basins, leaving large clear cuts in one basin and a honeycomb of small forest clearings in another basin. Whilst meteorological measurements and sub-basin streamflow discharge weirs in the basin were removed in the late 1980s, the federal government maintained the outlet streamflow discharge measurements and a nearby high-elevation meteorological station, and the Alberta provincial government maintained observation wells and a nearby fire weather station. Marmot Creek Research Basin was intensively re-instrumented with 12 automated meteorological stations, four sub-basin hydrometric sites, and seven snow survey transects starting in 2004 by the University of Saskatchewan Centre for Hydrology. The observations provide detailed information on meteorology, precipitation, soil moisture, snowpack, streamflow, and groundwater during the historical period from 1962 to 1987 and the modern period from 2005 to the present time. These data are ideal for monitoring climate change, developing hydrological process understanding, evaluating process algorithms and hydrological, cryospheric, or atmospheric models, and examining the response of basin hydrological cycling to changes in climate, extreme weather, and land cover through hydrological modelling and statistical analyses. The data presented are publicly available from Federated Research Data Repository (https://doi.org/10.20383/101.09, Fang et al., 2018).", "authors": [ "Fang, Xing", "Pomeroy, John W.", "DeBeer, Chris M.", "Harder, Phillip", "Siemens, Evan" ], "keywords": [ "" ], "year": "2019", "source": "EARTH SYSTEM SCIENCE DATA", "publication_type": "J", "point2d": [ -27.979373931884766, -9.770544052124023 ], "cluster": 12.0 }, { "idx": 380, "title": "China's Agricultural Irrigation and Water Conservancy Projects: A Policy Synthesis and Discussion of Emerging Issues", "abstract": "The United Nations (UN) has identified 17 Sustainable Development Goals (SDGs) to tackle major barriers to sustainable development by 2030. Achieving these goals will rely on the contribution of all nations and require balancing trade-offs among different sectors. Water and food insecurity have long been the two major challenges facing China. To address these challenges and achieve the SDGs, China needs to safeguard its agricultural irrigation and water conservancy projects. Although China is making efforts to transition its agricultural development to a sustainable trajectory by promoting water-saving irrigation, a number of issues are emerging, both with policy reforms and technological innovations. Through synthesizing the historical development of agriculture and its relationship with policy and political regimes, this paper identifies four major issues that are challenging the sustainability transformation of China's agricultural irrigation system and water conservancy projects: (1) problems with financial policy coordination between central and local governments; (2) the lack of incentives for farmers to construct and maintain irrigation infrastructure; (3) conflicts between decentralized operation of land and benefits from shared irrigation infrastructure; and (4) deterioration of small-scale irrigation infrastructure calls for action. In addressing these challenges, policy changes are required: government financial accountability at all levels needs to be clarified; subsidies need to be raised for the construction and management of small-scale irrigation and water conservancy projects; local non-profit organizations need to be established to enhance co-management between farmers and government.", "authors": [ "Du, Lijuan", "Xu, Li", "Li, Yanping", "Liu, Changshun", "Li, Zhenhua", "Wong, Jefferson S.", "Lei, Bo" ], "keywords": [ "sustainable agriculture", "Asia", "China", "SDGs", "policy synthesis", "water management" ], "year": "2019", "source": "SUSTAINABILITY", "publication_type": "J", "point2d": [ 42.9969367980957, -38.416053771972656 ], "cluster": 4.0 }, { "idx": 383, "title": "CE-QUAL-W2 model of dam outflow elevation impact on temperature, dissolved oxygen and nutrients in a reservoir", "abstract": "Dams are typically designed to serve as flood protection, provide water for irrigation, human and animal consumption, and harness hydropower. Despite these benefits, dam operations can have adverse effects on in-reservoir and downstream water temperature regimes, biogeochemical cycling and aquatic ecosystems. We present a water quality dataset of water withdrawal scenarios generated after implementing the 2D hydrodynamic and water quality model, CE-QUAL-W2. The scenarios explore how six water extraction scenarios, starting at 5 m above the reservoir bottom at the dam and increasing upward at 10 m intervals to 55 m, influence water quality in Lake Diefenbaker reservoir, Saskatchewan, Canada. The model simulates daily water temperature, dissolved oxygen, total phosphorus, phosphate as phosphorus, labile phosphorus, total nitrogen, nitrate as nitrogen, labile nitrogen, and ammonium at 87 horizontal segments and at 60 water depths during the 2011-2013 period. This dataset intends to facilitate a broader investigation of in-reservoir nutrient dynamics under dam operations, and to extend the understanding of reservoir nutrient dynamics globally.", "authors": [ "Lindenschmidt, Karl-Erich", "Carr, Meghan K.", "Sadeghian, Amir", "Morales-Marin, Luis" ], "keywords": [ "" ], "year": "2019", "source": "SCIENTIFIC DATA", "publication_type": "J", "point2d": [ 35.07029342651367, -6.824248790740967 ], "cluster": 10.0 }, { "idx": 384, "title": "A novel stochastic modelling approach for operational real-time ice jam flood forecasting", "abstract": "Forecasting ice jams and their consequential flooding is more challenging than predicting open water flood conditions. This is due to the chaotic nature of ice jam formation since slight changes in water and ice flows, location of the ice jam toe along the river and initial water levels at the time of jam formation can lead to marked differences in the outcome of backwater level elevations and flood severity. In this paper, we introduce a novel, operational real-time flood forecasting system that captures this stochastic nature of ice-jam floods and places the forecasts in a probabilistic context in the form of flood hazard maps (probability of flood extents and depths). This novel system was tested successfully for the ice-cover breakup period in the spring of 2018 along the Athabasca River at the Town of Fort McMurray, Canada.", "authors": [ "Lindenschmidt, Karl-Erich", "Rokaya, Prabin", "Das, Apurba", "Li, Zhaoqin", "Richard, Dominique" ], "keywords": [ "Operational hydrology", "Real-time flood forecasting", "Ice jams", "Athabasca River", "Fort McMurray" ], "year": "2019", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -3.4107117652893066, -42.432071685791016 ], "cluster": 16.0 }, { "idx": 385, "title": "Detecting intercepted snow on mountain needleleaf forest canopies using satellite remote sensing", "abstract": "Snow interception in cold regions needleleaf forest canopies is a crucial process that controls local snow accumulation and redistribution over > 20% of the Earth's land surface. Various ground-based methods exist to measure intercepted snow load, however all are based on single-tree measurements and are difficult to implement. No research has focussed on detecting large areal intercepted snow loads and no studies have assessed the use of satellite observations. In this study, four remote sensing indices (NDSI, NDVI, albedo, and land surface temperature (LST)) were retrieved from Landsat images to study their sensitivity to canopy intercepted snow and the possibility of using them to detect the presence of intercepted snow. The results indicate that presence of intercepted snow on canopy increased NDSI and albedo, but decreased NDVI. Intercepted snow presence also decreased the areal variability of NDSI and NDVI while increasing that of albedo. For these three indices, the differences between snow-free and snowcovered canopies were correlated to topography and forest canopy cover. Of these indices, NDSI changed the greatest. Intercepted snow noticeably decreased the LST difference between forest and open areas in springtime while the influence in wintertime was relatively smaller. An intercepted snow detection approach that uses both NDSI and NDVI to classify pixels into either snowcovered canopy or other (snow-free canopy and non-forest areas) is proposed here. A case study applying this approach compared remote sensing detection to simulations by the snow interception and sublimation model implemented in the Cold Regions Hydrological Modelling platform (CRHM). This used local meteorological observations from the pine, spruce and fir forest covered Marmot Creek Research Basin in the Canadian Rockies. The remote sensing detection of intercepted snow agreed well with CRHM simulations for continuous forests (83%) and less well for sparse forests (72%) and clearings with small trees (70%). Therefore, the approach is suitable for intercepted snow detection over continuous evergreen canopies. This technique provides a new capability for large-scale snow interception model validation and data assimilation to cold regions hydrological forecasting models.", "authors": [ "Lv, Zhibang", "Pomeroy, John W." ], "keywords": [ "Landsat", "Snow interception", "Coniferous forests", "NDSI", "NDVI", "Albedo", "LST" ], "year": "2019", "source": "REMOTE SENSING OF ENVIRONMENT", "publication_type": "J", "point2d": [ -53.74314880371094, -0.21405771374702454 ], "cluster": 8.0 }, { "idx": 386, "title": "Assimilating snow observations to snow interception process simulations", "abstract": "Snow interception is a crucial hydrological process in cold regions needleleaf forests, but is rarely measured directly. Indirect estimates of snow interception can be made by measuring the difference in the increase in snow accumulation between the forest floor and a nearby clearing over the course of a storm. Pairs of automatic weather stations with acoustic snow depth sensors provide an opportunity to estimate this, if snow density can be estimated reliably. Three approaches for estimating fresh snow density were investigated: weighted post-storm density increments from the physically based Snobal model, fresh snow density estimated empirically from air temperature (Hedstrom, N. R., et al. [1998]. Hydrological Processes, 12, 1611-1625), and fresh snow density estimated empirically from air temperature and wind speed (Jordan, R. E., et al. [1999]. Journal of Geophysical Research, 104, 7785-7806). Automated snow depth observations from adjacent forest and clearing sites and estimated snow densities were used to determine snowstorm snow interception in a subalpine forest in the Canadian Rockies, Alberta, Canada. Then the estimated snow interception and measured interception information from a weighed, suspended tree and a time-lapse camera were assimilated into a model, which was created using the Cold Regions Hydrological Modelling platform (CRHM), using Ensemble Kalman Filter or a simple rule-based direct insertion method. Interception determined using density estimates from the Hedstrom-Pomeroy fresh snow density equation agreed best with observations. Assimilating snow interception information from automatic snow depth measurements improved modelled snow interception timing by 7% and magnitude by 13%, compared to an open loop simulation driven by a numerical weather model; its accuracy was close to that simulated using locally observed meteorological data. Assimilation of tree-measured snow interception improved the snow interception simulation timing and magnitude by 18 and 19%, respectively. Time-lapse camera snow interception information assimilation improved the snow interception simulation timing by 32% and magnitude by 7%. The benefits of assimilation were greatly influenced by assimilation frequency and quality of the forcing data.", "authors": [ "Lv, Zhibang", "Pomeroy, John W." ], "keywords": [ "CRHM", "data assimilation", "EnKF", "fresh snow density", "GEM", "modelling", "snow depth", "Snow interception" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -52.37534713745117, 0.09347796440124512 ], "cluster": 8.0 }, { "idx": 387, "title": "Evaluation of SNODAS Snow Water Equivalent in Western Canada and Assimilation Into a Cold Region Hydrological Model", "abstract": "Snow water equivalent (SWE) is one of the most hydrologically important physical properties of a snowpack. The U.S. National Weather Service's Snow Data Assimilation System (SNODAS) provides snow products at high spatial (1 km(2)) and temporal (daily) resolution for the contiguous United States and southern Canada. This study evaluated the SNODAS SWE product in the boreal forest, prairie, and Canadian Rockies of western Canada against extensive snow survey measurements. SNODAS was found to work well in sheltered environments, to overestimate SWE under needle-leaf forests, and to be unable to capture the spatial variation of SWE in windswept prairie and alpine environments. Results indicate that SNODAS SWE accuracy is strongly influenced by the missing blowing snow redistribution and canopy energetics and snow interception and sublimation processes in the mass balance calculations of the SNODAS model and by erroneous precipitation data forcing the model. To demonstrate how errors caused by missing processes can be corrected in areas with low assimilation frequency, SNODAS data were assimilated into a physically based hydrological model created using the modular Cold Region Hydrological Modelling (CRHM) platform that includes blowing and intercepted snow redistribution and subcanopy melt energetic processes. This approach decreased the overestimation of SWE compared to SNODAS from 135 to 79% in the study area and suggests that snow assimilation modeled SWE quality can be improved if snow redistribution, sublimation, and subcanopy melt processes are incorporated.", "authors": [ "Lv, Zhibang", "Pomeroy, John W.", "Fang, Xing" ], "keywords": [ "snow water equivalent", "SNODAS", "snow redistribution", "Canadian Rockies", "prairie", "boreal forest" ], "year": "2019", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -50.832157135009766, -2.8322393894195557 ], "cluster": 12.0 }, { "idx": 388, "title": "The Canadian Hydrological Model (CHM) v1.0: a multi-scale, multi-extent, variable-complexity hydrological model - design and overview", "abstract": "Despite debate in the rainfall-runoff hydrology literature about the merits of physics-based and spatially distributed models, substantial work in cold-region hydrology has shown improved predictive capacity by including physics-based process representations, relatively high-resolution semi-distributed and fully distributed discretizations, and the use of physically identifiable parameters that require limited calibration. While there is increasing motivation for modelling at hyper-resolution (< 1 km) and snowdrift-resolving scales (approximate to 1 to 100 m), the capabilities of existing cold-region hydrological models are computationally limited at these scales. Here, a new distributed model, the Canadian Hydrological Model (CHM), is presented. Although designed to be applied generally, it has a focus for application where cold-region processes play a role in hydrology. Key features include the ability to do the following: capture spatial heterogeneity in the surface discretization in an efficient manner via variable-resolution unstructured meshes; include multiple process representations; change, remove, and decouple hydrological process algorithms; work at both a point and spatially distributed scale; scale to multiple spatial extents and scales; and utilize a variety of forcing fields (boundary and initial conditions). This paper focuses on the overall model philosophy and design, and it provides a number of cold-region-specific features and examples.", "authors": [ "Marsh, Christopher B.", "Pomeroy, John W.", "Wheater, Howard S." ], "keywords": [ "" ], "year": "2020", "source": "GEOSCIENTIFIC MODEL DEVELOPMENT", "publication_type": "J", "point2d": [ -23.669021606445312, -12.414318084716797 ], "cluster": 12.0 }, { "idx": 389, "title": "A Finite Volume Blowing Snow Model for Use With Variable Resolution Meshes", "abstract": "Blowing snow is ubiquitous in cold, windswept environments. In some regions, blowing snow sublimation losses can ablate a notable fraction of the seasonal snowfall. It is advantageous to predict alpine snow regimes at the spatial scale of snowdrifts (approximate to 1 to 100 m) because of the role of snow redistribution in governing the duration and volume of snowmelt. However, blowing snow processes are often neglected due to computational costs. Here, a three-dimensional blowing snow model is presented that is spatially discretized using a variable resolution unstructured mesh. This represents the heterogeneity of the surface explicitly yet, for the case study reported, gained a 62% reduction in computational elements versus a fixed-resolution mesh and resulted in a 44% reduction in total runtime. The model was evaluated for a subarctic mountain basin using transects of measured snow water equivalent (SWE) in a tundra valley. Including blowing snow processes improved the prediction of SWE by capturing inner-annual snowdrift formation, more than halved the total mean bias error, and increased the coefficient of variation of SWE from 0.04 to 0.31 better matching the observed CV (0.41). The use of a variable resolution mesh did not dramatically degrade the model performance. Comparison with a constant resolution mesh showed a similar CV and RMSE as the variable resolution mesh. The constant resolution mesh had a smaller mean bias error. A sensitivity analysis showed that snowdrift locations and immediate up-wind sources of blowing snow are the most sensitive areas of the landscape to wind speed variations.", "authors": [ "Marsh, Christopher B.", "Pomeroy, John W.", "Spiteri, Raymond J.", "Wheater, Howard S." ], "keywords": [ "" ], "year": "2020", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -53.26919174194336, -5.404154300689697 ], "cluster": 12.0 }, { "idx": 390, "title": "Seasonal effects of a hydropeaking dam on a downstream benthic macroinvertebrate community", "abstract": "As more hydroelectric dams regulate rivers to meet growing energy demands, there is ongoing concern about downstream effects, including impacts on downstream benthic macroinvertebrate (BMI) communities. Hydropeaking is a common hydroelectric practice where short-term variation in power production leads to large and often rapid fluctuations in discharge and water level. There are key knowledge gaps on the ecosystem impacts of hydropeaking in large rivers, the seasonality of these impacts, and whether dams can be managed to lessen impacts. We assessed how patterns of hydropeaking affect abundance, taxonomic richness, and relative tolerance of BMIs in the Saskatchewan River (Saskatchewan, Canada). Reaches immediately (<2 km) downstream of the dam generally had high densities of BMIs and comparable taxonomic diversity relative to upstream locations but were characterized by lower ratios of sensitive (e.g., Ephemeroptera, Plecoptera, and Trichoptera) to tolerant (e.g., Chironomidae) taxa. The magnitude of effect varied with seasonal changes in discharge. Understanding the effects of river regulation on BMI biodiversity and river health has implications for mitigating the impacts of hydropeaking dams on downstream ecosystems. Although we demonstrated that a hydropeaking dam may contribute to a significantly different downstream BMI assemblage, we emphasize that seasonality is a key consideration. The greatest differences between upstream and downstream locations occurred in spring, suggesting standard methods of late summer and fall sampling may underestimate ecosystem-scale impacts.", "authors": [ "Mihalicz, Jordan E.", "Jardine, Timothy D.", "Baulch, Helen M.", "Phillips, Iain D." ], "keywords": [ "benthos", "biotic index", "hydropower dam", "large river", "Northern Great Plains", "river health", "seasonality" ], "year": "2019", "source": "RIVER RESEARCH AND APPLICATIONS", "publication_type": "J", "point2d": [ 65.92684173583984, -3.6293582916259766 ], "cluster": 19.0 }, { "idx": 391, "title": "Changes in streamflow and water temperature affect fish habitat in the Athabasca River basin in the context of climate change", "abstract": "Changes to natural flow and air temperature in the context of climate change can have impacts on physiology, distribution and survival of fish. Of particular interest is the Athabasca River basin, a highly biologically productive basin that includes one of the largest boreal freshwater inland river deltas in the world and serves as habitat for many fish species. Earlier melt events, higher winter and spring flows and lower summer flows are expected as a consequence of climate change in this basin. Here, we model changes in river flow and water temperature under changing climate scenarios through the integration of a physically-based semi-distributed hydrological model and a 1D stream water temperature model forced by climate change scenarios. The modeled changes in streamflow and water temperature are used to predict changes in habitat suitability for the Athabasca Rainbow Trout (ART) (Oncorhynchus mykiss), a unique ecotype of trout considered as a 'species at risk'. The results indicate that future flow decreases in most of the basin can lead to reduced flow velocities and water depths making current ART habitat suboptimal. Also, warming low-land habitats and increasing water temperatures will increase metabolic rates and stress fish forcing them to migrate upstream to cooler waters confining their habitat range.", "authors": [ "Morales-Marin, L. A.", "Rokaya, P.", "Sanyal, P. R.", "Sereda, J.", "Lindenschmidt, K. E." ], "keywords": [ "Fish habitat", "Water temperature", "streamflow", "Climate change", "Athabasca River" ], "year": "2019", "source": "ECOLOGICAL MODELLING", "publication_type": "J", "point2d": [ 3.0175693035125732, -0.5703026652336121 ], "cluster": 16.0 }, { "idx": 393, "title": "Anthropocene flooding: Challenges for science and society", "abstract": "", "authors": [ "Razavi, Saman", "Gober, Patricia", "Maier, Holger R.", "Brouwer, Roy", "Wheater, Howard" ], "keywords": [ "" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 16.758495330810547, 24.450237274169922 ], "cluster": 18.0 }, { "idx": 394, "title": "Correlation among parameters and boundary conditions in river ice models", "abstract": "In river ice modelling, deterministic river ice models are often embedded into a Monte-Carlo framework to generate ensembles of backwater staging for jams of varying length and location, and for different combinations of model parameters and boundary conditions. In this approach, values for parameters and boundary conditions are usually sampled independently (of each other) from their probability distributions. However, many of the parameters and boundary conditions are interdependent and thus warrant sampling methods that consider correlation effects. But, such correlation studies have not been previously conducted for river ice models, which is the main motivation for this study. A review of literature was performed to compile data from more than 40 different ice-jam case studies from 24 ice-jam prone locations in Canada and the United States. Then correlations among parameters and boundary conditions in three commonly used river ice models were investigated. The results show that the model parameters in river ice models are ice-jam centric and have varying degrees of correlations, but boundary conditions are independent of each other and, instead, have potentially stronger ties to catchment characteristics, fluvial geomorphology and meteorological conditions. The findings of this study provide important insights in understanding and improving parameterization, calibration and ensemble modelling of river ice models.", "authors": [ "Rokaya, Prabin", "Lindenschmidt, Karl-Erich" ], "keywords": [ "Boundary conditions", "Correlation", "Cold region", "Ice processes", "Parameters", "River ice models", "Stochasticity" ], "year": "2020", "source": "MODELING EARTH SYSTEMS AND ENVIRONMENT", "publication_type": "J", "point2d": [ -6.025330543518066, -43.46177291870117 ], "cluster": 16.0 }, { "idx": 395, "title": "Climatic effects on ice phenology and ice-jam flooding of the Athabasca River in western Canada", "abstract": "In cold region environments, any alteration in the hydro-climatic regime can have profound impacts on river ice processes. This paper studies the implications of hydro-climatic trends on river ice processes, particularly on the freeze-up and ice-cover breakup along the Athabasca River in Fort McMurray in western Canada, which is an area very prone to ice-jam flooding. Using a stochastic approach in a one-dimensional hydrodynamic river ice model, a relationship between overbank flow and breakup discharge is established. Furthermore, the likelihood of ice-jam flooding in the future (2041-2070 period) is assessed by forcing a hydrological model with meteorological inputs from the Canadian regional climate model driven by two atmospheric-ocean general circulation climate models. Our results show that the probability of ice-jam flooding for the town of Fort McMurray in the future will be lower, but extreme ice-jam flood events are still probable.", "authors": [ "Rokaya, Prabin", "Morales-Marin, Luis", "Bonsal, Barrie", "Wheater, Howard", "Lindenschmidt, Karl-Erich" ], "keywords": [ "ice-jam floods", "hydro-climatic trends", "ice phenology", "flood risk", "Athabasca River", "Canada" ], "year": "2019", "source": "HYDROLOGICAL SCIENCES JOURNAL-JOURNAL DES SCIENCES HYDROLOGIQUES", "publication_type": "J", "point2d": [ -9.891583442687988, -39.80309295654297 ], "cluster": 1.0 }, { "idx": 396, "title": "Impacts of future climate on the hydrology of a northern headwaters basin and its implications for a downstream deltaic ecosystem", "abstract": "Anthropogenic and climatic-induced changes to flow regimes pose significant risks to river systems. Northern rivers and their deltas are particularly vulnerable due to the disproportionate warming of the Northern Hemisphere compared with the Southern Hemisphere. Of special interest is the Peace-Athabasca Delta (PAD) in western Canada, a productive deltaic lake and wetland ecosystem, which has been recognized as a Ramsar site. Both climate- and regulation-induced changes to the hydrological regime of the Peace River have raised concerns over the delta's ecological health. With the damming of the headwaters, the role of downstream unregulated tributaries has become more important in maintaining, to a certain degree, a natural flow regime, particularly during open-water conditions. However, their flow contributions to the mainstem river under future climatic conditions remain largely uncertain. In this study, we first evaluated the ability of a land-surface hydrological model to simulate hydro-ecological relevant indicators, highlighting the model's strengths and weaknesses. Then, we investigated the streamflow conditions in the Smoky River, the largest unregulated tributary of the Peace River, in the 2071-2100 versus the 1981-2010 periods. Our modelling results revealed significant changes in the hydrological regime of the Smoky River, such as increased discharge in winter (+190%) and spring (+130%) but reduced summer flows (-33%) in the 2071-2100 period compared with the baseline period, which will have implications for the sustainability of the downstream PAD. In particular, the projected reductions in 30-day and 90-day maximum flows in the Smoky River will affect open-water flooding, which is important in maintaining lake levels and connectivity to perimeter delta wetlands in the Peace sector of the PAD. The evaluation of breakup and freeze-up flows for the 2071-2100 period showed mixed implications for the ice-jam flooding, which is essential for recharging high-elevation deltaic basins. Thus, despite projected increase in annual and spring runoff in the 2071-2100 period from the Smoky sub-basin, the sustainability of the PAD still remains uncertain.", "authors": [ "Rokaya, Prabin", "Peters, Daniel L.", "Elshamy, Mohamed", "Budhathoki, Sujata", "Lindenschmidt, Karl-Erich" ], "keywords": [ "climate", "floods", "hydro-ecological indicators", "hydrological assessment", "ice-jam", "model evaluation", "Peace-Athabasca Delta", "Smoky River" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -10.549748420715332, -31.548320770263672 ], "cluster": 13.0 }, { "idx": 397, "title": "Summary and synthesis of Changing Cold Regions Network (CCRN) research in the interior of western Canada - Part 1: Projected climate and meteorology", "abstract": "The interior of western Canada, up to and including the Arctic, has experienced rapid change in its climate, hydrology, cryosphere, and ecosystems, and this is expected to continue. Although there is general consensus that warming will occur in the future, many critical issues remain In this first of two articles, attention is placed on atmospheric-related issues that range from large scales down to individual precipitation events. Each of these is considered in terms of expected change organized by season and utilizing mainly business-as-usual climate scenario information. Large-scale atmospheric circulations affecting this region are projected to shift differently in each season, with conditions that are conducive to the development of hydroclimate extremes in the domain becoming substantially more intense and frequent after the mid-century. When coupled with warming temperatures, changes in the large-scale atmospheric drivers lead to enhancements of numerous water-related and temperature-related extremes. These include winter snowstorms, freezing rain, drought, forest fires, as well as atmospheric forcing of spring floods, although not necessarily summer convection. Collective insights of these atmospheric findings are summarized in a consistent, connected physical framework.", "authors": [ "Stewart, Ronald E.", "Szeto, Kit K.", "Bonsal, Barrie R.", "Hanesiak, John M.", "Kochtubajda, Bohdan", "Li, Yanping", "Theriault, Julie M.", "DeBeer, Chris M.", "Tam, Benita Y.", "Li, Zhenhua", "Liu, Zhuo", "Bruneau, Jennifer A.", "Duplessis, Patrick", "Marinier, Sebastien", "Matte, Dominic" ], "keywords": [ "" ], "year": "2019", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -24.894495010375977, -16.840837478637695 ], "cluster": 1.0 }, { "idx": 398, "title": "High-resolution regional climate modeling and projection over western Canada using a weather research forecasting model with a pseudo-global warming approach", "abstract": "Climate change poses great risks to western Canada's ecosystem and socioeconomical development. To assess these hydroclimatic risks under high-end emission scenario RCP8.5, this study used the Weather Research Forecasting (WRF) model at a convection-permitting (CP) 4 km resolution to dynamically downscale the mean projection of a 19-member CMIP5 ensemble by the end of the 21st century. The CP simulations include a retrospective simulation (CTL, 2000-2015) for verification forced by ERA-Interim and a pseudo-global warming (PGW) for climate change projection forced with climate change forcing (2071-2100 to 1976-2005) from CMIP5 ensemble added on ERA-Interim. The retrospective WRF-CTL's surface air temperature simulation was evaluated against Canadian daily analysis ANUS-PLIN, showing good agreements in the geographical distribution with cold biases east of the Canadian Rockies, especially in spring. WRF-CTL captures the main pattern of observed precipitation distribution from CaPA and ANUS-PLIN but shows a wet bias near the British Columbia coast in winter and over the immediate region on the lee side of the Canadian Rockies. The WRF-PGW simulation shows significant warming relative to CTL, especially over the polar region in the northeast during the cold season, and in daily minimum temperature. Precipitation changes in PGW over CTL vary with the seasons: in spring and late autumn precipitation increases in most areas, whereas in summer in the Saskatchewan River basin and southern Canadian Prairies, the precipitation change is negligible or decreased slightly. With almost no increase in precipitation and much more evapotranspiration in the future, the water availability during the growing season will be challenging for the Canadian Prairies. The WRF-PGW projected warming is less than that by the CMIP5 ensemble in all seasons. The CMIP5 ensemble projects a 10 %-20% decrease in summer precipitation over the Canadian Prairies and generally agrees with WRF-PGW except for regions with significant terrain. This difference may be due to the much higher resolution of WRF being able to more faithfully represent small-scale summer convection and orographic lifting due to steep terrain. WRF-PGW shows an increase in high-intensity precipitation events and shifts the distribution of precipitation events toward more extremely intensive events in all seasons. Due to this shift in precipitation intensity to the higher end in the PGW simulation, the seemingly moderate increase in the total amount of precipitation in summer east of the Canadian Rockies may underestimate the increase in flooding risk and water shortage for agriculture. The change in the probability distribution of precipitation intensity also calls for innovative bias-correction methods to be developed for the application of the dataset when bias correction is required. High-quality meteorological observation over the region is needed for both forcing high-resolution climate simulation and conducting verification. The high-resolution downscaled climate simulations provide abundant opportunities both for investigating local-scale atmospheric dynamics and for studying climate impacts on hydrology, agriculture, and ecosystems.", "authors": [ "Li, Yanping", "Li, Zhenhua", "Zhang, Zhe", "Chen, Liang", "Kurkute, Sopan", "Scaff, Lucia", "Pan, Xicai" ], "keywords": [ "" ], "year": "2019", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -32.93126678466797, -32.36956024169922 ], "cluster": 1.0 }, { "idx": 399, "title": "Representation and improved parameterization of reservoir operation in hydrological and land-surface models", "abstract": "Reservoirs significantly affect flow regimes in watershed systems by changing the magnitude and timing of streamflows. Failure to represent these effects limits the performance of hydrological and land-surface models (H-LSMs) in the many highly regulated basins across the globe and limits the applicability of such models to investigate the futures of watershed systems through scenario analysis (e.g., scenarios of climate, land use, or reservoir regulation changes). An adequate representation of reservoirs and their operation in an H-LSM is therefore essential for a realistic representation of the downstream flow regime. In this paper, we present a general parametric reservoir operation model based on piecewise-linear relationships between reservoir storage, inflow, and release to approximate actual reservoir operations. For the identification of the model parameters, we propose two strategies: (a) a generalized parameterization that requires a relatively limited amount of data and (b) direct calibration via multi-objective optimization when more data on historical storage and release are available. We use data from 37 reservoir case studies located in several regions across the globe for developing and testing the model. We further build this reservoir operation model into the MESH (Modelisation Environmentale-Surface et Hydrologie) modeling system, which is a large-scale H-LSM. Our results across the case studies show that the proposed reservoir model with both parameter-identification strategies leads to improved simulation accuracy compared with the other widely used approaches for reservoir operation simulation. We further show the significance of enabling MESH with this reservoir model and discuss the interdependent effects of the simulation accuracy of natural processes and that of reservoir operations on the overall model performance. The reservoir operation model is generic and can be integrated into any H-LSM.", "authors": [ "Yassin, Fuad", "Razavi, Saman", "Elshamy, Mohamed", "Davison, Bruce", "Sapriza-Azuri, Gonzalo", "Wheater, Howard" ], "keywords": [ "" ], "year": "2019", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ 10.416433334350586, -58.5029296875 ], "cluster": 16.0 }, { "idx": 400, "title": "Composition Wheels: Visualizing dissolved organic matter using common composition metrics across a variety of Canadian ecozones", "abstract": "Dissolved organic matter (DOM) is a ubiquitous component of aquatic systems, impacting aquatic health and drinking water quality. These impacts depend on the mixture of organic molecules that comprise DOM. Changing climates are altering both the amount and character of DOM being transported from the terrestrial system into adjacent surface waters, yet DOM composition is not monitored as often as overall concentration. Many DOM characterization methods exist, confounding comparison of DOM composition across different studies. The objective of this research is to determine which parameters in a suite of relatively simple and common DOM characterization techniques explain the most variability in DOM composition from surface and groundwater sites. Further, we create a simple visualization tool to easily compare compositional differences in DOM. A large number of water samples (n = 250) was analyzed from six Canadian ecozones for DOM concentration, ultraviolet-visible light absorbance, molecular size, and elemental ratios. Principal component analyses was used to identify quasi-independent DOM compositional parameters that explained the highest variability in the dataset: spectral slope, specific-UV absorbance at 255nm, humic substances fraction, and dissolved organic carbon to dissolved organic nitrogen ratio. A 'Composition Wheel' was created by plotting these four parameters as a polygon. Our results find similarities in DOM composition irrespective of site differences in vegetation and climate. Further, two main end-member Composition Wheel shapes were revealed that correspond to DOM in organic-rich groundwaters and DOM influenced by photodegradation. The Composition Wheel approach uses easily visualized differences in polygon shape to quantify how DOM evolves by natural processes along the aquatic continuum and to track sources and degradation of DOM.", "authors": [ "Aukes, Pieter J. K.", "Schiff, Sherry L." ], "keywords": [ "" ], "year": "2021", "source": "PLOS ONE", "publication_type": "J", "point2d": [ 34.704532623291016, 37.816192626953125 ], "cluster": 19.0 }, { "idx": 402, "title": "Structural calibration of an semi-distributed hydrological model of the Liard River basin", "abstract": "The development of hydrological models that produce practically useful and physically defensible results is an ongoing challenge in hydrology. This challenge is further compounded in large, spatially variable basins with sparse data, where a detailed understanding of a basin's hydrological response may be limited. This study presents an iterative and stepwise calibration strategy for model structure and parameters for a hydrological model of the 275,000 km(2)Liard River basin in northern Canada. The calibration procedure was optimized to exploit and represent available data at 29 stream gauges and included the use of multiple data sources to constrain model calibration and improve model function. A flexible modelling framework was used to allow the explicit inclusion of locally varied model structure within the calibration procedure. The final model exhibits strong performance in both calibration and validation, and represents significantly different hydrological responses in different portions of the basin well. The calibration procedure helped to identify differences in hydrological processes within the basin which have not been considered by other models of the Liard. The ability to modify model structure in order to account for different hydrological regimes in different parts of the basin is demonstrated to improve model performance locally and globally.", "authors": [ "Brown, Genevieve", "Craig, James R." ], "keywords": [ "Hydrological model", "flexible model structure", "calibration" ], "year": "2020", "source": "CANADIAN WATER RESOURCES JOURNAL", "publication_type": "J", "point2d": [ -1.5385839939117432, -15.653579711914062 ], "cluster": 16.0 }, { "idx": 403, "title": "Fire characteristics and environmental conditions shape plant communities via regeneration strategy", "abstract": "Climate change is altering disturbance regimes outside historical norms, which can impact biodiversity by selecting for plants with particular traits. The relative impact of disturbance characteristics on plant traits and community structure may be mediated by environmental gradients. We aimed to understand how wildfire impacted understory plant communities and plant regeneration strategies along gradients of environmental conditions and wildfire characteristics in boreal forests. We established 207 plots (60 m(2)) in recently burned stands and 133 plots in mature stands with no recent fire history in comparable gradients of stand type, site moisture (drainage) and soil organic layer (SOL) depth in two ecozones in Canada's Northwest Territories. At each plot, we recorded all vascular plant taxa in the understory and measured the regeneration strategy (seeder, resprouter, survivor) in burned plots, along with seedbed conditions (mineral soil and bryophyte cover). Dispersal, longevity and growth form traits were determined for each taxon. Fire characteristics measured included proportion of pre-fire SOL combusted (fire severity), date of burn (fire seasonality) and pre-fire stand age (time following fire). Results showed understory community composition was altered by fire. However, burned and mature stands had similar plant communities in wet sites with deep SOL. In the burned plots, regeneration strategies were determined by fire severity, drainage and pre- and post-fire SOL depth. Resprouters were more common in wet sites with deeper SOL and lower fire severity, while seeders were associated with drier sites with thinner SOL and greater fire severity. This led to drier burned stands being compositionally different from their mature counterparts and seedbed conditions were important. Our study highlights the importance of environment-wildfire interactions in shaping plant regeneration strategies and patterns of understory plant community structure across landscapes, and the overriding importance of SOL depth and site drainage in mediating fire severity, plant regeneration and community structure.", "authors": [ "Day, Nicola J.", "White, Alison L.", "Johnstone, Jill F.", "Degre-Timmons, Genevieve E.", "Cumming, Steven G.", "Mack, Michelle C.", "Turetsky, Merritt R.", "Walker, Xanthe J.", "Baltzer, Jennifer L." ], "keywords": [ "plant functional traits", "RLQ and fourth corner analysis", "soil drainage", "taiga plains", "taiga shield", "vegetation change" ], "year": "2020", "source": "ECOGRAPHY", "publication_type": "J", "point2d": [ -19.35262107849121, 74.94790649414062 ], "cluster": 15.0 }, { "idx": 404, "title": "A Coupled Thermal-Hydraulic-Mechanical Approach to Modeling the Impact of Roadbed Frost Loading on Water Main Failure", "abstract": "Subsurface pipe failures in cold regions are generally believed to be exacerbated by differential strain in shallow soils induced by seasonal freeze and thaw cycles. The transient stress-strain fields resulting from soil water phase change may influence the occurrence of local buried pipe breaks including those related to urban water mains. This work proposes that freezing-induced frost loading results in uneven stress-strain distributions along the buried water mains placing them at risk of bending, breaking, and/or leaking. A coupled thermal-hydraulic-mechanical (THM) model was developed to illustrate the interactions among moisture, temperature, and stress-strain fields within variably saturated freezing soils. Several typical cases involving highly frost-susceptible and lower frost-susceptible soils underlying roadbeds were examined. Results show that the magnitude of frost-induced compressive stress and strain changes between different frost-susceptible soils can vary significantly. Such substantial differences in stress-strain fields would increase the breakage risk of water mains buried within different types of soils. Furthermore, even water mains buried within soils with low frost-susceptibility are at risk when additional sources of soil water exist and are available to migrate to the freezing front. To reduce the risk of damage to buried pipe-like infrastructure, such as municipal water mains, from soil freezing phenomena, the selected backfill material should have fairly consistent frost susceptibility or a broad zone of transition should be considered between materials with significantly different frost susceptibility. In addition, buried pipes should be kept as far away from external sources of subsurface water as possible considering the potential for the water source to exacerbate the level of risk to the pipe.", "authors": [ "Huang, Xiang", "Rudolph, David L.", "Glass, Brittney" ], "keywords": [ "" ], "year": "2022", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -42.24104690551758, 22.596546173095703 ], "cluster": 2.0 }, { "idx": 405, "title": "A Coupled Thermal-Hydraulic-Mechanical Approach to Modeling the Impact of Roadbed Frost Loading on Water Main Failure", "abstract": "Subsurface pipe failures in cold regions are generally believed to be exacerbated by differential strain in shallow soils induced by seasonal freeze and thaw cycles. The transient stress-strain fields resulting from soil water phase change may influence the occurrence of local buried pipe breaks including those related to urban water mains. This work proposes that freezing-induced frost loading results in uneven stress-strain distributions along the buried water mains placing them at risk of bending, breaking, and/or leaking. A coupled thermal-hydraulic-mechanical (THM) model was developed to illustrate the interactions among moisture, temperature, and stress-strain fields within variably saturated freezing soils. Several typical cases involving highly frost-susceptible and lower frost-susceptible soils underlying roadbeds were examined. Results show that the magnitude of frost-induced compressive stress and strain changes between different frost-susceptible soils can vary significantly. Such substantial differences in stress-strain fields would increase the breakage risk of water mains buried within different types of soils. Furthermore, even water mains buried within soils with low frost-susceptibility are at risk when additional sources of soil water exist and are available to migrate to the freezing front. To reduce the risk of damage to buried pipe-like infrastructure, such as municipal water mains, from soil freezing phenomena, the selected backfill material should have fairly consistent frost susceptibility or a broad zone of transition should be considered between materials with significantly different frost susceptibility. In addition, buried pipes should be kept as far away from external sources of subsurface water as possible considering the potential for the water source to exacerbate the level of risk to the pipe.", "authors": [ "Huang, Xiang", "Rudolph, David L.", "Glass, Brittney" ], "keywords": [ "" ], "year": "2022", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -42.24104690551758, 22.596546173095703 ], "cluster": 2.0 }, { "idx": 406, "title": "Evaluating temporal patterns of metals concentrations in floodplain lakes of the Athabasca Delta (Canada) relative to pre-industrial baselines", "abstract": "Sediment quality monitoring is widely used to quantify extent of river pollution, but requires knowledge of pre-disturbance conditions in the potentially altered landscape. This has long been identified as a critical aspect to develop for addressing concerns of river pollution in the Alberta Oil Sands Region. Here, we use analyses of sediment cores from eight floodplain lakes spanning a 67 river-km transect across the Athabasca Delta to define pre-1920 (pre-industrial) baseline concentrations for vanadium and five primary pollutants. We then evaluate if sediment metals concentrations have become enriched above baseline since onset of oil sands development and other industrial activities. Results demonstrate no enrichment of metals concentrations (except zinc at one lake) and absence of consistent temporal increases above pre-industrial baselines. Thus, natural processes continue to dominate metal deposition in floodplain lakes of the Athabasca Delta -- an important finding to inform stewardship decisions. The pre-1920 metals concentrations baselines offer a useful tool for ongoing sediment monitoring in aquatic ecosystems of the Athabasca Delta. (C) 2019 The Author(s). Published by Elsevier B.V.", "authors": [ "Kay, M. L.", "Wiklund, J. A.", "Remmer, C. R.", "Owca, T. J.", "Klemt, W. H.", "Neary, L. K.", "Brown, K.", "MacDonald, E.", "Thomson, K.", "Vucic, J. M.", "Wesenberg, K.", "Hall, R. I.", "Wolfe, B. B." ], "keywords": [ "Wood Buffalo National Park", "River sediment quality", "Alberta oil sands", "Aquatic ecosystem monitoring", "Environmental impact assessment", "Paleolimnology" ], "year": "2020", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 48.3897819519043, -3.2996275424957275 ], "cluster": 19.0 }, { "idx": 408, "title": "Spatial and stratigraphic variation of near-surface ground ice in discontinuous permafrost of the taiga shield", "abstract": "The acceleration of permafrost thaw due to warming, wetting, and disturbance is altering circumpolar landscapes. The effect of thaw is largely determined by ground ice content in near-surface permafrost, making the characterization and prediction of ground ice content critical. Here we evaluate the spatial and stratigraphic variation of near-surface ground ice characteristics in the dominant forest types in the North Slave region near Yellowknife, Northwest Territories, Canada. Physical variation in the permafrost was assessed through cryostructure, soil properties, and volumetric ice content, and relationships between these parameters were determined. Near-surface ground ice characteristics were contrasted between forest types. In black spruce forests the top of the permafrost was ice-rich and characterized by lenticular and ataxitic cryostructures, indicating the presence of an intermediate layer. Most white spruce/birch forests showed similar patterns; however, an increase in the active layer thickness and permafrost thaw at some sites have eradicated the transition zone, and the large ice lenses encountered at depth reflect segregated ground ice developed during initial downward aggradation of permafrost. Our findings indicate that white spruce/birch terrain will be less sensitive than black spruce forests to near-surface permafrost thaw. However, if permafrost thaws completely, white spruce/birch terrain will probably be transformed into wetland-thaw lake complexes due to high ground ice content at depth.", "authors": [ "Paul, Jason R.", "Kokelj, Steven V.", "Baltzer, Jennifer L." ], "keywords": [ "black spruce", "Great Slave lowlands", "near-surface ground ice", "transition zone", "white birch", "white spruce", "Yellowknife" ], "year": "2021", "source": "PERMAFROST AND PERIGLACIAL PROCESSES", "publication_type": "J", "point2d": [ -24.025352478027344, 39.437957763671875 ], "cluster": 13.0 }, { "idx": 409, "title": "Spatial and stratigraphic variation of near-surface ground ice in discontinuous permafrost of the taiga shield", "abstract": "The acceleration of permafrost thaw due to warming, wetting, and disturbance is altering circumpolar landscapes. The effect of thaw is largely determined by ground ice content in near-surface permafrost, making the characterization and prediction of ground ice content critical. Here we evaluate the spatial and stratigraphic variation of near-surface ground ice characteristics in the dominant forest types in the North Slave region near Yellowknife, Northwest Territories, Canada. Physical variation in the permafrost was assessed through cryostructure, soil properties, and volumetric ice content, and relationships between these parameters were determined. Near-surface ground ice characteristics were contrasted between forest types. In black spruce forests the top of the permafrost was ice-rich and characterized by lenticular and ataxitic cryostructures, indicating the presence of an intermediate layer. Most white spruce/birch forests showed similar patterns; however, an increase in the active layer thickness and permafrost thaw at some sites have eradicated the transition zone, and the large ice lenses encountered at depth reflect segregated ground ice developed during initial downward aggradation of permafrost. Our findings indicate that white spruce/birch terrain will be less sensitive than black spruce forests to near-surface permafrost thaw. However, if permafrost thaws completely, white spruce/birch terrain will probably be transformed into wetland-thaw lake complexes due to high ground ice content at depth.", "authors": [ "Paul, Jason R.", "Kokelj, Steven V.", "Baltzer, Jennifer L." ], "keywords": [ "black spruce", "Great Slave lowlands", "near-surface ground ice", "transition zone", "white birch", "white spruce", "Yellowknife" ], "year": "2021", "source": "PERMAFROST AND PERIGLACIAL PROCESSES", "publication_type": "J", "point2d": [ -24.025352478027344, 39.437957763671875 ], "cluster": 13.0 }, { "idx": 410, "title": "Assimilate, process and analyse thermal dissipation sap flow data using the TREX r package", "abstract": "A key ecophysiological measurement is the flow of water (or sap) along the tree's water-transport system, which is an essential process for maintaining the hydraulic connection within the soil-plant-atmosphere continuum. The thermal dissipation method (TDM) is widespread in the scientific community for measuring sap flow and has provided novel insights into water use and its environmental sensitivity, from the tree- to the forest-stand level. Yet, methodological approaches to determine sap flux density (SFD) from raw TDM measurements remain case-specific, introducing uncertainties and hampering data syntheses and meta-analyses. Here, we introduce the r package TREX (TRee sap flow EXtractor), incorporating a wide range of sap flow data-processing procedures to quantify SFD from raw TDM measurements. TREX provides functions for (a) importing and assimilating raw measurements, (b) data quality control and filtering and (c) calculating standardized SFD outputs and their associated uncertainties according to different data-processing methods. A case study using a Norway spruce tree illustrates TREX's functionalities, featuring interactive data curation and generating outputs in a reproducible and transparent way. The calculations of SFD in TREX can, for instance, use the original TDM calibration coefficients, user-supplied calibration parameters or calibration data from a recently compiled database of 22 studies and 37 species. Moreover, the package includes an automatic procedure for quantifying the sensitivity and uncertainty of the obtained results to user-defined assumptions and parameter values, by means of a state-of-the-art global sensitivity analysis. Time series of plant ecophysiological measurements are becoming increasingly available and enhance our understanding of climate change impacts on tree functioning. TREX allows for establishing a baseline for data processing of TDM measurements and supports comparability between case studies, facilitating robust, transparent and reproducible large-scale syntheses of sap flow patterns. Moreover, TREX facilitates the simultaneous application of multiple common data-processing approaches to convert raw data to physiological relevant quantities. This allows for robust quantification of the impact (i.e. sensitivity and uncertainty) of user-specific choices and methodological assumptions, which is necessary for process understanding and policy making.", "authors": [ "Peters, Richard L.", "Pappas, Christoforos", "Hurley, Alexander G.", "Poyatos, Rafael", "Flo, Victor", "Zweifel, Roman", "Goossens, Willem", "Steppe, Kathy" ], "keywords": [ "calibration", "global sensitivity analysis", "sap flux density", "thermal dissipation method", "transpiration", "uncertainty analysis", "whole‐", "tree water use" ], "year": "2021", "source": "METHODS IN ECOLOGY AND EVOLUTION", "publication_type": "J", "point2d": [ -57.69926452636719, 51.23234176635742 ], "cluster": 3.0 }, { "idx": 412, "title": "Effect of snow microstructure variability on Ku-band radar snow water equivalent retrievals", "abstract": "Spatial variability in snowpack properties negatively impacts our capacity to make direct measurements of snow water equivalent (SWE) using satellites. A comprehensive data set of snow microstructure (94 profiles at 36 sites) and snow layer thickness (9000 vertical profiles across nine trenches) collected over two winters at Trail Valley Creek, NWT, Canada, was applied in synthetic radiative transfer experiments. This allowed for robust assessment of the impact of estimation accuracy of unknown snow microstructural characteristics on the viability of SWE retrievals. Depth hoar layer thickness varied over the shortest horizontal distances, controlled by subnivean vegetation and topography, while variability in total snowpack thickness approximated that of wind slab layers. Mean horizontal correlation lengths of layer thickness were less than a metre for all layers. Depth hoar was consistently similar to 30% of total depth, and with increasing total depth the proportion of wind slab increased at the expense of the decreasing surface snow layer. Distinct differences were evident between distributions of layer properties; a single median value represented density and specific surface area (SSA) of each layer well. Spatial variability in microstructure of depth hoar layers dominated SWE retrieval errors. A depth hoar SSA estimate of around 7% under the median value was needed to accurately retrieve SWE. In shallow snowpacks < 0:6 m, depth hoar SSA estimates of +/- 5%-10% around the optimal retrieval SSA allowed SWE retrievals within a tolerance of similar to 30 mm. Where snowpacks were deeper than similar to 30 cm, accurate values of representative SSA for depth hoar became critical as retrieval errors were exceeded if the median depth hoar SSA was applied.", "authors": [ "Rutter, Nick", "Sandells, Melody J.", "Derksen, Chris", "King, Joshua", "Toose, Peter", "Wake, Leanne", "Watts, Tom", "Essery, Richard", "Roy, Alexandre", "Royer, Alain", "Marsh, Philip", "Larsen, Chris", "Sturm, Matthew" ], "keywords": [ "" ], "year": "2019", "source": "CRYOSPHERE", "publication_type": "J", "point2d": [ -65.30218505859375, 2.5445001125335693 ], "cluster": 8.0 }, { "idx": 414, "title": "Increasing wildfires threaten historic carbon sink of boreal forest soils", "abstract": "Boreal forest fires emit large amounts of carbon into the atmosphere primarily through the combustion of soil organic matter(1-3). During each fire, a portion of this soil beneath the burned layer can escape combustion, leading to a net accumulation of carbon in forests over multiple fire events(4). Climate warming and drying has led to more severe and frequent forest fires(5-7), which threaten to shift the carbon balance of the boreal ecosystem from net accumulation to net loss(1), resulting in a positive climate feedback(8). This feedback will occur if organic-soil carbon that escaped burning in previous fires, termed 'legacy carbon', combusts. Here we use soil radiocarbon dating to quantitatively assess legacy carbon loss in the 2014 wildfires in the Northwest Territories of Canada(2). We found no evidence for the combustion of legacy carbon in forests that were older than the historic fire-return interval of northwestern boreal forests(9). In forests that were in dry landscapes and less than 60 years old at the time of the fire, legacy carbon that had escaped burning in the previous fire cycle was combusted. We estimate that 0.34 million hectares of young forests (<60 years) that burned in the 2014 fires could have experienced legacy carbon combustion. This implies a shift to a domain of carbon cycling in which these forests become a net source-instead of a sink-of carbon to the atmosphere over consecutive fires. As boreal wildfires continue to increase in size, frequency and intensity(7), the area of young forests that experience legacy carbon combustion will probably increase and have a key role in shifting the boreal carbon balance.", "authors": [ "Walker, Xanthe J.", "Baltzer, Jennifer L.", "Cumming, Steven G.", "Day, Nicola J.", "Ebert, Christopher", "Goetz, Scott", "Johnstone, Jill F.", "Potter, Stefano", "Rogers, Brendan M.", "Schuur, Edward A. G.", "Turetsky, Merritt R.", "Mack, Michelle C." ], "keywords": [ "" ], "year": "2019", "source": "NATURE", "publication_type": "J", "point2d": [ -28.64544105529785, 73.32462310791016 ], "cluster": 15.0 }, { "idx": 416, "title": "Past variation in Lower Peace River ice-jam flood frequency", "abstract": "Opposing interpretations of Lower Peace River ice-jam flood frequency data sets are at the centre of identifying causes of reduced freshwater availability in the Peace-Athabasca Delta (northern Alberta), a Ramsar Wetland of International Importance and a major contributor to Wood Buffalo National Park's listing as a UNESCO World Heritage Site. Recently, conclusions drawn from statistical inference of traditional knowledge and historical observation sources suggested that flood frequency was accelerating during 1880-1967 and then declined coincident with hydroelectric regulation of Peace River flow since 1968 that altered the river's hydrograph. In contrast, prior paleolimnological measurements of laminated sediments from oxbow lakes proximal to the Peace River have, along with alternate presentation of the traditional knowledge and historical observation sources, identified flood frequency was in decline for decades preceding river regulation due to climate change since the Little Ice Age. Here we revisit these data sets and, specifically, review their inherent uncertainties to assess their value and limitations. The notion of increasing versus decreasing flood frequency in the decades preceding river regulation (1880-1967) is tested using previously published paleohydrological records from perched lakes in the delta. Those records from lakes most proximal and sensitive to changes in the flow regime of the Peace River show increasing influence of lake evaporation during 1880-1967, consistent with long-term decline in flood frequency. Reconciling uncertainties of multiple lines-of-evidence and their findings should inform decisions by UNESCO on the World Heritage status of Wood Buffalo National Park and execution of the park's federally funded Action Plan. New paleolimnological studies that have recently been launched will continue to probe the hydrological history of the Peace-Athabasca Delta to serve as a foundation for effective stewardship.", "authors": [ "Wolfe, Brent B.", "Hall, Roland, I", "Wiklund, Johan A.", "Kay, Mitchell L." ], "keywords": [ "Peace-Athabasca Delta", "ice-jam flood frequency", "WAC Bennett Dam", "river regulation", "climate change", "paleolimnology" ], "year": "2020", "source": "ENVIRONMENTAL REVIEWS", "publication_type": "J", "point2d": [ 6.315695762634277, 12.479073524475098 ], "cluster": 13.0 }, { "idx": 417, "title": "Widespread decline in winds delayed autumn foliar senescence over high latitudes", "abstract": "The high northern latitudes (>50 degrees) experienced a pronounced surface stilling (i.e., decline in winds) with climate change. As a drying factor, the influences of changes in winds on the date of autumn foliar senescence (DFS) remain largely unknown and are potentially important as a mechanism explaining the interannual variability of autumn phenology. Using 183,448 phenological observations at 2,405 sites, long-term site-scale water vapor and carbon dioxide flux measurements, and 34 y of satellite greenness data, here we show that the decline in winds is significantly associated with extended DFS and could have a relative importance comparable with temperature and precipitation effects in contributing to the DFS trends. We further demonstrate that decline in winds reduces evapotranspiration, which results in less soil water losses and consequently more favorable growth conditions in late autumn. In addition, declining winds also lead to less leaf abscission damage which could delay leaf senescence and to a decreased cooling effect and therefore less frost damage. Our results are potentially useful for carbon flux modeling because an improved algorithm based on these findings projected overall widespread earlier DFS than currently expected by the end of this century, contributing potentially to a positive feedback to climate.", "authors": [ "Wu, Chaoyang", "Wang, Jian", "Ciais, Philippe", "Penuelas, Josep", "Zhang, Xiaoyang", "Sonnentag, Oliver", "Tian, Feng", "Wang, Xiaoyue", "Wang, Huanjiong", "Liu, Ronggao", "Fu, Yongshuo H.", "Ge, Quansheng" ], "keywords": [ "climate change", "foliar senescence", "high latitudes" ], "year": "2021", "source": "PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA", "publication_type": "J", "point2d": [ -63.61097717285156, 69.83889770507812 ], "cluster": 17.0 }, { "idx": 419, "title": "Storms and Precipitation Across the continental Divide Experiment (SPADE)", "abstract": "The Canadian Rockies are a triple-continental divide, whose high mountains are drained by major snow-fed and rain-fed rivers flowing to the Pacific, Atlantic, and Arctic Oceans. The objective of the April-June 2019 Storms and Precipitation Across the continental Divide Experiment (SPADE) was to determine the atmospheric processes producing precipitation on the eastern and western sides of the Canadian Rockies during springtime, a period when upslope events of variable phase dominate precipitation on the eastern slopes. To do so, three observing sites across the divide were instrumented with advanced meteorological sensors. During the 13 observed events, the western side recorded only 25% of the eastern side's precipitation accumulation, rainfall occurred rather than snowfall, and skies were mainly clear. Moisture sources and amounts varied markedly between events. An atmospheric river landfall in California led to moisture flowing persistently northward and producing the longest duration of precipitation on both sides of the divide. Moisture from the continental interior always produced precipitation on the eastern side but only in specific conditions on the western side. Mainly slow-falling ice crystals, sometimes rimed, formed at higher elevations on the eastern side (>3 km MSL), were lifted, and subsequently drifted westward over the divide during nonconvective storms to produce rain at the surface on the western side. Overall, precipitation generally crossed the divide in the Canadian Rockies during specific spring-storm atmospheric conditions although amounts at the surface varied with elevation, condensate type, and local and large-scale flow fields.", "authors": [ "Theriault, Julie M.", "Leroux, Nicolas R.", "Stewart, Ronald E.", "Bertoncini, Andre", "Dery, Stephen J.", "Pomeroy, John W.", "Thompson, Hadleigh D.", "Smith, Hilary", "Mariani, Zen", "Desroches-Lapointe, Aurelie", "Mitchell, Selina", "Almonte, Juris" ], "keywords": [ "Field experiment", "Mixed precipitation", "Moisture", "moisture budget", "Orographic effects", "Storm environments", "Mountain meteorology" ], "year": "2022", "source": "BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY", "publication_type": "J", "point2d": [ -50.781044006347656, -21.00769805908203 ], "cluster": 1.0 }, { "idx": 420, "title": "Trends of actual and potential evapotranspiration based on Bouchet's complementary concept in a cold and arid steppe site of Northeastern Asia", "abstract": "Due to complex natural water flux processes and the ambiguous explanation of Bouchet's complementary theory, site-level investigations on evapotranspiration (ET) and related climate variables assist in understanding the regional hydrological response to climate change. In this study, site specific empirical parameters were incorporated in the Bouchet's complementary relationship (CR) and potential and actual ET were estimated by CR method and subsequently validated by 6 years of ground-based vapor flux observations. Time series analysis, correlation analysis and principal regression analysis were conducted to reveal the characteristics of climate change and the controlling factor(s) of the variations of potential ET and actual ET. The results show that this region is exhibiting a combined warming and drying trend over the past decades with two change points that occurred in 1993 and in 2000. Potential ET was predominantly influenced by temperature and vapor pressure deficit, while actual ET was mostly influenced by vegetation activity. Potential ET was found to be increasing concurrently with declining actual ET to constitute nearly a symmetric complementary relationship over the past decades. This study help to enhance our understanding of the regional hydrological response to climate change. Further studies are needed to partition the actual ET into transpiration and other components and to reveal the role of vegetation activity in determining regional ET as well as water balance.", "authors": [ "You, Guangyong", "Arain, M. Altaf", "Wang, Shusen", "Lin, Naifeng", "Wu, Dan", "McKenzie, Shawn", "Zou, Changxin", "Liu, Bo", "Zhang, Xiaohua", "Gao, Jixi" ], "keywords": [ "Bouchet complementary theory", "Actual evapotranspiration", "Vegetation activity" ], "year": "2019", "source": "AGRICULTURAL AND FOREST METEOROLOGY", "publication_type": "J", "point2d": [ -58.92917251586914, 46.50798797607422 ], "cluster": 3.0 }, { "idx": 421, "title": "Climate indices to characterize climatic changes across southern Canada", "abstract": "The present study analyses the impacts of past and future climate change on extreme weather events for southern parts of Canada from 1981 to 2100. A set of precipitation and temperature-based indices were computed using the downscaled Coupled Model Intercomparison Project Phase 5 (CMIP5) multi-model ensemble projections at 8 km resolution over the 21st Century for two representative concentration pathway (RCP) scenarios: RCP4.5 and RCP8.5. The results show that this region is expected to experience stronger warming and a higher increase in precipitation extremes in future. Generally, projected changes in minimum temperature will be greater than changes in maximum temperature, as shown by respective indices. A decrease in frost days and an increase in warm nights will be expected. By 2100 there will be no cool nights and cool days. Daily minimum and maximum temperatures will increase by 12 and 7 degrees C, respectively, under the RCP8.5 scenario, when compared with the reference period 1981-2000. The highest warming in minimum temperature and decrease in cool nights and days will occur in Ontario and Quebec provinces close to the Great Lakes and Hudson Bay. The highest warming in maximum temperature will occur in the southern parts of Alberta and Saskatchewan. Annual total precipitation is expected to increase by about 16% and the occurrence of heavy precipitation events by five days. The highest increase in annual total precipitation will occur in the northern parts of Ontario and Quebec and in western British Columbia.", "authors": [ "Wazneh, Hussein", "Arain, M. Altaf", "Coulibaly, Paulin" ], "keywords": [ "climate change", "climate indices", "CMIP5", "extreme events", "future climate projection" ], "year": "2020", "source": "METEOROLOGICAL APPLICATIONS", "publication_type": "J", "point2d": [ -30.178985595703125, -35.93581771850586 ], "cluster": 1.0 }, { "idx": 422, "title": "Atmospheric circulation amplifies shift of winter streamflow in southern Ontario", "abstract": "Flooding is a major concern for Canadian society as it is the costliest natural disaster type in Canada. Southern Ontario, which houses one-third of the Canadian population, is located in an area of high vulnerability for floods. The most significant floods in the region have historically occurred during the months of March and April due to snowmelt coupled with extreme rain events. However, during the last three decades, there has been a shift of flooding events to earlier months. The aim of this study was to understand the impacts of atmospheric circulation on the temporal shift of streamflow and high flow events observed in southern Ontario over 1957-2013 period. Predominant weather regimes over North America, corresponding to recurrent meteorological situations, were identified using a discretization of daily geopotential height at 500HpA level (Z500). A regime-normalized hypothetical temperature and precipitation dataset was constructed to quantify the contribution of atmospheric circulation on streamflow response. The hypothetical dataset was used as input in the Precipitation Runoff Modeling System (PRMS), a rainfall-runoff semi-distributed hydrological model, and applied to four watersheds in southern Ontario. The results showed an increase in the temporal frequency of the regime identified here as High Pressure (HP) close to eight occurrences per decade. Regime HP, characterized by a northern position of the polar vortex, is correlated with a positive phase of the NAO and is associated with warm and wet conditions over southern Ontario during winter. The temporal increase in HP contributed more than 40% of the increase in streamflow in winter and 30-45% decrease in streamflow in April. This atmospheric situation also contributed to increase the number of high flows by 25-50% in January. These results are important to improve the seasonal forecasting of high flows and to assess the uncertainty in the temporal evolution of streamflow in the Great Lakes region.", "authors": [ "Champagne, Olivier", "Arain, M. Altaf", "Coulibaly, Paulin" ], "keywords": [ "Streamflow", "Hydrological modelling", "Precipitation Runoff Modeling System (PRMS)", "Weather regimes", "Southern Ontario", "Atmospheric circulation" ], "year": "2019", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -23.8469181060791, -26.800025939941406 ], "cluster": 1.0 }, { "idx": 423, "title": "Carotenoid based vegetation indices for accurate monitoring of the phenology of photosynthesis at the leaf-scale in deciduous and evergreen trees", "abstract": "Carotenoid pigments play an important role in the seasonal regulation of photosynthesis and photoprotection of overwintering conifers. Because the seasonal changes in the rate of photosynthetic CO2 assimilation are linked to changes in carotenoid pigment composition, it has been suggested that carotenoid sensitive vegetation indices might be used to track the otherwise invisible phenology of photosynthesis of conifer forests through remote sensing of leaf spectral reflectance. In this study we aimed to assess differences in the seasonal regulation of photosynthesis and the associated variation of carotenoids and chlorophylls at the leaf-scale for eastern white pine, red maple and white oak, in order to understand if photosynthetic and photoprotective processes are adequately represented by different vegetation indices over the course of the year. For this purpose we measured maximum rates of CO2 assimilation (A(max)), quantified photosynthetic pigments, estimated photochemical and non-photochemical quenching processes via chlorophyll fluorescence and determined leaf spectral reflectance in pine, maple and oak trees over the course of two years. Seasonal variation in A(max), used here as a proxy for photosynthetic phenology, and photosynthetic pigments were adequately represented by the normalized difference vegetation index (NDVI) for the deciduous trees. For pine, NDVI overestimated photosynthetic activity for most of the year and was hence not able to represent photosynthetic phenology, due to the fact that needle chlorophyll content shows only little variation over the course of the year. By contrast, using the photochemical reflectance index (PRI) and the chlorophyll/carotenoid index (CCI), which both detect variations in carotenoids, we were able to observe an improved representation of the seasonal variation of CO2 assimilation and photosynthetic phenology for the two deciduous and the conifer species. Based on the accurate detection of the seasonal regulation of leaf-scale photosynthetic activity for all three species, we conclude that carotenoid-sensitive vegetation indices are promising tools to improve monitoring of phenology in both deciduous and conifer forests.", "authors": [ "Wong, Christopher Y. S.", "D'Odorico, Petra", "Bhathena, Yazad", "Arain, M. Altaf", "Ensminger, Ingo" ], "keywords": [ "Leaf pigments", "Photochemical and non-photochemical quenching", "Photochemical reflectance index (PRI)", "Chlorophyll/carotenoid index (CCI)", "Photosynthetic phenology" ], "year": "2019", "source": "REMOTE SENSING OF ENVIRONMENT", "publication_type": "J", "point2d": [ -69.76793670654297, 63.97488784790039 ], "cluster": 17.0 }, { "idx": 424, "title": "Vegetation Functional Properties Determine Uncertainty of Simulated Ecosystem Productivity: A Traceability Analysis in the East Asian Monsoon Region", "abstract": "Global and regional projections of climate change by Earth system models are limited by their uncertain estimates of terrestrial ecosystem productivity. At the middle to low latitudes, the East Asian monsoon region has higher productivity than forests in Europe-Africa and North America, but its estimate by current generation of terrestrial biosphere models (TBMs) has seldom been systematically evaluated. Here, we developed a traceability framework to evaluate the simulated gross primary productivity (GPP) by 15 TBMs in the East Asian monsoon region. The framework links GPP to net primary productivity, biomass, leaf area and back to GPP via incorporating multiple vegetation functional properties of carbon-use efficiency (CUE), vegetation C turnover time (tau(veg)), leaf C fraction (F-leaf), specific leaf area (SLA), and leaf area index (LAI)-level photosynthesis (P-LAI), respectively. We then applied a relative importance algorithm to attribute intermodel variation at each node. The results showed that large intermodel variation in GPP over 1901-2010 were mainly propagated from their different representation of vegetation functional properties. For example, SLA explained 77% of the intermodel difference in leaf area, which contributed 90% to the simulated GPP differences. In addition, the models simulated higher CUE (18.1 21.3%), tau(veg) (18.2 26.9%), and SLA (27.436.5%) than observations, leading to the overestimation of simulated GPP across the East Asian monsoon region. These results suggest the large uncertainty of current TBMs in simulating GPP is largely propagated from their poor representation of the vegetation functional properties and call for a better understanding of the covariations between plant functional properties in terrestrial ecosystems.", "authors": [ "Cui, Erqian", "Huang, Kun", "Arain, Muhammad Altaf", "Fisher, Joshua B.", "Huntzinger, Deborah N.", "Ito, Akihiko", "Luo, Yiqi", "Jain, Atul K.", "Mao, Jiafu", "Michalak, Anna M.", "Niu, Shull", "Parazoo, Nicholas C.", "Peng, Changhui", "Peng, Shushi", "Poulter, Benjamin", "Ricciuto, Daniel M.", "Schaefer, Kevin M.", "Schwalm, Christopher R.", "Shi, Xiaoying", "Tian, Hanqin", "Wang, Weile", "Wang, Jinsong", "Wei, Yaxing", "Yan, Enrong", "Yan, Liming", "Zeng, Ning", "Zhu, Qiuan", "Xia, Jianyang" ], "keywords": [ "environmental drivers", "initial conditions", "model uncertainty", "MsTMIP", "relative importance", "vegetation functional property" ], "year": "2019", "source": "GLOBAL BIOGEOCHEMICAL CYCLES", "publication_type": "J", "point2d": [ -58.008567810058594, 61.31550979614258 ], "cluster": 17.0 }, { "idx": 425, "title": "Field-experiment constraints on the enhancement of the terrestrial carbon sink by CO(2 )fertilization", "abstract": "Clarifying how increased atmospheric CO2 concentration (eCO(2)) contributes to accelerated land carbon sequestration remains important since this process is the largest negative feedback in the coupled carbon-climate system. Here, we constrain the sensitivity of the terrestrial carbon sink to eCO(2) over the temperate Northern Hemisphere for the past five decades, using 12 terrestrial ecosystem models and data from seven CO2 enrichment experiments. This constraint uses the heuristic finding that the northern temperate carbon sink sensitivity to eCO(2) is linearly related to the site-scale sensitivity across the models. The emerging data-constrained eCO(2) sensitivity is 0.64 +/- 0.28 PgC yr(-1) per hundred ppm of eCO(2). Extrapolating worldwide, this northern temperate sensitivity projects the global terrestrial carbon sink to increase by 3.5 +/- 1.9 PgC yr(-1) for an increase in CO2 of 100 ppm. This value suggests that CO2 fertilization alone explains most of the observed increase in global land carbon sink since the 1960s. More CO2 enrichment experiments, particularly in boreal, arctic and tropical ecosystems, are required to explain further the responsible processes.", "authors": [ "Liu, Yongwen", "Piao, Shilong", "Gasser, Thomas", "Ciais, Philippe", "Yang, Hui", "Wang, Han", "Keenan, Trevor F.", "Huang, Mengtian", "Wan, Shiqiang", "Song, Jian", "Wang, Kai", "Janssens, Ivan A.", "Penuelas, Josep", "Huntingford, Chris", "Wang, Xuhui", "Arain, Muhammad Altaf", "Fang, Yuanyuan", "Fisher, Joshua B.", "Huang, Maoyi", "Huntzinger, Deborah N.", "Ito, Akihiko", "Jain, Atul K.", "Mao, Jiafu", "Michalak, Anna M.", "Peng, Changhui", "Poulter, Benjamin", "Schwalm, Christopher", "Shi, Xiaoying", "Tian, Hanqin", "Wei, Yaxing", "Zeng, Ning", "Zhu, Qiuan", "Wang, Tao" ], "keywords": [ "" ], "year": "2019", "source": "NATURE GEOSCIENCE", "publication_type": "J", "point2d": [ -41.277400970458984, 56.91649627685547 ], "cluster": 17.0 }, { "idx": 426, "title": "Global vegetation biomass production efficiency constrained by models and observations", "abstract": "Plants use only a fraction of their photosynthetically derived carbon for biomass production (BP). The biomass production efficiency (BPE), defined as the ratio of BP to photosynthesis, and its variation across and within vegetation types is poorly understood, which hinders our capacity to accurately estimate carbon turnover times and carbon sinks. Here, we present a new global estimation of BPE obtained by combining field measurements from 113 sites with 14 carbon cycle models. Our best estimate of global BPE is 0.41 +/- 0.05, excluding cropland. The largest BPE is found in boreal forests (0.48 +/- 0.06) and the lowest in tropical forests (0.40 +/- 0.04). Carbon cycle models overestimate BPE, although models with carbon-nitrogen interactions tend to be more realistic. Using observation-based estimates of global photosynthesis, we quantify the global BP of non-cropland ecosystems of 41 +/- 6 Pg C/year. This flux is less than net primary production as it does not contain carbon allocated to symbionts, used for exudates or volatile carbon compound emissions to the atmosphere. Our study reveals a positive bias of 24 +/- 11% in the model-estimated BP (10 of 14 models). When correcting models for this bias while leaving modeled carbon turnover times unchanged, we found that the global ecosystem carbon storage change during the last century is decreased by 67% (or 58 Pg C).", "authors": [ "He, Yue", "Peng, Shushi", "Liu, Yongwen", "Li, Xiangyi", "Wang, Kai", "Ciais, Philippe", "Arain, M. Altaf", "Fang, Yuanyuan", "Fisher, Joshua B.", "Goll, Daniel", "Hayes, Daniel", "Huntzinger, Deborah N.", "Ito, Akihiko", "Jain, Atul K.", "Janssens, Ivan A.", "Mao, Jiafu", "Campioli, Matteo", "Michalak, Anna M.", "Peng, Changhui", "Penuelas, Josep", "Poulter, Benjamin", "Qin, Dahe", "Ricciuto, Daniel M.", "Schaefer, Kevin", "Schwalm, Christopher R.", "Shi, Xiaoying", "Tian, Hanqin", "Vicca, Sara", "Wei, Yaxing", "Zeng, Ning", "Zhu, Qiuan" ], "keywords": [ "biomass production", "BPE", "carbon sink", "emergent constraint", "terrestrial biosphere model" ], "year": "2020", "source": "GLOBAL CHANGE BIOLOGY", "publication_type": "J", "point2d": [ -55.688297271728516, 58.733367919921875 ], "cluster": 17.0 }, { "idx": 427, "title": "Global vegetation biomass production efficiency constrained by models and observations", "abstract": "Plants use only a fraction of their photosynthetically derived carbon for biomass production (BP). The biomass production efficiency (BPE), defined as the ratio of BP to photosynthesis, and its variation across and within vegetation types is poorly understood, which hinders our capacity to accurately estimate carbon turnover times and carbon sinks. Here, we present a new global estimation of BPE obtained by combining field measurements from 113 sites with 14 carbon cycle models. Our best estimate of global BPE is 0.41 +/- 0.05, excluding cropland. The largest BPE is found in boreal forests (0.48 +/- 0.06) and the lowest in tropical forests (0.40 +/- 0.04). Carbon cycle models overestimate BPE, although models with carbon-nitrogen interactions tend to be more realistic. Using observation-based estimates of global photosynthesis, we quantify the global BP of non-cropland ecosystems of 41 +/- 6 Pg C/year. This flux is less than net primary production as it does not contain carbon allocated to symbionts, used for exudates or volatile carbon compound emissions to the atmosphere. Our study reveals a positive bias of 24 +/- 11% in the model-estimated BP (10 of 14 models). When correcting models for this bias while leaving modeled carbon turnover times unchanged, we found that the global ecosystem carbon storage change during the last century is decreased by 67% (or 58 Pg C).", "authors": [ "He, Yue", "Peng, Shushi", "Liu, Yongwen", "Li, Xiangyi", "Wang, Kai", "Ciais, Philippe", "Arain, M. Altaf", "Fang, Yuanyuan", "Fisher, Joshua B.", "Goll, Daniel", "Hayes, Daniel", "Huntzinger, Deborah N.", "Ito, Akihiko", "Jain, Atul K.", "Janssens, Ivan A.", "Mao, Jiafu", "Campioli, Matteo", "Michalak, Anna M.", "Peng, Changhui", "Penuelas, Josep", "Poulter, Benjamin", "Qin, Dahe", "Ricciuto, Daniel M.", "Schaefer, Kevin", "Schwalm, Christopher R.", "Shi, Xiaoying", "Tian, Hanqin", "Vicca, Sara", "Wei, Yaxing", "Zeng, Ning", "Zhu, Qiuan" ], "keywords": [ "biomass production", "BPE", "carbon sink", "emergent constraint", "terrestrial biosphere model" ], "year": "2020", "source": "GLOBAL CHANGE BIOLOGY", "publication_type": "J", "point2d": [ -55.688297271728516, 58.733367919921875 ], "cluster": 17.0 }, { "idx": 428, "title": "Cryptic phenology in plants: Case studies, implications, and recommendations", "abstract": "Plant phenology-the timing of cyclic or recurrent biological events in plants-offers insight into the ecology, evolution, and seasonality of plant-mediated ecosystem processes. Traditionally studied phenologies are readily apparent, such as flowering events, germination timing, and season-initiating budbreak. However, a broad range of phenologies that are fundamental to the ecology and evolution of plants, and to global biogeochemical cycles and climate change predictions, have been neglected because they are cryptic-that is, hidden from view (e.g., root production) or difficult to distinguish and interpret based on common measurements at typical scales of examination (e.g., leaf turnover in evergreen forests). We illustrate how capturing cryptic phenology can advance scientific understanding with two case studies: wood phenology in a deciduous forest of the northeastern USA and leaf phenology in tropical evergreen forests of Amazonia. Drawing on these case studies and other literature, we argue that conceptualizing and characterizing cryptic plant phenology is needed for understanding and accurate prediction at many scales from organisms to ecosystems. We recommend avenues of empirical and modeling research to accelerate discovery of cryptic phenological patterns, to understand their causes and consequences, and to represent these processes in terrestrial biosphere models.", "authors": [ "Albert, Loren P.", "Restrepo-Coupe, Natalia", "Smith, Marielle N.", "Wu, Jin", "Chavana-Bryant, Cecilia", "Prohaska, Neill", "Taylor, Tyeen C.", "Martins, Giordane A.", "Ciais, Philippe", "Mao, Jiafu", "Arain, M. Altaf", "Li, Wei", "Shi, Xiaoying", "Ricciuto, Daniel M.", "Huxman, Travis E.", "McMahon, Sean M.", "Saleska, Scott R." ], "keywords": [ "climate change", "dynamic global vegetation models", "plant ecology", "plant physiology", "seasonality", "terrestrial biosphere models", "whole plant biology" ], "year": "2019", "source": "GLOBAL CHANGE BIOLOGY", "publication_type": "J", "point2d": [ -61.22887420654297, 70.6470947265625 ], "cluster": 17.0 }, { "idx": 429, "title": "No trends in spring and autumn phenology during the global warming hiatus", "abstract": "Phenology plays a fundamental role in regulating photosynthesis, evapotranspiration, and surface energy fluxes and is sensitive to climate change. The global mean surface air temperature data indicate a global warming hiatus between 1998 and 2012, while its impacts on global phenology remains unclear. Here we use long-term satellite and FLUXNET records to examine phenology trends in the northern hemisphere before and during the warming hiatus. Our results based on the satellite record show that the phenology change rate slowed down during the warming hiatus. The analysis of the long-term FLUXNET measurements, mainly within the warming hiatus, shows that there were no widespread advancing (or delaying) trends in spring (or autumn) phenology. The lack of widespread phenology trends partly led to the lack of widespread trends in spring and autumn carbon fluxes. Our findings have significant implications for understanding the responses of phenology to climate change and the climate-carbon feedbacks.", "authors": [ "Wang, Xufeng", "Xiao, Jingfeng", "Li, Xin", "Cheng, Guodong", "Ma, Mingguo", "Zhu, Gaofeng", "Arain, M. Altaf", "Black, T. Andrew", "Jassal, Rachhpal S." ], "keywords": [ "" ], "year": "2019", "source": "NATURE COMMUNICATIONS", "publication_type": "J", "point2d": [ -62.38658905029297, 69.9239730834961 ], "cluster": 17.0 }, { "idx": 430, "title": "Solar-induced chlorophyll fluorescence exhibits a universal relationship with gross primary productivity across a wide variety of biomes", "abstract": "In our recent study in Global Change Biology (Li et al., ), we examined the relationship between solar-induced chlorophyll fluorescence (SIF) measured from the Orbiting Carbon Observatory-2 (OCO-2) and gross primary productivity (GPP) derived from eddy covariance flux towers across the globe, and we discovered that there is a nearly universal relationship between SIF and GPP across a wide variety of biomes. This finding reveals the tremendous potential of SIF for accurately mapping terrestrial photosynthesis globally.", "authors": [ "Xiao, Jingfeng", "Li, Xing", "He, Binbin", "Arain, M. Altaf", "Beringer, Jason", "Desai, Ankur R.", "Emmel, Carmen", "Hollinger, David Y.", "Krasnova, Alisa", "Mammarella, Ivan", "Noe, Steffen M.", "Ortiz, Penelope Serrano", "Rey-Sanchez, Camilo", "Rocha, Adrian V.", "Varlagin, Andrej" ], "keywords": [ "" ], "year": "2019", "source": "GLOBAL CHANGE BIOLOGY", "publication_type": "J", "point2d": [ -62.67837905883789, 58.56484603881836 ], "cluster": 17.0 }, { "idx": 431, "title": "Memory effects of climate and vegetation affecting net ecosystem CO2 fluxes in global forests", "abstract": "Forests play a crucial role in the global carbon (C) cycle by storing and sequestering a substantial amount of C in the terrestrial biosphere. Due to temporal dynamics in climate and vegetation activity, there are significant regional variations in carbon dioxide (CO2) fluxes between the biosphere and atmosphere in forests that are affecting the global C cycle. Current forest CO2 flux dynamics are controlled by instantaneous climate, soil, and vegetation conditions, which carry legacy effects from disturbances and extreme climate events. Our level of understanding from the legacies of these processes on net CO2 fluxes is still limited due to their complexities and their long-term effects. Here, we combined remote sensing, climate, and eddy-covariance flux data to study net ecosystem CO2 exchange (NEE) at 185 forest sites globally. Instead of commonly used non-dynamic statistical methods, we employed a type of recurrent neural network (RNN), called Long Short-Term Memory network (LSTM) that captures information from the vegetation and climate's temporal dynamics. The resulting data-driven model integrates interannual and seasonal variations of climate and vegetation by using Landsat and climate data at each site. The presented LSTM algorithm was able to effectively describe the overall seasonal variability (Nash-Sutcliffe efficiency, NSE = 0.66) and across-site (NSE = 0.42) variations in NEE, while it had less success in predicting specific seasonal and interannual anomalies (NSE = 0.07). This analysis demonstrated that an LSTM approach with embedded climate and vegetation memory effects outperformed a non-dynamic statistical model (i.e. Random Forest) for estimating NEE. Additionally, it is shown that the vegetation mean seasonal cycle embeds most of the information content to realistically explain the spatial and seasonal variations in NEE. These findings show the relevance of capturing memory effects from both climate and vegetation in quantifying spatio-temporal variations in forest NEE.", "authors": [ "Besnard, Simon", "Carvalhais, Nuno", "Arain, M. Altaf", "Black, Andrew", "Brede, Benjamin", "Buchmann, Nina", "Chen, Jiquan", "Clevers, Jan G. P. W.", "Dutrieux, Loic P.", "Gans, Fabian", "Herold, Martin", "Jung, Martin", "Kosugi, Yoshiko", "Knohl, Alexander", "Law, Beverly E.", "Paul-Limoges, Eugenie", "Lohila, Annalea", "Merbold, Lutz", "Roupsard, Olivier", "Valentini, Riccardo", "Wolf, Sebastian", "Zhang, Xudong", "Reichstein, Markus" ], "keywords": [ "" ], "year": "2019", "source": "PLOS ONE", "publication_type": "J", "point2d": [ -46.38526153564453, 61.175350189208984 ], "cluster": 17.0 }, { "idx": 432, "title": "Effects of Damming on River Nitrogen Fluxes: A Global Analysis", "abstract": "Damming creates biogeochemical hotspots along rivers that modify the riverine flow of nutrients, including nitrogen (N). Here, we quantify the impact of dams on global riverine N fluxes using a reservoir N mass balance model. In-reservoir processes represented in the model include primary production, mineralization of organic N, denitrification, and sedimentary burial. In addition, we explicitly account for N fixation as a source of N, assuming that the N to phosphorus (P) ratio of the inflow regulates the magnitude of N fixation in reservoirs. The model is scaled up via a Monte Carlo analysis that yields global relationships between N elimination in reservoirs, either by denitrification or burial, and the hydraulic residence time. These relationships are then combined with N loads to the world's dam reservoirs generated by the Global-NEWS model and the estimated N fixation fluxes. According to the results, in year 2000, worldwide N fixation in reservoirs was on the order of 70 Gmol yr(-1), while denitrification and burial in reservoirs eliminated around 270 Gmol yr(-1), equal to 7% of N loading to the global river network. The latter is predicted to double to 14% by 2030, mainly as a result of the current boom in dam building. The results further imply that, largely due to N fixation in reservoirs, damming causes a global upward shift in riverine N:P ratios, thus lessening N limitation in receiving water bodies.", "authors": [ "Akbarzadeh, Zahra", "Maavara, Taylor", "Slowinski, Stephanie", "Van Cappellen, Philippe" ], "keywords": [ "nitrogen", "river damming", "nitrogen fixation", "denitrification", "burial", "elimination" ], "year": "2019", "source": "GLOBAL BIOGEOCHEMICAL CYCLES", "publication_type": "J", "point2d": [ 34.99604797363281, -4.548564434051514 ], "cluster": 10.0 }, { "idx": 433, "title": "High Sensitivity of Lake Hypoxia to Air Temperatures, Winds, and Nutrient Loading: Insights From a 3-D Lake Model", "abstract": "A three-dimensional hydrodynamic-ecological model is applied to Lake Erie to predict the response of dissolved oxygen (DO) to independent changes in air temperature, wind speeds and total phosphorus (TP) loading. Warmer temperatures and lower wind speeds increased the size and duration of hypoxic and anoxic regions by lengthening the stratified period. Decreased wind speed increased hypolimnion thickness while decreasing its temperature and DO consumption rate. Decreased TP loading improved DO conditions with a reduction of 75% effectively abolishing hypoxia. Anoxia was more sensitive to air temperature, wind, and nutrient changes than was hypoxia. New metrics that capture the spatial and temporal dimensions of low DO conditions were more sensitive than the commonly cited maximum areas of hypoxia or anoxia. Over most of the relevant range of forcing factors, the simple and first-order effect of a 1 degrees C temperature change was equivalent to a 10-14% change in TP loads, while a 1% change in wind speed was equivalent to a 2-3% change in TP loads. Reduced ice cover in warmer climates will likely increase air temperature effects even further.", "authors": [ "Bocaniov, Serghei A.", "Lamb, Kevin G.", "Liu, Wentao", "Rao, Yerubandi R.", "Smith, Ralph E. H." ], "keywords": [ "climate", "hypoxia", "anoxia", "lake", "nutrients", "meteorology" ], "year": "2020", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 53.5446662902832, 13.086435317993164 ], "cluster": 19.0 }, { "idx": 434, "title": "Bioretention cells under cold climate conditions: Effects of freezing and thawing on water infiltration, soil structure, and nutrient removal", "abstract": "Bioretention cells are a popular control strategy for stormwater volume and quality, but their efficiency for water infiltration and nutrient removal under cold climate conditions has been poorly studied. In this work, soil cores were collected from an active bioretention cell containing engineered soil material amended with a phosphate sorbent medium. The cores were used in laboratory column experiments conducted to obtain a detailed characterization of the soil's bioretention performance during six consecutive freeze-thaw cycles (FTCs, from -10 to +10 degrees C). At the start of each FTC, the experimental column undergoing the Fits and a control column kept at room temperature were supplied with a solution containing 25 mg/L of bromide, nitrate and phosphate. Water saturated conditions were established to mimic the presence of an internal water storage zone to support anaerobic nitrate removal. At the end of each FTC, the pore solution was allowed to drain from the columns. The results indicate that the FTCs enhanced the infiltration efficiency of the soil: with each successive cycle the drainage rate increased in the experimental column. Freezing and thawing also increased the saturated hydraulic conductivity of the bioretention soil. X-ray tomography imaging identified a key role of macro-pore formation in maintaining high infiltration rates. Both aqueous nitrate and phosphate supplied to the columns were nearly completely removed from solution. Sufficiently long retention times and the presence of the internal water storage zone promoted anaerobic nitrate elimination despite the low temperatures. Dissolved phosphate was efficiently trapped at all depths in the soil columns, with <= 2% of the added stormwater phosphate recovered in the drainage effluent. These findings imply that, when designed properly, bioretention cells can support high infiltration rates and mitigate nutrient pollution in cold climates. (C) 2018 Elsevier B.V. All rights reserved.", "authors": [ "Ding, Brenden", "Rezanezhad, Fereidoun", "Gharedaghloo, Behrad", "Van Cappellen, Philippe", "Passeport, Elodie" ], "keywords": [ "Biomtention cells", "Infiltration", "Nitrate", "Phosphate", "Freeze - Thaw cycles", "Pollution" ], "year": "2019", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 36.76251983642578, 24.23094940185547 ], "cluster": 18.0 }, { "idx": 435, "title": "Thirty-five years of restoring Great Lakes Areas of Concern: Gradual progress, hopeful future", "abstract": "In 1985, remedial action plan development was initiated to restore impaired beneficial uses in 42 Great Lakes Areas of Concern (ADCs). A 43rd AOC was designated in 1991. AOC restoration has not been easy as it requires networks focused on gathering stakeholders, coordinating efforts, and ensuring use restoration. As of 2019, seven AOCs were delisted, two were designated as Areas of Concern in Recovery, and 79 of 137 known use impairments in Canadian AOCs and 90 of 255 known use impairments in U.S. AOCs were eliminated. Between 1985 and 2019, a total of $22.78 billion U.S. was spent on restoring all AOCs. Pollution prevention investments should be viewed as spending to avoid future cleanups, and AOC restoration investments should be viewed as spending to help revitalize communities that has over a 3 to 1 return on investment. The pace of U.S. AOC restoration has accelerated under the Great Lakes Legacy Act (GLLA) and Great Lakes Restoration Initiative (GLRI). Sustained funding through U.S. programs like GLRI and GLLA and Canadian programs such as Canada-Ontario Agreement Respecting Great Lakes Water Quality and Ecosystem Health and the Great Lakes Protection Initiative is needed to restore all AOCs. Other major AOC program achievements include use of locally-designed ecosystem approaches, contaminated sediment remediation, habitat rehabilitation, controlling eutrophication, and advancing science. Key lessons learned include: ensure meaningful public participation; engage local leaders; establish a compelling vision; establish measurable targets; practice adaptive management; build partnerships; pursue collaborative financing; build a record of success; quantify benefits; and focus on life after delisting. (C) 2020 The Authors. Published by Elsevier B.V. on behalf of International Association for Great Lakes Research.", "authors": [ "Hartig, John H.", "Krantzberg, Gail", "Alsip, Peter" ], "keywords": [ "Great Lakes Areas of Concern", "Remedial Action Plans", "Ecosystem approach" ], "year": "2020", "source": "JOURNAL OF GREAT LAKES RESEARCH", "publication_type": "J", "point2d": [ 55.17506790161133, -4.187520503997803 ], "cluster": 19.0 }, { "idx": 436, "title": "The Groundwater Recovery Paradox in South India", "abstract": "Reported groundwater recovery in South India has been attributed to both increasing rainfall and political interventions. Findings of increasing groundwater levels, however, are at odds with reports of well failure and decreases in the land area irrigated from shallow wells. We argue that recently reported results are skewed by the problem of survivor bias, with dry or defunct wells being systematically excluded from trend analyses due to missing data. We hypothesize that these dry wells carry critical information about groundwater stress that is missed when data are filtered. Indeed, we find strong correlations between missing well data and metrics related to climate stress and groundwater development, indicative of a systemic bias. Using two alternative metrics, which take into account information from dry and defunct wells, our results demonstrate increasing groundwater stress in South India. Our refined approach for identifying groundwater depletion hot spots is critical for policy interventions and resource allocation. Plain Language Summary Over the last century, groundwater has become an important source of freshwater to meet agricultural and drinking water needs. Increasing use of groundwater has contributed to depletion of groundwater reserves around the world, with India being at the forefront of this problem. Recent studies suggest that groundwater levels have been increasing in South India due to increasing rainfall and political interventions. This finding is at odds with local reports of groundwater stress, and increasing well failures. Our study explains this disagreement by showing that previous conclusions have been skewed by the problem of survivor bias, with wells with data gaps being routinely excluded from analysis of long-term groundwater storage trends. We find that traditional groundwater trend assessment methods are not suitable for hard-rock aquifer systems that characterize South India. Indeed, strong correlation exists between climate and groundwater stress and wells with missing data, indicative of a systemic bias. We develop metrics that use data from these wells, and show using these metrics increasing evidence of groundwater stress in South India over the last two decades (1996 to 2016). Our results provide insight into the management of groundwater depletion in India, while highlighting potential biases in groundwater sustainability assessments globally.", "authors": [ "Hora, Tejasvi", "Srinivasan, Veena", "Basu, Nandita B." ], "keywords": [ "" ], "year": "2019", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ 15.63093376159668, 28.895660400390625 ], "cluster": 4.0 }, { "idx": 437, "title": "Revisiting governance principles for effective Remedial Action Plan implementation and capacity building", "abstract": "The creation of Remedial Action Plans for the Great Lakes Areas of Concern was an experiment in addressing anthropogenic stress on human and nonhuman uses of the nearshore zones, invoking new governance paradigms. This article examines how positive governance attributes and negative governance deficits can benefit from an adaptive governance approach. More specifically, it explores best practises in governance for environmental management and suggests a framework in which Areas of Concern approaches can achieve adaptive capacity. This research also aims to identify gaps in current governance arrangements in the ongoing effort to regenerate excellence in the Areas of Concern, with a view forward to nearshore governance frameworks under both Annex 1 and Annex 2 of the Great Lakes Water Quality Agreement Protocol of 2012.", "authors": [ "Krantzberg, Gail" ], "keywords": [ "good governance", "collaborative decision making" ], "year": "2018", "source": "AQUATIC ECOSYSTEM HEALTH & MANAGEMENT", "publication_type": "J", "point2d": [ 55.21886444091797, -5.104955673217773 ], "cluster": 4.0 }, { "idx": 439, "title": "Carbon release and transformation from coastal peat deposits controlled by submarine groundwater discharge: a column experiment study", "abstract": "Although the majority of coastal sediments consist of sandy material, in some areas marine ingression caused the submergence of terrestrial carbon-rich peat soils. This affects the coastal carbon balance, as peat represents a potential carbon source. We performed a column experiment to better understand the coupled flow and biogeochemical processes governing carbon transformations in submerged peat under coastal fresh groundwater (GW) discharge and brackish water intrusion. The columns contained naturally layered sediments with and without peat (organic carbon content in peat 39 +/- 14 wt%), alternately supplied with oxygen-rich brackish water from above and oxygen-poor, low-saline GW from below. The low-saline GW discharge through the peat significantly increased the release and ascent of dissolved organic carbon (DOC) from the peat (delta C-13(DOC) - 26.9 parts per thousand to - 27.7 parts per thousand), which was accompanied by the production of dissolved inorganic carbon (DIC) and emission of carbon dioxide (CO2), implying DOC mineralization. Oxygen respiration, sulfate (SO42-) reduction, and methane (CH4) formation were differently pronounced in the sediments and were accompanied with higher microbial abundances in peat compared to sand with SO42--reducing bacteria clearly dominating methanogens. With decreasing salinity and SO42- concentrations, CH4 emission rates increased from 16.5 to 77.3 mu mol m(-2) d(-1) during a 14-day, low-saline GW discharge phase. In contrast, oxygenated brackish water intrusion resulted in lower DOC and DIC pore water concentrations and significantly lower CH4 and CO2 emissions. Our study illustrates the strong dependence of carbon cycling in shallow coastal areas with submerged peat deposits on the flow and mixing dynamics within the subterranean estuary.", "authors": [ "Kreuzburg, Matthias", "Rezanezhad, Fereidoun", "Milojevic, Tatjana", "Voss, Maren", "Gosch, Lennart", "Liebner, Susanne", "Van Cappellen, Philippe", "Rehder, Gregor" ], "keywords": [ "" ], "year": "2020", "source": "LIMNOLOGY AND OCEANOGRAPHY", "publication_type": "J", "point2d": [ 6.324330806732178, 34.35485076904297 ], "cluster": 18.0 }, { "idx": 440, "title": "What is the future of water quality trading?", "abstract": "A comprehensive review of experiences with water quality trading (WQT) programs worldwide is presented, spanning altogether more than 4 decades. A new WQT database is built, extracting data and information from existing review papers, complemented with gray and published literature about individual trading programs. Key aspects that affect trading volumes and program continuation are identified and categorized. No single success or fail factor emerges from this review, typically a mix of factors play a role. There is potential for WQT to evolve further and serve as a cost-effective pollution control instrument, but this requires nudging political will to regulate nonpoint source.", "authors": [ "Liu, Haiyan", "Brouwer, Roy" ], "keywords": [ "institutional design", "meta-review", "optimal trading ratio", "success and fail factors", "water quality trading" ], "year": "2023", "source": "CONTEMPORARY ECONOMIC POLICY", "publication_type": "J", "point2d": [ 47.8955078125, -32.478126525878906 ], "cluster": 11.0 }, { "idx": 441, "title": "Turnover and legacy of sediment-associated PAH in a baseflow-dominated river", "abstract": "Polycyclic Aromatic Hydrocarbons (PAH) ubiquitously occur in rivers and threaten the aquatic ecosystem. Understanding their fate and behaviour in rivers can help in improving management strategies. We develop a particle-facilitated transport model considering suspended sediments with sorbed PAH from different origins to investigate the turnover and legacy of sediment-bound PAH in the baseflow-dominated Ammer River in southwest Germany. Our model identifies the contributions of dissolved and particle-bound PAH during wet and dry periods to the annual load. The analysis of in-stream processes enables investigating the average turnover times of sediments and attached PAH for the main stem of the river. The legacy of sediment-bound PAH is studied by running the model assuming a 50% reduction in PAH emissions after the introduction of environmental regulation in the 1970s. Our results show that sediment-bound and dissolved PAH account for 75% and 25% of the annual PAH load, respectively. PAH are mainly emitted from urban areas that contribute over 74% to the total load. In steep reaches, the turnover times of sediments and attached PAH are similar, whereas they differ by 1-2 orders of magnitude in reaches with very mild slopes. Flow rates significantly affect PAH fluxes between the mobile water and the riverbed over the entire river. Total PAH fluxes from the river bed to the mobile water are simulated to occur when the discharge is larger than 5 m(3)s(-1). River segments with large sediment storage show a potential of PAH legacy, which may have caused a PAH release over 10-20 years after the implementation of environmental regulation. This study is useful for assessing environmental impacts of PAH in rivers (e.g., their contribution to the river-water toxicity) and exemplifies that the longitudinal distribution, turnover, and legacy potential of PAH in a river system require a mechanistic understanding of river hydraulics and sediment transport. (C) 2019 Elsevier B.V. All rights reserved.", "authors": [ "Liu, Yan", "Zarfl, Christiane", "Basu, Nandita B.", "Cirpka, Olaf A." ], "keywords": [ "Particle-facilitated transport", "PAH", "Turnover", "Legacy" ], "year": "2019", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 48.61357498168945, 34.63936233520508 ], "cluster": 18.0 }, { "idx": 442, "title": "Modeling the Fate of Pharmaceuticals in a Fourth-Order River Under Competing Assumptions of Transient Storage", "abstract": "Quantifying the degradation of micropollutants in streams is important for river-water quality management. While biodegradation is believed to be enhanced in transient-storage zones of rivers, it can also occur in the main channel. Photodegradation is restricted to the main channel and surface transient-storage zones. In this study, we propose a transient-storage model framework to address the transport and fate of micropollutants in different domains of a river. We fitted the model to nighttime and daytime measurements of a tracer and four pharmaceuticals in River Steinlach, Germany. We could separate the surface and subsurface fractions of the total transient-storage zone by fitting fluorescein photodegradation at daytime versus conservative nighttime transport. In reactive transport, we tested two model variants, allowing biodegradation in the main channel or restricting it to the transient-storage zones, obtaining similar model performances but different degradation rate coefficients. Carbamazepine is relatively conservative; photodegradation of metoprolol and venlafaxine can be quantitatively attributed to the main channel and surface transient-storage zone; metoprolol, venlafaxine, and sulfamethoxazole undergo biodegradation. We projected a decrease of overall pollutant removal under higher flow conditions, regardless of attributing biodegradation to specific river compartments. Our study indicates that model-based analysis of daytime and nighttime field experiments allows (1) distinguishing photodegradation and biodegradation, (2) reducing equifinality of surface and subsurface transient-storage, and (3) estimating biodegradation in different domains under different assumptions. However, entirely reducing the equifinality of attributing biodegradation to different compartments is hardly possible in lowland rivers with only limited transient storage.", "authors": [ "Liu, Y.", "Zarfl, C.", "Basu, N. B.", "Cirpka, O. A." ], "keywords": [ "" ], "year": "2020", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 49.34132766723633, 35.47011184692383 ], "cluster": 18.0 }, { "idx": 443, "title": "Understanding and managing the re-eutrophication of Lake Erie: Knowledge gaps and research priorities", "abstract": "Eutrophication of freshwaters is already a problem in many regions globally and will probably worsen as human populations grow and consume more resources. The ability of researchers and governments to anticipate, mitigate, and restore eutrophic freshwaters in a cohesive, integrated manner suffers from key uncertainties in our understanding of the watershed-to-lake continuum. Here, we use Lake Erie and its watershed as an example of a system in which there is a pressing need to resolve these uncertainties. In recent history, Lake Erie both suffered and recovered from serious eutrophication and related issues. More recently, however, there has been a resurgence of eutrophication and associated harmful algal blooms in Lake Erie, with symptoms reminiscent of prior eutrophication. This resurgence has led the USA and Canadian governments to commit to substantially reducing P inputs into Lake Erie in an effort to control eutrophication. We illustrate how key uncertainties about Lake Erie and its watershed contribute to challenges we face in restoring this ecosystem and propose avenues for their resolution. To this end, we contend that an ecosystem approach will be required for managing the eutrophication of freshwaters.", "authors": [ "Mohamed, Mohamed N.", "Wellen, Christopher", "Parsons, Chris T.", "Taylor, William D.", "Arhonditsis, George", "Chomicki, Krista M.", "Boyd, Duncan", "Weidman, Paul", "Mundle, Scott O. C.", "Van Cappellen, Philippe", "Sharpley, Andrew N.", "Haffner, Douglas G." ], "keywords": [ "Lake Erie", "eutrophication", "land use", "nutrients", "ecosystem", "restoration" ], "year": "2019", "source": "FRESHWATER SCIENCE", "publication_type": "J", "point2d": [ 48.366573333740234, 6.3730316162109375 ], "cluster": 19.0 }, { "idx": 444, "title": "Snow water equivalent prediction in a mountainous area using hybrid bagging machine learning approaches", "abstract": "Snow Water Equivalent (SWE) is one of the most critical variables in mountainous watersheds and needs to be considered in water resources management plans. As direct measurement of SWE is difficult and empirical equations are highly uncertain, the present study aimed to obtain accurate predictions of SWE using machine learning methods. Five standalone algorithms of tree-based [M5P and random tree (RT)], rule-based [M5Rules (M5R)] and lazy-based learner (IBK and Kstar) and five novel hybrid bagging-based algorithms (BA) with standalone models (i.e., BA-M5P, BA-RT, BA-IBK, BA-Kstar and BA-M5R) were developed. A total of 2550 snow measurements were collected from 62 snow and rain-gauge stations located in 13 mountainous provinces in Iran. Data including ice beneath the snow (IBS), fresh snow depth (FSD), length of snow sample (LSS), snow density (SDN), snow depth (SD) and time of falling (TS) were measured. Based on the Pearson correlation between inputs (IBS, FSD, LSS, SDN, SD and TS) and output (SWE), six different input combinations were constructed. The dataset was separated into two groups (70% and 30% of the data) by a cross-validation technique for model construction (training dataset) and model evaluation (testing dataset), respectively. Different visual and quantitative metrics (e.g., Nash-Sutcliffe efficiency (NSE)) were used for evaluating model accuracy. It was found that SD had the highest correlation with SWE in Iran (r = 0.73). In general, the bootstrap aggregation (i.e., bagging) hybrid machine learning methods (BA-M5P, BA-RT, BA-IBK, BA-Kstar and BA-M5R) increased prediction accuracy when compared to each standalone method. While BA-M5R had the highest prediction accuracy (NSE = 0.83) (considering all six input variables), BA-IBK could predict SWE with high accuracy (NSE = 0.71) using only two input variables (SD and LSS). Our findings demonstrate that SWE can be accurately predicted through a variety of machine learning methods using easily measurable variables and may be useful for applications in other mountainous regions across the globe.", "authors": [ "Khosravi, Khabat", "Golkarian, Ali", "Omidvar, Ebrahim", "Hatamiafkoueieh, Javad", "Shirali, Masoud" ], "keywords": [ "Snow water equivalent", "Snow depth", "Machine learning", "Bagging", "Iran" ], "year": "2023", "source": "ACTA GEOPHYSICA", "publication_type": "J", "point2d": [ -35.69383239746094, -6.595027923583984 ], "cluster": 8.0 }, { "idx": 445, "title": "A DNA-based biosensor for aqueous Hg(II): Performance under variable pH, temperature and competing ligand composition", "abstract": "Mercury (Hg) is a toxic metal posing major health risks to human beings and wildlife. The characterization of Hg fate and transport in aquatic environments is hindered by a lack of sensitive, selective and easily field-deployable analytical techniques. Here we assess the reliability and performance of a Hg2+ sensor based on the selective binding of Hg2+ to a thymine-rich DNA under environmentally-relevant conditions. Experimental results indicate that the interactions between the DNA and SYBR Green I, which produce the detection fluorescence signal, are significantly impacted by pH, metal ligands and natural dissolved organic matter (NDOM). These interferences are largely eliminated by immobilizing the DNA in a polyacrylamide hydrogel, although high concentrations of NDOM, such as fulvic acids, still affect the sensor's performance due to competitive binding of Hg2+. The binding of Hg2+ to NDOM, however, can be accounted for via equilibrium speciation calculations, which also yield the complexation constant for Hg2+ binding to the DNA in the hydrogel. The equilibrium calculations reproduce the results for the entire set of experimental conditions, from simple electrolyte solutions to complex aqueous compositions mimicking natural lake waters, and across large ranges of pH (3-10) and temperature (5-50 degrees C).", "authors": [ "Pi, Kunfu", "Liu, Juewen", "Van Cappellen, Philippe" ], "keywords": [ "Mercury", "Environmental monitoring", "Biosensor", "DNA-functionalized hydrogel", "Dissolved organic matter" ], "year": "2020", "source": "JOURNAL OF HAZARDOUS MATERIALS", "publication_type": "J", "point2d": [ 82.09196472167969, 38.72848892211914 ], "cluster": 6.0 }, { "idx": 446, "title": "Detroit River phosphorus loads: Anatomy of a binational watershed", "abstract": "As a result of increased harmful algal blooms and hypoxia in Lake Erie, the US and Canada revised their phosphorus loading targets under the 2012 Great Lakes Water Quality Agreement. The focus of this paper is the Detroit River and its watershed, a source of 25% of the total phosphorus (TP) load to Lake Erie. Its load declined 37% since 1998, due chiefly to improvements at the regional Great Lakes Water Authority Water Resource Recovery Facility (WRRF) in Detroit and phosphorus sequestered by zebra and quagga mussels in Lake Huron. In addition to the 54% of the load from Lake Huron, nonpoint sources contribute 57% of the TP load and 50% of the dissolved reactive phosphorus load, with the remaining balance from point sources. After Lake Huron, the largest source is the WRRF, which has already reduced its load by over 40%. Currently, loads from Lake Huron and further reductions from the WRRF are not part of the reduction strategy, therefore remaining watershed sources will need to decline by 72% to meet the Water Quality Agreement target - a daunting challenge. Because other urban sources are very small, most of the reduction would have to come from agriculturally-dominated lands. The most effective way to reduce those loads is to apply combinations of practices like cover crops, buffer strips, wetlands, and applying fertilizer below the soil surface on the lands with the highest phosphorus losses. However, our simulations suggest even extensive conservation on those lands may not be enough. (C) 2019 International Association for Great Lakes Research. Published by Elsevier B.V. All rights reserved.", "authors": [ "Scavia, Donald", "Bocaniov, Serghei A.", "Dagnew, Awoke", "Hu, Yao", "Kerkez, Branko", "Long, Colleen M.", "Muenich, Rebecca L.", "Read, Jennifer", "Vaccaro, Lynn", "Wang, Yu-Chen" ], "keywords": [ "Detroit River", "Phosphorus", "Nutrient loads", "Lake Huron", "Lake Erie", "Load reduction" ], "year": "2019", "source": "JOURNAL OF GREAT LAKES RESEARCH", "publication_type": "J", "point2d": [ 48.978492736816406, 7.4403252601623535 ], "cluster": 19.0 }, { "idx": 447, "title": "Retrieval of ice/water observations from synthetic aperture radar imagery for use in lake ice data assimilation", "abstract": "High-resolution lake ice/water observations retrieved from satellite imagery through efficient, automated methods can provide critical information to lake ice forecasting systems. Synthetic aperture radar (SAR) data is well-suited to this purpose due to its high spatial resolution (approximately 50 m). With recent increases in the volume of SAR data available, the development of automated retrieval methods for these data is a priority for operational centres. However, automated retrieval of ice/water data from SAR imagery is difficult, due to ambiguity in ice and open water signatures, both in terms of image tone and in terms of parameterized texture features extracted from these images. Convolutional neural networks (CNNs) can learn features from imagery in an automated manner, and have been found effective in previous studies on sea ice concentration estimation from SAR. In this study the use of CNNs to retrieve ice/ water observations from dual-polarized SAR imagery of two of the Laurentian Great Lakes, Lake Erie and Lake Ontario, is investigated. For data assimilation, it is crucial that the retrieved observations are of high quality. To this end, quality control measures based on the uncertainty of the CNN output to eliminate incorrect retrievals are discussed and demonstrated. The quality control measures are found to be effective in both dual-polarized and single-polarized retrievals. The ability of the CNN to downscale the coarse resolution training labels is demonstrated qualitatively. (C) 2020 The Authors. Published by Elsevier B.V. on behalf of International Association for Great Lakes Research.", "authors": [ "Scott, K. Andrea", "Xu, Linlin", "Pour, Homa Kheyrollah" ], "keywords": [ "Lake ice", "Synthetic aperture radar", "Data assimilation" ], "year": "2020", "source": "JOURNAL OF GREAT LAKES RESEARCH", "publication_type": "J", "point2d": [ -81.09651184082031, 2.1598541736602783 ], "cluster": 2.0 }, { "idx": 448, "title": "Response to Comment on Legacy nitrogen may prevent achievement of water quality goals in the Gulf of Mexico", "abstract": "Ballard et al. argue that our prediction of a 30-year or longer recovery time for Gulf of Mexico water quality is highly uncertain, and that much shorter time lags are equally likely. We demonstrate that their argument, based on the use of a two-component regression model, does not sufficiently consider fundamental watershed processes or multiple lines of evidence suggesting the existence of decadal-scale lags.", "authors": [ "Van Meter, K. J.", "Van Cappellen, P.", "Basu, N. B." ], "keywords": [ "" ], "year": "2019", "source": "SCIENCE", "publication_type": "J", "point2d": [ 34.82967758178711, 1.1076797246932983 ], "cluster": 19.0 }, { "idx": 449, "title": "Identifying the groundwater sustainability implications of water policy in High-Use situations in the laurentian great Lakes basin", "abstract": "Although the Laurentian Great Lakes Basin contains the largest global store of fresh water, long-term groundwater storage (GWS) decline has been observed in some aquifers supplying communities that intensely use the resource. We consider a hallmark of effective groundwater use policy to be the regulation of aquifer pumping rates consistent with the physical-environmental determinants of sustainable aquifer yield. In this context, we examine policies, from the binational to municipal governance levels, to identify features that can lead to GWS decline in aquifers supplying these communities. As the physical-environmental characteristics determining sustainable yield span many climates and geological settings within the Basin, our findings highlight the need for policies to adapt to local conditions. We urge devolving more management roles to municipal level institutions which, as the nexus between people and central government, may be better poised to set policies in a participatory manner considering the unique physical-environmental characteristics of the aquifers on which their communities rely.", "authors": [ "Weekes, Khafi", "Krantzberg, Gail", "Pinheiro, Maria Vizeu" ], "keywords": [ "Groundwater", "policy", "sustainability", "Laurentian Great Lakes Basin" ], "year": "2019", "source": "CANADIAN WATER RESOURCES JOURNAL", "publication_type": "J", "point2d": [ 17.50248908996582, 27.32407569885254 ], "cluster": 4.0 }, { "idx": 450, "title": "A quantitative analysis of drinking water advisories in Saskatchewan Indigenous and rural communities 2012-2016", "abstract": "This study complements the existing literature on disparities associated with Indigenous and non-Indigenous small drinking water systems. The team took a quantitative approach and assessed relationships between seasonality, location, and type of community against the number of drinking water advisories in Saskatchewan for a 4-year period from 2012 to 2016. Generalised estimating equations were used to determine significant factors contributing to the likelihood of drinking water advisories comparing Indigenous to non-Indigenous communities of similar sizes. Results indicated that the season and the interaction between community type and region (north vs. south) were significant in the model for counts of advisories. Reserve communities in the north had a drinking water advisory count that was 5.19 times greater than those of reserves in the south, 2.63 times greater than counts for towns in the south and 4.94 times greater than those of villages in the south. Additional comparisons indicated that reserves in the north had 2.43 times as many advisories as villages in the north, but towns situated in the south part of the province had 1.98 times as many advisories as reserves in the south, and 1.88 times as many advisories as villages in the south. The work confirms heightened risk among northern Indigenous communities and suggests that increased attention to, and investment in, securing water resources is necessary in rural Saskatchewan and globally.", "authors": [ "McLeod, Lianne", "Bharadwaj, Lalita Anne", "Daigle, Joanne", "Waldner, Cheryl", "Bradford, Lori Elisabet Ann" ], "keywords": [ "Small drinking water systems", "drinking water advisories", "generalized estimating equation", "Indigenous communities" ], "year": "2020", "source": "CANADIAN WATER RESOURCES JOURNAL", "publication_type": "J", "point2d": [ 64.61410522460938, -23.33103370666504 ], "cluster": 4.0 }, { "idx": 455, "title": "Risk Perception and Human Health Risk in Rural Communities Consuming Unregulated Well Water in Saskatchewan, Canada", "abstract": "Rural communities dependent on unregulated drinking water are potentially at increased health risk from exposure to contaminants. Perception of drinking water safety influences water consumption, exposure, and health risk. A community-based participatory approach and probabilistic Bayesian methods were applied to integrate risk perception in a holistic human health risk assessment. Tap water arsenic concentrations and risk perception data were collected from two Saskatchewan communities. Drinking water health standards were exceeded in 67% (51/76) of households in Rural Municipality #184 (RM184) and 56% (25/45) in Beardy's and Okemasis First Nation (BOFN). There was no association between the presence of a health exceedance and risk perception. Households in RM184 or with an annual income >$50,000 were most likely to have in-house water treatment. The probability of consuming tap water perceived as safe (92%) or not safe (0%) suggested that households in RM184 were unlikely to drink water perceived as not safe. The probability of drinking tap water perceived as safe (77%) or as not safe (11%) suggested households in BOFN contradicted their perception and consumed water perceived as unsafe. Integration of risk perception lowered the adult incremental lifetime cancer risk by 3% to 1.3 x 10(-5) (95% CI 8.4 x 10(-8) to 9.0 x 10(-5)) for RM184 and by 8.9 x 10(-6) (95% CI 2.2 x 10(-7) to 5.9 x 10(-5)) for BOFN. Probability of exposure to arsenic concentrations >1:100,000, negligible cancer risk, was 23% for RM184 and 22% for BOFN.", "authors": [ "Ford, Lorelei", "Waldner, Cheryl", "Sanchez, Javier", "Bharadwaj, Lalita" ], "keywords": [ "Arsenic", "Bayesian", "First Nation", "health risk", "risk perception" ], "year": "2019", "source": "RISK ANALYSIS", "publication_type": "J", "point2d": [ 66.80487823486328, -21.99239730834961 ], "cluster": 7.0 }, { "idx": 456, "title": "Reclaiming Indigenous Planning as a Pathway to Local Water Security", "abstract": "Access to drinkable water is essential to human life. The consequence of unsafe drinking water can be damaging to communities and catastrophic to human health. Today, one in five First Nation communities in Canada is on a boil water advisory, with some advisories lasting over 10 years. Factors contributing to this problem stretch back to colonial structures and institutional arrangement that reproduce woefully inadequate community drinking water systems. Notwithstanding these challenges, First Nation communities remain diligent, adaptive, and innovative in their efforts to provide drinkable water to their community members. One example is through the practice of source water protection planning. Source water is untreated water from groundwater or surface water that supplies drinking water for human consumption. Source water protection is operationalized through land and water planning activities aimed at reducing the risk of contamination from entering a public drinking water supply. Here, we introduce a source water protection planning process at Muskowekwan First Nation, Treaty 4, Saskatchewan. The planning process followed a community-based participatory approach guided by trust, respect, and reciprocity between community members and university researchers. Community members identified threats to the drinking water source followed by restorative land management actions to reduce those threats. The result of this process produced much more than a planning document but engaged multiple community members in a process of empowerment and self-determination. The process of plan-making produced many unintended results including human-land connectivity, reconnection with the water spirit, as well as the reclaiming of indigenous planning. Source water protection planning may not correct all the current water system inadequacies that exist on many First Nations, but it will empower communities to take action to protect their drinking water sources for future generations as a pathway to local water security.", "authors": [ "Patrick, Robert J.", "Grant, Kellie", "Bharadwaj, Lalita" ], "keywords": [ "water security", "Canada", "Saskatchewan", "First Nations", "drinking water", "source water protection planning", "colonization" ], "year": "2019", "source": "WATER", "publication_type": "J", "point2d": [ 64.7926025390625, -25.440696716308594 ], "cluster": 4.0 }, { "idx": 457, "title": "Garbage in, Garbage Out Does Not Hold True for Indigenous Community Flood Extent Modeling in the Prairie Pothole Region", "abstract": "Extensive land use changes and uncertainties arising from climate change in recent years have contributed to increased flood magnitudes in the Canadian Prairies and threatened the vulnerabilities of many small and indigenous communities. There is, thus, a need to create modernized flood risk management tools to support small and rural communities' preparations for future extreme events. In this study, we developed spatial flood information for an indigenous community in Central Saskatchewan using LiDAR based DEM and a spatial modeling tool, the wetland DEM ponding model (WDPM). A crucial element of flood mapping in this study was community engagement in data collection, scenario description for WDPM, and flood map validation. Community feedback was also used to evaluate the utility of the modelled flood outputs. The results showed the accuracy of WDPM outputs could be improved not only with the quality of DEM but also with additional community-held information on contributing areas (watershed information). Based on community feedback, this accessible, spatially-focused modeling approach can provide relevant information for community spatial planning and developing risk management strategies. Our study found community engagement to be valuable in flood modeling and mapping by: providing necessary data, validating input data through lived experiences, and providing alternate scenarios to be used in future work. This research demonstrates the suitability and utility of LiDAR and WDPM complemented by community participation for improving flood mapping in the Prairie Pothole Region (PPR). The approach used in the study also serves as an important guide for applying transdisciplinary tools and methods for establishing good practice in research and helping build resilient communities in the Prairies.", "authors": [ "Thapa, Anuja", "Bradford, Lori", "Strickert, Graham", "Yu, Xiaolei", "Johnston, Anthony", "Watson-Daniels, Kelsey" ], "keywords": [ "flood risk", "flood mapping", "LiDAR", "spatial modeling", "GIS", "Prairie Pothole Region", "community flood management" ], "year": "2019", "source": "WATER", "publication_type": "J", "point2d": [ 39.606788635253906, -31.129392623901367 ], "cluster": 4.0 }, { "idx": 458, "title": "Incorporating social dimensions in hydrological and water quality modeling to evaluate the effectiveness of agricultural beneficial management practices in a Prairie River Basin", "abstract": "There is growing interest to develop processes for creating user-informed watershed scale models of hydrology and water quality and to assist in decision-making for balanced policies for managing watersheds. Watershed models can be enhanced with the incorporation of social dimensions of watershed management as brought forward by participants such as the perspectives, values, and norms of people that depend on the land, water, and ecosystems for sustenance, economies, and overall wellbeing. In this work, we explore the value of combining both qualitative and quantitative methods and social science data to enhance salience and legitimacy of watershed models so that end-users are more engaged. We discuss pilot testing and engagement workshops for building and testing a systems dynamics model of the Qu'Appelle Valley to gather insights from local farmers and understand their perceptions of Beneficial Management Practices (BMPs). Mixed-method workshops with agricultural producers in the Qu'Appelle Watershed gathered feedback on the developing model and the incorporation of social determinants affecting decision-making. Analysis of focus groups and factor analysis of Q-sorts were used to identify the desired components of the model, and whether it supported farmers' understanding of the potential effects of BMPs on water quality. We explored farmers' engagement with models testing BMPs and the potential of incorporating their decision processes within the model itself. Finally, we discuss the reception of the process and the practicality of the approach in providing legitimate and credible decision support tools for a community of farmers.", "authors": [ "Bradford, Lori", "Thapa, Anuja", "Duffy, Ashleigh", "Hassanzadeh, Elmira", "Strickert, Graham", "Noble, Bram", "Lindenschmidt, Karl-Erich" ], "keywords": [ "Watershed modeling", "System dynamic modeling", "Beneficial management practices", "Saskatchewan", "Mixed method", "Q methodology", "Qu'Appelle River Basin" ], "year": "2020", "source": "ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH", "publication_type": "J", "point2d": [ 46.35072326660156, -36.38486099243164 ], "cluster": 4.0 }, { "idx": 459, "title": "A new flow for Canadian young hydrologists: Key scientific challenges addressed by research cultural shifts", "abstract": "", "authors": [ "Aubry-Wake, Caroline", "Somers, Lauren D.", "Alcock, Haley", "Anderson, Aspen M.", "Azarkhish, Amin", "Bansah, Samuel", "Bell, Nicole M.", "Biagi, Kelly", "Castaneda-Gonzalez, Mariana", "Champagne, Olivier", "Chesnokova, Anna", "Coone, Devin", "Gauthier, Tasha-Leigh J.", "Ghimire, Uttam", "Glas, Nathan", "Hrach, Dylan M.", "Lai, Oi Yin", "Lamontagne-Halle, Pierrick", "Leroux, Nicolas R.", "Lyon, Laura", "Mandal, Sohom", "Nasri, Bouchra R.", "Popovic, Natasa", "Rankin, Tracy E.", "Rasouli, Kabir", "Robinson, Alexis", "Sanyal, Palash", "Shatilla, Nadine J.", "Van Huizen, Brandon", "Wilkinson, Sophie", "Williamson, Jessica", "Zaremehrjardy, Majid" ], "keywords": [ "" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -19.845624923706055, -18.43522834777832 ], "cluster": 18.0 }, { "idx": 460, "title": "Preferential elution of ionic solutes in melting snowpacks: Improving process understanding through field observations and modeling in the Rocky Mountains", "abstract": "The preferential elution of ions from melting snowpacks is a complex problem that has been linked to temporary acidification of water bodies. However, the understanding of these processes in snowpacks around the world, including the polar regions that are experiencing unprecedented warming and melting, remains limited despite being instrumental in supporting climate change adaptation. In this study, data collected from a snowmelt lysimeter and snowpits at meadow and forest-gap sites in a high elevation watershed in Colorado were combined with the PULSE multi-phase snowpack chemistry model to investigate the controls of meltwater chemistry and preferential elution. The snowdepth at the meadow site was 64% of that at the forest-gap site, and the snowmelt rate was greater there (meadow snowpit) due to higher solar irradiance. Cations such as Ca2+ and NH4+ were deposited mostly within the upper layers of both the meadow and forest-gap snowpacks, and acid anions such as NO3- and SO42- were more evenly distributed. The snow ion concentrations were generally greater at the forest-gap snowpit, except for NH4-, which indicates that wind erosion of wet and dry deposited ions from the meadow may have reduced concentrations of residual snow. Furthermore, at the forest-gap site, snow interception and scavenging processes such as sublimation, ventilation, and throughfall led to particular ion enrichment of Ca2+, Mg2+, K+, Cl, SO42- and NO3-. Model simulations and observations highlight that preferential elution is enhanced by low snowmelt rates, with the model indicating that this is due to lower dilution rates and increased contact time and area between the percolating meltwater and the snow. Results suggest that low snowmelt rates can cause multiple early meltwater ionic pulses for ions subject to lower ion exclusion. Ion exclusion rates at the grain-size level have been estimated for the first time. (C) 2019 Elsevier B.V. All rights reserved.", "authors": [ "Costa, Diogo", "Sexstone, Graham A.", "Pomeroy, John W.", "Campbell, Donald H.", "Clow, David W.", "Mast, Alisa" ], "keywords": [ "Meltwater chemistry", "Snow chemistry", "Preferential elution", "Snow ion exclusion", "Snowmelt", "Cryosphere", "Numerical modeling" ], "year": "2020", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ -25.19135856628418, 20.91603660583496 ], "cluster": 12.0 }, { "idx": 461, "title": "Characterization of contrasting flow and thermal regimes in two adjacent subarctic alpine headwaters in Northwest Canada", "abstract": "Alpine headwaters in subarctic regions are particularly sensitive to climate change, yet there is little information on stream thermal regimes in these areas and how they might respond to global warming. In this paper, we characterize and compare the hydrological and thermal regimes of two subarctic headwater alpine streams within an empirical framework. The streams investigated are located within two adjacent catchments with similar geology, size, elevation and landscape, Granger Creek (GC) and Buckbrush Creek (BB), which are part of the Wolf Creek Research Basin in the Yukon Territory, Canada. Hydrometeorological and high-resolution stream temperature data were collected throughout summer 2016. Both sites exhibited a flow regime typical of cold alpine headwater catchments influenced by frozen ground and permafrost. Comparatively, GC was characterized by a flashier response with more extreme flows, than BB. In both sites, stream temperature was highly variable and very responsive to short-term changes in climatic conditions. On average, stream temperature in BB was slightly higher than in GC (respectively 5.8 and 5.7 degrees C), but less variable (average difference between 75th and 25th quantiles of 1.6 and 2.0 degrees C). Regression analysis between mean daily air and stream temperature suggested that a greater relative (to stream flow) groundwater contribution in BB could more effectively buffer atmospheric fluctuations. Heat fluxes were derived and utilized to assess their relative contribution to the energy balance. Overall, non-advective fluxes followed a daily pattern highly correlated to short-wave radiation. G1enerally, solar radiation and latent heat were respectively the most important heat source and sink, while air-water interface processes were major factors driving nighttime stream temperature fluctuations.", "authors": [ "Fabris, Luca", "Rolick, Ryan L.", "Kurylyk, Barret L.", "Carey, Sean K." ], "keywords": [ "climate change", "energy balance", "flow regime", "heat budget", "permafrost", "regression analysis", "stream temperature", "subarctic alpine headwaters" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -8.931288719177246, 0.4806322157382965 ], "cluster": 13.0 }, { "idx": 462, "title": "Characterization of contrasting flow and thermal regimes in two adjacent subarctic alpine headwaters in Northwest Canada", "abstract": "Alpine headwaters in subarctic regions are particularly sensitive to climate change, yet there is little information on stream thermal regimes in these areas and how they might respond to global warming. In this paper, we characterize and compare the hydrological and thermal regimes of two subarctic headwater alpine streams within an empirical framework. The streams investigated are located within two adjacent catchments with similar geology, size, elevation and landscape, Granger Creek (GC) and Buckbrush Creek (BB), which are part of the Wolf Creek Research Basin in the Yukon Territory, Canada. Hydrometeorological and high-resolution stream temperature data were collected throughout summer 2016. Both sites exhibited a flow regime typical of cold alpine headwater catchments influenced by frozen ground and permafrost. Comparatively, GC was characterized by a flashier response with more extreme flows, than BB. In both sites, stream temperature was highly variable and very responsive to short-term changes in climatic conditions. On average, stream temperature in BB was slightly higher than in GC (respectively 5.8 and 5.7 degrees C), but less variable (average difference between 75th and 25th quantiles of 1.6 and 2.0 degrees C). Regression analysis between mean daily air and stream temperature suggested that a greater relative (to stream flow) groundwater contribution in BB could more effectively buffer atmospheric fluctuations. Heat fluxes were derived and utilized to assess their relative contribution to the energy balance. Overall, non-advective fluxes followed a daily pattern highly correlated to short-wave radiation. G1enerally, solar radiation and latent heat were respectively the most important heat source and sink, while air-water interface processes were major factors driving nighttime stream temperature fluctuations.", "authors": [ "Fabris, Luca", "Rolick, Ryan L.", "Kurylyk, Barret L.", "Carey, Sean K." ], "keywords": [ "climate change", "energy balance", "flow regime", "heat budget", "permafrost", "regression analysis", "stream temperature", "subarctic alpine headwaters" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -8.736021041870117, 0.8569682836532593 ], "cluster": 13.0 }, { "idx": 463, "title": "Automatic mapping and geomorphometry extraction technique for crevasses in geodetic mass-balance calculations at Haig Glacier, Canadian Rockies", "abstract": "Finely resolved geodetic data provide an opportunity to assess the extent and morphology of crevasses and their change over time. Crevasses have the potential to bias geodetic measurements of elevation and mass change unless they are properly accounted for. We developed a framework that automatically maps and extracts crevasse geometry and masks them where they interfere with surface mass-balance assessment. Our study examines airborne light detection and ranging digital elevation models (LiDAR DEMs) from Haig Glacier, which is experiencing a transient response in its crevassed upper regions as the glacier thins, using a self-organizing map algorithm. This method successfully extracts and characterizes similar to 1000 crevasses, with an overall accuracy of 94%. The resulting map provides insight into stress and flow conditions. The crevasse mask also enables refined geodetic estimates of summer mass balance. From differencing of September and April LiDAR DEMs, the raw LiDAR DEM gives a 9% overestimate in the magnitude of glacier thinning over the summer: -5.48 m compared with a mean elevation change of -5.02 m when crevasses are masked out. Without identification and removal of crevasses, the LiDAR-derived summer mass balance therefore has a negative bias relative to the glaciological surface mass balance.", "authors": [ "Foroutan, Marzieh", "Marshall, Shawn J.", "Menounos, Brian" ], "keywords": [ "Crevasses", "glaciological instruments and methods", "remote sensing" ], "year": "2019", "source": "JOURNAL OF GLACIOLOGY", "publication_type": "J", "point2d": [ -49.8156852722168, 3.335437774658203 ], "cluster": 8.0 }, { "idx": 464, "title": "Application of distributed temperature sensing for mountain permafrost mapping", "abstract": "Permafrost distribution in mountains is typically more heterogeneous relative to low-relief environments due to greater variability in the factors controlling the ground thermal regime, such as topography, snow depth, and sediment grain size (e.g., coarse blocks). Measuring and understanding the geothermal variability in high mountains remains challenging due to logistical constraints. This study presents one of the first applications of distributed temperature sensing (DTS) in periglacial environments to measure ground surface temperatures in a mountain permafrost area at much higher spatial resolution than possible with conventional methods using discrete temperature sensors. DTS measures temperature along a fibre-optic cable at high spatial resolution (i.e., <= 1 m). Its use can be limited by power supply and calibration requirements, although recent methodological developments have relaxed some of these restrictions. Spatially continuous DTS measurements at a studied rock glacier provided greater resolution of geothermal variability and facilitated the interpretation of bottom temperature of snowpack data to map patchy permafrost distribution. This research highlights the potential for DTS to be a useful tool for permafrost mapping, ground thermal regime interpretation, conceptual geothermal model development, and numerical model evaluation in areas of heterogeneous mountain permafrost.", "authors": [ "Harrington, Jordan S.", "Hayashi, Masaki" ], "keywords": [ "bottom temperature of snowpack", "BTS", "coarse blocks", "DTS", "ground surface temperature", "rock glacier" ], "year": "2019", "source": "PERMAFROST AND PERIGLACIAL PROCESSES", "publication_type": "J", "point2d": [ -32.09674072265625, 41.3768424987793 ], "cluster": 8.0 }, { "idx": 465, "title": "The Impact of Variable Horizon Shade on the Growing Season Energy Budget of a Subalpine Headwater Wetland", "abstract": "Surface energy budgets are important to the ecohydrology of complex terrain, where land surfaces cycle in and out of shadows creating distinct microclimates. Shading in such environments can help regulate downstream flow over the course of a growing season, but our knowledge on how shadows impact the energy budget and consequently ecohydrology in montane ecosystems is very limited. We investigated the influence of horizon shade on the surface energy fluxes of a subalpine headwater wetland in the Canadian Rocky Mountains during the growing season. During the study, surface insolation decreased by 60% (32% due to evolving horizon shade and 28% from seasonality). The influence of shade on the energy budget varied between two distinct periods: (1) Stable Shade, when horizon shade was constant and reduced sunlight by 2 h per day; and (2) Dynamic Shade, when shade increased and reduced sunlight by 0.18 h more each day, equivalent to a 13% reduction in incoming shortwave radiation and 16% in net radiation. Latent heat flux, the dominant energy flux at our site, varied temporally because of changes in incoming radiation, atmospheric demand, soil moisture and shade. Horizon shade controlled soil moisture at our site by prolonging snowmelt and reducing evapotranspiration in the late growing season, resulting in increased water storage capacity compared to other mountain wetlands. With the mounting risk of climate-change-driven severe spring flooding and late season droughts downstream of mountain headwaters, shaded subalpine wetlands provide important ecohydrological and mitigation services that are worthy of further study and mapping. This will help us better understand and protect mountain and prairie water resources.", "authors": [ "Hrach, Dylan M.", "Petrone, Richard M.", "Van Huizen, Brandon", "Green, Adam", "Khomik, Myroslava" ], "keywords": [ "horizon shade", "solar radiation", "energy budget", "Canadian Rocky Mountains", "subalpine wetland", "latent heat flux" ], "year": "2021", "source": "ATMOSPHERE", "publication_type": "J", "point2d": [ -19.270761489868164, 11.032791137695312 ], "cluster": 13.0 }, { "idx": 466, "title": "Analysis of growing season carbon and water fluxes of a subalpine wetland in the Canadian Rocky Mountains: Implications of shade on ecosystem water use efficiency", "abstract": "Mountain regions are an important regulator in the global water cycle through their disproportionate water contribution. Often referred to as the Water Towers of the World, mountains contribute 40%-60% of the world's annual surface flow. Shade is a common feature in mountains, where complex terrain cycles land surfaces in and out of shadows over daily and seasonal scales, which can impact water use. This study investigated the turbulent water and carbon dioxide (CO2) fluxes during the snow-free period in a subalpine wetland in the Canadian Rocky Mountains, from 7 June to 10 September 2018. Shading had a significant and substantial effect on water and CO2 fluxes at our site. When considering data from the entire study period, each hourly increase of shade per day reduced evapotranspiration (ET) and gross primary production (GPP) by 0.42 mm and 0.77 g C m(-2), equivalent to 17% and 15% per day, respectively. However, the variability in shading changed throughout the study, it was stable to start and increased towards the end. Only during the peak growing season, the site experienced days with both stable and increasing shade. During this time, we found that shade, caused by the local complex terrain, reduced ET and potentially increased GPP, likely due to enhanced diffuse radiation. The overall result was greater water use efficiency during periods of increased shading in the peak growing season. These findings suggest that shaded subalpine wetlands can store large volumes of water for late season runoff and are productive through short growing seasons.", "authors": [ "Hrach, Dylan M.", "Petrone, Richard M.", "Green, Adam", "Khomik, Myroslava" ], "keywords": [ "Canadian Rocky Mountains", "carbon dioxide fluxes", "complex terrain", "evapotranspiration", "gross primary production", "shading", "water use efficiency", "wetlands" ], "year": "2022", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -19.86379051208496, 10.971085548400879 ], "cluster": 13.0 }, { "idx": 467, "title": "Biomic river restoration: A new focus for river management", "abstract": "River management based solely on physical science has proven to be unsustainable and unsuccessful, evidenced by the fact that the problems this approach intended to solve (e.g., flood hazards, water scarcity, and channel instability) have not been solved and long-term deterioration in river environments has reduced the capacity of rivers to continue meeting the needs of society. In response, there has been a paradigm shift in management over the past few decades, towards river restoration. But the ecological, morphological, and societal benefits of river restoration have, on the whole, been disappointing. We believe that this stems from the fact that restoration overrelies on the same physical analyses and approaches, with flowing water still regarded as the universally predominant driver of channel form and structural intervention seen as essential to influencing fluvial processes. We argue that if river restoration is to reverse long-standing declines in river functions, it is necessary to recognize the influence of biology on river forms and processes and re-envisage what it means to restore a river. This entails shifting the focus of river restoration from designing and constructing stable channels that mimic natural forms to reconnecting streams within balanced and healthy biomes, and so levering the power of biology to influence river processes. We define this new approach as biomic river restoration.", "authors": [ "Johnson, Matthew F.", "Thorne, Colin R.", "Castro, Janine M.", "Kondolf, G. Mathias", "Mazzacano, Celeste Searles", "Rood, Stewart B.", "Westbrook, Cherie" ], "keywords": [ "anthrome", "biogeomorphology", "biome", "ecosystem engineering", "river management", "river restoration", "working with natural processes" ], "year": "2020", "source": "RIVER RESEARCH AND APPLICATIONS", "publication_type": "J", "point2d": [ 13.778769493103027, -3.354966402053833 ], "cluster": 18.0 }, { "idx": 468, "title": "Near-0 degrees C surface temperature and precipitation type patterns across Canada", "abstract": "The 0 degrees C temperature threshold is critical for many meteorological and hydrological processes driven by melting and freezing in the atmosphere, surface, and sub-surface and by the associated precipitation varying between rain, freezing rain, wet snow, and snow. This threshold is especially important in cold regions such as Canada, because it is linked with freeze-thaw, snowmelt, and permafrost. This study develops a Canada-wide perspective on near-0 degrees C conditions using hourly surface temperature and precipitation type observations from 92 climate stations for the period from 1981 to 2011. In addition, nine stations from various climatic regions are selected for further analysis. Near-0 degrees C conditions are defined as periods when the surface temperature is between 2 and 2 degrees C. Near-0 degrees C conditions occur often across all regions of the country, although the annual number of days and hours and the duration of these events varies dramatically. Various types of precipitation (e.g., rain, freezing rain, wet snow, and ice pellets) sometimes occur with these temperatures. Near-0 degrees C conditions and the reported precipitation type occurrences tend to be higher in Atlantic Canada, although high values also occur in other regions. Trends of most temperature-based and precipitation-based indicators show little or no change despite a systematic warming in annual surface temperatures over Canada. Over the annual cycle, near-0 degrees C temperatures and precipitation often exhibit a pattern: short durations occur around summer, driven by the diurnal cycle, and a tendency toward longer durations around winter, associated with storms. There is also a tendency for near-0 degrees C surface temperatures to occur more often than expected relative to other temperature windows at some stations due, at least in part, to diabatic cooling and heating that take place with melting and freezing, respectively, in the atmosphere and at the surface.", "authors": [ "Mekis, Eva", "Stewart, Ronald E.", "Theriault, Julie M.", "Kochtubajda, Bohdan", "Bonsal, Barrie R.", "Liu, Zhuo" ], "keywords": [ "" ], "year": "2020", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -51.933284759521484, -29.302000045776367 ], "cluster": 1.0 }, { "idx": 469, "title": "Flood Risk Management in Canada's Prairie Provinces: an Analysis of Decision-Maker Priorities and Policy Preferences", "abstract": "If the aim of flood risk management (FRM) is to increase society's resilience to floods, then a holistic treatment of flood risk is required that addresses flood prevention, defence, mitigation, preparation, and response and recovery. Progressing resilience-based management to flood risk requires both diversity and coordination of policy across multiple jurisdictions. Decision makers and the types of FRM policy decisions they make play a key role in implementing FRM policies and strategies that progress flood resilience. This paper explores how policy preferences held by FRM decision makers relate to the characteristics of resilient FRM policy. The research was conducted in three flood-prone provinces in western Canada using a multi-criteria analytical approach. The results show that while decision maker FRM priorities are similar across the Canadian Prairies, their preferred FRM policies differ. Further, preferred FRM policies were largely resistance-based and influenced at least as much by flood experiences and perceptions of flood risk as by more obvious administrative pressures such as cost, public acceptability, and environmental protection. Several observations emerge from these results for advancing a coordinated, diversified approach to FRM which is required for resilience, both for western Canada and for FRM more broadly.", "authors": [ "Morrison, Alasdair", "Noble, Bram F.", "Westbrook, Cherie J." ], "keywords": [ "Flood risk management", "Decision support", "Flood resilience", "Flood adaptation", "Flood governance" ], "year": "2019", "source": "ENVIRONMENTAL MANAGEMENT", "publication_type": "J", "point2d": [ 37.09441375732422, -31.736099243164062 ], "cluster": 11.0 }, { "idx": 470, "title": "Multi-year evaluation of airborne geodetic surveys to estimate seasonal mass balance, Columbia and Rocky Mountains, Canada", "abstract": "Seasonal measurements of glacier mass balance provide insight into the relation between climate forcing and glacier change. To evaluate the feasibility of using remotely sensed methods to assess seasonal balance, we completed tandem airborne laser scanning (ALS) surveys and field-based glaciological measurements over a 4-year period for six alpine glaciers that lie in the Columbia and Rocky Mountains, near the headwaters of the Columbia River, British Columbia, Canada. We calculated annual geodetic balance using coregistered late summer digital elevation models (DEMs) and distributed estimates of density based on surface classification of ice, snow, and firn surfaces. Winter balance was derived using coregistered late summer and spring DEMs, as well as density measurements from regional snow survey observations and our glaciological measurements. Geodetic summer balance was calculated as the difference between winter and annual balance. Winter mass balance from our glaciological observations averaged 1.95 +/- 0.09 m w.e. (meter water equivalent), 4% larger than those derived from geodetic surveys. Average glaciological summer and annual balance were 3% smaller and 3% larger, respectively, than our geodetic estimates. We find that distributing snow, firn, and ice density based on surface classification has a greater influence on geodetic annual mass change than the density values themselves. Our results demonstrate that accurate assessments of seasonal mass change can be produced using ALS over a series of glaciers spanning several mountain ranges. Such agreement over multiple seasons, years, and glaciers demonstrates the ability of high-resolution geodetic methods to increase the number of glaciers where seasonal mass balance can be reliably estimated.", "authors": [ "Pelto, Ben M.", "Menounos, Brian", "Marshall, Shawn J." ], "keywords": [ "" ], "year": "2019", "source": "CRYOSPHERE", "publication_type": "J", "point2d": [ -49.40547180175781, 6.066278457641602 ], "cluster": 8.0 }, { "idx": 471, "title": "Processes governing snow ablation in alpine terrain detailed measurements from the Canadian Rockies", "abstract": "The spatial distribution of snow water equivalent (SWE) and melt are important for estimating areal melt rates and snow-cover depletion (SCD) dynamics but are rarely measured in detail during the late ablation period. This study contributes results from high-resolution observations made using large numbers of sequential aerial photographs taken from an unmanned aerial vehicle on an alpine ridge in the Fortress Mountain Snow Laboratory in the Canadian Rocky Mountains from May to July in 2015. Using structure-from-motion and thresholding techniques, spatial maps of snow depth, snow cover and differences in snow depth (dHS) during ablation were generated in very high resolution as proxies for spatial SWE, spatial ablation rates and SCD. The results indicate that the initial distribution of snow depth was highly variable due to overwinter snow redistribution; thus, the subsequent distribution of dHS was also variable due to albedo, slope/aspect and other unaccountable differences. However, the initial distribution of snow depth was 5 times more variable than that of the subsequent dHS values, which varied by a factor of 2 between the north and south aspects. dHS patterns were somewhat spatially persistent over time but had an insubstantial impact on SCD curves, which were overwhelmingly governed by the initial distribution of snow depth. The reason for this is that only a weak spatial correlation developed between the initial snow depth and dHS. Previous research has shown that spatial correlations between SWE and ablation rates can strongly influence SCD curves. Reasons for the lack of a correlation in this study area were analysed and a generalisation to other regions was discussed. The following questions were posed: what is needed for a large spatial correlation between initial snow depth and dHS? When should snow depth and dHS be taken into account to correctly model SCD? The findings of this study suggest that hydrological and atmospheric models need to incorporate realistic distributions of SWE, melt energy and cold content; therefore, they must account for realistic correlations (i.e. not too large or too small) between SWE and melt in order to accurately model SCD.", "authors": [ "Schirmer, Michael", "Pomeroy, John W." ], "keywords": [ "" ], "year": "2020", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -53.66032409667969, -1.954599380493164 ], "cluster": 8.0 }, { "idx": 472, "title": "Linking Atmospheric Rivers to Annual and Extreme River Runoff in British Columbia and Southeastern Alaska", "abstract": "This study quantifies the contribution of atmospheric rivers (ARs) to annual and extreme river runoff and evaluates the relationships between watershed characteristics and AR-related maximum river runoff across British Columbia and southeastern Alaska (BCSAK). Datasets used include gauged runoff from 168 unregulated watersheds, topographic characteristics of those watersheds, a regionalARcatalog, and integrated vapor transport fields for water years (WYs) 1979-2016. ARs contribute similar to 22% of annual river runoff along the Coast and Insular Mountains watersheds, which decreases inland to similar to 11% in the watersheds of the Interior Mountains and Plateau. Average association between ARs and annual maximum river runoff attains >80%, >50%, and <50% along the watersheds of the western flanks of the Coast Mountains, the Interior Mountains, and Interior Plateau, respectively. There is no significant change in AR-related extreme annual maximum runoff across BCSAK during 1979-2016. AR conditions occur during 25 out of 32 of the flood-related natural disasters in British Columbia duringWYs 1979-2016. AR-related annual maximum runoff magnitude is significantly higher than non-AR-related annual maximum runoff for 30% of the watersheds studied. Smaller and steeper watersheds closer to the coast are more susceptible to AR-related annual maximum runoff than their inland counterparts. These results illustrate the importance of AR activity as a major control for the distribution of peak runoff in BCSAK. This work provides insights on the hydrological response of watersheds of northwestern North America to landfalling ARs that may improve flood risk assessment and disaster management in this region.", "authors": [ "Sharma, Aseem R.", "Dery, Stephen J." ], "keywords": [ "Atmosphere", "Atmosphere-land interaction", "Climate variability", "Climatology", "Hydrology" ], "year": "2020", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -19.059450149536133, -33.7117919921875 ], "cluster": 16.0 }, { "idx": 473, "title": "Contribution of Atmospheric Rivers to Annual, Seasonal, and Extreme Precipitation Across British Columbia and Southeastern Alaska", "abstract": "Lying in the frontline of the prevailing midlatitude westerlies, British Columbia and southeastern Alaska (BCSAK) often receive copious amounts of precipitation through atmospheric rivers (ARs). This study quantifies the contribution of ARs to annual, seasonal, and extreme precipitation across BCSAK from 1979 to 2012 using a recently developed high-resolution gridded precipitation data set, a regional AR catalog, and integrated vapor transport fields calculated from a reanalysis data set. On average, ARs contribute 13% of total annual precipitation with the higher contribution along the coastal regions (up to 33%), parts of which are one of the wettest locations on Earth, followed by the Columbia and Rocky Mountains (9%-15%). The highest contributions occur during September (up to 57%) and October (up to 49%). The contribution of ARs to extreme precipitation attains >90% along the western arc of the Coast Mountains and the coastal regions of BCSAK. ARs act as the main synoptic-scale mechanism that brings rainfall to the Rocky Mountains in winter. The probability of observing AR-related precipitation increases over the study period; however, no change occurs in the average AR-related precipitation amount for most of BCSAK during 1979-2012. This work provides insights on the critical role ARs play on the water resources of northwestern North America and has broader implications on community water supply and management, hydropower operations, and flood risk assessment and mitigation.", "authors": [ "Sharma, A. R.", "Dery, S. J." ], "keywords": [ "atmospheric rivers", "precipitation", "extreme precipitation", "British Columbia", "southeastern Alaska" ], "year": "2020", "source": "JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES", "publication_type": "J", "point2d": [ -19.73204231262207, -34.1867561340332 ], "cluster": 1.0 }, { "idx": 474, "title": "Variability and trends of landfalling atmospheric rivers along the Pacific Coast of northwestern North America", "abstract": "Atmospheric rivers (ARs), defined as narrow, transient corridors of strong moisture transport in the lower troposphere, are important phenomena for freshwater recharge and water resources, especially along the west coast of North America. This study presents the variability and trends of landfalling ARs (LARs) along the higher (53.5 degrees-60.0 degrees N) and lower (47.0 degrees-53.5 degrees N) latitudes of British Columbia and southeastern Alaska (BCSAK) during the 1948-2016 period. Moreover, we present the synoptic evolution and distribution of LARs in BCSAK during different phases of ocean-atmosphere climate variability using a six-hourly AR catalogue from the Scripps Institution of Oceanography and reanalysis data from the National Centers for Environmental Prediction/National Center for Atmospheric Research. During 1948-2016, BCSAK averages 35 +/- 5 LARs annually, with the highest frequency during fall (13 +/- 2) and lowest during spring (5 +/- 2). The frequency of LARs across BCSAK rises during the study period, and the increase between 1979 and 2016 is statistically significant (p < .05). A strong ridge over the Pacific Northwest and BC and a trough over the Gulf of Alaska and the Northeastern Pacific Ocean favours AR landfalls at the higher and lower latitudes, respectively. BCSAK experiences greater numbers of LARs during neutral phases of El Nino/Southern Oscillation, the 2013/2014 Pacific oceanic blob, and during the positive phases of the Pacific Decadal Oscillation and Pacific North American Pattern.", "authors": [ "Sharma, Aseem R.", "Dery, Stephen J." ], "keywords": [ "atmospheric rivers", "British Columbia", "southeastern Alaska", "synoptic evolution", "trends" ], "year": "2020", "source": "INTERNATIONAL JOURNAL OF CLIMATOLOGY", "publication_type": "J", "point2d": [ -20.614614486694336, -35.10589599609375 ], "cluster": 1.0 }, { "idx": 475, "title": "Assessing inter-annual and seasonal patterns of DOC and DOM quality across a complex alpine watershed underlain by discontinuous permafrost in Yukon, Canada", "abstract": "High-latitude environments store approximately half of the global organic carbon pool in peatlands, organic soils and permafrost, while large Arctic rivers convey an estimated 18-50 Tg Ca-1 to the Arctic Ocean. Warming trends associated with climate change affect dissolved organic carbon (DOC) export from terrestrial to riverine environments. However, there is limited consensus as to whether exports will increase or decrease due to complex interactions between climate, soils, vegetation, and associated production, mobilization and transport processes. A large body of research has focused on large river system DOC and dissolved organic matter (DOM) lability and observed trends conserved across years, whereas investigation at smaller watershed scales show that thermokarst and fire have a transient impact on hydrologically mediated solute transport. This study, located in theWolf Creek Research Basin situated similar to 20 km south of Whitehorse, YT, Canada, utilizes a nested design to assess seasonal and annual patterns of DOC and DOM composition across diverse landscape types (headwater, wetland and lake) and watershed scales. Peak DOC concentration and export occurred during freshet, as is the case in most northern watersheds; however, peaks were lower than a decade ago at the headwater site Granger Creek. DOM composition was most variable during freshet with high A254 and SUVA(254) and low FI and BIX. DOM composition was relatively insensitive to flow variation during summer and fall. The influence of increasing watershed scale and downstream mixing of landscape contributions was an overall dampening of DOC concentrations and optical indices with increasing groundwater contribution. Forecasted vegetation shifts, enhanced permafrost and seasonal thaw, earlier snowmelt, increased rainfall and other projected climate-driven changes will alter DOM sources and transport pathways. The results from this study support a projected shift from predominantly organic soils (high aromaticity and less fresh) to decomposing vegetation (more fresh and lower aromaticity). These changes may also facilitate flow and transport via deeper flow pathways and enhance groundwater contributions to runoff.", "authors": [ "Shatilla, Nadine J.", "Carey, Sean K." ], "keywords": [ "" ], "year": "2019", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ 30.732574462890625, 37.32619094848633 ], "cluster": 13.0 }, { "idx": 476, "title": "Assessing inter-annual and seasonal patterns of DOC and DOM quality across a complex alpine watershed underlain by discontinuous permafrost in Yukon, Canada", "abstract": "High-latitude environments store approximately half of the global organic carbon pool in peatlands, organic soils and permafrost, while large Arctic rivers convey an estimated 18-50 Tg Ca-1 to the Arctic Ocean. Warming trends associated with climate change affect dissolved organic carbon (DOC) export from terrestrial to riverine environments. However, there is limited consensus as to whether exports will increase or decrease due to complex interactions between climate, soils, vegetation, and associated production, mobilization and transport processes. A large body of research has focused on large river system DOC and dissolved organic matter (DOM) lability and observed trends conserved across years, whereas investigation at smaller watershed scales show that thermokarst and fire have a transient impact on hydrologically mediated solute transport. This study, located in theWolf Creek Research Basin situated similar to 20 km south of Whitehorse, YT, Canada, utilizes a nested design to assess seasonal and annual patterns of DOC and DOM composition across diverse landscape types (headwater, wetland and lake) and watershed scales. Peak DOC concentration and export occurred during freshet, as is the case in most northern watersheds; however, peaks were lower than a decade ago at the headwater site Granger Creek. DOM composition was most variable during freshet with high A254 and SUVA(254) and low FI and BIX. DOM composition was relatively insensitive to flow variation during summer and fall. The influence of increasing watershed scale and downstream mixing of landscape contributions was an overall dampening of DOC concentrations and optical indices with increasing groundwater contribution. Forecasted vegetation shifts, enhanced permafrost and seasonal thaw, earlier snowmelt, increased rainfall and other projected climate-driven changes will alter DOM sources and transport pathways. The results from this study support a projected shift from predominantly organic soils (high aromaticity and less fresh) to decomposing vegetation (more fresh and lower aromaticity). These changes may also facilitate flow and transport via deeper flow pathways and enhance groundwater contributions to runoff.", "authors": [ "Shatilla, Nadine J.", "Carey, Sean K." ], "keywords": [ "" ], "year": "2019", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ 30.732574462890625, 37.32619094848633 ], "cluster": 13.0 }, { "idx": 477, "title": "HYDROLOGICAL FUNCTION OF A MOUNTAIN FEN AT LOW ELEVATION UNDER DRY CONDITIONS", "abstract": "Mountain fens are limited in their spatial extent but are vital ecosystems for biodiversity, habitat, and carbon and water cycling. Studies of fen hydrological function in northern regions indicate the timing and magnitude of runoff is variable, with atmospheric and environmental conditions playing key roles in runoff production. How the complex ecohydrological processes of mountain fens that govern water storage and release as well as peat accumulation will respond to a warmer and less snowy future climate is unclear. To provide insight, we studied the hydrological processes and function of Sibbald fen, located at the low end of the known elevation range in the Canadian Rocky Mountains, over a dry period. We added an evapotranspiration function to the Spence hydrological function method to better account for storage loss. When frozen in spring and early summer, the fen primarily transmits water. When thawed, the fen's hydrological function switches from water transmission to water release, leading to a summertime water table decline of nearly 1 m. Rainfall events larger than 5 mm can transiently switch fen hydrological function to storage, followed by contribution, depending on antecedent conditions. The evapotranspiration function was dominant only for a brief period in late June and early July when rainfall was low and the ground was still partially frozen, even though evapotranspiration accounted for the largest loss of storage from the system. This research highlights the mechanisms by which mountain peatlands supply baseflow during drought conditions, and the importance of frozen ground and rainfall in regulating their hydrological function. The study has important implications for the sustainability of low elevation mountain fens under climate change.", "authors": [ "Streich, Stephanie C.", "Westbrook, Cherie J." ], "keywords": [ "Canadian Rocky Mountains", "drought", "hydrological function", "groundwater-surface water interactions", "peatland", "seasonal frost" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -16.951475143432617, 4.743678092956543 ], "cluster": 13.0 }, { "idx": 478, "title": "Using stable isotopes to estimate travel times in a data-sparse Arctic catchment: Challenges and possible solutions", "abstract": "Use of isotopes to quantify the temporal dynamics of the transformation of precipitation into run-off has revealed fundamental new insights into catchment flow paths and mixing processes that influence biogeochemical transport. However, catchments underlain by permafrost have received little attention in isotope-based studies, despite their global importance in terms of rapid environmental change. These high-latitude regions offer limited access for data collection during critical periods (e.g., early phases of snowmelt). Additionally, spatio-temporal variable freeze-thaw cycles, together with the development of an active layer, have a time variant influence on catchment hydrology. All of these characteristics make the application of traditional transit time estimation approaches challenging. We describe an isotope-based study undertaken to provide a preliminary assessment of travel times at Siksik Creek in the western Canadian Arctic. We adopted a model-data fusion approach to estimate the volumes and isotopic characteristics of snowpack and meltwater. Using samples collected in the spring/summer, we characterize the isotopic composition of summer rainfall, melt from snow, soil water, and stream water. In addition, soil moisture dynamics and the temporal evolution of the active layer profile were monitored. First approximations of transit times were estimated for soil and streamwater compositions using lumped convolution integral models and temporally variable inputs including snowmelt, ice thaw, and summer rainfall. Comparing transit time estimates using a variety of inputs revealed that transit time was best estimated using all available inflows (i.e., snowmelt, soil ice thaw, and rainfall). Early spring transit times were short, dominated by snowmelt and soil ice thaw and limited catchment storage when soils are predominantly frozen. However, significant and increasing mixing with water in the active layer during the summer resulted in more damped steam water variation and longer mean travel times (similar to 1.5years). The study has also highlighted key data needs to better constrain travel time estimates in permafrost catchments.", "authors": [ "Tetzlaff, Doerthe", "Piovano, Thea", "Ala-Aho, Pertti", "Smith, Aaron", "Carey, Sean K.", "Marsh, Philip", "Wookey, Philip A.", "Street, Lorna E.", "Soulsby, Chris" ], "keywords": [ "active layer", "Arctic headwaters", "isotopes", "permafrost", "transit times" ], "year": "2018", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -6.807878017425537, 15.473677635192871 ], "cluster": 12.0 }, { "idx": 479, "title": "Using stable isotopes to estimate travel times in a data-sparse Arctic catchment: Challenges and possible solutions", "abstract": "Use of isotopes to quantify the temporal dynamics of the transformation of precipitation into run-off has revealed fundamental new insights into catchment flow paths and mixing processes that influence biogeochemical transport. However, catchments underlain by permafrost have received little attention in isotope-based studies, despite their global importance in terms of rapid environmental change. These high-latitude regions offer limited access for data collection during critical periods (e.g., early phases of snowmelt). Additionally, spatio-temporal variable freeze-thaw cycles, together with the development of an active layer, have a time variant influence on catchment hydrology. All of these characteristics make the application of traditional transit time estimation approaches challenging. We describe an isotope-based study undertaken to provide a preliminary assessment of travel times at Siksik Creek in the western Canadian Arctic. We adopted a model-data fusion approach to estimate the volumes and isotopic characteristics of snowpack and meltwater. Using samples collected in the spring/summer, we characterize the isotopic composition of summer rainfall, melt from snow, soil water, and stream water. In addition, soil moisture dynamics and the temporal evolution of the active layer profile were monitored. First approximations of transit times were estimated for soil and streamwater compositions using lumped convolution integral models and temporally variable inputs including snowmelt, ice thaw, and summer rainfall. Comparing transit time estimates using a variety of inputs revealed that transit time was best estimated using all available inflows (i.e., snowmelt, soil ice thaw, and rainfall). Early spring transit times were short, dominated by snowmelt and soil ice thaw and limited catchment storage when soils are predominantly frozen. However, significant and increasing mixing with water in the active layer during the summer resulted in more damped steam water variation and longer mean travel times (similar to 1.5years). The study has also highlighted key data needs to better constrain travel time estimates in permafrost catchments.", "authors": [ "Tetzlaff, Doerthe", "Piovano, Thea", "Ala-Aho, Pertti", "Smith, Aaron", "Carey, Sean K.", "Marsh, Philip", "Wookey, Philip A.", "Street, Lorna E.", "Soulsby, Chris" ], "keywords": [ "active layer", "Arctic headwaters", "isotopes", "permafrost", "transit times" ], "year": "2018", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -7.195641040802002, 15.233595848083496 ], "cluster": 12.0 }, { "idx": 480, "title": "Spatial patterns of temporal changes in Canadian Prairie streamflow using an alternative trend assessment approach", "abstract": "Changes in Canadian Prairie streamflow, particularly trends over time, have not been well studied but are particularly relevant for food and water security in this vast agricultural region. Streamflow records for this region are often unsuitable for conventional trend analysis; streams are often intermittent and have only a few days per year with flow, and stations operate only during the warm season, because of a lack of flow during the very cold Prairie winter. This study takes an alternative approach; streamflow data for the period from March to October for individual years between 1910 and 2015 from 169 hydrometric stations from the Prairie and adjacent areas in Canada were converted to annual cumulative runoff series. These 5895 individual station-years were then clustered based upon their shape, using dynamic time warping. Three clusters of cumulative annual runoff were found; the first and most common type has infrequent days with flow and low total annual runoff [0-50 mm], the second has more days with flow and slightly greater runoff [48-175 mm], and the least common third type has the fewest days without flow, includes perennial streams, and has much greater annual runoff [ > 173 mm]. For each hydrometric station a time series of annual cluster memberships was created. Trends in the fractions of cluster types were determined using logistic regression, with spatial groupings of these time series over five-year periods. Trends in the fractions of types within an ecoregion indicate spatially consistent and organized changes in the pattern of runoff over the region. In the western Canadian Prairies, particularly in the Mixed Grassland and Cypress Upland ecoregions, drying is occurring, as indicated by the increased frequency of the dry type. In the northern and eastern Canadian Prairies, conditions are shifting to greater runoffs, particularly in the Aspen Parkland, where the wet types are increasing in frequency.", "authors": [ "Whitfield, Paul H.", "Shook, K. R.", "Pomeroy, J. W." ], "keywords": [ "Prairie streams", "Trend assessment", "Dynamic time warping", "Logistic regression", "Ecoregion" ], "year": "2020", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -14.048721313476562, -15.07217025756836 ], "cluster": 1.0 }, { "idx": 481, "title": "Lake Ice-Water Classification of RADARSAT-2 Images by Integrating IRGS Segmentation with Pixel-Based Random Forest Labeling", "abstract": "Changes to ice cover on lakes throughout the northern landscape has been established as an indicator of climate change and variability, expected to have implications for both human and environmental systems. Monitoring lake ice cover is also required to enable more reliable weather forecasting across lake-rich northern latitudes. Currently, the Canadian Ice Service (CIS) monitors lakes using synthetic aperture radar (SAR) and optical imagery through visual interpretation, with total lake ice cover reported weekly as a fraction out of ten. An automated method of classification would allow for more detailed records to be delivered operationally. In this research, we present an automatic ice-mapping approach which integrates unsupervised segmentation from the Iterative Region Growing using Semantics (IRGS) algorithm with supervised random forest (RF) labeling. IRGS first locally segments homogeneous regions in an image, then merges similar regions into classes across the entire scene. Recently, these output regions were manually labeled by the user to generate ice maps, or were labeled using a Support Vector Machine (SVM) classifier. Here, three labeling methods (Manual, SVM, and RF) are applied after IRGS segmentation to perform ice-water classification on 36 RADARSAT-2 scenes of Great Bear Lake (Canada). SVM and RF classifiers are also tested without integration with IRGS. An accuracy assessment has been performed on the results, comparing outcomes with author-generated reference data, as well as the reported ice fraction from CIS. The IRGS-RF average classification accuracy for this dataset is 95.8%, demonstrating the potential of this automated method to provide detailed and reliable lake ice cover information operationally.", "authors": [ "Hoekstra, Marie", "Jiang, Mingzhe", "Clausi, David A.", "Duguay, Claude" ], "keywords": [ "classification", "gray-level co-occurrence matrix (GLCM)", "iterative region growing using semantics (IRGS)", "RADARSAT-2", "lake ice", "random forest (RF)", "support vector machine (SVM)" ], "year": "2020", "source": "REMOTE SENSING", "publication_type": "J", "point2d": [ -80.83932495117188, 4.477519512176514 ], "cluster": 2.0 }, { "idx": 482, "title": "Assessing the Performance of Methods for Monitoring Ice Phenology of the World's Largest High Arctic Lake Using High-Density Time Series Analysis of Sentinel-1 Data", "abstract": "Lake ice is a dominant component of Canada's landscape and can act as an indicator for how freshwater aquatic ecosystems are changing with warming climates. While lake ice monitoring through government networks has decreased in the last three decades, the increased availability of remote sensing images can help to provide consistent spatial and temporal coverage for areas with annual ice cover. Synthetic aperture radar (SAR) data are commonly used for lake ice monitoring, due to the acquisition of images in any condition (time of day or weather). Using Sentinel-1 A/B images, a high-density time series of SAR images was developed for Lake Hazen in Nunavut, Canada, from 2015-2018. These images were used to test two different methods of monitoring lake ice phenology: one method using the first difference between SAR images and another that applies the Otsu segmentation method. Ice phenology dates determined from the two methods were compared with visual interpretation of the Sentinel-1 images. Mean errors for the pixel comparison of the first difference method ranged 3-10 days for ice-on and ice-off, while average error values for the Otsu method ranged 2-10 days. Mean errors for comparisons of different sections of the lake ranged 0-15 days for the first difference method and 2-17 days for the Otsu method. This research demonstrates the value of temporally consistent image acquisition for improving the accuracy of lake ice monitoring.", "authors": [ "Murfitt, Justin", "Duguay, Claude R." ], "keywords": [ "Synthetic Aperture Radar", "lake ice", "Cryosphere", "High Density Time Series", "Sentinel-1" ], "year": "2020", "source": "REMOTE SENSING", "publication_type": "J", "point2d": [ -78.43724060058594, 4.872583866119385 ], "cluster": 2.0 }, { "idx": 484, "title": "In Situ Estimates of Freezing/Melting Point Depression in Agricultural Soils Using Permittivity and Temperature Measurements", "abstract": "We present a method to characterize soil moisture freeze-thaw events and freezing/melting point depression using permittivity and temperature measurements, readily available from in situ sources. In cold regions soil freeze-thaw processes play a critical role in the surface energy and water balance, with implications ranging from agricultural yields to natural disasters. Although monitoring of the soil moisture phase state is of critical importance, there is an inability to interpret soil moisture instrumentation in frozen conditions. To address this gap, we investigated the freeze-thaw response of a widely used soil moisture probe, the HydraProbe, in the laboratory. Soil freezing curves (SFCs) and soil thawing curves (STCs) were identified using the relationship between soil permittivity and temperature. The permittivity SFC/STC was fit using a logistic growth model to estimate the freezing/melting point depression (T-f/m) and its spread (s). Laboratory results showed that the fitting routine requires permittivity changes greater than 3.8 to provide robust estimates and suggested that a temperature bias is inherent in horizontally placed HydraProbes. We tested the method using field measurements collected over the last 7 years from the Environment and Climate Change Canada and the University of Guelph's Kenaston Soil Moisture Network in Saskatchewan, Canada. By dividing the time series into freeze-thaw events and then into individual transitions, the permittivity SFC/STC was identified. The freezing and melting point depression for the network was estimated as T-f/m = - 0.35 +/- 0.2,with T-f = - 0.41 +/- 0.22 degrees C and T-m = - 0.29 +/- 0.16 degrees C, respectively.", "authors": [ "Lara, R. Pardo", "Berg, A. A.", "Warland, J.", "Tetlock, Erica" ], "keywords": [ "soil moisture", "freeze thaw", "freezing point depression", "soil freezing curve", "seasonally frozen ground", "cryosphere" ], "year": "2020", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -76.1386947631836, 26.117433547973633 ], "cluster": 2.0 }, { "idx": 486, "title": "On the sensitivity of modelled groundwater recharge estimates to rain gauge network scale", "abstract": "Rainfall is often the largest component of the water budget and even a small uncertainty percentage may lead to challenges for accurately estimating groundwater recharge as a calculated residual within a water budget approach. Watersheds are a common scale for water budget assessment, and rainfall monitoring networks typically have widely spaced gauges that are frequently outside the watershed of interest. The effects of rainfall spatial variability and uncertainty on groundwater recharge estimates have received little attention and may influence water budget-derived recharge estimations. In the present study, the influence of spatial density in rainfall measurement on the numerical estimation of groundwater recharge was investigated through a series of modelling scenarios utilizing field data obtained from progressively denser rain gauge networks associated with a typical watershed in southern Ontario. The uncertainty of the recharge component of the water budget was used as a metric to aid interpretation of results. The scenarios employed networks composed of: 1) one nearby national weather station (within 3 km), 2) a regional network of six stations (within 30 km), and 3) a local network of six stations, five of which were within the selected watershed. A coupled and fully distributed hydrologic model (MIKE SHE) was used in the scenario analysis and applied to the Alder Creek watershed on the Waterloo Moraine near Kitchener-Waterloo, Ontario. Rainfall showed poor spatial correlation, even at the daily time scale. Average annual results over a three-year period showed that recharge rates varied up to 140 mm per year (similar to 40% of previously estimated annual recharge) among scenarios, with differences between scenarios greater than the water budget uncertainty during one of the years. These findings suggest that the availability of local rainfall measurements has the potential to influence the calibration of transient watershed hydrogeological models.", "authors": [ "Wiebe, Andrew J.", "Rudolph, David L." ], "keywords": [ "Rainfall spatial variability", "Groundwater recharge", "Water budget", "Uncertainty", "MIKE SHE", "Rainfall correlation" ], "year": "2020", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -3.1729328632354736, -21.161184310913086 ], "cluster": 10.0 }, { "idx": 487, "title": "On the sensitivity of modelled groundwater recharge estimates to rain gauge network scale", "abstract": "Rainfall is often the largest component of the water budget and even a small uncertainty percentage may lead to challenges for accurately estimating groundwater recharge as a calculated residual within a water budget approach. Watersheds are a common scale for water budget assessment, and rainfall monitoring networks typically have widely spaced gauges that are frequently outside the watershed of interest. The effects of rainfall spatial variability and uncertainty on groundwater recharge estimates have received little attention and may influence water budget-derived recharge estimations. In the present study, the influence of spatial density in rainfall measurement on the numerical estimation of groundwater recharge was investigated through a series of modelling scenarios utilizing field data obtained from progressively denser rain gauge networks associated with a typical watershed in southern Ontario. The uncertainty of the recharge component of the water budget was used as a metric to aid interpretation of results. The scenarios employed networks composed of: 1) one nearby national weather station (within 3 km), 2) a regional network of six stations (within 30 km), and 3) a local network of six stations, five of which were within the selected watershed. A coupled and fully distributed hydrologic model (MIKE SHE) was used in the scenario analysis and applied to the Alder Creek watershed on the Waterloo Moraine near Kitchener-Waterloo, Ontario. Rainfall showed poor spatial correlation, even at the daily time scale. Average annual results over a three-year period showed that recharge rates varied up to 140 mm per year (similar to 40% of previously estimated annual recharge) among scenarios, with differences between scenarios greater than the water budget uncertainty during one of the years. These findings suggest that the availability of local rainfall measurements has the potential to influence the calibration of transient watershed hydrogeological models.", "authors": [ "Wiebe, Andrew J.", "Rudolph, David L." ], "keywords": [ "Rainfall spatial variability", "Groundwater recharge", "Water budget", "Uncertainty", "MIKE SHE", "Rainfall correlation" ], "year": "2020", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -3.1729328632354736, -21.161184310913086 ], "cluster": 10.0 }, { "idx": 489, "title": "Where Is the Bottom of a Watershed?", "abstract": "Watersheds have served as one of our most basic units of organization in hydrology for over 300 years (Dooge, 1988, https://doi.org/10.1080/02626668809491223; McDonnell, 2017, https://doi.org/10.1038/ ngeo2964; Perrault, 1674, https://www.abebooks.com/first-edition/lorigine-fontaines-Perrault-Pierre-PetitImprimeur/21599664536/bd). With growing interest in groundwater-surface water interactions and subsurface flow paths, hydrologists are increasingly looking deeper. But the dialog between surface water hydrologists and groundwater hydrologists is still embryonic, and many basic questions are yet to be posed, let alone answered. One key question is: where is the bottom of a watershed? Knowing where to draw the bottom boundary has not yet been fully addressed in the literature, and how to define the watershed bottom is a fraught question. There is large variability across physical and conceptual models regarding how to implement a watershed bottom, and what counts as deep varies markedly in different communities. In this commentary, we seek to initiate a dialog on existing approaches to defining the bottom of the watershed. We briefly review the current literature describing how different communities typically frame the answer of just how deep we should look and identify situations where deep flow paths are key to developing realistic conceptual models of watershed systems. We then review the common conceptual approaches used to delineate the watershed lower boundary. Finally, we highlight opportunities to trigger this potential research area at the interface of catchment hydrology and hydrogeology.", "authors": [ "Condon, Laura E.", "Markovich, Katherine H.", "Kelleher, Christa A.", "McDonnell, Jeffrey J.", "Ferguson, Grant", "McIntosh, Jennifer C." ], "keywords": [ "" ], "year": "2020", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 3.9701905250549316, -11.882474899291992 ], "cluster": 18.0 }, { "idx": 490, "title": "Conventional Oil-The Forgotten Part of the Water-Energy Nexus", "abstract": "The impacts of unconventional oil and gas production via high-volume hydraulic fracturing (HVHF) on water resources, such as water use, groundwater and surface water contamination, and disposal of produced waters, have received a great deal of attention over the past decade. Conventional oil and gas production (e.g., enhanced oil recovery [EOR]), which has been occurring for more than a century in some areas of North America, shares the same environmental concerns, but has received comparatively little attention. Here, we compare the amount of produced water versus saltwater disposal (SWD) and injection for EOR in several prolific hydrocarbon producing regions in the United States and Canada. The total volume of saline and fresh to brackish water injected into depleted oil fields and nonproductive formations is greater than the total volume of produced waters in most regions. The addition of fresh to brackish makeup water for EOR may account for the net gain of subsurface water. The total amount of water injected and produced for conventional oil and gas production is greater than that associated with HVHF and unconventional oil and gas production by well over a factor of 10. Reservoir pressure increases from EOR and SWD wells are low compared to injection of fluids for HVHF, however, the longer duration of injections could allow for greater solute transport distances and potential for contamination. Attention should be refocused from the subsurface environmental impacts of HVHF to the oil and gas industry as a whole.", "authors": [ "McIntosh, Jennifer C.", "Ferguson, Grant" ], "keywords": [ "" ], "year": "2019", "source": "GROUNDWATER", "publication_type": "J", "point2d": [ 11.950541496276855, 31.686813354492188 ], "cluster": 18.0 }, { "idx": 491, "title": "Selenium oxyanion bioconcentration in natural freshwater periphyton", "abstract": "Selenium (Se) enrichment has been demonstrated to vary by several orders of magnitude among species of planktonic algae. This is a substantial source of uncertainty when modelling Se biodynamics in aquatic systems. In addition, Se bioconcentration data are largely lacking for periphytic species of algae, and for multi-species periphyton biofilms, adding to the challenge of modelling Se transfer in periphyton-based food webs. To better predict Se dynamics in periphyton dominated, freshwater ecosystems, the goal of this study was to assess the relative influence of periphyton community composition on the uptake of waterborne Se oxyanions. Naturally grown freshwater periphyton communities, sampled from five different water bodies, were exposed to environmentally relevant concentrations of selenite [Se(IV)] or selenate [Se(VI)] (nominal concentrations of 5 and 25 mu g Se L-1) under similar, controlled laboratory conditions for a period of 8 days. Unique periphyton assemblages were derived from the five different field sites, as confirmed by light microscopy and targeted DNA sequencing of the plastid 23S rRNA gene in algae. Selenium accumulation demonstrated a maximum of 23.6-fold difference for Se(IV) enrichment and 2.1-fold difference for Se(VI) enrichment across the periphyton/biofilm assemblages tested. The assemblage from one field site demonstrated both high accumulation of Se(IV) and iron, and was subjected to additional experimentation to elucidate the mechanism(s) of Se accumulation. Selenite accumulation (at nominal concentrations of 5 and 25 mu g Se L-1 and mean pH of 7.5 across all treatment replicates) was assessed in both unaltered and heat-killed periphyton, and in periphyton from the same site grown without light to exclude phototrophic organisms. Following an exposure length of 8 days, all periphyton treatments showed similar levels of Se accumulation, indicating that much of the apparent uptake of Se(IV) was due to non-biological processes (i.e., surface adsorption). The results of this study will help reduce uncertainty in the prediction of Se dynamics and food-chain transfer in freshwater environments. Further exploration of the ecological consequences of extracellular adsorption of Se(IV) to periphyton, rather than intracellular absorption, is recommended to further refine predictions related to Se biodynamics in freshwater food webs.", "authors": [ "Markwart, Blue", "Liber, Karsten", "Xie, Yuwei", "Raes, Katherine", "Hecker, Markus", "Janz, David", "Doig, Lorne E." ], "keywords": [ "Freshwater", "Periphyton", "Selenium", "Enrichment function" ], "year": "2019", "source": "ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY", "publication_type": "J", "point2d": [ 62.55396270751953, 9.713066101074219 ], "cluster": 19.0 }, { "idx": 492, "title": "Detecting Amphibians in Agricultural Landscapes Using Environmental DNA Reveals the Importance of Wetland Condition", "abstract": "Amphibians are declining worldwide, in part because of large-scale degradation of habitat from agriculture and pervasive pathogens. Yet a common North American amphibian, the wood frog (Lithobates sylvaticus), ranges widely and persists in agricultural landscapes. Conventional survey techniques rely on visual encounters and dip-netting efforts, but detectability limits the ability to test for the effects of environmental variables on amphibian habitat suitability. We used environmental DNA to determine the presence of wood frogs and an amphibian pathogen (ranavirus) in Prairie Pothole wetlands and investigated the effects of 32 water quality, wetland habitat, and landscape-level variables on frog presence at sites representing different degrees of agricultural intensity. Several wetland variables influenced wood frog presence, the most influential being those associated with wetland productivity (i.e., nutrients), vegetation buffer width, and proportion of the surrounding landscape that is comprised of other water bodies. Wood frog presence was positively associated with higher dissolved phosphorus (>0.4 mg/L), moderate dissolved nitrogen (0.1-0.2 mg/L), lower chlorophyll a (<= 15 mu g/L), wider vegetation buffers (>= 10 m), and more water on the landscape (>= 0.25). These results highlight the effects of environmental factors at multiple scales on the presence of amphibians in this highly modified landscape-namely the importance of maintaining wetland water quality, vegetation buffers, and surrounding habitat heterogeneity. Environ Toxicol Chem 2019;38:2750-2763. (c) 2019 SETAC", "authors": [ "Ruso, Gabrielle E.", "Morrissey, Christy A.", "Hogan, Natacha S.", "Sheedy, Claudia", "Gallant, Melanie J.", "Jardine, Tim" ], "keywords": [ "Agriculture", "Pesticides", "eDNA", "Habitat", "Prairie pothole region", "Ranavirus", "Wetlands" ], "year": "2019", "source": "ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY", "publication_type": "J", "point2d": [ 61.276309967041016, -8.1073579788208 ], "cluster": 0.0 }, { "idx": 493, "title": "Sedimentary DNA reveals over 150 years of ecosystem change by human activities in Lake Chao, China", "abstract": "Understanding the extent and directionality of the impact of human activities on ecosystems is directly related to their management and protection. However, the lack of historical data limits our understanding of ecosystem changes with long-term exposure to human activities. Recently, lake sedimentary DNA (sedDNA) has become a powerful tool for revealing changes in ecosystems at the century and millennium scales. Here, we used sedDNA to reveal the dynamic of the microbial community (including bacteria and micro-eukaryotes) in Lake Chao over the past 150 years, and further explored the effects of long-term nutrient and heavy metal loads on these communities. Our data show that nutrient and heavy metal loads in Lake Chao have increased by ca. 2 to 4-fold since the 1960s. In response, the community structure, diversity, and ecological network of bacteria and microeukaryotes changed significantly during the 1960s, the 1980s and the 2010s. Importantly, community structure was more sensitive to human activities than diversity. We also found that the relative abundance of some taxa associated with nitrification and algal blooms (e.g., taxa in Nitrospira sp., Peridinales) has increased ca. 100-fold since the 1960s. Nutrient could better explain the variation in the bacterial community (ca. twice as much as heavy metal), while heavy metal explained micro-eukaryotes better (ca. 3 or 5-fold as much as nutrient). In particular, based on parsimonious models from distance-based linear model (distLM), we further identified that Pb is the key factor affecting the bacterial and micro-eukaryotes community in Lake Chao in addition to nutrient. Our study reveals the impacts of long-term human activities on lake ecosystems from multiple perspectives of nutrient and heavy metal loads, community structure, diversity and ecological network, these findings will contribute to the management and conservation of lakes in the future.", "authors": [ "Li, Feilong", "Zhang, Xiaowei", "Xie, Yuwei", "Wang, Jizhong" ], "keywords": [ "SedDNA", "Long-term dynamics", "Rare taxa", "Nutrient", "Heavy metal", "Sediment core" ], "year": "2019", "source": "ENVIRONMENT INTERNATIONAL", "publication_type": "J", "point2d": [ 72.65547943115234, 13.283331871032715 ], "cluster": 19.0 }, { "idx": 494, "title": "Controls on evapotranspiration from jack pine forests in the Boreal Plains Ecozone", "abstract": "The exchanges of water, energy and carbon between the land surface and the atmosphere are tightly coupled, so that errors in simulating evapotranspiration lead to errors in simulating both the water and carbon balances. Areas with seasonally frozen soils present a particular challenge due to the snowmelt-dominated hydrology and the impact of soil freezing on the soil hydraulic properties and plant root water uptake. Land surface schemes that have been applied in high latitudes often have reported problems with simulating the snowpack and runoff. Models applied at the Boreal Ecosystem Research and Monitoring Sites in central Saskatchewan have consistently over-predicted evapotranspiration as compared with flux tower estimates. We assessed the performance of two Canadian land surface schemes (CLASS and CLASS-CTEM) for simulating point-scale evapotranspiration at an instrumented jack pine sandy upland site in the southern edge of the boreal forest in Saskatchewan, Canada. Consistent with past reported results, these models over-predicted evapotranspiration, as compared with flux tower observations, but only in the spring period. Looking systematically at soil properties and vegetation characteristics, we found that the dominant control on evapotranspiration within these models was the canopy conductance. However, the problem of excessive spring ET could not be solved satisfactorily by changing the soil or vegetation parameters. The model overestimation of spring ET coincided with the overestimation of spring soil liquid water content. Improved algorithms for the infiltration of snowmelt into frozen soils and plant-water uptake during the snowmelt and soil thaw periods may be key to addressing the biases in spring ET.", "authors": [ "Nazarbakhsh, Mahtab", "Ireson, Andrew M.", "Barr, Alan G." ], "keywords": [ "boreal forest", "eco-hydrology", "evapotranspiration", "land surface schemes", "seasonally frozen soils", "snowmelt", "soil hydraulic properties", "vegetation characteristics" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -24.728431701660156, 10.7747802734375 ], "cluster": 3.0 }, { "idx": 495, "title": "Comparison of the Effects of Extraction Techniques on Mass Spectrometry Profiles of Dissolved Organic Compounds in Oil Sand Process-Affected Water", "abstract": "Recent advances in mass spectrometry have facilitated chemical characterization and profiling of complex environmental mixtures such as oil sand process-affected water (OSPW) and identification of previously unresolved chemicals. However, because OSPW is a complex mixture of salts, metals, suspended particulate matter, and dissolved organics, extraction techniques are required to reduce the effects of signal suppression/enhancement. In this work, Orbitrap, ultrahigh resolution mass spectrometry was used to perform a comprehensive comparison of solid phase extraction (SPE) and liquid-liquid extraction (LLE) techniques on profiling of dissolved organic chemicals in OSPW. When operated in negative ion mode, extraction of naphthenic acid (NAs-O-2) was dependent on acidification of OSPW samples for C-18 and LLE techniques. However, when applying a hydrophilic lipophilic balance (HLB) sorbent (ABN) SPE technique, the extractability of NAs was independent of pH. When operated in positive ion mode, for all extraction methods, nitrogen- and sulfur-containing species were more abundant and diverse in basic extracts than in acidic extracts and ABN extracted the greatest number of chemical species including nitrogen-, sulfur-, and oxygen-containing species. Overall, this study supports the utility of HLB SPE techniques for profiling of species of dissolved organic chemicals in OSPW at environmentally relevant pH.", "authors": [ "Alharbi, Hattan A.", "Morandi, Garrett D.", "Jones, Paul D.", "Wisemanl, Steve B.", "Giesy, John P." ], "keywords": [ "" ], "year": "2019", "source": "ENERGY & FUELS", "publication_type": "J", "point2d": [ 84.22037506103516, 4.493467330932617 ], "cluster": 0.0 }, { "idx": 496, "title": "Vanadium and thallium exhibit biodilution in a northern river food web", "abstract": "Trophic transfer of contaminants dictates concentrations and potential toxic effects in top predators, yet biomagnification behaviour of many trace elements is poorly understood. We examined concentrations of vanadium and thallium, two globally-distributed and anthropogenically-enriched elements, in a food web of the Slave River, Northwest Territories, Canada. We found that tissue concentrations of both elements declined with increasing trophic position as measured by delta N-15. Slopes of log [element] versus delta N-15 regressions were both negative, with a steeper slope for V (-0.369) compared with Tl (-0.099). These slopes correspond to declines of 94% with each step in the food chain for V and 54% with each step in the food chain for Tl. This biodilution behaviour for both elements meant that concentrations in fish were well below values considered to be of concern for the health of fish-eating consumers. Further study of these elements in food webs is needed to allow a fuller understanding of biomagnification patterns across a range of species and systems. (C) 2019 Elsevier Ltd. All rights reserved.", "authors": [ "Jardine, Timothy D.", "Doig, Lorne E.", "Jones, Paul D.", "Bharadwaj, Lalita", "Carr, Meghan", "Tendler, Brett", "Lindenschmidt, Karl-Erich" ], "keywords": [ "Trophic transfer", "Trace elements", "Fishes", "Invertebrates", "Periphyton", "Slave river" ], "year": "2019", "source": "CHEMOSPHERE", "publication_type": "J", "point2d": [ 73.71067810058594, -11.615730285644531 ], "cluster": 0.0 }, { "idx": 497, "title": "Metals and PFAS in stormwater and surface runoff in a semi-arid Canadian city subject to large variations in temperature among seasons", "abstract": "Because compounds accumulate through dry periods and enter aquatic systems in just a few seasonal events such as snowmelt and summer storms, surface waters in semi-arid, cold regions, such as the Canadian Prairies, are particularly vulnerable to loading of contaminant from runoff events from surfaces. This study assessed concentrations of metals and selected trace organics entering a river via surface runoff from an urban region and how these semi-arid regions with large seasonal variations in temperature might differ from more temperate regions. Selected potentially harmful elements (PHEs) including, Mn with Cr, Cu, Zn, Ba and U all exceeded guideline discharge values set by the Canadian Council of the Ministers of the Environment (CCME) by as much as 16-fold. Variation among discharges during spring, summer and winter was observed. For example, across the whole city, an estimated 6 kg of zinc was discharged in a spring storm, 36 kg in a summer storm and 17 tonnes in snowmelt. The mass of Zn discharged is similar to the annual loading estimated for Stockholm, Sweden, but in Saskatoon, Saskatchewan, Canada, the bulk of runoff was during snowmelt. The mean sum of poly- and per-fluoroalkyl substances (PFAS) in stormwater was 9.0 ng L-1, which is consistent with concentrations observed in other Canadian cities (6.5-16 ng L-1). These concentrations of PFAS are likely due to dispersed sources and orders of magnitude less than thresholds for toxicity to fish and aquatic invertebrates.", "authors": [ "Codling, Garry", "Yuan, Hongda", "Jones, Paul D.", "Giesy, John P.", "Hecker, Markus" ], "keywords": [ "Inorganic", "Organic", "Contaminants", "Stormwater", "Snowmelt", "Seasonality", "PFAS", "North America", "Prairies" ], "year": "2020", "source": "ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH", "publication_type": "J", "point2d": [ 44.900211334228516, -1.755855917930603 ], "cluster": 19.0 }, { "idx": 498, "title": "Abundances and concentrations of brominated azo dyes detected in indoor dust", "abstract": "Dust samples were collected from four indoor environments, including childcare facilities, houses, hair salons, and a research facility from the USA and were analyzed for brominated compounds using full scan liquid chromatography high-resolution mass spectrometry. A total of 240 brominated compounds were detected in these dust samples, and elemental formulas were predicted for 120 more abundant ions. In addition to commonly detected brominated flame retardants (BFRs), nitrogen-containing brominated azo dyes (BADs) were among the most frequently detected and abundant. Specifically, greater abundances of BADs were detected in indoor dusts from daycares and salons compared to houses and the research facility. Using authentic standards, a quantitative method was established for two BADs (DB373: Disperse Blue 373 and DV93: Disperse Violet 93) and 2-bromo-4,6-dinitroaniline, a commonly used precursor in azo dye production, in indoor dust. Generally, greater concentrations of DB373 (<= 3850 ng/g) and DV93 (<= 1190 ng/g) were observed in indoor dust from daycares highlighting children as a susceptible population to potential health risk from exposure to BADs. These data are important because, to date, targeted analysis of brominated compounds in indoor environments has focused mainly on BFRs and appears to underestimate the total amount of brominated compounds. (C) 2019 Elsevier Ltd. All rights reserved.", "authors": [ "Dhungana, Birendra", "Peng, Hui", "Kutarna, Steven", "Umbuzeiro, Gisela", "Shrestha, Sujan", "Liu, Jing", "Jones, Paul D.", "Subedi, Bikram", "Giesy, John P.", "Cobb, George P." ], "keywords": [ "House dust", "Brominated compounds", "Flame retardants", "Mutagenic", "High-resolution mass spectrometry" ], "year": "2019", "source": "ENVIRONMENTAL POLLUTION", "publication_type": "J", "point2d": [ 85.0517349243164, -3.4464213848114014 ], "cluster": 6.0 }, { "idx": 499, "title": "An Evaluation of Block-Maximum-Based Estimation of Very Long Return Period Precipitation Extremes with a Large Ensemble Climate Simulation", "abstract": "The recurring devastation caused by extreme events underscores the need for reliable estimates of their intensity and frequency. Operational frequency and intensity estimates are very often obtained from generalized extreme value (GEV) distributions fitted to samples of annual maxima. GEV distributed random variables are max-stable, meaning that the maximum of a sample of several values drawn from a given GEV distribution is again GEV distributed with the same shape parameter. Long-period return value estimation relies on this property of the distribution. The data to which the models are fitted may not, however, be max-stable. Observational records are generally too short to assess whether max-stability holds in the upper tail of the observations. Large ensemble climate simulations, from which we can obtain very large samples of annual extremes, provide an opportunity to assess whether max-stability holds in a model-simulated climate and to quantify the impact of the lack of max-stability on very long period return-level estimates. We use a recent large ensemble simulation of the North American climate for this purpose. We find that the annual maxima of short-duration precipitation extremes tend not to be max-stable in the simulated climate, as indicated by systematic variation in the estimated shape parameter as block length is increased from 1 to 20 years. We explore how the lack of max-stability affects the estimation of very long period return levels and discuss reasons why short-duration precipitation extremes may not be max-stable.", "authors": [ "Ben Alaya, M. A.", "Zwiers, F.", "Zhang, X." ], "keywords": [ "" ], "year": "2020", "source": "JOURNAL OF CLIMATE", "publication_type": "J", "point2d": [ -30.863222122192383, -61.14936065673828 ], "cluster": 14.0 }, { "idx": 500, "title": "A bivariate approach to estimating the probability of very extreme precipitation events", "abstract": "We describe in this paper a semi-parametric bivariate extreme value approach for studying rare extreme precipitation events considered as events that result from a combination of extreme precipitable water (PW) in the atmospheric column above the location where the event occurred and extreme precipitation efficiency, described as the ratio between precipitation and PW. An application of this framework to historical 6-h precipitation accumulations simulated by the Canadian Regional Climate Model CanRCM4 shows that uncertainties and biases of very long-period return level estimates can be substantially reduced relative to the standard univariate approach that fits Generalized Extreme Value distributions to samples of annual maxima of extreme precipitation even when using modest amounts of data.", "authors": [ "Ben Alaya, Mohamed Ali", "Zwiers, Francis W.", "Zhang, Xuebin" ], "keywords": [ "Precipitation extreme", "Precipitable water", "Precipitation efficiency", "Statistical frequency analysis", "Extreme value theory", "Conditional approach to multivariate extreme values" ], "year": "2020", "source": "WEATHER AND CLIMATE EXTREMES", "publication_type": "J", "point2d": [ -30.016633987426758, -51.719757080078125 ], "cluster": 14.0 }, { "idx": 501, "title": "Estimating concurrent climate extremes: A conditional approach", "abstract": "Simultaneous concurrence of extreme values across multiple climate variables can result in large societal and environmental impacts. Therefore, there is growing interest in understanding these concurrent extremes. In many applications, not only the frequency but also the magnitude of concurrent extremes are of interest. One way to approach this problem is to study the distribution of one climate variable given that another is extreme. In this work we develop a statistical framework for estimating bivariate concurrent extremes via a conditional approach, where univariate extreme value modeling is combined with dependence modeling of the conditional tail distribution using techniques from quantile regression and extreme value analysis to quantify concurrent extremes. We focus on the distribution of daily wind speed conditioned on daily precipitation taking its seasonal maximum. The Canadian Regional Climate Model large ensemble is used to assess the performance of the proposed framework both via a simulation study with specified dependence structure and via an analysis of the climate model-simulated dependence structure.", "authors": [ "Huang, Whitney K.", "Monahan, Adam H.", "Zwiers, Francis W." ], "keywords": [ "Concurrent wind and precipitation extremes", "Quantile regression", "Conditional extreme value model", "Large climate ensembles" ], "year": "2021", "source": "WEATHER AND CLIMATE EXTREMES", "publication_type": "J", "point2d": [ -30.77045440673828, -52.9564208984375 ], "cluster": 14.0 }, { "idx": 502, "title": "Changes in Annual Extremes of Daily Temperature and Precipitation in CMIP6 Models", "abstract": "This study presents an analysis of daily temperature and precipitation extremes with return periods ranging from 2 to 50 years in phase 6 of the Coupled Model Intercomparison Project (CMIP6) multimodel ensemble of simulations. Judged by similarity with reanalyses, the new-generation models simulate the present-day temperature and precipitation extremes reasonably well. In line with previous CMIP simulations, the new simulations continue to project a large-scale picture of more frequent and more intense hot temperature extremes and precipitation extremes and vanishing cold extremes under continued global warming. Changes in temperature extremes outpace changes in global annual mean surface air temperature (GSAT) over most landmasses, while changes in precipitation extremes follow changes in GSAT globally at roughly the Clausius-Clapeyron rate of similar to 7% degrees C-1. Changes in temperature and precipitation extremes normalized with respect to GSAT do not depend strongly on the choice of forcing scenario or model climate sensitivity, and do not vary strongly over time, but with notable regional variations. Over the majority of land regions, the projected intensity increases and relative frequency increases tend to be larger for more extreme hot temperature and precipitation events than for weaker events. To obtain robust estimates of these changes at local scales, large initial-condition ensemble simulations are needed. Appropriate spatial pooling of data from neighboring grid cells within individual simulations can, to some extent, reduce the needed ensemble size.", "authors": [ "Li, Chao", "Zwiers, Francis", "Zhang, Xuebin", "Li, Guilong", "Sun, Ying", "Wehner, Michael" ], "keywords": [ "Extreme events", "Temperature", "Precipitation", "Climate change" ], "year": "2021", "source": "JOURNAL OF CLIMATE", "publication_type": "J", "point2d": [ -43.79090118408203, -72.20104217529297 ], "cluster": 14.0 }, { "idx": 503, "title": "Changes in Annual Extremes of Daily Temperature and Precipitation in CMIP6 Models", "abstract": "This study presents an analysis of daily temperature and precipitation extremes with return periods ranging from 2 to 50 years in phase 6 of the Coupled Model Intercomparison Project (CMIP6) multimodel ensemble of simulations. Judged by similarity with reanalyses, the new-generation models simulate the present-day temperature and precipitation extremes reasonably well. In line with previous CMIP simulations, the new simulations continue to project a large-scale picture of more frequent and more intense hot temperature extremes and precipitation extremes and vanishing cold extremes under continued global warming. Changes in temperature extremes outpace changes in global annual mean surface air temperature (GSAT) over most landmasses, while changes in precipitation extremes follow changes in GSAT globally at roughly the Clausius-Clapeyron rate of similar to 7% degrees C-1. Changes in temperature and precipitation extremes normalized with respect to GSAT do not depend strongly on the choice of forcing scenario or model climate sensitivity, and do not vary strongly over time, but with notable regional variations. Over the majority of land regions, the projected intensity increases and relative frequency increases tend to be larger for more extreme hot temperature and precipitation events than for weaker events. To obtain robust estimates of these changes at local scales, large initial-condition ensemble simulations are needed. Appropriate spatial pooling of data from neighboring grid cells within individual simulations can, to some extent, reduce the needed ensemble size.", "authors": [ "Li, Chao", "Zwiers, Francis", "Zhang, Xuebin", "Li, Guilong", "Sun, Ying", "Wehner, Michael" ], "keywords": [ "Extreme events", "Temperature", "Precipitation", "Climate change" ], "year": "2021", "source": "JOURNAL OF CLIMATE", "publication_type": "J", "point2d": [ -43.79090118408203, -72.20104217529297 ], "cluster": 14.0 }, { "idx": 504, "title": "Determining the Anthropogenic Greenhouse Gas Contribution to the Observed Intensification of Extreme Precipitation", "abstract": "This study conducts a detection and attribution analysis of the observed changes in extreme precipitation during 1951-2015. Observed and CMIP6 multimodel simulated changes in annual maximum daily and consecutive 5-day precipitation are compared using an optimal fingerprinting technique for different spatial scales from global land, Northern Hemisphere extratropics, tropics, three continental regions (North America and western and eastern Eurasia), and global dry and wet land areas (as defined by their average extreme precipitation intensities). Results indicate that anthropogenic greenhouse gas influence is robustly detected in the observed intensification of extreme precipitation over the global land and most of the subregions considered, all with clear separation from natural and anthropogenic aerosol forcings. Also, the human-induced greenhouse gas increases are found to be a dominant contributor to the observed increase in extreme precipitation intensity, which largely follows the increased moisture availability under global warming. Plain Language Summary Human influences have been identified in the observed intensification of extreme precipitation at global and continental scales, but quantifying the contribution of greenhouse gas increases remains challenging. Here, we isolate anthropogenic greenhouse gas impacts on the observed intensification of extreme precipitation during 1951-2015 by comparing observations with CMIP6 individual forcing experiments. Results show that greenhouse gas influences are detected over the global land, Northern Hemisphere extratropics, western and eastern Eurasia, and global dry and wet regions, which are separable from other external forcings such as solar and volcanic activities and anthropogenic aerosols. The human-induced greenhouse gas increases are also found to explain most of the observed changes in extreme precipitation intensity, which are consistent with the increased moisture availability with warming. Our results provide the first quantitative evidence for the dominant influence of human-made greenhouse gases on extreme precipitation increase.", "authors": [ "Paik, Seungmok", "Min, Seung-Ki", "Zhang, Xuebin", "Donat, Markus G.", "King, Andrew D.", "Sun, Qiaohong" ], "keywords": [ "" ], "year": "2020", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -41.16810607910156, -62.33565902709961 ], "cluster": 14.0 }, { "idx": 505, "title": "Science, Data, and the Struggle for Standing in Environmental Governance", "abstract": "Here, we explore how people entangled in natural resource conflicts employ and discuss data. We draw on ethnographic research with two cases of conflict: salmon fisheries in Alaska, USA, and agricultural water management in Saskatchewan, Canada. Both cases illustrate how data, through the scientization of environmental governance, can become a means of empowerment and disempowerment: empowering those with access and influence over data and disempowering those without such access. In both locales, people find it necessary to perform their expertise, justify the veracity of their data, and discount the data held by others if they wish to achieve or maintain standing. We call this datamentality and draw lessons from these cases for how we can structure environmental governance such that it benefits from robust data and science while meeting the needs of individuals, avoiding or managing power struggles, and protecting the rights of all involved.", "authors": [ "Loring, Philip A.", "Harrison, Hannah L.", "Gaspard, Valencia", "Minnes, Sarah", "Baulch, Helen M." ], "keywords": [ "Best available science", "conflict", "data", "governance", "governmentality", "natural resources", "power", "scientization" ], "year": "2021", "source": "SOCIETY & NATURAL RESOURCES", "publication_type": "J", "point2d": [ 57.38018798828125, -32.33543014526367 ], "cluster": 4.0 }, { "idx": 506, "title": "Seeing beneath disputes: A transdisciplinary framework for diagnosing complex conservation conflicts", "abstract": "Conservation conflicts are pressing social and environmental sustainability issues, and the complex underlying causes and escalating factors of such conflicts can often be difficult to understand. Appropriate tools are needed for breaking down complex conservation conflicts into their varied, heterogenous parts so their nature and the complex relationships between them may be better understood and addressed using appropriate interventions. Importantly, these tools must transcend disciplinary silos so as to be applicable across social science disciplines as well as within and outside of the academic context. This article synthesizes a breadth of conservation conflict literature to lay out a transdisciplinary framework for diagnosing complex conservation conflicts composed of six key aspects: complexity, emergence, and stages; conflict status; basis of contention and cognitive framing; state of knowledge; state of values; and interventions. This framework is based in systems thinking and differs from other key conservation conflict frameworks by using conflict emergence as a starting point. To complement this approach, our diagnostic tool encourages users to harness thinking based in storytelling and consider how a conservation conflict represents a larger ongoing narrative with depth, meaning, and containing complex, interrelated storylines. As poorly understood stakeholder disputes can seriously undermine conservation efforts, this framework pushes forward practical understandings of conservation conflict interventions by offering a novel, transdisciplinary diagnostic tool for better understanding their complex, multifaceted variables.", "authors": [ "Harrison, Hannah L.", "Loring, Philip A." ], "keywords": [ "Conservation conflict", "Framework", "Transdisciplinary", "Diagnostic", "Complexity" ], "year": "2020", "source": "BIOLOGICAL CONSERVATION", "publication_type": "J", "point2d": [ 57.15713119506836, -33.484291076660156 ], "cluster": 4.0 }, { "idx": 507, "title": "Testing hypothetical bias in a framed field experiment", "abstract": "Hypothetical bias is tested based on inter- and intra-respondent comparisons of choice behavior, applying a hypothetical and real choice experiment. The inter-respondent comparison commonly applied in the environmental and agricultural economics literature consists of a control group of buyers who are asked to hypothetically choose between conventional and organic beans and an experimental group of buyers who are endowed to purchase the same beans using an identical experimental design. Hypothetical bias is tested by comparing inter- and intra-respondents' (i) hypothetical and real choices, (ii) preference parameters of the estimated choice models related to hypothetical and real choices, and (iii) hypothetical and real willingness to pay (WTP). Choices in the experimental group are highly consistent when switching from hypothetical to real choices for this study's homegrown goods. However, after being endowed, the price sensitivity of lower income households drops, suggesting a house money effect. WTP derived from actual purchases is higher than WTP based on hypothetical choices, indicating a negative hypothetical bias, but differences are only significant in the case of the inter-respondent comparison. Actual prices paid by respondents in the field experiment appear to be considerably lower than the estimated WTP values and yield a mixed picture of hypothetical bias.", "authors": [ "Brouwer, Roy", "Tarfasa, Solomon" ], "keywords": [ "agricultural market", "choice experiment", "framed field experiment", "hypothetical bias", "inter-respondent comparison", "intra-respondent comparison", "willingness to pay" ], "year": "2020", "source": "CANADIAN JOURNAL OF AGRICULTURAL ECONOMICS-REVUE CANADIENNE D AGROECONOMIE", "publication_type": "J", "point2d": [ 45.667396545410156, -41.0551872253418 ], "cluster": 11.0 }, { "idx": 508, "title": "Hydrological and Seasonal Controls of Phosphorus in Northern Great Plains Agricultural Streams", "abstract": "Controls on nutrient transport in cold, low-relief agricultural regions vary dramatically among seasons. The spring snowmelt is often the dominant runoff and nutrient loading event of the year. However, climate change may increase the proportion of runoff occurring with rainfall, and there is an urgent need to understand seasonal controls on nutrient transport to understand how patterns may change in the future. In this study, we assess patterns and drivers of total P (TP) dynamics in eight streams draining agriculturally dominated watersheds, located in southern Manitoba, Canada. Data from three years of monitoring revealed highly coherent patterns of TP concentrations in streams, with pronounced peaks in the spring and midsummer across the region. This coherent pattern was in spite of considerable interannual variability in the magnitude and timing of discharge; in particular, a major storm event occurred in summer 2014, which resulted in more discharge than the preceding spring melt. Concentration-discharge model fits were generally poor or not significant, suggesting that runoff generation is not the primary driver of TP dynamics in the majority of streams. Seasonal patterns of conductivity and stream temperature suggest that mechanisms controlling TP vary by season; a spring TP concentration maximum may be related to surface runoff over frozen soils, whereas the summer TP maximum may be related to temperature-driven biogeochemical processes, which are not well represented in current conceptual or predictive models. These findings suggest that controls on stream TP concentrations are dynamic through the year, and responses to increases in dormant and nondormant season temperatures may depend on seasonally variable processes.", "authors": [ "Casson, Nora J.", "Wilson, Henry F.", "Higgins, Stephanie M." ], "keywords": [ "" ], "year": "2019", "source": "JOURNAL OF ENVIRONMENTAL QUALITY", "publication_type": "J", "point2d": [ 33.195308685302734, 13.143190383911133 ], "cluster": 10.0 }, { "idx": 509, "title": "Modelling nutrient dynamics in cold agricultural catchments: A review", "abstract": "The hydrology of cold regions has been studied for decades with substantial progress in process understanding and prediction. Simultaneously, work on nutrient yields from agricultural land in cold regions has shown much slower progress. Advancement of nutrient modelling is constrained by well-documented issues of spatial heterogeneity, climate dependency, data limitations and over-parameterization of models, as well as challenges specific to cold regions due to the complex (and often unknown) behaviour of hydro-biogeochemical processes at temperatures close to and below freezing where a phase change occurs. This review is a critical discussion of these issues by taking a close look at the conceptual models and methods behind used catchment nutrient models. The impact of differences in model structure and the methods used for the prediction of hydrological processes, erosion and biogeochemical cycles are examined. The appropriateness of scale, scope, and complexity of models are discussed to propose future research directions.", "authors": [ "Costa, Diogo", "Baulch, Helen", "Elliott, Jane", "Pomeroy, John", "Wheater, Howard" ], "keywords": [ "Seasonal snow cover", "Nutrient transport", "Cold region processes", "Hydrological controls", "Catchment models" ], "year": "2020", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 28.320751190185547, 11.472039222717285 ], "cluster": 10.0 }, { "idx": 510, "title": "Among-site variability in environmental and management characteristics: Effect on nutrient loss in agricultural tile drainage", "abstract": "Water quality issues, including harmful and nuisance algal blooms (HNABs), related to nitrogen (N) and phosphorus (P) exported from agricultural lands persist in the Great Lakes region. Previous work examining N and P loss from agricultural fields in portions of the United States (US) and Canada (CA) that drain into Lake Erie, consistently indicate significant nutrient loss from fields in Indiana and Ohio, US compared with those in southwestern Ontario, CA. The primary objective of this study was to examine variation in environmental and management characteristics from 30 sites (US: n = 28, CA: n = 2) located within the Lake Erie Basin and subsequently determine the influence of among-site variation on edge-of-field N and P losses. Using principal component analyses (PCA), we found that among-site variation was predominantly controlled by broad-scale patterns in fertilizer management practices and soil properties; however, N and P loss metrics were largely unexplained by these gradients. As such, fine-scale variability and the interaction of environmental and management characteristics at individual sites more strongly influenced N and P loss. Ultimately, these results further emphasize the importance of site- and nutrient-specific management plans that are needed to mitigate N and P losses from agricultural fields. Published by Elsevier B.V. on behalf of International Association for Great Lakes Research.", "authors": [ "Hanrahan, Brittany R.", "King, Kevin W.", "Macrae, Merrin L.", "Williams, Mark R.", "Stinner, Jedediah H." ], "keywords": [ "Agricultural land use", "Agricultural management", "Nitrogen", "Phosphorus" ], "year": "2020", "source": "JOURNAL OF GREAT LAKES RESEARCH", "publication_type": "J", "point2d": [ 40.302513122558594, 8.697093963623047 ], "cluster": 10.0 }, { "idx": 511, "title": "Seasonal nutrient export dynamics in a mixed land use subwatershed of the Grand River, Ontario, Canada", "abstract": "Algal blooms in the Great Lakes are a concern due to excess nutrient loading from non-point sources; however, there is uncertainty over the relative contributions of various non-point sources under different types of land use in rural watersheds, particularly over annual time scales. Four nested subwatersheds in Southern Ontario, Canada (one natural woodlot, two agricultural and one mixed agricultural and urban) were monitored over one year to identify peak periods ('hot moments') and areas ('hot spots') of nutrient (dissolved reactive phosphorus, DRP; total phosphorus, TP; and nitrate, NOT) export and discharge. Annual nutrient export was small at the natural site (0.001 kg DRP ha(-1); 0.004 kg TP ha(-1); 0.04 kg NO3-N ha(-1)) compared to the agricultural and mixed-use sites (0.10-0.15 kg DRP ha(-1); 0.70-0.94 kg TP ha(-1); 9.15-11.55 kg NO3-N ha(-1)). Temporal patterns in P concentrations were similar throughout the sites, where spring was the dominant season for P export, irrespective of land use. Within the Hopewell Creek watershed, P and N hot spots existed that were consistently hot spots across all events with the location of these hot spots driven by local land use patterns, where there was elevated P export from a dairy-dominated sub-watershed and elevated N export from both of the two agricultural subwatersheds. These estimates of seasonal- and event-based nutrient loads and discharge across nested sub-watersheds contribute to the growing body of evidence demonstrating the importance of identifying critical areas and periods in which to emphasize management efforts. (C) 2019 International Association for Great Lakes Research. Published by Elsevier B.V. All rights reserved.", "authors": [ "Irvine, Cameron", "Macrae, Merrin", "Morison, Matthew", "Petrone, Richard" ], "keywords": [ "Phosphorus", "Nitrate", "Tile drainage", "Hot spots", "Hot moments", "Agriculture" ], "year": "2019", "source": "JOURNAL OF GREAT LAKES RESEARCH", "publication_type": "J", "point2d": [ 40.57112503051758, 9.757619857788086 ], "cluster": 10.0 }, { "idx": 512, "title": "Contribution of Overland and Tile Flow to Runoff and Nutrient Losses from Vertisols in Manitoba, Canada", "abstract": "This study quantified the contributions of overland and tile flow to total runoff (sum of overland and tile flow) and nutrient losses in a Vertisolic soil in the Red River valley (Manitoba, Canada), a region with a cold climate where tile drainage is rapidly expanding. Most annual runoff occurred as overland flow (72-89%), during spring snowmelt and large spring and summer storms. Tile drains did not flow in early spring due to frozen ground. Although tiles flowed in late spring and summer (33-100% of event flow), this represented a small volume of annual runoff (10-25%), which is in stark contrast with what has been observed in other tile-drained landscapes. Median daily flow-weighted mean concentrations of soluble reactive P (SRP) and total P (TP) were significantly greater in overland flow than in tile flow (p < 0.001), but the reverse pattern was observed for NO3-N (p < 0.001). Overland flow was the primary export pathway for both P and NO3-N, accounting for > 95% of annual SRP and TP and 50 to 60% of annual NO3-N losses. Data suggest that tile drains do not exacerbate P export from Vertisols in the Red River valley because they are decoupled from the surface by soil-ice during snowmelt, which is the primary time for P loss. However, NO3-N loading to downstream water bodies may be exacerbated by tiles, particularly during spring and summer storms after fertilizer application.", "authors": [ "Kokulan, Vivekananthan", "Macrae, M. L.", "Lobb, D. A.", "Ali, G. A." ], "keywords": [ "" ], "year": "2019", "source": "JOURNAL OF ENVIRONMENTAL QUALITY", "publication_type": "J", "point2d": [ 38.80409622192383, 16.205835342407227 ], "cluster": 10.0 }, { "idx": 513, "title": "Agricultural Water Quality in Cold Climates: Processes, Drivers, Management Options, and Research Needs", "abstract": "Cold agricultural regions are important sites of global food production. This has contributed to widespread water quality degradation influenced by processes and hydrologic pathways that differ from warm region analogues. In cold regions, snowmelt is often a dominant period of nutrient loss. Freeze-thaw processes contribute to nutrient mobilization. Frozen ground can limit infiltration and interaction with soils, and minimal nutrient uptake during the nongrowing season may govern nutrient export from agricultural catchments. This paper reviews agronomic, biogeochemical, and hydrological characteristics of cold agricultural regions and synthesizes findings of 23 studies that are published in this special section, which provide new insights into nutrient cycling and hydrochemical processes, model developments, and the efficacy of different potentially beneficial management practices (BMPs) across varied cold regions. Growing evidence suggests the need to redefine optimum soil phosphorus levels and input regimes in cold regions to allow achievement of water quality targets while still supporting strong agricultural productivity. Practices should be considered through a regional and site-specific lens, due to potential interactions between climate, hydrology, vegetation, and soils, which influence the efficacy of nutrient, crop, water, and riparian buffer management. This leads to differing suitability of BMPs across varied cold agricultural regions. We propose a systematic approach (CUPCAKE), to achieve water quality objectives in variable and changing climates, which combines nutrient transport process Conceptualization, Understanding BMP functions, Predicting effects of variability and change, Consideration of producer input and agronomic and environmental tradeoffs, practice Adaptation, Knowledge mobilization, and Evaluation of water quality improvement.", "authors": [ "Liu, Jian", "Baulch, Helen M.", "Macrae, Merrin L.", "Wilson, Henry F.", "Elliott, Jane A.", "Bergstrom, Lars", "Glenn, Aaron J.", "Vadas, Peter A." ], "keywords": [ "" ], "year": "2019", "source": "JOURNAL OF ENVIRONMENTAL QUALITY", "publication_type": "J", "point2d": [ 29.500329971313477, 11.264290809631348 ], "cluster": 10.0 }, { "idx": 514, "title": "Evaluating Hydrologic Response in Tile-Drained Landscapes: Implications for Phosphorus Transport", "abstract": "Phosphorus (P) loss in agricultural discharge has typically been associated with surface runoff; however, tile drains have been identified as a key P pathway due to preferential transport. Identifying when and where these pathways are active may establish high-risk periods and regions that are vulnerable for P loss. A synthesis of high-frequency, runoff data from eight cropped fields across the Great Lakes region of North America over a 3-yr period showed that both surface and tile flow occurred year-round, although tile flow occurred more frequently. The relative timing of surface and tile flow activation was classified into four response types to infer runoff-generation processes. Response types were found to vary with season and soil texture. In most events across all sites, tile responses preceded surface flow, whereas the occurrence of surface flow prior to tile flow was uncommon. The simultaneous activation of pathways, indicating rapid connectivity through the vadose zone, was seldom observed at the loam sites but occurred at clay sites during spring and summer. Surface flow at the loam sites was often generated as saturation-excess, a phenomenon rarely observed on the clay sites. Contrary to expectations, significant differences in P loads in tiles were not apparent under the different response types. This may be due to the frequency of the water quality sampling or may indicate that factors other than surface-tile hydrologic connectivity drive tile P concentrations. This work provides new insight into spatial and temporal differences in runoff mechanisms in tile-drained landscapes.", "authors": [ "Macrae, M. L.", "Ali, G. A.", "King, K. W.", "Plach, J. M.", "Pluer, W. T.", "Williams, M.", "Morison, M. Q.", "Tang, W." ], "keywords": [ "" ], "year": "2019", "source": "JOURNAL OF ENVIRONMENTAL QUALITY", "publication_type": "J", "point2d": [ 39.525543212890625, 19.609094619750977 ], "cluster": 10.0 }, { "idx": 515, "title": "Mapping erosion and deposition in an agricultural landscape: Optimization of UAV image acquisition schemes for SfM-MVS", "abstract": "Structure-from-motion (SfM) and multi-view stereo (MVS) algorithms coupled with the use of unmanned aerial vehicles (UAVs) have become a popular tool in the geosciences for modelling complex landscapes on-demand allowing for high-resolution topographic change-detection studies to be conducted at minimal cost. To identify the effects of UAV image orientation on the accuracy of SfM-MVS 3D surface models, we tested four different UAV image acquisition schemes that incorporated both nadir and oblique imagery of an agricultural field. The coupling of nadir and oblique imaging angles led to the highest surface model accuracy in the absence of ground control points (GCPs; vertical RMSE: 0.047 m, horizontal RMSE: 0.019 m), while with a normative distribution of GCPs the nadir-only image sets had similar accuracy metrics (vertical RMSE 0.028 m, hotizontal RMSE 0.017 m) to surface models generated with nadir and oblique imaging angles (vertical RMSE 0.028 m, horizontal RMSE 0.013 m). Homologous keypoint matching between nadir and oblique imagery was poor when the survey conditions were bright and the surface texture of the field was homogeneous, leading to broad-scale vertical noise in the generated surface models. Results indicate that a nadir-only image set accompanied with a dense deployment of GCPs is the most ideal for SfM-MVS agricultural 3D surface reconstructions. The diachronic analysis of surface models generated from nadir-only image sets were able to detect surface-change > 0.040 m in depth (i.e., rill and gully erosion, depositional zones) and were comparable to results obtained from a terrestrial laser scanner. Stable GCPs should be used where possible to ensure precise co-registration between subsequent UAV surveys.", "authors": [ "Meinen, Benjamin U.", "Robinson, Derek T." ], "keywords": [ "Unmanned aerial vehicle", "UAV", "Structure-from-motion", "SfM", "Erosion", "Change-detection", "Agriculture", "Oblique", "Nadir" ], "year": "2020", "source": "REMOTE SENSING OF ENVIRONMENT", "publication_type": "J", "point2d": [ -59.10005569458008, 5.435440540313721 ], "cluster": 8.0 }, { "idx": 516, "title": "Seasonality of Phosphorus and Nitrate Retention in Riparian Buffers", "abstract": "Measurement of the retention of dissolved nutrients in riparian areas with snowmelt runoff are much less common than for rainfall runoff, but low rates of uptake or the release of nutrients with snowmelt have been attributed to frozen soils, lower biotic uptake, and release of nutrients from senesced vegetation. In the research presented here, we evaluate whether the potential for uptake of dissolved reactive phosphorus (DRP) and NO3- differ significantly between snowmelt and summer seasons with flow through 13 riparian buffers downstream of cropland in Manitoba, Canada. Flow-through buffers in small channels are typical in this landscape, and pulsed releases of a conservative tracer and dissolved nutrients were used to measure uptake rates. Although mean uptake rates of NO3- were higher in summer than for snowmelt, responses varied widely. Aerial uptake rate of DRP showed a significant negative relationships with soil Olsen-P (r(2) = 0.54, p < 0.001) and a P saturation index (r(2) = 0.48, p < 0.001) across both seasons. Biological processes may be of greater importance for NO3- retention, but DRP retention appears to be driven by adsorption-desorption regardless of season. Olsen-P is identified as a good indicator of potential for release or retention of DRP in riparian buffers with fine-textured calcareous soils, for both snowmelt and summer seasons. Soil testing may be a good tool to aid in the siting of new buffers and to track the effectiveness of management interventions to remove P from riparian areas, such as harvest of vegetation.", "authors": [ "Satchithanantham, Sanjayan", "English, Blair", "Wilson, Henry" ], "keywords": [ "" ], "year": "2019", "source": "JOURNAL OF ENVIRONMENTAL QUALITY", "publication_type": "J", "point2d": [ 32.353912353515625, 16.30027961730957 ], "cluster": 10.0 }, { "idx": 517, "title": "Changes to rainfall, snowfall, and runoff events during the autumn-winter transition in the Rocky Mountains of North America", "abstract": "In cold conditions, early winter precipitation occurs as snowfall and contributes to the accumulating seasonal snowpack. In a warming climate, precipitation may occur as rainfall in mountainous areas. Detecting changes during seasonal transitions is difficult because these may encompass changes in timing, magnitude and phase, which may not be consistent between years. In this study, a sampling window from September to December is used to assess trends in magnitude, frequency and duration (of rainfall, snowfall and runoff events) in 127 climate stations and 128 watersheds with more than 30 years of record across the Rocky Mountains of North America. Rainfall events have increasing frequencies and durations, and magnitude trends are predominantly increasing at mid-latitude and mid-elevation. Snowfall events have the largest numbers of significant trends, with both increasing and decreasing trends in each of magnitude, frequency and duration. Snowfall events have decreasing frequencies and durations in the northern low-elevation sites and increasing frequencies and durations at the southern high-elevation sites. Trends in runoff events are less common than for rainfall and snowfall but are greater than expected by chance, and show similar frequency and duration patterns to snowfall trends. Snowfall and runoff events are decreasing in frequency and duration north of Wyoming and increasing to the south. Snowfall magnitude is generally decreasing to the north and increasing to the south, with runoff magnitude trends showing the reverse.", "authors": [ "Whitfield, Paul H.", "Shook, Kevin R." ], "keywords": [ "" ], "year": "2020", "source": "CANADIAN WATER RESOURCES JOURNAL", "publication_type": "J", "point2d": [ -36.432804107666016, -15.111668586730957 ], "cluster": 12.0 }, { "idx": 518, "title": "Landscape Controls on Nutrient Export during Snowmelt and an Extreme Rainfall Runoff Event in Northern Agricultural Watersheds", "abstract": "In the northern Great Plains, most runoff transport of N, and P to surface waters has historically occurred with snowmelt. In recent years, significant rainfall runoff events have become more frequent and intense in the region. Here, we examine the influence of landscape characteristics on hydrology and nutrient export in nine tributary watersheds of the Assiniboine River in Manitoba, Canada, during snowmelt runoff and with an early summer extreme rainfall runoff event (ERRE). All watersheds included in the study have land use that is primarily agricultural, but with differing proportions of land remaining as wetlands, grassland, and that has been artificially drained. Those watersheds with greater capacity for storage of water in surface depressions (noneffective contributing areas) exhibited lower rates of runoff and nutrient export with snowmelt. During the ERRE, higher export of total P (TP), but not total N, was observed from those watersheds with larger amounts of contributing area that had been added through artificial surface drainage, and this was associated primarily with higher TP concentrations. Increasing or restoring the storage of water on the landscape is likely to reduce nutrient export; however, the importance of antecedent conditions was evident during the ERRE, when small surface depressions were at or near capacity from snowmelt. Total P concentrations observed during the summer ERRE were as high as those observed with snowmelt, and N/P ratios were significantly lower. If the frequency of summer ERREs increases with climate change, this is likely to result in negative water quality outcomes.", "authors": [ "Wilson, Henry F.", "Casson, Nora J.", "Glenn, Aaron J.", "Badiou, Pascal", "Boychuk, Lyle" ], "keywords": [ "" ], "year": "2019", "source": "JOURNAL OF ENVIRONMENTAL QUALITY", "publication_type": "J", "point2d": [ 34.48029327392578, 13.451542854309082 ], "cluster": 10.0 }, { "idx": 519, "title": "Near-Surface Soils as a Source of Phosphorus in Snowmelt Runoff from Cropland", "abstract": "In northern regions, a high proportion of annual runoff and phosphorus (P) export from cropland occurs with snowmelt. In this study, we analyze 57 site-years of field-scale snowmelt runoff data from 16 small watersheds draining fine-textured soils (clay or clay loam) in Manitoba, Canada. These fields were selected across gradients of soil P (2.4 to 26.7 mg kg(-1), 0-to 15-cm Olsen P), tillage intensity (high frequency to long-term no-till), and fertilizer input. The strongest predictor of flow-weighted mean concentrations of total dissolved P (TDP) in snowmelt runoff was Olsen P in the top 5 cm of soil (r(2) = 0.45, p < 0.01). Residual variation in this relationship related positively to volumetric soil moisture and negatively to water yield. Although Olsen P levels were relatively consistent from year to year, suggesting control by long-term fertilization and tillage history, Olsen P stratification (ratio of 0-5/0-15 cm) increased with rates of fertilizer application. Particulate P (PP) comprised < 34% of total P on average, and concentrations were not well predicted by soil or management characteristics. Loads of PP and TDP exported during snowmelt were primarily a function of water yield and size of accumulated snowpack; however, residual variation in the TDP relationship correlated positively with both soil moisture and Olsen P. Retention of runoff water on the landscape could reduce loads, but careful management of near-surface soil P is required to prevent snowmelt runoff losses of P at the source and to reduce the potential for the eutrophication of downstream aquatic ecosystems.", "authors": [ "Wilson, Henry", "Elliott, Jane", "Macrae, Merrin", "Glenn, Aaron" ], "keywords": [ "" ], "year": "2019", "source": "JOURNAL OF ENVIRONMENTAL QUALITY", "publication_type": "J", "point2d": [ 33.82870101928711, 15.83483600616455 ], "cluster": 10.0 }, { "idx": 520, "title": "A watershed classification approach that looks beyond hydrology: application to a semi-arid, agricultural region in Canada", "abstract": "Classification and clustering approaches provide a means to group watersheds according to similar attributes, functions, or behaviours, and can aid in managing natural resources. Although they are widely used, approaches based on hydrological response parameters restrict analyses to regions where well-developed hydrological records exist, and overlook factors contributing to other management concerns, including biogeochemistry and ecology. In the Canadian Prairie, hydrometric gauging is sparse and often seasonal. Moreover, large areas are endorheic and the landscape is highly modified by human activity, complicating classification based solely on hydrological parameters. We compiled climate, geological, topographical, and land-cover data from the Prairie and conducted a classification of watersheds using a hierarchical clustering of principal components. Seven classes were identified based on the clustering of watersheds, including those distinguishing southern Manitoba, the pothole region, river valleys, and grasslands. Important defining variables were climate, elevation, surficial geology, wetland distribution, and land cover. In particular, three classes occur almost exclusively within regions that tend not to contribute to major river systems, and collectively encompass the majority of the study area. The gross difference in key characteristics across the classes suggests that future water management and climate change may carry with them heterogeneous sets of implications for water security across the Prairie. This emphasizes the importance of developing management strategies that target sub-regions expected to behave coherently as current human-induced changes to the landscape will affect how watersheds react to change. The study provides the first classification of watersheds within the Prairie based on climatic and biophysical attributes, with the framework used being applicable to other regions where hydrometric data are sparse. Our findings provide a foundation for addressing questions related to hydrological, biogeochemical, and ecological behaviours at a regional level, enhancing the capacity to address issues of water security.", "authors": [ "Wolfe, Jared D.", "Shook, Kevin R.", "Spence, Chris", "Whitfield, Colin J." ], "keywords": [ "" ], "year": "2019", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -13.722143173217773, -13.709257125854492 ], "cluster": 10.0 }, { "idx": 521, "title": "Experiments on restoring alluvial cover in straight and meandering rivers using gravel augmentation", "abstract": "Successful management of natural and engineered channels with discontinuous alluvial cover requires knowledge of how the cover develops and evolves. We report on physical model experiments designed to compare alluvial cover dynamics in straight and sinuous fixed-bed channels at a range of gravel-bed material supply rates and constant discharge conditions. Experiments investigated the formation of alluvial cover from a bare bed, relationships between equilibrium cover characteristics and sediment supply rate, and the evolution of an initial uniform cover of varying thickness. A stable partially-alluviated state is achieved in both the straight and sinuous channels for a range of sediment supply rates. The areal extent and stored mass of the cover increase progressively with supply rate, and the rate of increase is higher in the straight channel. While alluvial cover develops from isolated patches in the straight channel, cover in the sinuous channel develops as well-defined bars, with deposition on the inside of bends and expanding outwards along the channel as cover area increases. Artificially emplaced cover quickly adjusts to a cover extent within 4-20% of that formed from a bare bed at the same feed rate, with initial cover thickness only influencing the final cover in the sinuous channel. Neither the sinuous nor the straight channel can sustain an alluvial cover in the absence of upstream sediment supply. This study can inform the management of semi-alluvial channels because it highlights the primary roles of sediment supply and planform geometry in maintaining an alluvial cover in natural and engineered channels.", "authors": [ "Welber, Matilde", "Papangelakis, Elli", "Ashmore, Peter", "MacVicar, Bruce" ], "keywords": [ "alluvial cover", "physical model", "planform geometry", "river restoration", "sediment augmentation", "semi-alluvial" ], "year": "2020", "source": "RIVER RESEARCH AND APPLICATIONS", "publication_type": "J", "point2d": [ 10.469098091125488, -6.994228363037109 ], "cluster": 18.0 }, { "idx": 522, "title": "Field tests of an improved sediment tracer including non-intrusive measurement of burial depth", "abstract": "Radio-frequency identification (RFID) transponders are now widely used to track sediment in a variety of environments. A recent innovation placed the transponder inside of a rotating inner mechanism that is designed to minimize missed detections due to burial and shielding or 'signal collision' effects between tracers, while also allowing a rapid measurement of the burial depth of the particle. Here we test a developed protocol for burial depth measurement and deploy the 'Wobblestone' tracers in the field for the first time. Results show that new tracers can be reliably positioned in the horizontal plane (median error +/- 0.03 m) and that the burial depth can be accurately measured (similar to 0.02 m maximum error). The field study was characterized by high mobility and travel lengths, and similar to 20% of the tracers were buried at depths up to 0.15 m. A comparison of exponential distributions for travel length of surface deposited and buried tracers indicate that the buried tracers on average traveled farther and earlier in the flood event. Tracers that did not move were also buried at one site as a result of sediment transport from upstream. Overall the technique has great potential for characterizing vertical mixing and understanding this rarely considered control on sediment transport. (c) 2020 John Wiley & Sons, Ltd.", "authors": [ "Cain, Aryn", "MacVicar, Bruce" ], "keywords": [ "sediment transport", "tracers", "radio-frequency identification (RFID)", "passive integrated transponder (PIT) tags", "burial depth" ], "year": "2020", "source": "EARTH SURFACE PROCESSES AND LANDFORMS", "publication_type": "J", "point2d": [ 17.45036506652832, -5.525842666625977 ], "cluster": 18.0 }, { "idx": 527, "title": "Bisphenol A Electrochemical Sensor Using Graphene Oxide and beta-Cyclodextrin-Functionalized Multi-Walled Carbon Nanotubes", "abstract": "Bisphenol A, an endocrine disrupting compound, is widely used in food and beverage packaging, and it then leaches in food and source water cycles, and thus must be monitored. Here, we report a simple, low-cost and sensitive electrochemical sensor using graphene oxide and beta-cyclodextrin functionalized multiwalled carbon nanotubes for the detection of BPA in water. This sensor electrode system combines the high surface area of graphene oxide and carbon nanotubes, and the superior host-guest interaction capability of beta-cyclodextrin. A diffusion-controlled oxidation reaction involving equal numbers of protons and electrons facilitated the electrochemical sensing of BPA. The sensor showed a two-step linear response from 0.05 to 5 mu M and 5-30 mu M with a limit of detection of 6 nM. The sensors also exhibited a reproducible and stable response over one month with negligible interference from common inorganic and organic species, and an excellent recovery with real water samples. The proposed electrochemical sensor can be promising for the development of simple low-cost water quality monitoring system for monitoring of BPA in water.", "authors": [ "Alam, Arif U.", "Deen, M. Jamal" ], "keywords": [ "" ], "year": "2020", "source": "ANALYTICAL CHEMISTRY", "publication_type": "J", "point2d": [ 85.06570434570312, 45.75779342651367 ], "cluster": 6.0 }, { "idx": 528, "title": "Fully Integrated, Simple, and Low-Cost Electrochemical Sensor Array for in Situ Water Quality Monitoring", "abstract": "Rapid, accurate and inexpensive monitoring of water quality parameters is indispensable for continued water safety, especially in resource-limited areas. Most conventional sensing systems either can only monitor one parameter at a time or lack user-friendly on-site monitoring capabilities. A fully integrated electrochemical sensor array is an excellent solution to this barrier. Electrochemical sensing methods involve transduction of water quality parameters where chemical interactions are converted to electrical signals. The challenge remains in designing low-cost, easy-to-use, and highly sensitive sensor array that can continuously monitor major water quality parameters such as pH, free chlorine, temperature along with emerging pharmaceutical contaminants, and heavy metal without the use of expensive laboratory-based techniques and trained personnel. Here, we overcame this challenge through realizing a fully integrated electrochemical sensing system that offers simultaneous monitoring of pH (57.5 mV/pH), free chlorine (186 nA/ppm), and temperature (16.9 mV/degrees C) and on-demand monitoring of acetaminophen and 17 beta-estradiol (<10 nM) and heavy metal (<10 ppb), bridging the technological gap between signal transduction, processing, wireless transmission, and smartphone interfacing. This was achieved by merging nanomaterials and carbon nanotube-based sensors fabricated on microscopic glass slides controlled by a custom-designed readout circuit, a potentiostat, and an Android app. The sensing system can be easily modified and programmed to integrate other sensors, a capability that can be exploited to monitor a range of water quality parameters. We demonstrate the integrated system for monitoring tap, swimming pool, and lake water. This system opens the possibility for a wide range of low-cost and ubiquitous environmental monitoring applications.", "authors": [ "Alam, Arif U.", "Clyne, Dennis", "Jin, Hao", "Hu, Nan-Xing", "Deen, M. Jamal" ], "keywords": [ "water quality monitoring", "electrochemical sensing", "acetaminophen", "estrogen", "heavy metal", "pH", "free chlorine", "temperature" ], "year": "2020", "source": "ACS SENSORS", "publication_type": "J", "point2d": [ 78.49188995361328, 42.496334075927734 ], "cluster": 6.0 }, { "idx": 529, "title": "Electrochemical sensing of lead in drinking water using beta-cyclodextrin-modified MWCNTs", "abstract": "A simple, facile and low-cost modification of multiwalled carbon nanotubes (MWCNT) with beta-cyclodextrin (beta CD) through a physical (Phys) and a covalent approach via Steglich esterification (SE) is demonstrated for the detection of lead (Pb). The Pb sensing performance is governed by the amount of beta CD present in the MWCNT-beta CD matrix and the physical/chemical attachment of beta CD with MWCNT. The physically modified MWCNT-beta CD based electrode showed high sensitivity of 98 nA/ppb with a limit of detection of 0.9 ppb but poorer reliability, whereas the chemically modified MWCNT-beta CD electrode results in moderate sensitivity of 38.6 nA/ppb and a limit of detection of 2.3 ppb. The modified sensors showed reproducibility of more than 90% and reusability of at least six times. The proposed sensors offer a promising technology in developing a highly affordable and sensitive electrochemical sensing system for monitoring the Pb level in drinking water.", "authors": [ "Ul Alam, Arif", "Howlader, Matiar M. R.", "Hu, Nan-Xing", "Deen, M. Jamal" ], "keywords": [ "MWCNT", "beta-Cyclodextrin", "Electrochemical sensing", "Heavy metal", "Lead" ], "year": "2019", "source": "SENSORS AND ACTUATORS B-CHEMICAL", "publication_type": "J", "point2d": [ 85.7725830078125, 45.49809646606445 ], "cluster": 6.0 }, { "idx": 530, "title": "Anode surface modification regulates biofilm community population and the performance of micro-MFC based biochemical oxygen demand sensor", "abstract": "The anode surface is known to play an important role in the microbial growth and in mediating electron transfer between electroactive bacteria and the electrodes in power generating microbial fuel cells (MFCs). However, the effect of the anode surface and its modification on MFC-based biosensor performance has not been studied previously. In this study, our results show that the surface modification influences certain aspect of the biosensor performance. Plasma treatment makes the carbon cloth electrode hydrophilic with contact angle of 82 +/- 5 degrees from that of 139 +/- 3 degrees without treatment which consequently increases the amount of biofilm and produces higher current generation. Carbon nanotube (CNT) treatment doesn't increase the amount of biofilm but significantly changes its electroactive microorganism composition from 2.3% to 17.3% that improves current generation. Interestingly, the sensitivity of the MFC sensor was not improved by either of these treatments. These findings would be important for the optimized design and manufacturing of biosensing MFCs. (C) 2020 Elsevier Ltd. All rights reserved.", "authors": [ "Xiao, Nan", "Wu, Rong", "Huang, Jinhui Jeanne", "Selvaganapathy, P. Ravi" ], "keywords": [ "MFC biosensor", "Surface modification", "Plasma treatment", "CNT coating", "Microbial community composition" ], "year": "2020", "source": "CHEMICAL ENGINEERING SCIENCE", "publication_type": "J", "point2d": [ 72.83497619628906, 49.72193145751953 ], "cluster": 6.0 }, { "idx": 531, "title": "Influence of wastewater microbial community on the performance of miniaturized microbial fuel cell biosensor", "abstract": "Microbial fuel cells (MFCs) based sensors had been studied in measuring biochemical oxygen demand (BOD) or the equivalent chemical oxygen demand (COD) recently. Limited attention has been paid to the effect of the microbial communities in wastewater on the responses of these sensors. This study systematically evaluated, for the first time, the effect of wastewater samples from a variety of sources on the electrical response of a micro-fabricated double-chamber MFC device. It was found that the response of the MFC is positively correlated with the bacterial composition, in particular electroactive bacteria. The presence of aerobic bacteria in the sample reduces the current generation. These findings indicated that the bacterial content of the water sample could be a significant interference source and must be considered in the use of mu MFC-based sensors. Filtering samples may be effective in improving the reliability of these microsensors.", "authors": [ "Xiao, Nan", "Selvaganapathy, P. Ravi", "Wu, Rong", "Huang, Jinhui Jeanne" ], "keywords": [ "Microbial fuel cell biosensor", "Wastewater", "Microbial community", "BOD", "COD" ], "year": "2020", "source": "BIORESOURCE TECHNOLOGY", "publication_type": "J", "point2d": [ 74.30842590332031, 51.01903533935547 ], "cluster": 6.0 }, { "idx": 532, "title": "Development of a xurographically fabricated miniaturized low-cost, high-performance microbial fuel cell and its application for sensing biological oxygen demand", "abstract": "The rapid quantification of biological oxygen demand (BOD) plays an important role in environmental management, for instance, wastewater treatment. This study used xurographic fabrication technology to rapidly fabricate a low cost miniaturized microbial fuel cell (MFC) and demonstrated its suitability to measure BOD. The miniaturized sensor could be fabricated in 10 min with low cost of $0.5 U.S. per device. The reaction volume was designed to be 1.8 mu L to obtain faster response time. The sensor was tested using sodium acetate (NaAc) as a model BOD analyte. It could response to a wide range of BOD concentration between 20 and 490 mg/L which would cover the majority range of wastewater BOD concentration in a wastewater treatment plant. The response time of this microsensor was 1.1 min which was significantly shorter than other conventional methods for BOD measurements (5 days). This study demonstrated that the use of xurographic methods to fabricate MFCs could enable rapid fabrication of microsensors to measure BOD in a rapid manner. This study also identified the potential of the sensor for application in wastewater treatment plants to monitor BOD and provide guidance for controlling treatment processes.", "authors": [ "Xiao, Nan", "Wu, Rong", "Huang, Jinhui Jeanne", "Selvaganapathy, P. Ravi" ], "keywords": [ "Microbial fuel cell (MFC)", "Xurographic fabrication", "BOD biosensor", "Fast response", "Wastewater" ], "year": "2020", "source": "SENSORS AND ACTUATORS B-CHEMICAL", "publication_type": "J", "point2d": [ 75.18317413330078, 51.58131408691406 ], "cluster": 6.0 }, { "idx": 533, "title": "Optofluidic Dissolved Oxygen Sensing With Sensitivity Enhancement Through Multiple Reflections", "abstract": "The development of compact and low-cost dissolved oxygen (DO) sensors is essential for the continuous in situ monitoring of environmental water quality and wastewater treatment processes. The optical detection of dynamic and reversible quenching of fluorescent dyes by oxygen has been used for DO sensing. In this paper, we have optimized a multilayer optofluidic device based on the measurement of fluorescence quenching in a Ruthenium-based oxygen sensitive dye by employing total internal reflection (TIR) of the excitation light to achieve sensitivity enhancement for the detection of 0-20-ppm DO in water. The incident angles of light and sensitive layer thickness are optimized experimentally in order to increase the path length of light in the sensitive layer of the device through multiple reflections. A model is developed to demonstrate how light propagates through different layers of the device at varying angles of excitation and to describe the mechanism of fluorescence generation for each of the types of TIR observed. The design principles identified in this paper may be applied to the development and optimization of new multilayered optofluidic sensors by employing TIR for sensitivity enhancement.", "authors": [ "Mahoney, Eric James", "Hsu, Huan-Huan Leo", "Du, Fei", "Xiong, Bo", "Selvaganapathy, P. Ravi", "Fang, Qiyin" ], "keywords": [ "Dissolved oxygen", "environmental sensing", "optofluidics", "oxygen", "water" ], "year": "2019", "source": "IEEE SENSORS JOURNAL", "publication_type": "J", "point2d": [ 66.29710388183594, 43.2251091003418 ], "cluster": 6.0 }, { "idx": 534, "title": "Integrated Triboelectric Nanogenerators in the Era of the Internet of Things", "abstract": "Since their debut in 2012, triboelectric nanogenerators (TENGs) have attained high performance in terms of both energy density and instantaneous conversion, reaching up to 500 W m(-2) and 85%, respectively, synchronous with multiple energy sources and hybridized designs. Here, a comprehensive review of the design guidelines of TENGs, their performance, and their designs in the context of Internet of Things (IoT) applications is presented. The development stages of TENGs in large-scale self-powered systems and technological applications enabled by harvesting energy from water waves or wind energy sources are also reviewed. This self-powered capability is essential considering that IoT applications should be capable of operation anywhere and anytime, supported by a network of energy harvesting systems in arbitrary environments. In addition, this review paper investigates the development of self-charging power units (SCPUs), which can be realized by pairing TENGs with energy storage devices, such as batteries and capacitors. Consequently, different designs of power management circuits, supercapacitors, and batteries that can be integrated with TENG devices are also reviewed. Finally, the significant factors that need to be addressed when designing and optimizing TENG-based systems for energy harvesting and self-powered sensing applications are discussed.", "authors": [ "Ahmed, Abdelsalam", "Hassan, Islam", "El-Kady, Maher F.", "Radhi, Ali", "Jeong, Chang Kyu", "Selvaganapathy, Ponnambalam Ravi", "Zu, Jean", "Ren, Shenqiang", "Wang, Qing", "Kaner, Richard B." ], "keywords": [ "blue energy", "energy storage", "Internet of Things (IoT)", "power management", "smart cities", "triboelectric nanogenerators" ], "year": "2019", "source": "ADVANCED SCIENCE", "publication_type": "J", "point2d": [ 77.93739318847656, 58.9515495300293 ], "cluster": 6.0 }, { "idx": 535, "title": "Sink electrical discharge machining of hydrophobic surfaces", "abstract": "The phenomenon of hydrophobicity observed in such surfaces as lotus leaves is typically manifest by hierarchical structures on low-energy surfaces. Sustained interest in fabricating hydrophobic surfaces has resulted in a myriad of processes, which are but limited by their largely referring to soft materials and/or involving multiple process steps. The present work explored the application of electrical discharge machining (EDM) for the single-step manufacture of durable, metallic hydrophobic surfaces. Simple sink EDM in a hydrocarbon dielectric, with no special process kinematic or tooling requirements, is demonstrated to rapidly generate surfaces that are intrinsically water repellent, with contact angles approaching 150 degrees. (C) 2019 Published by Elsevier Ltd on behalf of CIRP.", "authors": [ "Guo, Changcheng", "Koshy, Philip", "Coelho, Felipe", "Selvaganapathy, P. Ravi" ], "keywords": [ "Material removal", "Texture", "Topography" ], "year": "2019", "source": "CIRP ANNALS-MANUFACTURING TECHNOLOGY", "publication_type": "J", "point2d": [ 69.21284484863281, 53.48295211791992 ], "cluster": 6.0 }, { "idx": 536, "title": "All printable snow-based triboelectric nanogenerator", "abstract": "The development of power generators that can function in harsh snowy environments and in contact with snow can be beneficial but challenging to accomplish. Herein, we introduce the first snow-based triboelectric nano-generator (snow-TENG) that can be used as an energy harvester and a multifunctional sensor based on the principle of snow-triboelectrification. In this work, we used a 3D printing technique for the precise design and deposition of the electrode and triboelectric layer, leading to flexible, stretchable and metal-free triboelectric generators. Based on the single electrode mode, the device can generate an instantaneous output power density as high as 0.2 mW/m(2), an open circuit voltage up to 8 V, and a current density of 40 mu A/m(2). In addition, the snow-TENG can function as a miniaturized weather station to monitor the weather in real time to provide accurate information about the snowfall rate, snow accumulation depth, wind direction, and speed in snowy and/or icy environments. In addition, the snow-TENG can be used as a wearable power source and biomechanical sensor to detect human body motions, which may prove useful for snow-related sports. Unlike conventional sensor platforms, our design works without the need for batteries or image processing systems. We envision these devices could potentially be integrated into solar panels to ensure continuous power supply during snowy weather conditions.", "authors": [ "Ahmed, Abdelsalam", "Hassan, Islam", "Mosa, Islam M.", "Elsanadidy, Esraa", "Phadke, Gayatri S.", "El-Kady, Maher F.", "Rusling, James F.", "Selvaganapathy, Ponnambalam Ravi", "Kaner, Richard B." ], "keywords": [ "All printable", "Snow-triboelectrification", "Arctic", "Energy harvesting", "Self-powered", "Weather station", "Wearables" ], "year": "2019", "source": "NANO ENERGY", "publication_type": "J", "point2d": [ 77.59781646728516, 59.5726203918457 ], "cluster": 6.0 }, { "idx": 537, "title": "Fire-retardant, self-extinguishing triboelectric nanogenerators", "abstract": "The development of highly sensitive sensors and power generators that could function efficiently in extreme temperatures and contact with fire can be lifesaving but challenging to accomplish. Herein, we report, for the first time, a fire-retardant and self-extinguishing triboelectric nanogenerator (FRTENG), which can be utilized as a motion sensor and/or power generator in occupations such as oil drilling, firefighting or working in extreme temperature environments with flammable and combustible materials. The device takes advantage of the excellent thermal properties of carbon derived from resorcinol-formaldehyde aerogel whose electrical, mechanical and triboelectric properties have been improved via the introduction of Polyacrylonitrile nanofibers and graphene oxide nanosheets. This FRTENG is not flammable even after 90 s of trying, whereas conventional triboelectric materials were entirely consumed by fire under the same conditions. The developed device shows exceptional charge transfer characteristics, leading to a potential difference up to 80 V and a current density up to 25 mu A/m(2). When integrated into firefighter's shoes, the FRTENG is able to discern the movements of a firefighter in hazardous situations, while providing the high thermal stability missing in conventional TENGs. The fire-retardant and self-extinguishing characteristics offered by the FRTENG makes it a path-breaking device for lifesaving wearable applications.", "authors": [ "Ahmed, Abdelsalam", "El-Kady, Maher F.", "Hassan, Islam", "Negm, Ayman", "Pourrahimi, Amir Masoud", "Muni, Mit", "Selvaganapathy, Ponnambalam Ravi", "Kaner, Richard B." ], "keywords": [ "Fire-retardant", "Self-Extinguishing", "Triboelectric nanogenerators", "Energy harvesting", "Wearable sensors" ], "year": "2019", "source": "NANO ENERGY", "publication_type": "J", "point2d": [ 77.22845458984375, 58.132354736328125 ], "cluster": 6.0 }, { "idx": 538, "title": "Suppression of Biofouling on a Permeable Membrane for Dissolved Oxygen Sensing Using a Lubricant-Infused Coating", "abstract": "Specific ranges of dissolved oxygen (DO) concentrations must be maintained in a waterbody for it to be hospitable for aquatic animals. DO sensor designs can employ selectively permeable membranes to isolate DO from untargeted compounds or organisms in waterbodies. Hence, the DO concentration can be monitored and the health of the water can be evaluated over time. However, the presence of bacteria in natural waterbodies can lead to the formation of biofilms that can block pores and prevent analyte from permeating the membrane, resulting in inaccurate readings. In this work, we demonstrate the implementation of a fluorosilane-based omniphobic lubricant-infused (OLI) coating on a selectively permeable membrane and investigate the rate of biofilm formation for a commercially available DO sensor. Coated and unmodified membranes were incubated in an environment undergoing accelerated bacterial growth, and the change in sensitivity was evaluated after 40, 100, 250, and 500 h. Our findings show that the OLI membranes attenuate biofouling by 70% and maintain sensitivity after 3 weeks of incubation, further demonstrating that oxygen transfer through the OLI coating is achievable. Meanwhile, unmodified membranes exhibit significant biofouling that results in a 3.35 higher rate of decay in oxygen measurement sensitivity and an over 70% decrease in static contact angle. These results show that the OLI coating can be applied on commercially available membranes to prevent biofouling. Therefore, OLI coatings are a suitable candidate to suppress biofilm formation in the widespread use of selectively permeable membranes for environmental, medical, and fluid separation applications.", "authors": [ "Osborne, Matthew", "Asomayajula, Aditya", "Shakeri, Amid", "Selvaganapathy, Ponnambalam Ravi", "Didar, Tohid F." ], "keywords": [ "biofouling", "bacteria", "biofilm", "membrane fouling", "lubricant-infused coating", "dissolved oxygen sensing" ], "year": "2019", "source": "ACS SENSORS", "publication_type": "J", "point2d": [ 68.8821029663086, 48.289588928222656 ], "cluster": 6.0 }, { "idx": 539, "title": "Target Self-Enhanced Selectivity in Metal-Specific DNAzymes", "abstract": "Highly selective recognition of metal ions by rational ligand design is challenging, and simple metal binding by biological ligands is often obscured by nonspecific interactions. In this work, binding-triggered catalysis is used and metal selectivity is greatly increased by increasing the number of metal ions involved, as exemplified in a series of in vitro selected RNA-cleaving DNAzymes. The cleavage junction is modified with a glycyl-histidine-functionalized tertiary amine moiety to provide multiple potential metal coordination sites. DNAzymes that bind 1, 2, and 3 Zn2+ ions, increased their selectivity for Zn2+ over Co2+ ions from approximately 20-, 1000-, to 5000-fold, respectively. This study offers important insights into metal recognition by combining rational ligand design and combinatorial selection, and it provides a set of new DNAzymes with excellent selectivity for Zn2+ ions.", "authors": [ "Huang, Po-Jung Jimmy", "de Rochambeau, Donatien", "Sleiman, Hanadi F.", "Liu, Juewen" ], "keywords": [ "aptamers", "biosensors", "DNAzymes", "metal ions", "SELEX" ], "year": "2020", "source": "ANGEWANDTE CHEMIE-INTERNATIONAL EDITION", "publication_type": "J", "point2d": [ 90.87557220458984, 34.36245346069336 ], "cluster": 6.0 }, { "idx": 541, "title": "Development and potential for point-of-care heavy metal sensing using microfluidic systems: A brief review", "abstract": "Heavy metal pollution on earth has evolved into a global issue causing serious risks to human health and other living entities and having an impact on sustainability. Accurate identification of metal contamination is often carried out in centralized facilities involving sampling, transportation, and the need for highly trained personnel, which becomes expensive, often causes delays in response to potential tragedies, and is prone to sample prop-erties changes. Rapid, affordable methods for point-of-care (POC) detection of heavy metals with reasonable accuracy are ideal to address these challenges enabling diligent monitoring of metal pollution. There have been many POC systems reported, however, the systems that could work with real samples in which heavy metals are present in a complex form at a low concentration are limited. Sample preparation is often needed for the accurate identification of metal ions. Microfluidics offers tremendous potential for sample preparation and integration with various detection methods such as optical and electrochemical methods for POC detection of heavy metals. This review is limited to reviewing the reported microfluidic-based POC devices for heavy metal sensing and providing a brief perspective on the integration of microwave sensing methods with microfluidic devices for heavy metal detection. This review starts with introducing microfluidic-based heavy metal sensing using optical and electrochemical methods and then focuses on briefly discussing the development and potential of integrating microwave sensing with microfluidic devices for heavy metal sensing. The principle of each method and the limit of detection are briefly discussed.", "authors": [ "Cui, Weijia", "Ren, Zhe", "Song, Yongxin", "Ren, Carolyn L." ], "keywords": [ "Heavymetalpollution", "Microfluidics", "Microwavesensing", "Point-of-care" ], "year": "2022", "source": "SENSORS AND ACTUATORS A-PHYSICAL", "publication_type": "J", "point2d": [ 79.2879867553711, 40.5630989074707 ], "cluster": 6.0 }, { "idx": 542, "title": "Detection of fouling on electrically conductive membranes by electrical impedance spectroscopy", "abstract": "Detecting the onset of membrane fouling is critical for effectively removing membrane foulants during microfiltration (MF) separation. This work investigates the use of electrical impedance spectroscopy (EIS) on the surface of electrically conductive membranes (ECMs) to measure early development of membrane surface fouling. An electrochemical cell was developed in which an ECM acted as a working electrode and a graphite electrode acted as the counter electrode. Conductive membranes were fabricated by coating single-walled/ double-walled carbon nanotubes (f-SW/DWCNT) on microfiltration polyethersulfone (PES) supporting membranes. Membrane fouling was simulated by pressure depositing different amounts of latex beads onto the surface of the membrane in a dead-end filtration cell. Changes in membrane water permeability were correlated to the degree of membrane fouling. Clean membranes had water permeability of 392 +/- 28 LMH/bar. Reduction of membrane water permeability of 13.8 +/- 3.3%, 15.8 +/- 4.7%, 17.8 +/- 0.5% and 27.1 +/- 4.6% were observed for membranes covered with 0.028 mg/m(2), 0.28 mg/m(2), 1.40 mg/m(2) and 2.80 mg/m(2) on the membranes, respectively. These small differences in fouling degree were statistically resolvable in measured Nyquist plots. It was observed that the diameter of the higher frequency charge transfer region (10(4)-10(6) Hz) of the Nyquist plot semicircles increased with greater fouling. These observations were hypothesized to correspond to decreasing surface conductivities of the membranes by the incorporation of insulating materials (latex beads) within the porous conductive coating. This proposed hypothesis was supported by measured EIS results modeled with a theoretical equivalent circuit. Fouled membrane surface conductivity, surface hydrophilicity, and pore size were measured by SEM, four-point probe conductivity, contact angle, and MWCO experiments, respectively, to compare conventional characterization techniques with non-destructive EIS measurements.", "authors": [ "Zhang, Nan", "Halali, Mohamad Amin", "de Lannoy, Charles-Francois" ], "keywords": [ "Membrane sensors", "Latex beads", "Fouling detection", "Single walled carbon nanotubes", "Nyquist plots" ], "year": "2020", "source": "SEPARATION AND PURIFICATION TECHNOLOGY", "publication_type": "J", "point2d": [ 70.7330551147461, 50.49921798706055 ], "cluster": 6.0 }, { "idx": 543, "title": "Inactivation of bacterial planktonic cells and biofilms by Cu(II)-activated peroxymonosulfate in the presence of chloride ion", "abstract": "The combination of Cu(II) with peroxymonosulfate (PMS) (i.e., the Cu(II)/PMS system) synergistically inactivated P. aeruginosa cells in the planktonic state, and in biofilms grown on RO membranes. The enhanced bacterial inactivation by the Cu(II)/PMS system appears to be due to the reactive oxidants produced by the catalytic reactions of the Cu(II)/Cu(I) redox couple with PMS. In the presence of chloride ion (Cl-), the Cu(II)/PMS system showed increased microbicidal effects on the planktonic P. aeruginosa cells, which was explained by the role of hypochlorous acid (HOCl) produced by the reaction of chloride with PMS. In addition, the combination of Cu(II) with HOCl showed synergistic microbicidal effects on the planktonic cells. Compared to planktonic cells, biofilm cells were more resistant to the Cu(II)/PMS treatment. Cl- did not significantly affect the inactivation of biofilm cells by the Cu(II)/PMS system. It is believed that the extracellular polymeric substances of biofilms play a role as oxidant sinks (particularly HOCl), protecting the cells inside the biofilm matrix. The HOCl-generating systems, such as PMS/Cl- and Cu(II)/PMS/Cl-, greatly degraded proteins and poly-saccharides in biofilms. Experiments on the cross-flow filtration of NaCl solution showed that the Cu(II)/PMS treatment of fouled RO membranes resulted in partial recovery of permeate flux.", "authors": [ "Lee, Hye-Jin", "Kim, Hyung-Eun", "Kim, Min Sik", "de Lannoy, Charles-Francois", "Lee, Changha" ], "keywords": [ "Biofilm", "Biofouling", "Reverse osmosis membrane", "Copper ion", "Peroxymonosulfate" ], "year": "2020", "source": "CHEMICAL ENGINEERING JOURNAL", "publication_type": "J", "point2d": [ 71.15033721923828, 46.5908088684082 ], "cluster": 6.0 }, { "idx": 544, "title": "Multiple Stressors in the Environment: The Effects of Exposure to an Antidepressant (Venlafaxine) and Increased Temperature on Zebrafish Metabolism", "abstract": "Aquatic organisms are continuously exposed to multiple environmental stressors working cumulatively to alter ecosystems. Wastewater-dominated environments are often riddled by a myriad of stressors, such as chemical and thermal stressors. The objective of this study was to examine the effects of an environmentally relevant concentration of a commonly prescribed antidepressant, venlafaxine (VFX) [1.0 mu g/L], in addition to a 5 degrees C increase in water temperature on zebrafish metabolism. Fish were chronically exposed (21 days) to one of four conditions: (i) 0 mu g/L VFX at 27 degrees C; (ii) 1.0 mu g/L VFX at 27 degrees C; (iii) 0 mu g/L VFX at 32 degrees C; (iv) 1.0 mu g/L VFX at 32 degrees C. Following exposure, whole-body metabolism was assessed by routine metabolic rate (RMR) measurements, whereas tissue-specific metabolism was assessed by measuring the activities of major metabolic enzymes in addition to glucose levels in muscle. RMR was significantly higher in the multi-stressed group relative to Control. The combination of both stressors resulted in elevated pyruvate kinase activity and glucose levels, while lipid metabolism was depressed, as measured by 3-hydroxyacyl CoA dehydrogenase activity. Citrate synthase activity increased with the onset of temperature, but only in the group treatment without VFX. Catalase activity was also elevated with the onset of the temperature stressor, however, that was not the case for the multi-stressed group, potentially indicating a deleterious effect of VFX on the anti-oxidant defense mechanism. The results of this study highlight the importance of multiple-stressor research, as it able to further bridge the gap between field and laboratory studies, as well as have the potential of yielding surprising results that may have not been predicted using a conventional single-stressor approach.", "authors": [ "Mehdi, Hossein", "Bragg, Leslie M.", "Servos, Mark R.", "Craig, Paul M." ], "keywords": [ "venlafaxine", "temperature", "metabolism", "zebrafish", "wastewater", "multiple stressors" ], "year": "2019", "source": "FRONTIERS IN PHYSIOLOGY", "publication_type": "J", "point2d": [ 74.58704376220703, 1.1656428575515747 ], "cluster": 0.0 }, { "idx": 545, "title": "Historical and Projected Changes to the Stages and Other Characteristics of Severe Canadian Prairie Droughts", "abstract": "Large-area, long-duration droughts are among Canada's costliest natural disasters. A particularly vulnerable region includes the Canadian Prairies where droughts have, and are projected to continue to have, major impacts. However, individual droughts often differ in their stages such as onset, growth, persistence, retreat, and duration. Using the Standardized Precipitation Evapotranspiration Index, this study assesses historical and projected future changes to the stages and other characteristics of severe drought occurrence across the agricultural region of the Canadian Prairies. Ten severe droughts occurred during the 1900-2014 period with each having unique temporal and spatial characteristics. Projected changes from 29 global climate models (GCMs) with three representative concentration pathways reveal an increase in severe drought occurrence, particularly toward the end of this century with a high emissions scenario. For the most part, the overall duration and intensity of future severe drought conditions is projected to increase mainly due to longer persistence stages, while growth and retreat stages are generally shorter. Considerable variability exists among individual GCM projections, including their ability to simulate observed severe drought characteristics. This study has increased understanding in potential future changes to a little studied aspect of droughts, namely, their stages and associated characteristics. This knowledge can aid in developing future adaptation strategies.", "authors": [ "Bonsal, Barrie", "Liu, Zhuo", "Wheaton, Elaine", "Stewart, Ronald" ], "keywords": [ "severe drought", "Canadian Prairies", "climate change", "drought stages", "drought characteristics", "drought risks" ], "year": "2020", "source": "WATER", "publication_type": "J", "point2d": [ -36.075965881347656, -35.774166107177734 ], "cluster": 1.0 }, { "idx": 546, "title": "Historical and Projected Changes to the Stages and Other Characteristics of Severe Canadian Prairie Droughts", "abstract": "Large-area, long-duration droughts are among Canada's costliest natural disasters. A particularly vulnerable region includes the Canadian Prairies where droughts have, and are projected to continue to have, major impacts. However, individual droughts often differ in their stages such as onset, growth, persistence, retreat, and duration. Using the Standardized Precipitation Evapotranspiration Index, this study assesses historical and projected future changes to the stages and other characteristics of severe drought occurrence across the agricultural region of the Canadian Prairies. Ten severe droughts occurred during the 1900-2014 period with each having unique temporal and spatial characteristics. Projected changes from 29 global climate models (GCMs) with three representative concentration pathways reveal an increase in severe drought occurrence, particularly toward the end of this century with a high emissions scenario. For the most part, the overall duration and intensity of future severe drought conditions is projected to increase mainly due to longer persistence stages, while growth and retreat stages are generally shorter. Considerable variability exists among individual GCM projections, including their ability to simulate observed severe drought characteristics. This study has increased understanding in potential future changes to a little studied aspect of droughts, namely, their stages and associated characteristics. This knowledge can aid in developing future adaptation strategies.", "authors": [ "Bonsal, Barrie", "Liu, Zhuo", "Wheaton, Elaine", "Stewart, Ronald" ], "keywords": [ "severe drought", "Canadian Prairies", "climate change", "drought stages", "drought characteristics", "drought risks" ], "year": "2020", "source": "WATER", "publication_type": "J", "point2d": [ -35.69538879394531, -36.04056167602539 ], "cluster": 1.0 }, { "idx": 547, "title": "Freezing Rain Events that Impacted the Province of New Brunswick, Canada, and Their Evolution in a Warmer Climate", "abstract": "Winter storms in eastern Canada can bring heavy precipitation, including large amounts of freezing rain. The resulting ice accumulation on structures such as trees and power lines can lead to widespread power outages and damage to infrastructure. The objective of this study is to provide a better understanding of the processes that led to extreme freezing rain events over New Brunswick (NB), Canada, during past events and how they may change in the future. To accomplish this, freezing rain events that affected the power network over NB were identified and analysed using high-resolution convection-permitting simulations. These simulations were produced from 2000 to 2013 climate data and using the pseudo global warming (WRF-PGW) approach, assuming warmer climate conditions. Our results show that through the process of cold air damming, the Appalachians enhance the development of strong temperature inversions, leading to an increase in the amount of freezing rain in central and southern NB. The occurrence of freezing rain events generally decreases by 40% in southern and eastern NB, while the occurrence of long-duration events (>6 h) increases slightly in northwestern NB in the WRF-PGW simulation. Overall, key local orographic effects that influence atmospheric conditions favorable for freezing precipitation were identified. This knowledge will enable us to better anticipate the impact of climate change on similar storms.", "authors": [ "Chartrand, Julien", "Theriault, Julie M.", "Marinier, Sebastien" ], "keywords": [ "freezing rain", "wet snow", "convection permitting climate models", "climatology", "winter storms" ], "year": "2023", "source": "ATMOSPHERE-OCEAN", "publication_type": "J", "point2d": [ -54.466583251953125, -28.10012435913086 ], "cluster": 1.0 }, { "idx": 548, "title": "Impacts of Predicting the Liquid Fraction of Mixed-Phase Particles on the Simulation of an Extreme Freezing Rain Event: The 1998 North American Ice Storm", "abstract": "A prognostic equation for the liquid fraction of mixed-phase particles has been recently added to the Predicted Particle Properties (P3) bulk microphysics scheme. Mixed-phase particles are necessary to simulate key microphysical processes leading to various winter precipitation types, such as ice pellets and freezing rain. To illustrate the impacts of predicting the bulk liquid fraction, the 1998 North American Ice Storm is simulated using the Weather Research and Forecasting (WRF) Model with the modified P3 scheme. It is found that simulating partial melting by predicting the bulk liquid fraction produces higher mass and number mixing ratios of rain. This leads to smaller rain sizes reaching the refreezing layer as well as a decrease in the freezing rain accumulation at the surface by up to 30% in some locations compared to when no liquid fraction is predicted. The increase in fall speed and density and decrease of particle diameter during partial melting combined with an improved representation of the refreezing process in the modified P3 leads to generally higher total solid surface precipitation rates than using the original P3 scheme. There is also an increase of solid precipitation in regions of ice pellet accumulation. Overall, the simulation of mixed-phase particles notably impacts the vertical and spatial distributions of precipitation properties.", "authors": [ "Cholette, Melissa", "Theriault, Julie M.", "Milbrandt, Jason A.", "Morrison, Hugh" ], "keywords": [ "" ], "year": "2020", "source": "MONTHLY WEATHER REVIEW", "publication_type": "J", "point2d": [ -65.37391662597656, -30.067358016967773 ], "cluster": 12.0 }, { "idx": 549, "title": "Impacts of Predicting the Liquid Fraction of Mixed-Phase Particles on the Simulation of an Extreme Freezing Rain Event: The 1998 North American Ice Storm", "abstract": "A prognostic equation for the liquid fraction of mixed-phase particles has been recently added to the Predicted Particle Properties (P3) bulk microphysics scheme. Mixed-phase particles are necessary to simulate key microphysical processes leading to various winter precipitation types, such as ice pellets and freezing rain. To illustrate the impacts of predicting the bulk liquid fraction, the 1998 North American Ice Storm is simulated using the Weather Research and Forecasting (WRF) Model with the modified P3 scheme. It is found that simulating partial melting by predicting the bulk liquid fraction produces higher mass and number mixing ratios of rain. This leads to smaller rain sizes reaching the refreezing layer as well as a decrease in the freezing rain accumulation at the surface by up to 30% in some locations compared to when no liquid fraction is predicted. The increase in fall speed and density and decrease of particle diameter during partial melting combined with an improved representation of the refreezing process in the modified P3 leads to generally higher total solid surface precipitation rates than using the original P3 scheme. There is also an increase of solid precipitation in regions of ice pellet accumulation. Overall, the simulation of mixed-phase particles notably impacts the vertical and spatial distributions of precipitation properties.", "authors": [ "Cholette, Melissa", "Theriault, Julie M.", "Milbrandt, Jason A.", "Morrison, Hugh" ], "keywords": [ "" ], "year": "2020", "source": "MONTHLY WEATHER REVIEW", "publication_type": "J", "point2d": [ -65.37391662597656, -30.067358016967773 ], "cluster": 12.0 }, { "idx": 550, "title": "Precipitation Type Distribution and Microphysical Processes During the 1998 Ice Storm Simulated Under Pseudo-Warmer Conditions", "abstract": "In the future, the intensity, phases, and frequency of precipitation are expected to change due to global warming, in particular during colder seasons when temperatures are near 0 degrees C. To investigate the impacts of warmer atmospheric conditions on the microphysical processes that lead to several precipitation types, the extreme 1998 Ice Storm was simulated using the Weather Research and Forecasting (WRF) model, with and without a pseudo-global warming. The pseudo-global warming approach simulates similar large-scale conditions but in warmer conditions, which allows for the assessment of thermodynamic feedback from cloud and precipitation microphysics. For both simulations, WRF was coupled with the Predicted Particle Properties (P3) bulk microphysics scheme that predicts the liquid fraction of mixed-phase particles. Results of the pseudo-global warming simulation show an increase of similar to 828 m in the upper 0 degrees C level and a northeastward migration (similar to 60 km) of the rain-snow transition region. The results also show a 20% decrease in domain-averaged freezing rain amounts, but with an increased maximum amount of 50%. The horizontal distance associated with a melting aloft and a refreezing layer near the surface is 105 km longer in southern Quebec due to the combined effects of the pseudo-warming and the presence of the Appalachian Mountains. The microphysical processes that lead to precipitation are impacted as well; the increased ice mass and riming conditions aloft in warmer temperatures result in higher liquid precipitation rates. This study contributes to our understanding of the changes in the fine-scale processes of an extreme storm, simulated with pseudo-global warming conditions. Key Points The major 1998 Ice Storm was simulated with the Weather Research and Forecasting model, with and without a pseudo-global warming A higher melting layer in warmer conditions led to more riming aloft, larger drops, and higher maximum amounts of rain and freezing rain The precipitation type transition region is wider in the warmer conditions over the geographical areas of both southern Quebec and Maine", "authors": [ "Cholette, Melissa", "Theriault, Julie Mireille" ], "keywords": [ "" ], "year": "2021", "source": "JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES", "publication_type": "J", "point2d": [ -62.46934509277344, -31.051612854003906 ], "cluster": 1.0 }, { "idx": 551, "title": "Precipitation Type Distribution and Microphysical Processes During the 1998 Ice Storm Simulated Under Pseudo-Warmer Conditions", "abstract": "In the future, the intensity, phases, and frequency of precipitation are expected to change due to global warming, in particular during colder seasons when temperatures are near 0 degrees C. To investigate the impacts of warmer atmospheric conditions on the microphysical processes that lead to several precipitation types, the extreme 1998 Ice Storm was simulated using the Weather Research and Forecasting (WRF) model, with and without a pseudo-global warming. The pseudo-global warming approach simulates similar large-scale conditions but in warmer conditions, which allows for the assessment of thermodynamic feedback from cloud and precipitation microphysics. For both simulations, WRF was coupled with the Predicted Particle Properties (P3) bulk microphysics scheme that predicts the liquid fraction of mixed-phase particles. Results of the pseudo-global warming simulation show an increase of similar to 828 m in the upper 0 degrees C level and a northeastward migration (similar to 60 km) of the rain-snow transition region. The results also show a 20% decrease in domain-averaged freezing rain amounts, but with an increased maximum amount of 50%. The horizontal distance associated with a melting aloft and a refreezing layer near the surface is 105 km longer in southern Quebec due to the combined effects of the pseudo-warming and the presence of the Appalachian Mountains. The microphysical processes that lead to precipitation are impacted as well; the increased ice mass and riming conditions aloft in warmer temperatures result in higher liquid precipitation rates. This study contributes to our understanding of the changes in the fine-scale processes of an extreme storm, simulated with pseudo-global warming conditions. Key Points The major 1998 Ice Storm was simulated with the Weather Research and Forecasting model, with and without a pseudo-global warming A higher melting layer in warmer conditions led to more riming aloft, larger drops, and higher maximum amounts of rain and freezing rain The precipitation type transition region is wider in the warmer conditions over the geographical areas of both southern Quebec and Maine", "authors": [ "Cholette, Melissa", "Theriault, Julie Mireille" ], "keywords": [ "" ], "year": "2021", "source": "JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES", "publication_type": "J", "point2d": [ -62.44222640991211, -30.552331924438477 ], "cluster": 1.0 }, { "idx": 552, "title": "The Severe Multi-Day October 2019 Snow Storm Over Southern Manitoba, Canada", "abstract": "A devastating storm struck southern Manitoba, Canada on 10-13 October 2019, producing a large region of mainly sticky and wet snow. Accumulations reached 75 cm, wind gusts exceeded 100 km h(-1), and surface temperature (T) remained near 0 degrees C (-1 degrees C <= T <= 1 degrees C) for up to 88 h. It produced the largest October snowfall and was the earliest to produce at least 20 cm since 1872 in Winnipeg. These factors led to unparalleled damage and power restoration challenges for Manitoba Hydro and, with leaves still largely on vegetation, the most damaging storm to Winnipeg's trees ever recorded. The storm's track was uncommon, and produced elevated convection related to buoyancy-driven instability and conditional symmetric instability (CSI), with a moist absolutely unstable layer (MAUL) near 500 hPa. Instabilities were released via lift through lower-tropospheric warm advection and frontogenesis, differential cyclonic vorticity advection, and jet streak dynamics. Precipitation bands, elevated convection, and lake effect snow bands enhanced local snowfall. Snow adhering to structures was not always wet but, when present, it sometimes occurred because of incomplete freezing of particles partially melted aloft in a near-surface (<100 m deep) inversion. Although other storms over the historical record have produced a similar combination of severe precipitation, temperature and wind conditions, none have done this for such a long period.", "authors": [ "Hanesiak, John", "Stewart, Ronald", "Painchaud-Niemi, Dylan", "Milrad, Shawn", "Liu, George", "Vieira, Michael", "Theriault, Julie", "Cholette, Melissa", "Ziolkowski, Kyle" ], "keywords": [ "snow storm", "wet snow", "severe wind", "CSI", "convection", "MAUL", "lightning", "electrical outages" ], "year": "2022", "source": "ATMOSPHERE-OCEAN", "publication_type": "J", "point2d": [ -54.686256408691406, -25.312395095825195 ], "cluster": 1.0 }, { "idx": 553, "title": "Changes in freezing rain occurrence over eastern Canada using convection-permitting climate simulations", "abstract": "Freezing precipitation has major consequences for ground and air transportation, the health of citizens, and power networks. Previous studies using coarse resolution climate models have shown a northward migration of freezing rain in the future. Increased model resolution can better define local topography leading to improved representation of conditions that are favorable for freezing rain. The goal of this study is to examine the climatology and characteristics of future freezing rain events using very-high resolution climate simulations. Historical and pseudo-global warming simulations with a 4-km horizontal grid length were used and compared with available observations. Simulations revealed a northerly shift of freezing rain occurrence, and an increase in the winter. Freezing rain was still shown to occur in the Saint-Lawrence River Valley in a warmer climate, primarily due to stronger wind channeling. Up to 50% of the future freezing rain events also occurred in present day climate within 12 h of each other. In northern Maine, they are typically shorter than 6 h in current climate and longer than 6 h in warmer conditions due to the onset of precipitation during low-pressure systems occurrences. The occurrence of freezing rain also locally increases slightly north of Quebec City in a warmer climate because of freezing rain that is produced by warm rain processes. Overall, the study shows that high-resolution regional climate simulations are needed to study freezing rain events in warmer climate conditions, because high horizontal resolutions better define small-scale topographic features and local physical mechanisms that have an influence on these events.", "authors": [ "Marinier, Sebastien", "Theriault, Julie M.", "Ikeda, Kyoko" ], "keywords": [ "Freezing rain", "Convection-permitting", "Winter storms", "Global warming" ], "year": "2023", "source": "CLIMATE DYNAMICS", "publication_type": "J", "point2d": [ -55.50685501098633, -29.189624786376953 ], "cluster": 1.0 }, { "idx": 554, "title": "Meteorological Factors Responsible for Major Power Outages during a Severe Freezing Rain Storm over Eastern Canada", "abstract": "Winter precipitation is the source of many inconveniences in many regions of North America, for both infrastructure and the economy. The ice storm that hit the Canadian Maritime Provinces on 24-26 January 2017 remains one of the most expensive in history for the province of New Brunswick. Up to 50 mm of freezing rain caused power outages across the province, depriving up to one-third of New Brunswick residences of electricity, with some outages lasting 2 weeks. This study aims to use high-resolution atmospheric modeling to investigate the meteorological conditions during this severe storm and their contribution to major power outages. The persistence of a deep warm layer aloft, coupled with the slow movement of the associated low pressure system, contributed to widespread ice accumulation. When combined with the strong winds observed, extensive damage to electricity networks was inevitable. A 2-m temperature cold bias was identified between the simulation and the observations, in particular during periods of freezing rain. In the northern part of New Brunswick, cold-air advection helped keep temperatures below 0 degrees C, while in southern regions, the 2-m temperature increased rapidly to slightly above 0 degrees C because of radiational heating. The knowledge gained in this study on the processes associated with either maintaining or stopping freezing rain will enhance the ability to forecast and, in turn, to mitigate the hazards associated with those extreme events. Significance StatementA slow-moving low pressure system produced up to 50 mm of freezing rain for 31 h along the east coast of New Brunswick, Canada, on 24-26 January 2017, causing unprecedented power outages. Warm-air advection aloft, along with a combination of higher wind speeds and large amounts of ice accumulation, created ideal conditions for severe freezing rain. The storm began with freezing rain along the entire north-south cross section of eastern New Brunswick and changed to rain only in the south, when local temperatures increased to >0 degrees C. Near-surface cold-air advection kept temperatures below 0 degrees C in the north. Warming from the latent heat produced by freezing contributed to persistent near-0 degrees C conditions during freezing rain.", "authors": [ "Theriault, Julie M. M.", "McFadden, Vanessa", "Thompson, Hadleigh D. D.", "Cholette, Melissa" ], "keywords": [ "Extreme events", "Freezing precipitation", "Latent heating", "cooling", "Numerical analysis", "modeling" ], "year": "2022", "source": "JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY", "publication_type": "J", "point2d": [ -53.76152420043945, -27.682889938354492 ], "cluster": 1.0 }, { "idx": 555, "title": "Seismic Lines in Treed Boreal Peatlands as Analogs for Wildfire Fuel Modification Treatments", "abstract": "Across the Boreal, there is an expansive wildland-society interface (WSI), where communities, infrastructure, and industry border natural ecosystems, exposing them to the impacts of natural disturbances, such as wildfire. Treed peatlands have previously received little attention with regard to wildfire management; however, their role in fire spread, and the contribution of peat smouldering to dangerous air pollution, have recently been highlighted. To help develop effective wildfire management techniques in treed peatlands, we use seismic line disturbance as an analog for peatland fuel modification treatments. To delineate below-ground hydrocarbon resources using seismic waves, seismic lines are created by removing above-ground (canopy) fuels using heavy machinery, forming linear disturbances through some treed peatlands. We found significant differences in moisture content and peat bulk density with depth between seismic line and undisturbed plots, where smouldering combustion potential was lower in seismic lines. Sphagnum mosses dominated seismic lines and canopy fuel load was reduced for up to 55 years compared to undisturbed peatlands. Sphagnum mosses had significantly lower smouldering potential than feather mosses (that dominate mature, undisturbed peatlands) in a laboratory drying experiment, suggesting that fuel modification treatments following a strategy based on seismic line analogs would be effective at reducing smouldering potential at the WSI, especially under increasing fire weather.", "authors": [ "Deane, Patrick Jeffrey", "Wilkinson, Sophie Louise", "Moore, Paul Adrian", "Waddington, James Michael" ], "keywords": [ "peat properties", "organic soil", "moisture retention", "wildfire management", "smouldering", "combustion" ], "year": "2020", "source": "FIRE-SWITZERLAND", "publication_type": "J", "point2d": [ -11.989765167236328, 72.73523712158203 ], "cluster": 9.0 }, { "idx": 556, "title": "Threshold peat burn severity breaks evaporation-limiting feedback", "abstract": "A suite of autogenic ecohydrological feedbacks and moss traits are important for protecting vast peatland carbon stocks following wildfire disturbance. Here, we examine how peat burn severity and water table depth (WTD) affect the strength of one such feedback-the hydrophobicity-evaporation feedback (HEF). The HEF is an evaporation-limiting feedback known to minimize water loss following wildfire. The peatland surface becomes hydrophobic creating an evaporative cap and thereby reducing post-fire evaporation; however, recent studies hypothesize that this is dependent on peat burn severity. To test this hypothesis, we studied plots along a peat burn severity gradient in a partially drained black spruce peatland that burned during the 2016 Fort McMurray Horse River wildfire. Evaporation rates were significantly lower in plots where hydrophobicity was present. Hydrophobicity was lowest in the severely burned area, and the average instantaneous evaporation rate (2.75 mm day(-1)) was significantly higher than moderately and typical-lightly burned areas (0.82 and 1.64 mm day(-1), respectively). Based on lab results, increasing WTD affected hydrophobicity within lightly burned (singed) feather moss samples but not in heavily burned feather moss, showing the importance of post-fire ground cover and in situ WTD. Our results provide evidence of a burn severity threshold where increased depth of burn removes the feather moss evaporative cap and causes the HEF to break down. We argue that this threshold has important implications for boreal peatlands, which are predicted to undergo climate-mediated pre-fire drying and increasing burn severities, potentially leading to further carbon losses due to enhanced post-fire drying and concomitant decomposition.", "authors": [ "Wilkinson, Sophie L.", "Verkaik, Gregory J.", "Moore, Paul A.", "Waddington, James M." ], "keywords": [ "water table", "water repellency", "tipping point", "carbon loss", "wildfire", "combustion" ], "year": "2020", "source": "ECOHYDROLOGY", "publication_type": "J", "point2d": [ -10.0728178024292, 68.51127624511719 ], "cluster": 9.0 }, { "idx": 557, "title": "Assessing Drivers of Cross-Scale Variability in Peat Smoldering Combustion Vulnerability in Forested Boreal Peatlands", "abstract": "Wildfire represents the largest areal disturbance of forested boreal peatlands and the spatial variability in the severity of these peat fires is both a leading source of uncertainty in boreal wildfire carbon emissions and a major challenge for regional wildfire management. Peat smoldering can emit large quantities of carbon and smoke to the atmosphere, and therefore can contribute to hazardous air quality. The wildland-industry interface and wildland-urban interface are both extensive across the sub-humid boreal plains (BP) ecozone where one-third of the area is covered by peatlands. As such, there is a growing research need to identify drivers of variability in smoldering combustion. This study uses hydrophysical peat properties to assess the drivers of cross-scale variability in peat smoldering combustion vulnerability in forested peatlands across the BP. Using a space-for-time chronosequence across the 120 year fire return interval and three main hydrogeological settings, and by incorporating hummock, hollow and margin locations, cross-scale variability is studied. We find that, based on peat properties such as specific yield (Sy) and gravimetric water content, forested peatland margins represent areas of high peat smoldering vulnerability, and that this is exacerbated with an increasing time-since-fire (stand-age). Although increasing Sy with time-since-fire in peatland middles may buffer water table drawdown, when accounting for increases in canopy fuel load, transpiration, and feather moss dominance forested peatland middles also become more vulnerable to smoldering combustion with time-since-fire. Moreover, the interaction of peatland margins with coarse- and heterogeneous-grained hydrogeological settings leads to lower Sy and higher density margin peat than in fine-grained settings, further increasing smoldering vulnerability. We estimate that forested peatland margins are vulnerable to combustion throughout their entire profile i.e., burn-out, under moderate-high water deficits in the BP. Furthermore, we identify peatland margin: total area ratio as a driver of smoldering vulnerability where small peatlands that are periodically disconnected from regional groundwater systems are the most vulnerable to high total peat carbon loss. We suggest that these drivers of cross-scale variability should be incorporated into peatland and wildfire management strategies, especially in areas near the wildland-industry and wildland-urban interface.", "authors": [ "Wilkinson, Sophie L.", "Moore, Paul A.", "Waddington, James M." ], "keywords": [ "peat properties", "carbon", "organic soil", "moisture retention", "specific yield", "wildfire" ], "year": "2019", "source": "FRONTIERS IN FORESTS AND GLOBAL CHANGE", "publication_type": "J", "point2d": [ -12.485102653503418, 67.35205841064453 ], "cluster": 9.0 }, { "idx": 558, "title": "The role of snow processes and hillslopes on runoff generation in present and future climates in a recently constructed watershed in the Athabasca oil sands region", "abstract": "Mine reclamation in the Athabasca oil sands region Canada, is required by law where companies must reconstruct disturbed landscapes into functioning ecosystems such as forests, wetlands, and lakes that existed in the Boreal landscape prior to mining. Winter is a major hydrological factor in this region as snow covers the landscape for 5-6 months and is similar to 25% of the annual precipitation, yet few studies have explored the influence of winter processes on the hydrology of constructed watersheds. One year (2017-2018) of intensive snow hydrology measurements are supplemented with 6 years (2013-2018) of meteorological measurements from the constructed Sandhill Fen watershed to: (a) understand snow accumulation and redistribution, snowmelt timing, rate, and partitioning, (b) apply a physically based model for simulating winter processes on hillslopes, and (c) evaluate the impact of soil prescriptions and climate change projections on winter processes in reclaimed systems. The 2017-2018 snow season was between November and April and snow water equivalent (SWE) ranged between 40 and 140 mm. Snow distribution was primarily influenced by topography with little influence of snow trapping from developing vegetation. Snow accumulation was most variable on hillslopes and redistribution was driven by slope position, with SWE greatest at the base of slopes and decreased toward crests. Snowmelt on hillslopes was controlled by slope aspect, as snow declined rapidly on west and south-facing slopes, compared with east and north-facing slopes. Unlike results previously reported on constructed uplands, snowmelt runoff from uplands was much less (similar to 30%), highlighting the influence of different construction materials. Model simulations indicate that antecedent soil moisture and soil temperature have a large influence on partitioning snowmelt over a range of observed conditions. Under a warmer and wetter climate, average annual peak SWE, and snow season duration could decline up to 52% and up to 61 days, respectively, while snowmelt runoff ceases completely under the warmest scenarios. Results suggest considerable future variability in snowmelt runoff from hillslopes, yet soil properties can be used to enhance vertical or lateral flows.", "authors": [ "Biagi, Kelly M.", "Carey, Sean K." ], "keywords": [ "climate change", "constructed wetland", "hillslope runoff", "oil sands", "reclamation", "snow hydrology" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -21.822559356689453, 3.0114686489105225 ], "cluster": 12.0 }, { "idx": 560, "title": "Identification of most spectrally distinguishable phenological stage of invasive Phramites australis in Lake Erie wetlands (Canada) for accurate mapping using multispectral satellite imagery", "abstract": "Phragmites australis (Cav.) Trin. ex Steudel subspecies australis is one of the worst plant invaders in wetlands of North America. Remote sensing is the most cost-effective method to track its spread given its widespread distribution and rapid colonization rate. We hypothesize that the morphological and/or physiological features associated with different phenological states of Phragmites can influence their reflectance signal and thus affect mapping accuracies. We tested this hypothesis by comparing classification accuracies of cloud-free images acquired by Landsat 7, Landsat 8, and Sentinel 2 at roughly monthly intervals over a calendar year for two wetlands in southern Ontario. We used the Support Vector Machines classification and employed field observations and image acquired from unmanned aerial vehicle (8 cm) to perform accuracy assessments. The highest Phragmites producer's, user's, and overall accuracy (96.00, 91.11, and 88.56% respectively) were provided by images acquired in late summer and fall period. During this period, green, Near Infrared, and Short-Wave Infrared bands generated more unique reflectance signals for Phragmites. Both Normalized Difference Vegetation Index and Normalized Difference Water Index showed significant difference between Phragmites and the most confused classes (cattail; Typha latifolia L., and meadow marsh) during the late summer and fall period. Since meadow marsh separated out best from Phragmites and cattail in the February image, we used it to mask the meadow marsh in the July image to reduce confusion. The unique reflectance signal of Phragmites in late summer and fall is likely due to prolonged greenness of Phragmites when compared to other wetland vegetation, large, distinct inflorescence, and the water content of Phragmites during this period.", "authors": [ "Rupasinghe, Prabha Amali", "Chow-Fraser, Patricia" ], "keywords": [ "Phragmites", "Wetlands", "Multispectral images", "SVM classification" ], "year": "2019", "source": "WETLANDS ECOLOGY AND MANAGEMENT", "publication_type": "J", "point2d": [ -58.80255889892578, 14.791376113891602 ], "cluster": 13.0 }, { "idx": 561, "title": "Heterogeneity of the peat profile and its role in unsaturated sodium chloride rise at field and laboratory scales", "abstract": "Resource extraction in Canada's boreal ecozone increases the risk of contaminant release into the area's extensive bog and fen peatlands. Lateral spreading, then upwards transport of solutes into the vadose zone of these moss-dominated ecosystems, could be toxic to vegetation. To evaluate the rate and character of contaminant rise in a subarctic bog, vadose zone-specific conductance and water content were measured in four hummocks similar to 5 m downslope of a 45-d 300-mg L-1 NaCl release. Four 30-cm-deep hummock peat mesocosms were extracted adjacent to the release site for an unsaturated evaporation-driven NaCl breakthrough experiment and subsequent parameterization. The field rate of solute accumulation was slower in near-surface (0-5 cm) peat, where low water contents limited pore connectivity. Solute accumulation was reduced by downward flushing by rain, though this was lesser in near surface moss where solute remained held in small disconnected pores. In the laboratory, Cl- rise reached the 15-cm depth in all mesocosms by Day 65. Sodium rise was 2.2 times slower, likely due to adsorption to the peat matrix. Rates of upwards solute movement were highly variable; the highest rates occurred in the mesocosm with small but hydrologically conductive pores near the surface, and the lowest occurred where vascular roots disrupted the physical structure of the peat. This research demonstrates that solute spilled into a bog peatland is likely to rise and be retained in the vadose zone. However, hydraulic and solute transport behaviors are sensitive to the vertical structure of peat, underscoring the need for extensive sampling and parameter characterization.", "authors": [ "Balliston, Nicole E.", "Price, Jonathan S." ], "keywords": [ "" ], "year": "2020", "source": "VADOSE ZONE JOURNAL", "publication_type": "J", "point2d": [ -5.16041898727417, 64.53246307373047 ], "cluster": 18.0 }, { "idx": 562, "title": "Improved groundwater table and L-band brightness temperature estimates for Northern Hemisphere peatlands using new model physics and SMOS observations in a global data assimilation framework", "abstract": "There is an urgent need to include northern peatland hydrology in global Earth system models to better understand land-atmosphere interactions and sensitivities of peatland functions to climate change, and, ultimately, to improve climate change predictions. In this study, we introduced for the first time peatland-specific model physics into an assimilation scheme for L-band brightness temperature (Tb) data from the Soil Moisture Ocean Salinity (SMOS) mission to improve groundwater table estimates. We conducted two sets of model-only and data assimilation experiments using the Catchment Land Surface Model (CLSM), applying (over peatlands only) in one of them a peatland-specific adaptation (PEATCLSM). The evaluation against in-situ measurements of peatland groundwater table depth indicates the superiority of PEATCLSM model physics and additionally improved performance after assimilating SMOS Tb observations. The better performance of PEATCLSM over nearly all Northern Hemisphere peatlands is further supported by the better agreement between SMOS Tb observations and Tb estimates from the model-only and data assimilation runs. Within the data assimilation scheme, PEATCLSM reduces Tb observation-minus-forecast residuals and leads to reduced data assimilation updates of water storage components and, thus, reduced water budget imbalances in the assimilation system.", "authors": [ "Bechtold, M.", "De Lannoy, G. J. M.", "Reichle, R. H.", "Roose, D.", "Balliston, N.", "Burdun, I", "Devito, K.", "Kurbatova, J.", "Strack, M.", "Zarov, E. A." ], "keywords": [ "Wetlands", "Ensemble Kalman filter", "Land surface model", "PEATCLSM", "Radiative transfer modeling", "Peatland hydrology", "Groundwater table depth", "Microtopography", "Boreal zone", "Microwave remote sensing", "Soil moisture", "Organic soil" ], "year": "2020", "source": "REMOTE SENSING OF ENVIRONMENT", "publication_type": "J", "point2d": [ -53.297210693359375, 24.90926742553711 ], "cluster": 8.0 }, { "idx": 563, "title": "Improved groundwater table and L-band brightness temperature estimates for Northern Hemisphere peatlands using new model physics and SMOS observations in a global data assimilation framework", "abstract": "There is an urgent need to include northern peatland hydrology in global Earth system models to better understand land-atmosphere interactions and sensitivities of peatland functions to climate change, and, ultimately, to improve climate change predictions. In this study, we introduced for the first time peatland-specific model physics into an assimilation scheme for L-band brightness temperature (Tb) data from the Soil Moisture Ocean Salinity (SMOS) mission to improve groundwater table estimates. We conducted two sets of model-only and data assimilation experiments using the Catchment Land Surface Model (CLSM), applying (over peatlands only) in one of them a peatland-specific adaptation (PEATCLSM). The evaluation against in-situ measurements of peatland groundwater table depth indicates the superiority of PEATCLSM model physics and additionally improved performance after assimilating SMOS Tb observations. The better performance of PEATCLSM over nearly all Northern Hemisphere peatlands is further supported by the better agreement between SMOS Tb observations and Tb estimates from the model-only and data assimilation runs. Within the data assimilation scheme, PEATCLSM reduces Tb observation-minus-forecast residuals and leads to reduced data assimilation updates of water storage components and, thus, reduced water budget imbalances in the assimilation system.", "authors": [ "Bechtold, M.", "De Lannoy, G. J. M.", "Reichle, R. H.", "Roose, D.", "Balliston, N.", "Burdun, I", "Devito, K.", "Kurbatova, J.", "Strack, M.", "Zarov, E. A." ], "keywords": [ "Wetlands", "Ensemble Kalman filter", "Land surface model", "PEATCLSM", "Radiative transfer modeling", "Peatland hydrology", "Groundwater table depth", "Microtopography", "Boreal zone", "Microwave remote sensing", "Soil moisture", "Organic soil" ], "year": "2020", "source": "REMOTE SENSING OF ENVIRONMENT", "publication_type": "J", "point2d": [ -53.6276741027832, 25.20011329650879 ], "cluster": 8.0 }, { "idx": 565, "title": "Spatial distribution of agricultural pesticide use and predicted wetland exposure in the Canadian Prairie Pothole Region", "abstract": "Agricultural pest control products are a major cause of degradation of water quality and biodiversity loss worldwide. In the Canadian Prairie Pothole Region, the landscape is characterized by millions of ecologically important wetlands, but also large farm sizes and high agrochemical use. Despite the region's agricultural intensity, the spatial extent of pesticide use and likelihood of pesticides contaminating surface water has been poorly studied. Here, we estimated the pesticide use patterns for three main groups (herbicides, fungicides and insecticides) using the most recent (2015) pesticide use survey data and digital crop maps. Furthermore, we developed a Wetland Pesticide Occurrence Index (WPOI; 1 km(2) resolution), to robustly estimate potential wetland exposure using spatially explicit data on pesticide use density, wetland density, precipitation and pesticide-specific physicochemical properties. In total, 39,236 metric tonnes of pesticides consisting of 94 active ingredients were applied to the Prairies in 2015. Herbicides had the highest density of use (24-183 kg/km(2)), followed by fungicides (0.4-23.8 kg/km(2)) and insecticides (0.4-3.6 kg/km(2)). Pesticide use differed by province; however, the major pesticides applied (e.g., glyphosate, prothioconazole, and thiamethoxam) were consistent across the region and were largely associated with wheat and canola crops. Although insecticides and fungicides had lower mass applied than herbicides, they had slightly higher overall WPOI scores. The predicted pesticide occurrence for insecticides and fungicides in wetlands was higher in the wetter central and eastern part of the Prairie region (WPOI = 0.6-1) compared to the drier western and southwestern part (WPOI = 0.1-0.6), suggesting that wetlands in much of Saskatchewan and southern Manitoba may be more vulnerable to higher and frequent contamination. Identifying crops, chemicals and landscapes with the greatest likelihood of pesticide contamination to wetlands will help prioritize future environmental monitoring programs and aid in assessing the ecological risk of specific pest control products in Canada's most agriculturally intensive region. (C) 2019 Elsevier B.V. All rights reserved.", "authors": [ "Malaj, Egina", "Liber, Karsten", "Morrissey, Christy A." ], "keywords": [ "Agriculture", "Fate", "Fungicide", "Herbicide", "Insecticide", "Pesticide", "Spatial modeling", "Mapping", "Wetlands" ], "year": "2020", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 38.1577033996582, -21.05521583557129 ], "cluster": 10.0 }, { "idx": 566, "title": "Estimation of depression-focussed groundwater recharge using chloride mass balance: problems and solutions across scales", "abstract": "This study evaluates the applicability of the chloride mass balance (CMB) method for groundwater recharge estimation in a semi-arid region in Canada, where recharge largely occurs under topographic depressions. The CMB applicability was tested at three scales: point-scale recharge rates at different topographical positions; average recharge rates incorporating multiple topographical positions on a local scale; and an identification of spatial trends of recharge on a regional scale. Agricultural chloride inputs were shown to be a major factor affecting chloride concentrations at all three scales, where elevated chloride concentrations in the shallow subsurface affected by agricultural inputs surpassed background concentrations by an order of magnitude. The propagation depth of elevated concentrations varied among study sites from being largely confined to the unsaturated zone to extending well into the saturated zone. Lateral chloride redistribution further affected the CMB applicability for point-scale recharge rates. Specific solutions enabling the CMB application in these conditions are presented, including runoff concentration measurements for point-scale estimates, using groundwater age tracers on a local scale, and using the harmonic mean concentration of a large number of samples on a regional scale.", "authors": [ "Pavlovskii, Igor", "Hayashi, Masaki", "Cey, Edwin E." ], "keywords": [ "Groundwater recharge", "Chloride mass balance", "Semi-arid", "Agriculture", "Unsaturated zone" ], "year": "2019", "source": "HYDROGEOLOGY JOURNAL", "publication_type": "J", "point2d": [ -5.1038994789123535, -21.15999984741211 ], "cluster": 10.0 }, { "idx": 567, "title": "Quantifying terrain controls on runoff retention and routing in the Northern Prairies", "abstract": "The role of hummocky terrain in governing runoff routing and focussing groundwater recharge in the Northern Prairies of North America is widely recognised. However, most hydrological studies in the region have not effectively utilised information on the surficial geology and associated landforms in large-scale hydrological characterization. The present study uses an automated digital elevation model (DEM) analysis of a 6500-km(2) area in the Northern Prairies to quantify hydrologically relevant terrain parameters for the common types of terrains in the prairies with different surficial deposits widespread in the prairies, namely, moraines and glaciolacustrine deposits. Runoff retention (and storage) capacity within depressions varies greatly between different surficial deposits and is comparable in magnitude with a typical amount of seasonal snowmelt runoff generation. The terrain constraint on potential runoff retention varies from a few millimetres in areas classified as moraine to tens of millimetres in areas classified as stagnant ice moraine deposits. Fluted moraine and glaciolacustrine deposits have intermediate storage capacity values. The study also identified the probability density function describing a number of immediate upstream neighbours for each depression in a fill-and-spill network. A relationship between depression parameters and surficial deposits, as well as identified depression network structure, allows parametrisation of hydrologic models outside of the high-resolution DEM coverage, which can still account for terrain variation in the Prairies.", "authors": [ "Pavlovskii, Igor", "Noorduijn, Saskia L.", "Liggett, Jessica E.", "Klassen, Jeanette", "Hayashi, Masaki" ], "keywords": [ "DEM analysis", "hummocky", "LiDAR", "prairies", "recharge", "runoff retention", "runoff routing", "terrain" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -7.781472682952881, -13.220796585083008 ], "cluster": 10.0 }, { "idx": 568, "title": "Characterization of the hydraulic conductivity of glacial till aquitards", "abstract": "Pleistocene-aged glacial sediments are found in many parts the Northern Hemisphere and are often composed of clay-rich tills which form aquitards that can control drainage and influence groundwater movement and contaminant transport. Site-scale investigations have characterized the hydraulic properties of till aquitards; however, the hydraulic conductivity of these units has not been quantitatively described at a regional scale of tens of kilometers. This study constrains regionally representative hydraulic conductivity estimates and characterizes the hydrogeological properties of Pleistocene-aged till aquitards from data collected at 15 sites compiled from 21 studies. The data quantify the scale dependence of hydraulic conductivity measurements in till aquitards and further define the relationship between hydraulic conductivity and depth. Data from centimeter-scale laboratory tests remained generally constant with depth, with a geometric mean hydraulic conductivity of 7.0 x 10(-11) m/s and a standard deviation of 0.4 orders of magnitude, while the meter-scale in-situ tests had a geometric mean of 4.9 x 10(-9) m/s and a standard deviation of 1.0 orders of magnitude at depths less than 10 m, and 3.7 x 10(-11) m/s and 0.2 order of magnitude at depths greater than 23 m. The results support the existence of a shallow fractured zone of higher hydraulic conductivity and a deeper zone characterized by matrix permeability. The observed data variability occurred primarily at the site scale, while the central tendency and variability of the data were consistent between sites separated by hundreds of kilometers suggesting that statistically derived, depth-defined regional hydraulic conductivity estimates can be meaningful.", "authors": [ "Ferris, David Milo", "Potter, Greg", "Ferguson, Grant" ], "keywords": [ "Interior Plains region", "Hydraulic properties", "Scale effects", "Hydraulic conductivity", "Glacial till" ], "year": "2020", "source": "HYDROGEOLOGY JOURNAL", "publication_type": "J", "point2d": [ 15.692072868347168, -9.199576377868652 ], "cluster": 18.0 }, { "idx": 569, "title": "Evaluating ecosystem services for agricultural wetlands: a systematic review and meta-analysis (Feb, 10.1007/s11273-022-09857-5, 2022)", "abstract": "", "authors": [ "Asare, Eric", "Mantyka-Pringle, Chrystal", "Anderson, Erik", "Belcher, Kenneth", "Clark, Robert" ], "keywords": [ "" ], "year": "2022", "source": "WETLANDS ECOLOGY AND MANAGEMENT", "publication_type": "J", "point2d": [ 47.834197998046875, -45.525115966796875 ], "cluster": 11.0 }, { "idx": 570, "title": "Assessment of Impacts of Climate Change on Tile Discharge and Nitrogen Yield Using the DRAINMOD Model", "abstract": "The detrimental impacts of agricultural subsurface tile flows and their associated pollutants on water quality is a major environmental issue in the Great Lakes region and many other places globally. A strong understanding of water quality indicators along with the contribution of tile-drained agriculture to water contamination is necessary to assess and reduce a significant source of non-point source pollution. In this study, DRAINMOD, a field-scale hydrology and water quality model, was applied to assess the impact of future climatic change on depth to water table, tile flow and associated nitrate loss from an 8.66 ha agricultural field near Londesborough, in Southwestern Ontario, Canada. The closest available climate data from a weather station approximately 10 km from the field site was used by the Ontario Ministry of Natural Resources and Forestry (MNRF) to generate future predictions of daily precipitation and maximum and minimum air temperatures required to create the weather files for DRAINMOD. Of the 28 models applied by MNRF, three models (CGCM3T47-Run5, GFDLCM2.0, and MIROC3.2hires) were selected based on the frequency of the models recommended for use in Ontario with SRA1B emission scenario. Results suggested that simulated tile flows and evapotranspiration (ET) in the 2071-2100 period are expected to increase by 7% and 14% compared to 1960-1990 period. Results also suggest that under future climates, significant increases in nitrate losses (about 50%) will occur along with the elevated tile flows. This work suggests that climate change will have a significant effect on field hydrology and water quality in tile-drained agricultural regions.", "authors": [ "Golmohammadi, Golmar", "Rudra, Ramesh P.", "Parkin, Gary W.", "Kulasekera, Priyantha B.", "Macrae, Merrin", "Goel, Pradeep K." ], "keywords": [ "field-scale hydrological models", "DRAINMOD", "tile drainage", "nitrate leaching", "climate change" ], "year": "2021", "source": "HYDROLOGY", "publication_type": "J", "point2d": [ 24.787263870239258, 6.524368762969971 ], "cluster": 10.0 }, { "idx": 571, "title": "Assessment of Impacts of Climate Change on Tile Discharge and Nitrogen Yield Using the DRAINMOD Model", "abstract": "The detrimental impacts of agricultural subsurface tile flows and their associated pollutants on water quality is a major environmental issue in the Great Lakes region and many other places globally. A strong understanding of water quality indicators along with the contribution of tile-drained agriculture to water contamination is necessary to assess and reduce a significant source of non-point source pollution. In this study, DRAINMOD, a field-scale hydrology and water quality model, was applied to assess the impact of future climatic change on depth to water table, tile flow and associated nitrate loss from an 8.66 ha agricultural field near Londesborough, in Southwestern Ontario, Canada. The closest available climate data from a weather station approximately 10 km from the field site was used by the Ontario Ministry of Natural Resources and Forestry (MNRF) to generate future predictions of daily precipitation and maximum and minimum air temperatures required to create the weather files for DRAINMOD. Of the 28 models applied by MNRF, three models (CGCM3T47-Run5, GFDLCM2.0, and MIROC3.2hires) were selected based on the frequency of the models recommended for use in Ontario with SRA1B emission scenario. Results suggested that simulated tile flows and evapotranspiration (ET) in the 2071-2100 period are expected to increase by 7% and 14% compared to 1960-1990 period. Results also suggest that under future climates, significant increases in nitrate losses (about 50%) will occur along with the elevated tile flows. This work suggests that climate change will have a significant effect on field hydrology and water quality in tile-drained agricultural regions.", "authors": [ "Golmohammadi, Golmar", "Rudra, Ramesh P.", "Parkin, Gary W.", "Kulasekera, Priyantha B.", "Macrae, Merrin", "Goel, Pradeep K." ], "keywords": [ "field-scale hydrological models", "DRAINMOD", "tile drainage", "nitrate leaching", "climate change" ], "year": "2021", "source": "HYDROLOGY", "publication_type": "J", "point2d": [ 24.40452003479004, 6.297006130218506 ], "cluster": 10.0 }, { "idx": 572, "title": "Biogeochemical and climate drivers of wetland phosphorus and nitrogen release: Implications for nutrient legacies and eutrophication risk", "abstract": "The dynamics and processes of nutrient cycling and release were examined for a lowland wetland-pond system, draining woodland in southern England. Hydrochemical and meteorological data were analyzed from 1997 to 2017, along with high-resolution in situ sensor measurements from 2016 to 2017. The results showed that even a relatively pristine wetland can become a source of highly bioavailable phosphorus (P), nitrogen (N), and silicon (Si) during low-flow periods of high ecological sensitivity. The drivers of nutrient release were primary production and accumulation of biomass, which provided a carbon (C) source for microbial respiration and, via mineralization, a source of bioavailable nutrients for P and N co-limited microorganisms. During high-intensity nutrient release events, the dominant N-cycling process switched from denitrification to nitrate ammonification, and a positive feedback cycle of P and N release was sustained over several months during summer and fall. Temperature controls on microbial activity were the primary drivers of short-term (day-to-day) variability in P release, with subdaily (diurnal) fluctuations in P concentrations driven by water body metabolism. Interannual relationships between nutrient release and climate variables indicated memory effects of antecedent climate drivers through accumulated legacy organic matter from the previous year's biomass production. Natural flood management initiatives promote the use of wetlands as nature-based solutions in climate change adaptation, flood management, and soil and water conservation. This study highlights potential water quality trade-offs and shows how the convergence of climate and biogeochemical drivers of wetland nutrient release can amplify background nutrient signals by mobilizing legacy nutrients, causing water quality impairment and accelerating eutrophication risk.", "authors": [ "Jarvie, Helen P.", "Pallett, Denise W.", "Schaefer, Stefanie M.", "Macrae, Merrin L.", "Bowes, Michael J.", "Farrand, Philip", "Warwick, Alan C.", "King, Stephen M.", "Williams, Richard J.", "Armstrong, Linda", "Nicholls, David J. E.", "Lord, William D.", "Rylett, Daniel", "Roberts, Colin", "Fisher, Nigel" ], "keywords": [ "" ], "year": "2020", "source": "JOURNAL OF ENVIRONMENTAL QUALITY", "publication_type": "J", "point2d": [ 33.39115524291992, 5.081811904907227 ], "cluster": 10.0 }, { "idx": 573, "title": "One size does not fit all: Toward regional conservation practice guidance to reduce phosphorus loss risk in the Lake Erie watershed", "abstract": "Agricultural phosphorus (P) losses to surface water bodies remain a global eutrophication concern, despite the application of conservation practices on farm fields. Although it is generally agreed upon that the use of multiple conservation practices (stacking) will lead to greater improvements to water quality, this may not be cost effective to farmers, reducing the likelihood of adoption. At present, wholesale recommendations of conservation practices are given; however, the application of specific conservation practices in certain environments (e.g., no-till with surface application, cover crops) may not be effective and can even lead to unintended consequences. In this paper, we present the Lake Erie watershed as a case study. The Lake Erie watershed contains regions with unique physical geographies that include differences in climate, soil, topography, and land use, which have implications for both P transport from agricultural fields and the efficacy of conservation practices in mitigating P losses. We define major regions within the Lake Erie watershed where common strategies for conservation practice implementation are appropriate, and we propose a five-step plan for bringing regionally tailored, adaptive, and cost-conscious conservation practice into watershed planning. Although this paper is specific to the Lake Erie watershed, our framework can be transferred across broader geographic regions to provide guidance for watershed planning.", "authors": [ "Macrae, Merrin", "Jarvie, Helen", "Brouwer, Roy", "Gunn, Grant", "Reid, Keith", "Joosse, Pam", "King, Kevin", "Kleinman, Peter", "Smith, Doug", "Williams, Mark", "Zwonitzer, Martha" ], "keywords": [ "" ], "year": "2021", "source": "JOURNAL OF ENVIRONMENTAL QUALITY", "publication_type": "J", "point2d": [ 43.9172477722168, 5.331737041473389 ], "cluster": 10.0 }, { "idx": 574, "title": "One size does not fit all: Toward regional conservation practice guidance to reduce phosphorus loss risk in the Lake Erie watershed", "abstract": "Agricultural phosphorus (P) losses to surface water bodies remain a global eutrophication concern, despite the application of conservation practices on farm fields. Although it is generally agreed upon that the use of multiple conservation practices (stacking) will lead to greater improvements to water quality, this may not be cost effective to farmers, reducing the likelihood of adoption. At present, wholesale recommendations of conservation practices are given; however, the application of specific conservation practices in certain environments (e.g., no-till with surface application, cover crops) may not be effective and can even lead to unintended consequences. In this paper, we present the Lake Erie watershed as a case study. The Lake Erie watershed contains regions with unique physical geographies that include differences in climate, soil, topography, and land use, which have implications for both P transport from agricultural fields and the efficacy of conservation practices in mitigating P losses. We define major regions within the Lake Erie watershed where common strategies for conservation practice implementation are appropriate, and we propose a five-step plan for bringing regionally tailored, adaptive, and cost-conscious conservation practice into watershed planning. Although this paper is specific to the Lake Erie watershed, our framework can be transferred across broader geographic regions to provide guidance for watershed planning.", "authors": [ "Macrae, Merrin", "Jarvie, Helen", "Brouwer, Roy", "Gunn, Grant", "Reid, Keith", "Joosse, Pam", "King, Kevin", "Kleinman, Peter", "Smith, Doug", "Williams, Mark", "Zwonitzer, Martha" ], "keywords": [ "" ], "year": "2021", "source": "JOURNAL OF ENVIRONMENTAL QUALITY", "publication_type": "J", "point2d": [ 43.80725860595703, 5.777340888977051 ], "cluster": 10.0 }, { "idx": 575, "title": "Pairing soil sampling with very-high resolution UAV imagery: An examination of drivers of soil and nutrient movement and agricultural productivity in southern Ontario", "abstract": "Soil erosion from agricultural lands continues to be a global societal problem. The movement of soils is often accompanied by nitrogen and phosphorus that are crucial to crop growth, but their redistribution from farm fields to waterways can reduce crop yields and degrade water quality. While within-field sediment and nutrient movement has been quantified using small plots and edge-of-field monitoring, these approaches fail to capture their spatial distribution. The pairing of soil sampling with unmanned aerial vehicle (UAV) data offers a novel and low-cost approach to map the spatial distribution of soil characteristics and nutrient concentrations within a farm field. UAV data are used to generate a digital terrain model and subsequently map within-field topographic variation and erosional flow pathways. Topographic variation is discretized into landform elements (flat, shoulder, backslope, footslope) that capture within-field heterogeneity and have potential for scaling out soil sampling to larger spatial extents. Our results show the controlling factor of water content and organic matter on crop yield, as represented by normalized difference vegetation index (NDVI). Significant differences in water content and organic matter were found across landform elements with increases in both parameters downslope. Upslope landform elements contained more sand content (9-20%) and had lower NDVI values than downslope elements. Complementing these findings, significant differences in organic matter, soluble nitrogen, and soluble reactive phosphorus occurred along erosional flow pathways. Our within-field results have implications for farmers, as our analysis of soil characteristics indicated that NDVI was positively correlated with water content (0.05), organic matter (0.15), silt (0.36), and clay (0.17) content and negatively correlated with soluble nitrogen ( - 0.47) and phosphorus ( - 0.30) concentrations. In addition to discussing the challenges and opportunities for expanding upon the presented research, we use a simple proof-of-concept hydrological model to demonstrate the potential role of hydrological connectivity and variable source area as a driver of within-field nutrient movement. The combination of our empirical results showing water content and organic matter as controlling factors on agricultural yield, the role of hydrological connectivity, and climate predictions of increased storm intensity suggest that additional research into the generation of novel time-series soil sampling and UAV-generated erosion and flow data could advance our understanding of the variations in soil characteristics and nutrient concentrations within individual farm fields.", "authors": [ "Pluer, E. G. Menzies", "Robinson, D. T.", "Meinen, B. U.", "Macrae, M. L." ], "keywords": [ "" ], "year": "2020", "source": "GEODERMA", "publication_type": "J", "point2d": [ -59.02728271484375, 6.551626682281494 ], "cluster": 10.0 }, { "idx": 576, "title": "Contribution of preferential flow to tile drainage varies spatially and temporally", "abstract": "Tile drainage of agricultural fields is a conduit for nutrient losses. Preferential flow in the soil can more directly connect surface runoff with tile drainage compared with matrix flow, which may also increase P losses. In this study, water temperature was monitored in surface runoff and tile drainage and electrical conductivity (EC) was measured in tile drainage at two sites in southern Ontario with different soil types (i.e., clay and loam). These data were used to estimate the percentage of preferential flow in tile drainage based on end member mixing. Estimates using temperature were compared with estimates using EC, and both were evaluated across seasons and hydrographs and compared with P concentration and load data. There was strong correlation (r = .83) between estimates of preferential flow using the two methods, but due to variability in surface temperatures, EC provided a less flashy estimate for preferential flow (Durbin-Watson statistics of 0.34 for temperature and 0.09 for EC). Preferential flow accounted for a higher percentage of tile drainage flow in clay soil than loam, but percentages were not significantly different between seasons or timing within events. Phosphorus concentrations and loads were weakly correlated with preferential flow, suggesting that P transport was influenced by other factors as well. Although further work is necessary to calibrate these methods for estimating preferential flow from continuously monitored temperature and EC, this technique can be applied to already collected data to model and test posited explanations of observed phenomena in P, other nutrients, and water transport from tile-drained agricultural land.", "authors": [ "Pluer, William T.", "Macrae, Merrin", "Buckley, Aaron", "Reid, Keith" ], "keywords": [ "" ], "year": "2020", "source": "VADOSE ZONE JOURNAL", "publication_type": "J", "point2d": [ 40.521785736083984, 20.6123046875 ], "cluster": 10.0 }, { "idx": 577, "title": "Joint Modeling of Crop and Irrigation in the central United States Using the Noah-MP Land Surface Model", "abstract": "Representing climate-crop interactions is critical to Earth system modeling. Despite recent progress in modeling dynamic crop growth and irrigation in land surface models (LSMs), transitioning these models from field to regional scales is still challenging. This study applies the Noah-MP LSM with dynamic crop-growth and irrigation schemes to jointly simulate the crop yield and irrigation amount for corn and soybean in the central United States. The model performance of crop yield and irrigation amount are evaluated at county-level against the USDA reports and USGS water withdrawal data, respectively. The bulk simulation (with uniform planting/harvesting management and no irrigation) produces significant biases in crop yield estimates for all planting regions, with root-mean-square-errors (RMSEs) being 28.1% and 28.4% for corn and soybean, respectively. Without an irrigation scheme, the crop yields in the irrigated regions are reduced due to water stress with RMSEs of 48.7% and 20.5%. Applying a dynamic irrigation scheme effectively improves crop yields in irrigated regions and reduces RMSEs to 22.3% and 16.8%. In rainfed regions, the model overestimates crop yields. Applying spatially varied planting and harvesting dates at state-level reduces crop yields and irrigation amount for both crops, especially in northern states. A nitrogen-stressed simulation is conducted and found that the improvement of irrigation on crop yields is limited when the crops are under nitrogen stress. Several uncertainties in modeling crop growth are identified, including yield-gap, planting date, rubisco capacity, and discrepancies between available data sets, pointing to future efforts to incorporating spatially varying crop parameters to better constrain crop growing seasons.", "authors": [ "Zhang, Zhe", "Barlage, Michael", "Chen, Fei", "Li, Yanping", "Helgason, Warren", "Xu, Xiaoyu", "Liu, Xing", "Li, Zhenhua" ], "keywords": [ "land surface model", "Earth system model", "crop", "irrigation", "parameters", "model uncertainties" ], "year": "2020", "source": "JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS", "publication_type": "J", "point2d": [ -58.467437744140625, 36.508853912353516 ], "cluster": 14.0 }, { "idx": 578, "title": "Joint Modeling of Crop and Irrigation in the central United States Using the Noah-MP Land Surface Model", "abstract": "Representing climate-crop interactions is critical to Earth system modeling. Despite recent progress in modeling dynamic crop growth and irrigation in land surface models (LSMs), transitioning these models from field to regional scales is still challenging. This study applies the Noah-MP LSM with dynamic crop-growth and irrigation schemes to jointly simulate the crop yield and irrigation amount for corn and soybean in the central United States. The model performance of crop yield and irrigation amount are evaluated at county-level against the USDA reports and USGS water withdrawal data, respectively. The bulk simulation (with uniform planting/harvesting management and no irrigation) produces significant biases in crop yield estimates for all planting regions, with root-mean-square-errors (RMSEs) being 28.1% and 28.4% for corn and soybean, respectively. Without an irrigation scheme, the crop yields in the irrigated regions are reduced due to water stress with RMSEs of 48.7% and 20.5%. Applying a dynamic irrigation scheme effectively improves crop yields in irrigated regions and reduces RMSEs to 22.3% and 16.8%. In rainfed regions, the model overestimates crop yields. Applying spatially varied planting and harvesting dates at state-level reduces crop yields and irrigation amount for both crops, especially in northern states. A nitrogen-stressed simulation is conducted and found that the improvement of irrigation on crop yields is limited when the crops are under nitrogen stress. Several uncertainties in modeling crop growth are identified, including yield-gap, planting date, rubisco capacity, and discrepancies between available data sets, pointing to future efforts to incorporating spatially varying crop parameters to better constrain crop growing seasons.", "authors": [ "Zhang, Zhe", "Barlage, Michael", "Chen, Fei", "Li, Yanping", "Helgason, Warren", "Xu, Xiaoyu", "Liu, Xing", "Li, Zhenhua" ], "keywords": [ "land surface model", "Earth system model", "crop", "irrigation", "parameters", "model uncertainties" ], "year": "2020", "source": "JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS", "publication_type": "J", "point2d": [ -58.467437744140625, 36.508853912353516 ], "cluster": 14.0 }, { "idx": 579, "title": "Energy and carbon fluxes from an oil sands pit lake", "abstract": "Currently, post-mining landscape plans in the Athabasca Oil Sand Region include large watersheds terminating in pit lakes. In 2012, Base Mine Lake (BML), was constructed with the aim of demonstrating technologies associated with lake reclamation in the region. This paper examines the first 6.5 years of lake-atmosphere energy and carbon exchange. Energetically, BML behaved similar to other northern lakes, storing large quantities of heat in the spring and releasing it in the fall as sensible and latent heat fluxes. At various times a hydrocarbon sheen formed on the lake, which may have suppressed evaporation. However, simple linear relationships failed to statistically quantify the impacts and more comprehensive modelling of the variability may be required. At daily scales, variability in evaporation was well explained by the product of vapour pressure deficit and wind speed as well as the available energy (R-2 = 0.74), while sensible heat was explained by the product of wind speed and the difference in air and surface temperature as well as available energy (R-2 = 0.85). Spring CH4 fluxes were high, particularly around ice melt, with a maximum flux of 3.3 g m(-2) day(-1). Otherwise fluxes were low, except during irregular periods. The peak flux of these periods occurred following similar to 58 h of continuously falling pressure, relating cyclone activity to these large periods of methane emissions. Annually, CO2 and CH4 fluxes were initially high, with median fluxes of 231 mg CO2 m(-2) h(-1) and 23 mg CH4 m(-2) h(-1) in 2014. However, the median fluxes reduced quickly and over the least three years of the study (2017 through 2019) the median fluxes declined to 36 mg CO2 m(-2) h(-1) and 10 mg CH4 m(-2) h(-1). Overall, BML behaves similar to other boreal lake ecosystems with above average carbon fluxes compared to other constructed reservoirs. (C) 2020 Elsevier B.V. All rights reserved.", "authors": [ "Clark, M. Graham", "Drewitt, Gordon B.", "Carey, Sean K." ], "keywords": [ "Oil sands", "Pit lake", "Mine closure", "Carbon emissions", "Evaporation", "Eddy covariance" ], "year": "2021", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 0.20689363777637482, 8.355034828186035 ], "cluster": 18.0 }, { "idx": 580, "title": "Detection of Potential Vernal Pools on the Canadian Shield (Ontario) Using Object-Based Image Analysis in Combination with Machine Learning", "abstract": "Vernal pools are small, temporary, forested wetlands of ecological importance with a high sensitivity to changing climate and land-use patterns. These ecosystems are under considerable development pressure in southeastern Georgian Bay, where mapping techniques are required to inform wise land-use decisions. Our mapping approach combines common machine learning techniques [random forest, support vector machines (SVMs)] with object-based image analysis. Using multispectral image segmentation on high-resolution orthoimagery, we first created objects and assigned classes based on field collected data. We then supplied machine learning algorithms with data from freely available sources (Ontario orthoimagery and Sentinel 2) and tested accuracy on a reserved dataset. We achieved producer's accuracies of 85 and 79% and user's accuracies of 78 and 84% for random forest and SVMs models, respectively. Difficulty differentiating between small, dark shadows and small, obscured pools accounted for many of the omission and commission errors. Our automated approach of vernal pool classification provides a relatively accurate, consistent, and fast mapping strategy compared to manual photointerpretation. Our models can be applied on a regional basis to help verify the locations of pools in an area of Ontario that is in critical need of more detailed ecological information.", "authors": [ "Luymes, Nick", "Chow-Fraser, Patricia" ], "keywords": [ "" ], "year": "2021", "source": "CANADIAN JOURNAL OF REMOTE SENSING", "publication_type": "J", "point2d": [ -58.969730377197266, 14.002728462219238 ], "cluster": 8.0 }, { "idx": 581, "title": "Upcycling wildfire-impacted boreal peats into porous carbons that efficiently remove phenolic micropollutants", "abstract": "Activated carbons have been widely used for water treatment due to their large surface area and structural stability. Their high cost has motivated the development of sustainable bio-based sorbents. However, their industrial acceptance within the water industry is limited by lower surface areas and poorer adsorptive capacities as compared with commercial sorbents. We herein report a green, high performance porous carbon produced from boreal peats for organic micropollutant removal. Boreal peatlands are increasingly damaged due to climate change-induced wildfires and droughts, which lead to increased run-off and impeded forest regrowth. Fireimpacted peatland soils therefore were excavated and converted into value-added porous carbons through ZnCl2 activation at low temperature (400 - 600 degrees C). These products have significantly higher surface areas (> 1377 m(2)/g) than commercial activated carbon Norit GSX (965 m(2)/g). Adsorption of p-nitrophenol, a micropollutant, onto the porous carbons is efficient, and superior to that of Norit GSX and most sorbents reported in the literature. Adsorption mainly occurred through multi-layer chemisorption and was impacted by the electron donor-acceptor complexes mechanism, pi-pi interactions and steric effects. Because of the massive environmental and economic benefits, peat porous carbons are strong candidates for use in large-scale water treatment facilities.", "authors": [ "Wu, Yichen", "Zhang, Nan", "de Lannoy, Charles-Francois" ], "keywords": [ "Feather moss", "Boreal peat", "p-nitrophenol", "Zinc chloride activation", "Bio-based porous carbon" ], "year": "2021", "source": "JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING", "publication_type": "J", "point2d": [ -1.864640474319458, 71.54558563232422 ], "cluster": 9.0 }, { "idx": 582, "title": "Scientists' warning on extreme wildfire risks to water supply", "abstract": "2020 is the year of wildfire records. California experienced its three largest fires early in its fire season. The Pantanal, the largest wetland on the planet, burned over 20% of its surface. More than 18 million hectares of forest and bushland burned during the 2019-2020 fire season in Australia, killing 33 people, destroying nearly 2500 homes, and endangering many endemic species. The direct cost of damages is being counted in dozens of billion dollars, but the indirect costs on water-related ecosystem services and benefits could be equally expensive, with impacts lasting for decades. In Australia, the extreme precipitation (200 mm day-1 in several location) that interrupted the catastrophic wildfire season triggered a series of watershed effects from headwaters to areas downstream. The increased runoff and erosion from burned areas disrupted water supplies in several locations. These post-fire watershed hazards via source water contamination, flash floods, and mudslides can represent substantial, systemic long-term risks to drinking water production, aquatic life, and socio-economic activity. Scenarios similar to the recent event in Australia are now predicted to unfold in the Western USA. This is a new reality that societies will have to live with as uncharted fire activity, water crises, and widespread human footprint collide all-around of the world. Therefore, we advocate for a more proactive approach to wildfire-watershed risk governance in an effort to advance and protect water security. We also argue that there is no easy solution to reducing this risk and that investments in both green (i.e., natural) and grey (i.e., built) infrastructure will be necessary. Further, we propose strategies to combine modern data analytics with existing tools for use by water and land managers worldwide to leverage several decades worth of data and knowledge on post-fire hydrology.", "authors": [ "Robinne, Francois-Nicolas", "Hallema, Dennis W.", "Bladon, Kevin D.", "Flannigan, Mike D.", "Boisrame, Gabrielle", "Brethaut, Christian M.", "Doerr, Stefan H.", "Di Baldassarre, Giuliano", "Gallagher, Louise A.", "Hohner, Amanda K.", "Khan, Stuart J.", "Kinoshita, Alicia M.", "Mordecai, Rua", "Nunes, Joao Pedro", "Nyman, Petter", "Santin, Cristina", "Sheridan, Gary", "Stoof, Cathelijne R.", "Thompson, Matthew P.", "Waddington, James M.", "Wei, Yu" ], "keywords": [ "climate change", "extreme events", "fire regime restoration", "forest ecosystem services", "risk governance", "socio-hydrology", "water security", "watershed protection" ], "year": "2021", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 23.07841682434082, -28.32815933227539 ], "cluster": 11.0 }, { "idx": 583, "title": "Scientists' warning on extreme wildfire risks to water supply", "abstract": "2020 is the year of wildfire records. California experienced its three largest fires early in its fire season. The Pantanal, the largest wetland on the planet, burned over 20% of its surface. More than 18 million hectares of forest and bushland burned during the 2019-2020 fire season in Australia, killing 33 people, destroying nearly 2500 homes, and endangering many endemic species. The direct cost of damages is being counted in dozens of billion dollars, but the indirect costs on water-related ecosystem services and benefits could be equally expensive, with impacts lasting for decades. In Australia, the extreme precipitation (200 mm day-1 in several location) that interrupted the catastrophic wildfire season triggered a series of watershed effects from headwaters to areas downstream. The increased runoff and erosion from burned areas disrupted water supplies in several locations. These post-fire watershed hazards via source water contamination, flash floods, and mudslides can represent substantial, systemic long-term risks to drinking water production, aquatic life, and socio-economic activity. Scenarios similar to the recent event in Australia are now predicted to unfold in the Western USA. This is a new reality that societies will have to live with as uncharted fire activity, water crises, and widespread human footprint collide all-around of the world. Therefore, we advocate for a more proactive approach to wildfire-watershed risk governance in an effort to advance and protect water security. We also argue that there is no easy solution to reducing this risk and that investments in both green (i.e., natural) and grey (i.e., built) infrastructure will be necessary. Further, we propose strategies to combine modern data analytics with existing tools for use by water and land managers worldwide to leverage several decades worth of data and knowledge on post-fire hydrology.", "authors": [ "Robinne, Francois-Nicolas", "Hallema, Dennis W.", "Bladon, Kevin D.", "Flannigan, Mike D.", "Boisrame, Gabrielle", "Brethaut, Christian M.", "Doerr, Stefan H.", "Di Baldassarre, Giuliano", "Gallagher, Louise A.", "Hohner, Amanda K.", "Khan, Stuart J.", "Kinoshita, Alicia M.", "Mordecai, Rua", "Nunes, Joao Pedro", "Nyman, Petter", "Santin, Cristina", "Sheridan, Gary", "Stoof, Cathelijne R.", "Thompson, Matthew P.", "Waddington, James M.", "Wei, Yu" ], "keywords": [ "climate change", "extreme events", "fire regime restoration", "forest ecosystem services", "risk governance", "socio-hydrology", "water security", "watershed protection" ], "year": "2021", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 23.194936752319336, -27.821109771728516 ], "cluster": 11.0 }, { "idx": 587, "title": "Summary and synthesis of Changing Cold Regions Network (CCRN) research in the interior of western Canada - Part 2: Future change in cryosphere, vegetation, and hydrology", "abstract": "The interior of western Canada, like many similar cold mid- to high-latitude regions worldwide, is undergoing extensive and rapid climate and environmental change, which may accelerate in the coming decades. Understanding and predicting changes in coupled climate-land-hydrological systems are crucial to society yet limited by lack of understanding of changes in cold-region process responses and interactions, along with their representation in most current-generation land-surface and hydrological models. It is essential to consider the underlying processes and base predictive models on the proper physics, especially under conditions of non-stationarity where the past is no longer a reliable guide to the future and system trajectories can be unexpected. These challenges were forefront in the recently completed Changing Cold Regions Network (CCRN), which assembled and focused a wide range of multi-disciplinary expertise to improve the understanding, diagnosis, and prediction of change over the cold interior of western Canada. CCRN advanced knowledge of fundamental cold-region ecological and hydrological processes through observation and experimentation across a network of highly instrumented research basins and other sites. Significant efforts were made to improve the functionality and process representation, based on this improved understanding, within the fine-scale Cold Regions Hydrological Modelling (CRHM) platform and the large-scale Modelisation Environmentale Communautaire (MEC) - Surface and Hydrology (MESH) model. These models were, and continue to be, applied under past and projected future climates and under current and expected future land and vegetation cover configurations to diagnose historical change and predict possible future hydrological responses. This second of two articles synthesizes the nature and understanding of cold-region processes and Earth system responses to future climate, as advanced by CCRN. These include changing precipitation and moisture feedbacks to the atmosphere; altered snow regimes, changing balance of snowfall and rainfall, and glacier loss; vegetation responses to climate and the loss of ecosystem resilience to wildfire and disturbance; thawing permafrost and its influence on landscapes and hydrology; groundwater storage and cycling and its connections to surface water; and stream and river discharge as influenced by the various drivers of hydrological change. Collective insights, expert elicitation, and model application are used to provide a synthesis of this change over the CCRN region for the late 21st century.", "authors": [ "DeBeer, Chris M.", "Wheater, Howard S.", "Pomeroy, John W.", "Barr, Alan G.", "Baltzer, Jennifer L.", "Johnstone, Jill F.", "Turetsky, Merritt R.", "Stewart, Ronald E.", "Hayashi, Masaki", "van der Kamp, Garth", "Marshall, Shawn", "Campbell, Elizabeth", "Marsh, Philip", "Carey, Sean K.", "Quinton, William L.", "Li, Yanping", "Razavi, Saman", "Berg, Aaron", "McDonnell, Jeffrey J.", "Spence, Christopher", "Helgason, Warren D.", "Ireson, Andrew M.", "Black, T. Andrew", "Elshamy, Mohamed", "Yassin, Fuad", "Davison, Bruce", "Howard, Allan", "Theriault, Julie M.", "Shook, Kevin", "Demuth, Michael N.", "Pietroniro, Alain" ], "keywords": [ "" ], "year": "2021", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -24.14746856689453, -15.149483680725098 ], "cluster": 1.0 }, { "idx": 588, "title": "Summary and synthesis of Changing Cold Regions Network (CCRN) research in the interior of western Canada - Part 2: Future change in cryosphere, vegetation, and hydrology", "abstract": "The interior of western Canada, like many similar cold mid- to high-latitude regions worldwide, is undergoing extensive and rapid climate and environmental change, which may accelerate in the coming decades. Understanding and predicting changes in coupled climate-land-hydrological systems are crucial to society yet limited by lack of understanding of changes in cold-region process responses and interactions, along with their representation in most current-generation land-surface and hydrological models. It is essential to consider the underlying processes and base predictive models on the proper physics, especially under conditions of non-stationarity where the past is no longer a reliable guide to the future and system trajectories can be unexpected. These challenges were forefront in the recently completed Changing Cold Regions Network (CCRN), which assembled and focused a wide range of multi-disciplinary expertise to improve the understanding, diagnosis, and prediction of change over the cold interior of western Canada. CCRN advanced knowledge of fundamental cold-region ecological and hydrological processes through observation and experimentation across a network of highly instrumented research basins and other sites. Significant efforts were made to improve the functionality and process representation, based on this improved understanding, within the fine-scale Cold Regions Hydrological Modelling (CRHM) platform and the large-scale Modelisation Environmentale Communautaire (MEC) - Surface and Hydrology (MESH) model. These models were, and continue to be, applied under past and projected future climates and under current and expected future land and vegetation cover configurations to diagnose historical change and predict possible future hydrological responses. This second of two articles synthesizes the nature and understanding of cold-region processes and Earth system responses to future climate, as advanced by CCRN. These include changing precipitation and moisture feedbacks to the atmosphere; altered snow regimes, changing balance of snowfall and rainfall, and glacier loss; vegetation responses to climate and the loss of ecosystem resilience to wildfire and disturbance; thawing permafrost and its influence on landscapes and hydrology; groundwater storage and cycling and its connections to surface water; and stream and river discharge as influenced by the various drivers of hydrological change. Collective insights, expert elicitation, and model application are used to provide a synthesis of this change over the CCRN region for the late 21st century.", "authors": [ "DeBeer, Chris M.", "Wheater, Howard S.", "Pomeroy, John W.", "Barr, Alan G.", "Baltzer, Jennifer L.", "Johnstone, Jill F.", "Turetsky, Merritt R.", "Stewart, Ronald E.", "Hayashi, Masaki", "van der Kamp, Garth", "Marshall, Shawn", "Campbell, Elizabeth", "Marsh, Philip", "Carey, Sean K.", "Quinton, William L.", "Li, Yanping", "Razavi, Saman", "Berg, Aaron", "McDonnell, Jeffrey J.", "Spence, Christopher", "Helgason, Warren D.", "Ireson, Andrew M.", "Black, T. Andrew", "Elshamy, Mohamed", "Yassin, Fuad", "Davison, Bruce", "Howard, Allan", "Theriault, Julie M.", "Shook, Kevin", "Demuth, Michael N.", "Pietroniro, Alain" ], "keywords": [ "" ], "year": "2021", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -23.73432731628418, -15.346302032470703 ], "cluster": 1.0 }, { "idx": 589, "title": "The Role of Circulation and Its Changes in Present and Future Atmospheric Rivers over Western North America", "abstract": "Performance in simulating atmospheric rivers (ARs) over western North America based on AR frequency and landfall latitude is evaluated for 10 models from phase 5 of the Coupled Model Intercomparison Project among which the CanESM2 model performs well. ARs are classified into southern, northern, and middle types using self-organizing maps in the ERA-Interim reanalysis and CanESM2. The southern type is associated with the development and eastward movement of anomalous lower pressure over the subtropical eastern Pacific, while the northern type is linked with the eastward movement of anomalous cyclonic circulation stimulated by warm sea surface temperatures over the subtropical western Pacific. The middle type is connected with the negative phase of North Pacific Oscillation-west Pacific teleconnection pattern. CanESM2 is further used to investigate projected AR changes at the end of the twenty-first century under the representative concentration pathway 8.5 scenario. AR definitions usually reference fixed integrated water vapor or integrated water vapor transport thresholds. AR changes under such definitions reflect both thermodynamic and dynamic influences. We therefore also use a modified AR definition that isolates change from dynamic influences only. The total AR frequency doubles compared to the historical period, with the middle AR type contributing the largest increases along the coasts of Vancouver Island and California. Atmospheric circulation (dynamic) changes decrease northern AR type frequency while increasing middle AR type frequency, indicating that future changes of circulation patterns modify the direct effect of warming on AR frequency, which would increase ARs (relative to fixed thresholds) almost everywhere along the North American coastline.", "authors": [ "Tan, Yaheng", "Zwiers, Francis", "Yang, Song", "Li, Chao", "Deng, Kaiqiang" ], "keywords": [ "Atmosphere", "North America", "Atmospheric circulation", "Mesoscale processes", "Climate change", "Climate models" ], "year": "2020", "source": "JOURNAL OF CLIMATE", "publication_type": "J", "point2d": [ -21.527931213378906, -38.202674865722656 ], "cluster": 14.0 }, { "idx": 590, "title": "The Role of Circulation and Its Changes in Present and Future Atmospheric Rivers over Western North America", "abstract": "Performance in simulating atmospheric rivers (ARs) over western North America based on AR frequency and landfall latitude is evaluated for 10 models from phase 5 of the Coupled Model Intercomparison Project among which the CanESM2 model performs well. ARs are classified into southern, northern, and middle types using self-organizing maps in the ERA-Interim reanalysis and CanESM2. The southern type is associated with the development and eastward movement of anomalous lower pressure over the subtropical eastern Pacific, while the northern type is linked with the eastward movement of anomalous cyclonic circulation stimulated by warm sea surface temperatures over the subtropical western Pacific. The middle type is connected with the negative phase of North Pacific Oscillation-west Pacific teleconnection pattern. CanESM2 is further used to investigate projected AR changes at the end of the twenty-first century under the representative concentration pathway 8.5 scenario. AR definitions usually reference fixed integrated water vapor or integrated water vapor transport thresholds. AR changes under such definitions reflect both thermodynamic and dynamic influences. We therefore also use a modified AR definition that isolates change from dynamic influences only. The total AR frequency doubles compared to the historical period, with the middle AR type contributing the largest increases along the coasts of Vancouver Island and California. Atmospheric circulation (dynamic) changes decrease northern AR type frequency while increasing middle AR type frequency, indicating that future changes of circulation patterns modify the direct effect of warming on AR frequency, which would increase ARs (relative to fixed thresholds) almost everywhere along the North American coastline.", "authors": [ "Tan, Yaheng", "Zwiers, Francis", "Yang, Song", "Li, Chao", "Deng, Kaiqiang" ], "keywords": [ "Atmosphere", "North America", "Atmospheric circulation", "Mesoscale processes", "Climate change", "Climate models" ], "year": "2020", "source": "JOURNAL OF CLIMATE", "publication_type": "J", "point2d": [ -21.527931213378906, -38.202674865722656 ], "cluster": 14.0 }, { "idx": 596, "title": "The Numerical Implementation of Land Models: Problem Formulation and Laugh Tests", "abstract": "The intent of this paper is to encourage improved numerical implementation of land models. Our contributions in this paper are twofold. First, we present a unified framework to formulate and implement land model equations. We separate the representation of physical processes from their numerical solution, enabling the use of established robust numerical methods to solve the model equations. Second, we introduce a set of synthetic test cases (the laugh tests) to evaluate the numerical implementation of land models. The test cases include storage and transmission of water in soils, lateral subsurface flow, coupled hydrological and thermodynamic processes in snow, and cryosuction processes in soil. We consider synthetic test cases as laugh tests for land models because they provide the most rudimentary test of model capabilities. The laugh tests presented in this paper are all solved with the Structure for Unifying Multiple Modeling Alternatives (SUMMA) model implemented using the Suite of Nonlinear and Differential/Algebraic Equation Solvers (SUNDIALS). The numerical simulations from SUMMA/SUNDIALS are compared against 1) solutions to the synthetic test cases from other models documented in the peer-reviewed literature, 2) analytical solutions, and 3) observations made in laboratory experiments. In all cases, the numerical simulations are similar to the benchmarks, building confidence in the numerical model implementation. We posit that some land models may have difficulty in solving these benchmark problems. Dedicating more effort to solving synthetic test cases is critical in order to build confidence in the numerical implementation of land models.", "authors": [ "Clark, Martyn P.", "Zolfaghari, Reza", "Green, Kevin R.", "Trim, Sean", "Knoben, Wouter J. M.", "Bennett, Andrew", "Nijssen, Bart", "Ireson, Andrew", "Spiteri, Raymond J." ], "keywords": [ "Diagnostics", "Hydrologic models", "Land surface model" ], "year": "2021", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ 7.276869773864746, -50.962730407714844 ], "cluster": 12.0 }, { "idx": 597, "title": "The Numerical Implementation of Land Models: Problem Formulation and Laugh Tests", "abstract": "The intent of this paper is to encourage improved numerical implementation of land models. Our contributions in this paper are twofold. First, we present a unified framework to formulate and implement land model equations. We separate the representation of physical processes from their numerical solution, enabling the use of established robust numerical methods to solve the model equations. Second, we introduce a set of synthetic test cases (the laugh tests) to evaluate the numerical implementation of land models. The test cases include storage and transmission of water in soils, lateral subsurface flow, coupled hydrological and thermodynamic processes in snow, and cryosuction processes in soil. We consider synthetic test cases as laugh tests for land models because they provide the most rudimentary test of model capabilities. The laugh tests presented in this paper are all solved with the Structure for Unifying Multiple Modeling Alternatives (SUMMA) model implemented using the Suite of Nonlinear and Differential/Algebraic Equation Solvers (SUNDIALS). The numerical simulations from SUMMA/SUNDIALS are compared against 1) solutions to the synthetic test cases from other models documented in the peer-reviewed literature, 2) analytical solutions, and 3) observations made in laboratory experiments. In all cases, the numerical simulations are similar to the benchmarks, building confidence in the numerical model implementation. We posit that some land models may have difficulty in solving these benchmark problems. Dedicating more effort to solving synthetic test cases is critical in order to build confidence in the numerical implementation of land models.", "authors": [ "Clark, Martyn P.", "Zolfaghari, Reza", "Green, Kevin R.", "Trim, Sean", "Knoben, Wouter J. M.", "Bennett, Andrew", "Nijssen, Bart", "Ireson, Andrew", "Spiteri, Raymond J." ], "keywords": [ "Diagnostics", "Hydrologic models", "Land surface model" ], "year": "2021", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ 8.164041519165039, -51.37485885620117 ], "cluster": 12.0 }, { "idx": 598, "title": "The Numerical Implementation of Land Models: Problem Formulation and Laugh Tests", "abstract": "The intent of this paper is to encourage improved numerical implementation of land models. Our contributions in this paper are twofold. First, we present a unified framework to formulate and implement land model equations. We separate the representation of physical processes from their numerical solution, enabling the use of established robust numerical methods to solve the model equations. Second, we introduce a set of synthetic test cases (the laugh tests) to evaluate the numerical implementation of land models. The test cases include storage and transmission of water in soils, lateral subsurface flow, coupled hydrological and thermodynamic processes in snow, and cryosuction processes in soil. We consider synthetic test cases as laugh tests for land models because they provide the most rudimentary test of model capabilities. The laugh tests presented in this paper are all solved with the Structure for Unifying Multiple Modeling Alternatives (SUMMA) model implemented using the Suite of Nonlinear and Differential/Algebraic Equation Solvers (SUNDIALS). The numerical simulations from SUMMA/SUNDIALS are compared against 1) solutions to the synthetic test cases from other models documented in the peer-reviewed literature, 2) analytical solutions, and 3) observations made in laboratory experiments. In all cases, the numerical simulations are similar to the benchmarks, building confidence in the numerical model implementation. We posit that some land models may have difficulty in solving these benchmark problems. Dedicating more effort to solving synthetic test cases is critical in order to build confidence in the numerical implementation of land models.", "authors": [ "Clark, Martyn P.", "Zolfaghari, Reza", "Green, Kevin R.", "Trim, Sean", "Knoben, Wouter J. M.", "Bennett, Andrew", "Nijssen, Bart", "Ireson, Andrew", "Spiteri, Raymond J." ], "keywords": [ "Diagnostics", "Hydrologic models", "Land surface model" ], "year": "2021", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ 7.366671562194824, -51.92144775390625 ], "cluster": 12.0 }, { "idx": 599, "title": "The Nutrient App: Developing a smartphone application for on-site instantaneous community-based NO3 and PO4 monitoring", "abstract": "Freshwater ecosystems, particularly those in agricultural areas, remain at risk of eutrophication due to anthropogenic inputs of nutrients. While community-based monitoring has helped improve awareness and spur action to mitigate nutrient loads, monitoring is challenging due to the reliance on expensive laboratory technology, poor data management, time lags between measurement and availability of results, and risk of sample degradation during transport or storage. In this study, an easy-to-use smartphone-based application (The Nutrient App) was developed to estimate NO3 and PO4 concentrations through the image-processing of on-site qualitative colorimetric-based results obtained via cheap commercially-available instantaneous test kits. The app was tested in rivers, wetlands, and lakes across Canada and relative errors between 30% (filtered samples) and 70% (unfiltered samples) were obtained for both NO3 and PO4. The app can be used to identify sources and hotspots of contamination, which can empower communities to take immediate remedial action to reduce nutrient pollution.", "authors": [ "Costa, Diogo", "Aziz, Uswah", "Elliott, Jane", "Baulch, Helen", "Roy, Banani", "Schneider, Kevin", "Pomeroy, John" ], "keywords": [ "Community-based monitoring", "Smartphone", "Mobile application", "Low cost", "Nitrate", "Phosphate" ], "year": "2020", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 75.97079467773438, 41.0258674621582 ], "cluster": 19.0 }, { "idx": 600, "title": "CROKAGE: effective solution recommendation for programming tasks by leveraging crowd knowledge", "abstract": "Developers often search for relevant code examples on the web for their programming tasks. Unfortunately, they face three major problems. First, they frequently need to read and analyse multiple results from the search engines to obtain a satisfactory solution. Second, the search is impaired due to a lexical gap between the query (task description) and the information associated with the solution (e.g., code example). Third, the retrieved solution may not be comprehensible, i.e., the code segment might miss a succinct explanation. To address these three problems, we propose CROKAGE (CrowdKnowledge Answer Generator), a tool that takes the description of a programming task (the query) as input and delivers a comprehensible solution for the task. Our solutions contain not only relevant code examples but also their succinct explanations written by human developers. The search for code examples is modeled as an Information Retrieval (IR) problem. We first leverage the crowd knowledge stored in Stack Overflow to retrieve the candidate answers against a programming task. For this, we use a fine-tuned IR technique, chosen after comparing 11 IR techniques in terms of performance. Then we use a multi-factor relevance mechanism to mitigate the lexical gap problem, and select the top quality answers related to the task. Finally, we perform natural language processing on the top quality answers and deliver the comprehensible solutions containing both code examples and code explanations unlike earlier studies. We evaluate and compare our approach against ten baselines, including the state-of-art. We show that CROKAGE outperforms the ten baselines in suggesting relevant solutions for 902 programming tasks (i.e., queries) of three popular programming languages: Java, Python and PHP. Furthermore, we use 24 programming tasks (queries) to evaluate our solutions with 29 developers and confirm that CROKAGE outperforms the state-of-art tool in terms of relevance of the suggested code examples, benefit of the code explanations and the overall solution quality (code + explanation).", "authors": [ "da Silva, Rodrigo Fernandes Gomes", "Roy, Chanchal K.", "Rahman, Mohammad Masudur", "Schneider, Kevin A.", "Paixao, Klerisson", "Dantas, Carlos Eduardo de Carvalho", "Maia, Marcelo de Almeida" ], "keywords": [ "Mining crowd knowledge", "Stack overflow", "Word embedding", "Code search" ], "year": "2020", "source": "EMPIRICAL SOFTWARE ENGINEERING", "publication_type": "J", "point2d": [ 34.645328521728516, -96.59127044677734 ], "cluster": 5.0 }, { "idx": 602, "title": "The proper care and feeding of CAMELS: How limited training data affects streamflow prediction", "abstract": "Accurate streamflow prediction largely relies on historical meteorological records and streamflow measurements. For many regions, however, such data are only scarcely available. Facing this problem, many studies simply trained their machine learning models on the region's available data, leaving possible repercussions of this strategy unclear. In this study, we evaluate the sensitivity of treeand LSTM-based models to limited training data, both in terms of geographic diversity and different time spans. We feed the models meteorological observations disseminated with the CAMELS dataset, and individually restrict the training period length, number of training basins, and input sequence length. We quantify how additional training data improve predictions and how many previous days of forcings we should feed the models to obtain best predictions for each training set size. Further, our findings show that treeand LSTM-based models provide similarly accurate predictions on small datasets, while LSTMs are superior given more training data.", "authors": [ "Gauch, Martin", "Mai, Juliane", "Lin, Jimmy" ], "keywords": [ "LSTM", "XGBoost", "CAMELS", "Streamflow prediction", "Machine learning" ], "year": "2021", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ -20.138395309448242, -64.27487182617188 ], "cluster": 16.0 }, { "idx": 603, "title": "The proper care and feeding of CAMELS: How limited training data affects streamflow prediction", "abstract": "Accurate streamflow prediction largely relies on historical meteorological records and streamflow measurements. For many regions, however, such data are only scarcely available. Facing this problem, many studies simply trained their machine learning models on the region's available data, leaving possible repercussions of this strategy unclear. In this study, we evaluate the sensitivity of treeand LSTM-based models to limited training data, both in terms of geographic diversity and different time spans. We feed the models meteorological observations disseminated with the CAMELS dataset, and individually restrict the training period length, number of training basins, and input sequence length. We quantify how additional training data improve predictions and how many previous days of forcings we should feed the models to obtain best predictions for each training set size. Further, our findings show that treeand LSTM-based models provide similarly accurate predictions on small datasets, while LSTMs are superior given more training data.", "authors": [ "Gauch, Martin", "Mai, Juliane", "Lin, Jimmy" ], "keywords": [ "LSTM", "XGBoost", "CAMELS", "Streamflow prediction", "Machine learning" ], "year": "2021", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ -20.560138702392578, -64.2222671508789 ], "cluster": 16.0 }, { "idx": 604, "title": "Great Lakes Runoff Intercomparison Project Phase 3: Lake Erie (GRIP-E)", "abstract": "Hydrologic model intercomparison studies help to evaluate the agility of models to simulate variables such as streamflow, evaporation, and soil moisture. This study is the third in a sequence of the Great Lakes Runoff Intercomparison Projects. The densely populated Lake Erie watershed studied here is an important international lake that has experienced recent flooding and shoreline erosion alongside excessive nutrient loads that have contributed to lake eutrophication. Understanding the sources and pathways of flows is critical to solve the complex issues facing this watershed. Seventeen hydrologic and land-surface models of different complexity are set up over this domain using the same meteorological forcings, and their simulated streamflows at 46 calibration and seven independent validation stations are compared. Results show that: (1) the good performance of Machine Learning models during calibration decreases significantly in validation due to the limited amount of training data; (2) models calibrated at individual stations perform equally well in validation; and (3) most distributed models calibrated over the entire domain have problems in simulating urban areas but outperform the other models in validation.", "authors": [ "Mai, Juliane", "Tolson, Bryan A.", "Shen, Hongren", "Gaborit, Etienne", "Fortin, Vincent", "Gasset, Nicolas", "Awoye, Herve", "Stadnyk, Tricia A.", "Fry, Lauren M.", "Bradley, Emily A.", "Seglenieks, Frank", "Temgoua, Andre G. T.", "Princz, Daniel G.", "Gharari, Shervan", "Haghnegahdar, Amin", "Elshamy, Mohamed E.", "Razavi, Saman", "Gauch, Martin", "Lin, Jimmy", "Ni, Xiaojing", "Yuan, Yongping", "McLeod, Meghan", "Basu, Nandita B.", "Kumar, Rohini", "Rakovec, Oldrich", "Samaniego, Luis", "Attinger, Sabine", "Shrestha, Narayan K.", "Daggupati, Prasad", "Roy, Tirthankar", "Wi, Sungwook", "Hunter, Tim", "Craig, James R.", "Pietroniro, Alain" ], "keywords": [ "" ], "year": "2021", "source": "JOURNAL OF HYDROLOGIC ENGINEERING", "publication_type": "J", "point2d": [ 28.669099807739258, -12.641010284423828 ], "cluster": 16.0 }, { "idx": 605, "title": "Great Lakes Runoff Intercomparison Project Phase 3: Lake Erie (GRIP-E)", "abstract": "Hydrologic model intercomparison studies help to evaluate the agility of models to simulate variables such as streamflow, evaporation, and soil moisture. This study is the third in a sequence of the Great Lakes Runoff Intercomparison Projects. The densely populated Lake Erie watershed studied here is an important international lake that has experienced recent flooding and shoreline erosion alongside excessive nutrient loads that have contributed to lake eutrophication. Understanding the sources and pathways of flows is critical to solve the complex issues facing this watershed. Seventeen hydrologic and land-surface models of different complexity are set up over this domain using the same meteorological forcings, and their simulated streamflows at 46 calibration and seven independent validation stations are compared. Results show that: (1) the good performance of Machine Learning models during calibration decreases significantly in validation due to the limited amount of training data; (2) models calibrated at individual stations perform equally well in validation; and (3) most distributed models calibrated over the entire domain have problems in simulating urban areas but outperform the other models in validation.", "authors": [ "Mai, Juliane", "Tolson, Bryan A.", "Shen, Hongren", "Gaborit, Etienne", "Fortin, Vincent", "Gasset, Nicolas", "Awoye, Herve", "Stadnyk, Tricia A.", "Fry, Lauren M.", "Bradley, Emily A.", "Seglenieks, Frank", "Temgoua, Andre G. T.", "Princz, Daniel G.", "Gharari, Shervan", "Haghnegahdar, Amin", "Elshamy, Mohamed E.", "Razavi, Saman", "Gauch, Martin", "Lin, Jimmy", "Ni, Xiaojing", "Yuan, Yongping", "McLeod, Meghan", "Basu, Nandita B.", "Kumar, Rohini", "Rakovec, Oldrich", "Samaniego, Luis", "Attinger, Sabine", "Shrestha, Narayan K.", "Daggupati, Prasad", "Roy, Tirthankar", "Wi, Sungwook", "Hunter, Tim", "Craig, James R.", "Pietroniro, Alain" ], "keywords": [ "" ], "year": "2021", "source": "JOURNAL OF HYDROLOGIC ENGINEERING", "publication_type": "J", "point2d": [ 28.669099807739258, -12.641010284423828 ], "cluster": 16.0 }, { "idx": 606, "title": "Performance improvements to modern hydrological models via lookup table optimizations", "abstract": "Distributed hydrological models predict the spatial variability in processes that govern observed mass and energy fluxes. A challenge associated with the use of these models is the computational burden associated with representing the Earth?s (sub)surface via millions of computational elements. This burden is exacerbated as more complex process representations are included because their parameterizations involve computationally intensive mathematical functions. Lookup tables (LUTs) approximate a mathematical function by interpolating precomputed values of the function. Highly accurate approximations are possible for substantially reduced computational costs. In this work, a general methodology using the C++ LUT library FunC is applied to identify and replace computationally intensive mathematical function evaluations in the Canadian Hydrological Model (CHM). The use of LUTs introduces a pointwise relative error below 10-8 and provides a reduction in run time of almost 20%. This work shows how LUTs can be implemented with relatively little pain and yield significant computational savings for distributed hydrological models.", "authors": [ "Marsh, Christopher B.", "Green, Kevin R.", "Wang, B.", "Spiteri, Raymond J." ], "keywords": [ "Hydrology", "Optimization", "Lookup table", "Snow", "Cold-regions" ], "year": "2021", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 9.38478946685791, -46.78097915649414 ], "cluster": 16.0 }, { "idx": 607, "title": "Performance improvements to modern hydrological models via lookup table optimizations", "abstract": "Distributed hydrological models predict the spatial variability in processes that govern observed mass and energy fluxes. A challenge associated with the use of these models is the computational burden associated with representing the Earth?s (sub)surface via millions of computational elements. This burden is exacerbated as more complex process representations are included because their parameterizations involve computationally intensive mathematical functions. Lookup tables (LUTs) approximate a mathematical function by interpolating precomputed values of the function. Highly accurate approximations are possible for substantially reduced computational costs. In this work, a general methodology using the C++ LUT library FunC is applied to identify and replace computationally intensive mathematical function evaluations in the Canadian Hydrological Model (CHM). The use of LUTs introduces a pointwise relative error below 10-8 and provides a reduction in run time of almost 20%. This work shows how LUTs can be implemented with relatively little pain and yield significant computational savings for distributed hydrological models.", "authors": [ "Marsh, Christopher B.", "Green, Kevin R.", "Wang, B.", "Spiteri, Raymond J." ], "keywords": [ "Hydrology", "Optimization", "Lookup table", "Snow", "Cold-regions" ], "year": "2021", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 9.733667373657227, -47.061405181884766 ], "cluster": 16.0 }, { "idx": 608, "title": "ID-correspondence: a measure for detecting evolutionary coupling", "abstract": "Evolutionary coupling is a well investigated phenomenon in software maintenance research and practice. Association rules and two related measures, support and confidence, have been used to identify evolutionary coupling among program entities. However, these measures only emphasize the co-change (i.e., changing together) frequency of entities and cannot determine whether the entities co-evolved by experiencing related changes. Consequently, the approach reports false positives and fails to detect evolutionary coupling among infrequently co-changed entities. We propose a new measure, identifier correspondence (id-correspondence), that quantifies the extent to which changes that occurred to the co-changed entities are related based on identifier similarity. Identifiers are the names given to different program entities such as variables, methods, classes, packages, interfaces, structures, unions etc. We use Dice-Sorensen co-efficient for measuring lexical similarity between the identifiers involved in the changed lines of the co-changed entities. Our investigation on thousands of revisions from nine subject systems covering three programming languages shows that id-correspondence can considerably improve the detection accuracy of evolutionary coupling. It outperforms the existing state-of-the-art evolutionary coupling based techniques with significantly higher recall and F-score in predicting future co-change candidates.", "authors": [ "Mondal, Manishankar", "Roy, Banani", "Roy, Chanchal K.", "Schneider, Kevin A." ], "keywords": [ "Evolutionary coupling", "Co-change", "Support", "Confidence", "Identifier correspondence" ], "year": "2021", "source": "EMPIRICAL SOFTWARE ENGINEERING", "publication_type": "J", "point2d": [ 29.25388526916504, -95.46546936035156 ], "cluster": 5.0 }, { "idx": 609, "title": "ID-correspondence: a measure for detecting evolutionary coupling", "abstract": "Evolutionary coupling is a well investigated phenomenon in software maintenance research and practice. Association rules and two related measures, support and confidence, have been used to identify evolutionary coupling among program entities. However, these measures only emphasize the co-change (i.e., changing together) frequency of entities and cannot determine whether the entities co-evolved by experiencing related changes. Consequently, the approach reports false positives and fails to detect evolutionary coupling among infrequently co-changed entities. We propose a new measure, identifier correspondence (id-correspondence), that quantifies the extent to which changes that occurred to the co-changed entities are related based on identifier similarity. Identifiers are the names given to different program entities such as variables, methods, classes, packages, interfaces, structures, unions etc. We use Dice-Sorensen co-efficient for measuring lexical similarity between the identifiers involved in the changed lines of the co-changed entities. Our investigation on thousands of revisions from nine subject systems covering three programming languages shows that id-correspondence can considerably improve the detection accuracy of evolutionary coupling. It outperforms the existing state-of-the-art evolutionary coupling based techniques with significantly higher recall and F-score in predicting future co-change candidates.", "authors": [ "Mondal, Manishankar", "Roy, Banani", "Roy, Chanchal K.", "Schneider, Kevin A." ], "keywords": [ "Evolutionary coupling", "Co-change", "Support", "Confidence", "Identifier correspondence" ], "year": "2021", "source": "EMPIRICAL SOFTWARE ENGINEERING", "publication_type": "J", "point2d": [ 29.25388526916504, -95.46546936035156 ], "cluster": 5.0 }, { "idx": 610, "title": "A machine learning based framework for code clone validation", "abstract": "A code clone is a pair of code fragments, within or between software systems that are similar. Since code clones often negatively impact the maintainability of a software system, several code clone detection techniques and tools have been proposed and studied over the last decade. However, the clone detection tools are not always perfect and their clone detection reports often contain a number of false positives or irrelevant clones from specific project management or user perspective. To detect all possible similar source code patterns in general, the clone detection tools work on the syntax level while lacking user-specific preferences. This often means the clones must be manually inspected before analysis in order to remove those false positives from consideration. This manual clone validation effort is very time-consuming and often error-prone, in particular for large-scale clone detection. In this paper, we propose a machine learning approach for automating the validation process. First, a training dataset is built by taking code clones from several clone detection tools for different subject systems and then manually validating those clones. Second, several features are extracted from those clones to train the machine learning model by the proposed approach. The trained algorithm is then used to automatically validate clones without human inspection. Thus the proposed approach can be used to remove the false positive clones from the detection results, automatically evaluate the precision of any clone detectors for any given set of datasets, evaluate existing clone benchmark datasets, or even be used to build new clone benchmarks and datasets with minimum effort. In an experiment with clones detected by several clone detectors in several different software systems, we found our approach has an accuracy of up to 87.4% when compared against the manual validation by multiple expert judges. The proposed method also shows better results in several comparative studies with the existing related approaches for clone classification. (C) 2020 Elsevier Inc. All rights reserved.", "authors": [ "Mostaeen, Golam", "Roy, Banani", "Roy, Chanchal K.", "Schneider, Kevin", "Svajlenko, Jeffrey" ], "keywords": [ "Code clones", "Validation", "Machine learning", "Clone management" ], "year": "2020", "source": "JOURNAL OF SYSTEMS AND SOFTWARE", "publication_type": "J", "point2d": [ 31.89313316345215, -95.41455078125 ], "cluster": 5.0 }, { "idx": 611, "title": "A universal cross language software similarity detector for open source software categorization", "abstract": "While there are novel approaches for detecting and categorizing similar software applications, previous research focused on detecting similarity in applications written in the same programming language and not on detecting similarity in applications written in different programming languages. Cross-language software similarity detection is inherently more challenging due to variations in language, application structures, support libraries used, and naming conventions. In this paper we propose a novel model, CroLSim, to detect similar software applications across different programming languages. We define a semantic relationship among cross-language libraries and API methods (both local and third party) using functional descriptions and a word-vector learning model. Our experiments show that CroLSim can successfully detect cross-language similar software applications, which outperforms all existing approaches (mean average precision rate of 0.65, confidence rate of 3.6, and 75% highly rated successful queries). Furthermore, we applied CroLSim to a source code repository to see whether our model can recommend cross-language source code fragments if queried directly with source code. From our experiments we found that CroLSim can recommend cross-language functional similar source code when source code is directly used as a query (average precision=0.28, recall=0.85, and F-Measure=0.40). (C) 2019 Published by Elsevier Inc.", "authors": [ "Nafi, Kawser Wazed", "Roy, Banani", "Roy, Chanchal K.", "Schneider, Kevin A." ], "keywords": [ "API Calls", "Doc2Vec", "Cross-Language software similarity detection", "Singular value decomposition" ], "year": "2020", "source": "JOURNAL OF SYSTEMS AND SOFTWARE", "publication_type": "J", "point2d": [ 33.431610107421875, -94.6055679321289 ], "cluster": 5.0 }, { "idx": 613, "title": "What about reservoirs? Questioning anthropogenic and climatic interferences on water availability", "abstract": "Water resources in semi-arid regions like the Mediterranean Basin are highly vulnerable because of the high variability of weather systems. Additionally, climate change is altering the timing and pattern of water availability in a region where growing populations are placing extra demands on water supplies. Importantly, how reservoirs and dams have an influence on the amount of water resources available is poorly quantified. Therefore, we examine the impact of reservoirs on water resources together with the impact of climate change in a semi-arid Mediterranean catchment. We simulated the Susurluk basin (23.779-km(2)) using the Soil and Water Assessment Tool (SWAT) model. We generate results for with (RSV) and without reservoirs (WRSV) scenarios. We run simulations for current and future conditions using dynamically downscaled outputs of the MPI-ESM-MR general circulation model under two greenhouse gas relative concentration pathways (RCPs) in order to reveal the coupled effect of reservoir and climate impacts. Water resources were then converted to their usages - blue water (water in aquifers and rivers), green water storage (water in the soil) and green water flow (water losses by evaporation and transpiration). The results demonstrate that all water resources except green water flow are projected to decrease under all RCPs compared to the reference period, both long-term and at seasonal scales. However, while water scarcity is expected in the future, reservoir storage is shown to be adequate to overcome this problem. Nevertheless, reservoirs reduce the availability of water, particularly in soil moisture stores, which increases the potential for drought by reducing streamflow. Furthermore, reservoirs cause water losses through evaporation from their open surfaces. We conclude that pressures to protect society from economic damage by building reservoirs have a strong impact on the fluxes of watersheds. This is additional to the effect of climate change on water resources.", "authors": [ "Akbas, Abdullah", "Freer, Jim", "Ozdemir, Hasan", "Bates, Paul D.", "Turp, M. Tufan" ], "keywords": [ "climate change", "Mediterranean", "reservoir effect", "SWAT", "water scarcity" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 22.8855037689209, -55.39754867553711 ], "cluster": 16.0 }, { "idx": 614, "title": "What about reservoirs? Questioning anthropogenic and climatic interferences on water availability", "abstract": "Water resources in semi-arid regions like the Mediterranean Basin are highly vulnerable because of the high variability of weather systems. Additionally, climate change is altering the timing and pattern of water availability in a region where growing populations are placing extra demands on water supplies. Importantly, how reservoirs and dams have an influence on the amount of water resources available is poorly quantified. Therefore, we examine the impact of reservoirs on water resources together with the impact of climate change in a semi-arid Mediterranean catchment. We simulated the Susurluk basin (23.779-km(2)) using the Soil and Water Assessment Tool (SWAT) model. We generate results for with (RSV) and without reservoirs (WRSV) scenarios. We run simulations for current and future conditions using dynamically downscaled outputs of the MPI-ESM-MR general circulation model under two greenhouse gas relative concentration pathways (RCPs) in order to reveal the coupled effect of reservoir and climate impacts. Water resources were then converted to their usages - blue water (water in aquifers and rivers), green water storage (water in the soil) and green water flow (water losses by evaporation and transpiration). The results demonstrate that all water resources except green water flow are projected to decrease under all RCPs compared to the reference period, both long-term and at seasonal scales. However, while water scarcity is expected in the future, reservoir storage is shown to be adequate to overcome this problem. Nevertheless, reservoirs reduce the availability of water, particularly in soil moisture stores, which increases the potential for drought by reducing streamflow. Furthermore, reservoirs cause water losses through evaporation from their open surfaces. We conclude that pressures to protect society from economic damage by building reservoirs have a strong impact on the fluxes of watersheds. This is additional to the effect of climate change on water resources.", "authors": [ "Akbas, Abdullah", "Freer, Jim", "Ozdemir, Hasan", "Bates, Paul D.", "Turp, M. Tufan" ], "keywords": [ "climate change", "Mediterranean", "reservoir effect", "SWAT", "water scarcity" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 23.274282455444336, -55.195960998535156 ], "cluster": 16.0 }, { "idx": 615, "title": "Warm-air entrainment and advection during alpine blowing snow events", "abstract": "Blowing snow transport has considerable impact on the hydrological cycle in alpine regions both through the redistribution of the seasonal snowpack and through sublimation back into the atmosphere. Alpine energy and mass balances are typically modeled with time-averaged approximations of sensible and latent heat fluxes. This oversimplifies nonstationary turbulent mixing in complex terrain and may overlook important exchange processes for hydrometeorological prediction. To determine if specific turbulent motions are responsible for warm- and dry-air advection during blowing snow events, quadrant analysis and variable interval time averaging was used to investigate turbulent time series from the Fortress Mountain Snow Laboratory alpine study site in the Canadian Rockies, Alberta, Canada, during the winter of 2015-2016. By analyzing wind velocity and sonic temperature time series with concurrent blowing snow, such turbulent motions were found to supply substantial sensible heat to near-surface wind flows. These motions were responsible for temperature fluctuations of up to 1 degrees C, a considerable change for energy balance estimation. A simple scaling relationship was derived that related the frequency of dominant downdraft and updraft events to their duration and local variance. This allows for the first parameterization of entrained or advected energy for time-averaged representations of blowing snow sublimation and suggests that advection can strongly reduce thermodynamic feedbacks between blowing snow sublimation and the near-surface atmosphere. The downdraft and updraft scaling relationship described herein provides a significant step towards a more physically based blowing snow sublimation model with more realistic mixing of atmospheric heat. Additionally, calculations of return frequencies and event durations provide a field-measurement context for recent findings of nonstationarity impacts on sublimation rates.", "authors": [ "Aksamit, Nikolas O.", "Pomeroy, John W." ], "keywords": [ "" ], "year": "2020", "source": "CRYOSPHERE", "publication_type": "J", "point2d": [ -53.50156021118164, -8.344656944274902 ], "cluster": 12.0 }, { "idx": 616, "title": "Warm-air entrainment and advection during alpine blowing snow events", "abstract": "Blowing snow transport has considerable impact on the hydrological cycle in alpine regions both through the redistribution of the seasonal snowpack and through sublimation back into the atmosphere. Alpine energy and mass balances are typically modeled with time-averaged approximations of sensible and latent heat fluxes. This oversimplifies nonstationary turbulent mixing in complex terrain and may overlook important exchange processes for hydrometeorological prediction. To determine if specific turbulent motions are responsible for warm- and dry-air advection during blowing snow events, quadrant analysis and variable interval time averaging was used to investigate turbulent time series from the Fortress Mountain Snow Laboratory alpine study site in the Canadian Rockies, Alberta, Canada, during the winter of 2015-2016. By analyzing wind velocity and sonic temperature time series with concurrent blowing snow, such turbulent motions were found to supply substantial sensible heat to near-surface wind flows. These motions were responsible for temperature fluctuations of up to 1 degrees C, a considerable change for energy balance estimation. A simple scaling relationship was derived that related the frequency of dominant downdraft and updraft events to their duration and local variance. This allows for the first parameterization of entrained or advected energy for time-averaged representations of blowing snow sublimation and suggests that advection can strongly reduce thermodynamic feedbacks between blowing snow sublimation and the near-surface atmosphere. The downdraft and updraft scaling relationship described herein provides a significant step towards a more physically based blowing snow sublimation model with more realistic mixing of atmospheric heat. Additionally, calculations of return frequencies and event durations provide a field-measurement context for recent findings of nonstationarity impacts on sublimation rates.", "authors": [ "Aksamit, Nikolas O.", "Pomeroy, John W." ], "keywords": [ "" ], "year": "2020", "source": "CRYOSPHERE", "publication_type": "J", "point2d": [ -53.13907241821289, -8.631816864013672 ], "cluster": 12.0 }, { "idx": 617, "title": "The evolving perceptual model of streamflow generation at the Panola Mountain Research Watershed", "abstract": "The Panola Mountain Research Watershed (PMRW) is a 41-hectare forested catchment within the Piedmont Province of the Southeastern United States. Observations, experimentation, and numerical modelling have been conducted at Panola over the past 35 years. But to date, these studies have not been fully incorporated into a more comprehensive synthesis. Here we describe the evolving perceptual understanding of streamflow generation mechanisms at the PMRW. We show how the long-term study has enabled insights that were initially unforeseen but are also unachievable in short-term studies. In particular, we discuss how the accumulation of field evidence, detailed site characterization, and modelling enabled a priori hypotheses to be formed, later rejected, and then further refined through repeated field campaigns. The extensive characterization of the soil and bedrock provided robust process insights not otherwise achievable from hydrometric measurements and numerical modelling alone. We focus on two major aspects of streamflow generation: the role of hillslopes (and their connection to the riparian zone) and the role of catchment storage in controlling fluxes and transit times of water in the catchment. Finally, we present location-independent hypotheses based on our findings at PMRW and suggest ways to assess the representativeness of PMRW in the broader context of headwater watersheds.", "authors": [ "Aulenbach, Brent T.", "Hooper, Richard P.", "van Meerveld, H. J. (Ilja)", "Burns, Douglas A.", "Freer, James E.", "Shanley, James B.", "Huntington, Thomas G.", "McDonnell, Jeffrey J.", "Peters, Norman E." ], "keywords": [ "catchment storage", "flow paths", "hillslope connectivity", "perceptual models", "Streamflow generation", "tracers" ], "year": "2021", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 12.377230644226074, -18.239023208618164 ], "cluster": 10.0 }, { "idx": 618, "title": "The evolving perceptual model of streamflow generation at the Panola Mountain Research Watershed", "abstract": "The Panola Mountain Research Watershed (PMRW) is a 41-hectare forested catchment within the Piedmont Province of the Southeastern United States. Observations, experimentation, and numerical modelling have been conducted at Panola over the past 35 years. But to date, these studies have not been fully incorporated into a more comprehensive synthesis. Here we describe the evolving perceptual understanding of streamflow generation mechanisms at the PMRW. We show how the long-term study has enabled insights that were initially unforeseen but are also unachievable in short-term studies. In particular, we discuss how the accumulation of field evidence, detailed site characterization, and modelling enabled a priori hypotheses to be formed, later rejected, and then further refined through repeated field campaigns. The extensive characterization of the soil and bedrock provided robust process insights not otherwise achievable from hydrometric measurements and numerical modelling alone. We focus on two major aspects of streamflow generation: the role of hillslopes (and their connection to the riparian zone) and the role of catchment storage in controlling fluxes and transit times of water in the catchment. Finally, we present location-independent hypotheses based on our findings at PMRW and suggest ways to assess the representativeness of PMRW in the broader context of headwater watersheds.", "authors": [ "Aulenbach, Brent T.", "Hooper, Richard P.", "van Meerveld, H. J. (Ilja)", "Burns, Douglas A.", "Freer, James E.", "Shanley, James B.", "Huntington, Thomas G.", "McDonnell, Jeffrey J.", "Peters, Norman E." ], "keywords": [ "catchment storage", "flow paths", "hillslope connectivity", "perceptual models", "Streamflow generation", "tracers" ], "year": "2021", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 12.132757186889648, -17.882095336914062 ], "cluster": 10.0 }, { "idx": 619, "title": "A history of TOPMODEL", "abstract": "The theory that forms the basis of TOPMODEL (a topography-based hydrological model) was first outlined by Mike Kirkby some 45 years ago. This paper recalls some of the early developments, the rejection of the first journal paper, the early days of digital terrain analysis, model calibration and validation, the various criticisms of the simplifying assumptions, and the relaxation of those assumptions in the dynamic forms of TOPMODEL. A final section addresses the question of what might be done now in seeking a simple, parametrically parsimonious model of hillslope and small catchment processes if we were starting again.", "authors": [ "Beven, Keith J.", "Kirkby, Mike J.", "Freer, Jim E.", "Lamb, Rob" ], "keywords": [ "" ], "year": "2021", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ 15.7344331741333, -44.673095703125 ], "cluster": 16.0 }, { "idx": 620, "title": "A history of TOPMODEL", "abstract": "The theory that forms the basis of TOPMODEL (a topography-based hydrological model) was first outlined by Mike Kirkby some 45 years ago. This paper recalls some of the early developments, the rejection of the first journal paper, the early days of digital terrain analysis, model calibration and validation, the various criticisms of the simplifying assumptions, and the relaxation of those assumptions in the dynamic forms of TOPMODEL. A final section addresses the question of what might be done now in seeking a simple, parametrically parsimonious model of hillslope and small catchment processes if we were starting again.", "authors": [ "Beven, Keith J.", "Kirkby, Mike J.", "Freer, Jim E.", "Lamb, Rob" ], "keywords": [ "" ], "year": "2021", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ 15.7344331741333, -44.673095703125 ], "cluster": 16.0 }, { "idx": 621, "title": "Developing observational methods to drive future hydrological science: Can we make a start as a community?", "abstract": "", "authors": [ "Beven, Keith", "Asadullah, Anita", "Bates, Paul", "Blyth, Eleanor", "Chappell, Nick", "Child, Stewart", "Cloke, Hannah", "Dadson, Simon", "Everard, Nick", "Fowler, Hayley J.", "Freer, Jim", "Hannah, David M.", "Heppell, Kate", "Holden, Joseph", "Lamb, Rob", "Lewis, Huw", "Morgan, Gerald", "Parry, Louise", "Wagener, Thorsten" ], "keywords": [ "" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -18.108203887939453, -20.064184188842773 ], "cluster": 16.0 }, { "idx": 622, "title": "Developing observational methods to drive future hydrological science: Can we make a start as a community?", "abstract": "", "authors": [ "Beven, Keith", "Asadullah, Anita", "Bates, Paul", "Blyth, Eleanor", "Chappell, Nick", "Child, Stewart", "Cloke, Hannah", "Dadson, Simon", "Everard, Nick", "Fowler, Hayley J.", "Freer, Jim", "Hannah, David M.", "Heppell, Kate", "Holden, Joseph", "Lamb, Rob", "Lewis, Huw", "Morgan, Gerald", "Parry, Louise", "Wagener, Thorsten" ], "keywords": [ "" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -18.427881240844727, -20.335556030273438 ], "cluster": 16.0 }, { "idx": 623, "title": "Spatial Dependence of Floods Shaped by Spatiotemporal Variations in Meteorological and Land-Surface Processes", "abstract": "Floods often affect large regions and cause adverse societal impacts. Regional flood hazard and risk assessments therefore require a realistic representation of spatial flood dependencies to avoid the overestimation or underestimation of risk. However, it is not yet well understood how spatial flood dependence, that is, the degree of co-occurrence of floods at different locations, varies in space and time and which processes influence the strength of this dependence. We identify regions in the United States with seasonally similar flood behavior and analyze processes governing spatial dependence. We find that spatial flood dependence varies regionally and seasonally and is generally strongest in winter and spring and weakest in summer and fall. Moreover, we find that land-surface processes are crucial in shaping the spatiotemporal characteristics of flood events. We conclude that the regional and seasonal variations in spatial flood dependencies must be considered when conducting current and future flood risk assessments.", "authors": [ "Brunner, Manuela, I", "Gilleland, Eric", "Wood, Andy", "Swain, Daniel L.", "Clark, Martyn" ], "keywords": [ "spatial dependence", "extremes", "flood", "precipitation", "weather patterns", "co-occurrence" ], "year": "2020", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -11.82940673828125, -65.61521911621094 ], "cluster": 16.0 }, { "idx": 624, "title": "Spatial Dependence of Floods Shaped by Spatiotemporal Variations in Meteorological and Land-Surface Processes", "abstract": "Floods often affect large regions and cause adverse societal impacts. Regional flood hazard and risk assessments therefore require a realistic representation of spatial flood dependencies to avoid the overestimation or underestimation of risk. However, it is not yet well understood how spatial flood dependence, that is, the degree of co-occurrence of floods at different locations, varies in space and time and which processes influence the strength of this dependence. We identify regions in the United States with seasonally similar flood behavior and analyze processes governing spatial dependence. We find that spatial flood dependence varies regionally and seasonally and is generally strongest in winter and spring and weakest in summer and fall. Moreover, we find that land-surface processes are crucial in shaping the spatiotemporal characteristics of flood events. We conclude that the regional and seasonal variations in spatial flood dependencies must be considered when conducting current and future flood risk assessments.", "authors": [ "Brunner, Manuela, I", "Gilleland, Eric", "Wood, Andy", "Swain, Daniel L.", "Clark, Martyn" ], "keywords": [ "spatial dependence", "extremes", "flood", "precipitation", "weather patterns", "co-occurrence" ], "year": "2020", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -12.310235023498535, -65.57090759277344 ], "cluster": 16.0 }, { "idx": 625, "title": "Flood spatial coherence, triggers, and performance in hydrological simulations: large-sample evaluation of four streamflow-calibrated models", "abstract": "Floods cause extensive damage, especially if they affect large regions. Assessments of current, local, and regional flood hazards and their future changes often involve the use of hydrologic models. A reliable hydrologic model ideally reproduces both local flood characteristics and spatial aspects of flooding under current and future climate conditions. However, uncertainties in simulated floods can be considerable and yield unreliable hazard and climate change impact assessments. This study evaluates the extent to which models calibrated according to standard model calibration metrics such as the widely used Kling-Gupta efficiency are able to capture flood spatial coherence and triggering mechanisms. To highlight challenges related to flood simulations, we investigate how flood timing, magnitude, and spatial variability are represented by an ensemble of hydrological models when calibrated on streamflow using the Kling-Gupta efficiency metric, an increasingly common metric of hydrologic model performance also in flood-related studies. Specifically, we compare how four well-known models (the Sacramento Soil Moisture Accounting model, SAC; the Hydrologiska Byrans Vattenbalansavdelning model, HBV; the variable infiltration capacity model, VIC; and the mesoscale hydrologic model, mHM) represent (1) flood characteristics and their spatial patterns and (2) how they translate changes in meteorologic variables that trigger floods into changes in flood magnitudes. Our results show that both the modeling of local and spatial flood characteristics are challenging as models underestimate flood magnitude, and flood timing is not necessarily well captured. They further show that changes in precipitation and temperature are not always well translated to changes in flood flow, which makes local and regional flood hazard assessments even more difficult for future conditions. From a large sample of catchments and with multiple models, we conclude that calibration on the integrated Kling-Gupta metric alone is likely to yield models that have limited reliability in flood hazard assessments, undermining their utility for regional and future change assessments. We underscore that such assessments can be improved by developing flood-focused, multi-objective, and spatial calibration metrics, by improving flood generating process representation through model structure comparisons and by considering uncertainty in precipitation input.", "authors": [ "Brunner, Manuela, I", "Melsen, Lieke A.", "Wood, Andrew W.", "Rakovec, Oldrich", "Mizukami, Naoki", "Knoben, Wouter J. M.", "Clark, Martyn P." ], "keywords": [ "" ], "year": "2021", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -6.237431049346924, -62.39351272583008 ], "cluster": 16.0 }, { "idx": 626, "title": "Flood spatial coherence, triggers, and performance in hydrological simulations: large-sample evaluation of four streamflow-calibrated models", "abstract": "Floods cause extensive damage, especially if they affect large regions. Assessments of current, local, and regional flood hazards and their future changes often involve the use of hydrologic models. A reliable hydrologic model ideally reproduces both local flood characteristics and spatial aspects of flooding under current and future climate conditions. However, uncertainties in simulated floods can be considerable and yield unreliable hazard and climate change impact assessments. This study evaluates the extent to which models calibrated according to standard model calibration metrics such as the widely used Kling-Gupta efficiency are able to capture flood spatial coherence and triggering mechanisms. To highlight challenges related to flood simulations, we investigate how flood timing, magnitude, and spatial variability are represented by an ensemble of hydrological models when calibrated on streamflow using the Kling-Gupta efficiency metric, an increasingly common metric of hydrologic model performance also in flood-related studies. Specifically, we compare how four well-known models (the Sacramento Soil Moisture Accounting model, SAC; the Hydrologiska Byrans Vattenbalansavdelning model, HBV; the variable infiltration capacity model, VIC; and the mesoscale hydrologic model, mHM) represent (1) flood characteristics and their spatial patterns and (2) how they translate changes in meteorologic variables that trigger floods into changes in flood magnitudes. Our results show that both the modeling of local and spatial flood characteristics are challenging as models underestimate flood magnitude, and flood timing is not necessarily well captured. They further show that changes in precipitation and temperature are not always well translated to changes in flood flow, which makes local and regional flood hazard assessments even more difficult for future conditions. From a large sample of catchments and with multiple models, we conclude that calibration on the integrated Kling-Gupta metric alone is likely to yield models that have limited reliability in flood hazard assessments, undermining their utility for regional and future change assessments. We underscore that such assessments can be improved by developing flood-focused, multi-objective, and spatial calibration metrics, by improving flood generating process representation through model structure comparisons and by considering uncertainty in precipitation input.", "authors": [ "Brunner, Manuela, I", "Melsen, Lieke A.", "Wood, Andrew W.", "Rakovec, Oldrich", "Mizukami, Naoki", "Knoben, Wouter J. M.", "Clark, Martyn P." ], "keywords": [ "" ], "year": "2021", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -6.47613000869751, -62.00650405883789 ], "cluster": 16.0 }, { "idx": 627, "title": "Challenges in modeling and predicting floods and droughts: A review", "abstract": "Predictions of floods, droughts, and fast drought-flood transitions are required at different time wales to develop management strategies targeted at minimizing negative societal and economic impacts. Forecasts at daily and seasonal scale are vital for early warning, estimation of event frequency for hydraulic design, and long-term projections for developing adaptation strategies to future conditions. All three types of predictions-forecasts, frequency estimates, and projections-typically treat droughts and floods independently, even though both types of extremes can be studied using related approaches and have similar challenges. In this review, we (a) identify challenges common to drought and flood prediction and their joint assessment and (b) discuss tractable approaches to tackle these challenges. We group challenges related to flood and drought prediction into four interrelated categories: data, process understanding, modeling and prediction, and human-water interactions. Data-related challenges include data availability and event definition. Process-related challenges include the multivariate and spatial characteristics of extremes, non-stationarities, and future changes in extremes. Modeling challenges arise in frequency analysis, stochastic, hydrological, earth system, and hydraulic modeling. Challenges with respect to human-water interactions lie in establishing links to impacts, representing human-water interactions, and science communication. We discuss potential ways of tackling these challenges including exploiting new data sources, studying droughts and floods in a joint framework, studying societal influences and compounding drivers, developing continuous stochastic models or non-stationary models, and obtaining stakeholder feedback. Tackling one or several of these challenges will improve flood and drought predictions and help to minimize the negative impacts of extreme events. This article is categorized under: Science of Water > Science of Water", "authors": [ "Brunner, Manuela I.", "Slater, Louise", "Tallaksen, Lena M.", "Clark, Martyn" ], "keywords": [ "droughts", "floods", "forecasting", "hydrologic extremes", "prediction" ], "year": "2021", "source": "WILEY INTERDISCIPLINARY REVIEWS-WATER", "publication_type": "J", "point2d": [ -14.88962459564209, -60.91374206542969 ], "cluster": 16.0 }, { "idx": 628, "title": "Challenges in modeling and predicting floods and droughts: A review", "abstract": "Predictions of floods, droughts, and fast drought-flood transitions are required at different time wales to develop management strategies targeted at minimizing negative societal and economic impacts. Forecasts at daily and seasonal scale are vital for early warning, estimation of event frequency for hydraulic design, and long-term projections for developing adaptation strategies to future conditions. All three types of predictions-forecasts, frequency estimates, and projections-typically treat droughts and floods independently, even though both types of extremes can be studied using related approaches and have similar challenges. In this review, we (a) identify challenges common to drought and flood prediction and their joint assessment and (b) discuss tractable approaches to tackle these challenges. We group challenges related to flood and drought prediction into four interrelated categories: data, process understanding, modeling and prediction, and human-water interactions. Data-related challenges include data availability and event definition. Process-related challenges include the multivariate and spatial characteristics of extremes, non-stationarities, and future changes in extremes. Modeling challenges arise in frequency analysis, stochastic, hydrological, earth system, and hydraulic modeling. Challenges with respect to human-water interactions lie in establishing links to impacts, representing human-water interactions, and science communication. We discuss potential ways of tackling these challenges including exploiting new data sources, studying droughts and floods in a joint framework, studying societal influences and compounding drivers, developing continuous stochastic models or non-stationary models, and obtaining stakeholder feedback. Tackling one or several of these challenges will improve flood and drought predictions and help to minimize the negative impacts of extreme events. This article is categorized under: Science of Water > Science of Water", "authors": [ "Brunner, Manuela I.", "Slater, Louise", "Tallaksen, Lena M.", "Clark, Martyn" ], "keywords": [ "droughts", "floods", "forecasting", "hydrologic extremes", "prediction" ], "year": "2021", "source": "WILEY INTERDISCIPLINARY REVIEWS-WATER", "publication_type": "J", "point2d": [ -14.449796676635742, -60.870296478271484 ], "cluster": 16.0 }, { "idx": 629, "title": "Toward open and reproducible environmental modeling by integrating online data repositories, computational environments, and model Application Programming Interfaces", "abstract": "Cyberinfrastructure needs to be advanced to enable open and reproducible environmental modeling research. Recent efforts toward this goal have focused on advancing online repositories for data and model sharing, online computational environments along with containerization technology and notebooks for capturing reproducible computational studies, and Application Programming Interfaces (APIs) for simulation models to foster intuitive programmatic control. The objective of this research is to show how these efforts can be integrated to support reproducible environmental modeling. We present first the high-level concept and general approach for integrating these three components. We then present one possible implementation that integrates HydroShare (an online repository), CUAHSI JupyterHub and CyberGIS-Jupyter for Water (computational environments), and pySUMMA (a model API) to support open and reproducible hydrologic modeling. We apply the example implementation for a hydrologic modeling use case to demonstrate how the approach can advance reproducible environmental modeling through the seamless integration of cyberinfrastructure services.", "authors": [ "Choi, Young-Don", "Goodall, Jonathan L.", "Sadler, Jeffrey M.", "Castronova, Anthony M.", "Bennett, Andrew", "Li, Zhiyu", "Nijssen, Bart", "Wang, Shaowen", "Clark, Martyn P.", "Ames, Daniel P.", "Horsburgh, Jeffery S.", "Yi, Hong", "Bandaragoda, Christina", "Seul, Martin", "Hooper, Richard", "Tarboton, David G." ], "keywords": [ "Open hydrology", "Reproducibility", "Modeling frameworks", "JupyterHub", "Containers" ], "year": "2021", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 27.20517349243164, -41.020755767822266 ], "cluster": 16.0 }, { "idx": 630, "title": "Toward open and reproducible environmental modeling by integrating online data repositories, computational environments, and model Application Programming Interfaces", "abstract": "Cyberinfrastructure needs to be advanced to enable open and reproducible environmental modeling research. Recent efforts toward this goal have focused on advancing online repositories for data and model sharing, online computational environments along with containerization technology and notebooks for capturing reproducible computational studies, and Application Programming Interfaces (APIs) for simulation models to foster intuitive programmatic control. The objective of this research is to show how these efforts can be integrated to support reproducible environmental modeling. We present first the high-level concept and general approach for integrating these three components. We then present one possible implementation that integrates HydroShare (an online repository), CUAHSI JupyterHub and CyberGIS-Jupyter for Water (computational environments), and pySUMMA (a model API) to support open and reproducible hydrologic modeling. We apply the example implementation for a hydrologic modeling use case to demonstrate how the approach can advance reproducible environmental modeling through the seamless integration of cyberinfrastructure services.", "authors": [ "Choi, Young-Don", "Goodall, Jonathan L.", "Sadler, Jeffrey M.", "Castronova, Anthony M.", "Bennett, Andrew", "Li, Zhiyu", "Nijssen, Bart", "Wang, Shaowen", "Clark, Martyn P.", "Ames, Daniel P.", "Horsburgh, Jeffery S.", "Yi, Hong", "Bandaragoda, Christina", "Seul, Martin", "Hooper, Richard", "Tarboton, David G." ], "keywords": [ "Open hydrology", "Reproducibility", "Modeling frameworks", "JupyterHub", "Containers" ], "year": "2021", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 27.20517349243164, -41.020755767822266 ], "cluster": 16.0 }, { "idx": 631, "title": "A Brief Analysis of Conceptual Model Structure Uncertainty Using 36 Models and 559 Catchments", "abstract": "The choice of hydrological model structure, that is, a model's selection of states and fluxes and the equations used to describe them, strongly controls model performance and realism. This work investigates differences in performance of 36 lumped conceptual model structures calibrated to and evaluated on daily streamflow data in 559 catchments across the United States. Model performance is compared against a benchmark that accounts for the seasonality of flows in each catchment. We find that our model ensemble struggles to beat the benchmark in snow-dominated catchments. In most other catchments model structure equifinality (i.e., cases where different models achieve similar high efficiency scores) can be very high. We find no relation between the number of model parameters and performance during either calibration or evaluation periods nor evidence of increased risk of overfitting for models with more parameters. Instead, the choice of model parametrization (i.e., which equations are used and how parameters are used within them) dictates the model's strengths and weaknesses. Results suggest that certain model structures are inherently better suited for certain objective functions and thus for certain study purposes. We find no clear relationships between the catchments where any model performs well and descriptors of those catchments' geology, topography, soil, and vegetation characteristics. Instead, model suitability seems to relate strongest to the streamflow regime each catchment generates, and we have formulated several tentative hypotheses that relate commonalities in model structure to similarities in model performance. Modeling results are made publicly available for further investigation.", "authors": [ "Knoben, W. J. M.", "Freer, J. E.", "Peel, M. C.", "Fowler, K. J. A.", "Woods, R. A." ], "keywords": [ "conceptual model comparison", "model structure uncertainty", "catchment modeling" ], "year": "2020", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 6.286721229553223, -59.55777359008789 ], "cluster": 16.0 }, { "idx": 632, "title": "A Brief Analysis of Conceptual Model Structure Uncertainty Using 36 Models and 559 Catchments", "abstract": "The choice of hydrological model structure, that is, a model's selection of states and fluxes and the equations used to describe them, strongly controls model performance and realism. This work investigates differences in performance of 36 lumped conceptual model structures calibrated to and evaluated on daily streamflow data in 559 catchments across the United States. Model performance is compared against a benchmark that accounts for the seasonality of flows in each catchment. We find that our model ensemble struggles to beat the benchmark in snow-dominated catchments. In most other catchments model structure equifinality (i.e., cases where different models achieve similar high efficiency scores) can be very high. We find no relation between the number of model parameters and performance during either calibration or evaluation periods nor evidence of increased risk of overfitting for models with more parameters. Instead, the choice of model parametrization (i.e., which equations are used and how parameters are used within them) dictates the model's strengths and weaknesses. Results suggest that certain model structures are inherently better suited for certain objective functions and thus for certain study purposes. We find no clear relationships between the catchments where any model performs well and descriptors of those catchments' geology, topography, soil, and vegetation characteristics. Instead, model suitability seems to relate strongest to the streamflow regime each catchment generates, and we have formulated several tentative hypotheses that relate commonalities in model structure to similarities in model performance. Modeling results are made publicly available for further investigation.", "authors": [ "Knoben, W. J. M.", "Freer, J. E.", "Peel, M. C.", "Fowler, K. J. A.", "Woods, R. A." ], "keywords": [ "conceptual model comparison", "model structure uncertainty", "catchment modeling" ], "year": "2020", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 6.6162638664245605, -59.57887649536133 ], "cluster": 16.0 }, { "idx": 633, "title": "Simulation of Preferential Flow in Snow With a 2-D Non-Equilibrium Richards Model and Evaluation Against Laboratory Data", "abstract": "Recent studies of water flow through dry porous media have shown progress in simulating preferential flow propagation. However, current methods applied to snowpacks have neglected the dynamic nature of the capillary pressure, such as conditions for capillary pressure overshoot, resulting in a rather limited representation of the water flow patterns through snowpacks observed in laboratory and field experiments. Indeed, previous snowmelt models using a water entry pressure to simulate preferential flow paths do not work for natural snowpack conditions where snow densities are less than 380 kg m(-3). Because preferential flow in snowpacks greatly alters the flow velocity and the timing of delivery of meltwater to the base of a snowpack early in the melt season, a better understanding of this process would aid hydrological predictions. This study presents a 2-D water flow through snow model that solves the non-equilibrium Richards equation. This model, coupled with random perturbations of snow properties, can represent realistic preferential flow patterns. Using 1-D laboratory data, two model parameters were linked to snow properties and model boundary conditions. Parameterizations of these model parameters were evaluated against 2-D snowpack observations from a laboratory experiment, and the resulting model sensitivity to varying inputs and boundary conditions was calculated. The model advances both the physical understanding of and ability to simulate water flow through snowpacks and can be used in the future to parameterize 1-D snowmelt models to incorporate flow variations due to preferential flow path formation.", "authors": [ "Leroux, Nicolas R.", "Marsh, Christopher B.", "Pomeroy, John W." ], "keywords": [ "non-equilibrium Richards equation", "preferential flow in snow", "capillary hysteresis", "saturation overshoot", "snowmelt", "meltwater modeling" ], "year": "2020", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -30.891454696655273, 21.03067970275879 ], "cluster": 12.0 }, { "idx": 634, "title": "Simulation of Preferential Flow in Snow With a 2-D Non-Equilibrium Richards Model and Evaluation Against Laboratory Data", "abstract": "Recent studies of water flow through dry porous media have shown progress in simulating preferential flow propagation. However, current methods applied to snowpacks have neglected the dynamic nature of the capillary pressure, such as conditions for capillary pressure overshoot, resulting in a rather limited representation of the water flow patterns through snowpacks observed in laboratory and field experiments. Indeed, previous snowmelt models using a water entry pressure to simulate preferential flow paths do not work for natural snowpack conditions where snow densities are less than 380 kg m(-3). Because preferential flow in snowpacks greatly alters the flow velocity and the timing of delivery of meltwater to the base of a snowpack early in the melt season, a better understanding of this process would aid hydrological predictions. This study presents a 2-D water flow through snow model that solves the non-equilibrium Richards equation. This model, coupled with random perturbations of snow properties, can represent realistic preferential flow patterns. Using 1-D laboratory data, two model parameters were linked to snow properties and model boundary conditions. Parameterizations of these model parameters were evaluated against 2-D snowpack observations from a laboratory experiment, and the resulting model sensitivity to varying inputs and boundary conditions was calculated. The model advances both the physical understanding of and ability to simulate water flow through snowpacks and can be used in the future to parameterize 1-D snowmelt models to incorporate flow variations due to preferential flow path formation.", "authors": [ "Leroux, Nicolas R.", "Marsh, Christopher B.", "Pomeroy, John W." ], "keywords": [ "non-equilibrium Richards equation", "preferential flow in snow", "capillary hysteresis", "saturation overshoot", "snowmelt", "meltwater modeling" ], "year": "2020", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -30.780532836914062, 21.56094741821289 ], "cluster": 12.0 }, { "idx": 635, "title": "Key Physicochemical Properties Dictating Gastrointestinal Bioaccessibility of Microplastics-Associated Organic Xenobiotics: Insights from a Deep Learning Approach", "abstract": "A potential risk from human uptake of microplastics is the release of plastics-associated xenobiotics, but the key physicochemical properties of microplastics controlling this process are elusive. Here, we show that the gastrointestinal bioaccessibility, assessed using an in vitro digestive model, of two model xenobiotics (pyrene, at 391-624 mg/kg, and 4-nonylphenol, at 3054-8117 mg/kg) bound to 18 microplastics (including pristine polystyrene, polyvinyl chloride, polyethylene terephthalate, polypropylene, thermoplastic polyurethane, and polyethylene, and two artificially aged samples of each polymer) covered wide ranges: 16.1-77.4% and 26.4-83.8%, respectively. Sorption/desorption experiments conducted in simulated gastric fluid indicated that structural rigidity of polymers was an important factor controlling bioaccessibility of the nonpolar, nonionic pyrene, likely by inducing physical entrapment of pyrene in porous domains, whereas polarity of microplastics controlled bioaccessibility of 4-nonylphenol, by regulating polar interactions. The changes of bioaccessibility induced by microplastics aging corroborated the important roles of polymeric structures and surface polarity in dictating sorption affinity and degree of desorption hysteresis, and consequently, gastrointestinal bioaccessibility. Variance-based global sensitivity analysis using a deep learning neural network approach further revealed that micropore volume was the most important microplastics property controlling bioaccessibility of pyrene, whereas the O/C ratio played a key role in dictating the bioaccessibility of 4-nonylphenol in the gastric tract.", "authors": [ "Liu, Xinlei", "Gharasoo, Mehdi", "Shi, Yu", "Sigmund, Gabriel", "Hueffer, Thorsten", "Duan, Lin", "Wang, Yongfeng", "Ji, Rong", "Hofmann, Thilo", "Chen, Wei" ], "keywords": [ "" ], "year": "2020", "source": "ENVIRONMENTAL SCIENCE & TECHNOLOGY", "publication_type": "J", "point2d": [ 56.74524688720703, 46.04700469970703 ], "cluster": 6.0 }, { "idx": 636, "title": "Key Physicochemical Properties Dictating Gastrointestinal Bioaccessibility of Microplastics-Associated Organic Xenobiotics: Insights from a Deep Learning Approach", "abstract": "A potential risk from human uptake of microplastics is the release of plastics-associated xenobiotics, but the key physicochemical properties of microplastics controlling this process are elusive. Here, we show that the gastrointestinal bioaccessibility, assessed using an in vitro digestive model, of two model xenobiotics (pyrene, at 391-624 mg/kg, and 4-nonylphenol, at 3054-8117 mg/kg) bound to 18 microplastics (including pristine polystyrene, polyvinyl chloride, polyethylene terephthalate, polypropylene, thermoplastic polyurethane, and polyethylene, and two artificially aged samples of each polymer) covered wide ranges: 16.1-77.4% and 26.4-83.8%, respectively. Sorption/desorption experiments conducted in simulated gastric fluid indicated that structural rigidity of polymers was an important factor controlling bioaccessibility of the nonpolar, nonionic pyrene, likely by inducing physical entrapment of pyrene in porous domains, whereas polarity of microplastics controlled bioaccessibility of 4-nonylphenol, by regulating polar interactions. The changes of bioaccessibility induced by microplastics aging corroborated the important roles of polymeric structures and surface polarity in dictating sorption affinity and degree of desorption hysteresis, and consequently, gastrointestinal bioaccessibility. Variance-based global sensitivity analysis using a deep learning neural network approach further revealed that micropore volume was the most important microplastics property controlling bioaccessibility of pyrene, whereas the O/C ratio played a key role in dictating the bioaccessibility of 4-nonylphenol in the gastric tract.", "authors": [ "Liu, Xinlei", "Gharasoo, Mehdi", "Shi, Yu", "Sigmund, Gabriel", "Hueffer, Thorsten", "Duan, Lin", "Wang, Yongfeng", "Ji, Rong", "Hofmann, Thilo", "Chen, Wei" ], "keywords": [ "" ], "year": "2020", "source": "ENVIRONMENTAL SCIENCE & TECHNOLOGY", "publication_type": "J", "point2d": [ 57.21546173095703, 46.200035095214844 ], "cluster": 6.0 }, { "idx": 637, "title": "The Maimai M8 experimental catchment database: Forty years of process-based research on steep, wet hillslopes", "abstract": "", "authors": [ "McDonnell, Jeffrey J.", "Gabrielli, Chris", "Ameli, Ali", "Ekanayake, Jagath", "Fenicia, Fabrizio", "Freer, Jim", "Graham, Chris", "McGlynn, Brian", "Morgenstern, Uwe", "Pietroniro, Alain", "Sayama, Takahiro", "Seibert, Jan", "Stewart, Mike", "Vache, Kellie", "Weiler, Markus", "Woods, Ross" ], "keywords": [ "isotope tracing", "rainfall-runoff processes", "runoff modeling", "steep hillslopes", "subsurface stormflow" ], "year": "2021", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 13.658032417297363, -16.872058868408203 ], "cluster": 10.0 }, { "idx": 638, "title": "TIER version 1.0: an open-source Topographically InformEd Regression (TIER) model to estimate spatial meteorological fields", "abstract": "This paper introduces the Topographically InformEd Regression (TIER) model, which uses terrain attributes in a regression framework to distribute in situ observations of precipitation and temperature to a grid. The framework enables our understanding of complex atmospheric processes (e.g., orographic precipitation) to be encoded into a statistical model in an easy-to-understand manner. TIER is developed in a modular fashion with key model parameters exposed to the user. This enables the user community to easily explore the impacts of our methodological choices made to distribute sparse, irregularly spaced observations to a grid in a systematic fashion. The modular design allows incorporating new capabilities in TIER. Intermediate processing variables are also output to provide a more complete understanding of the algorithm and any algorithmic changes. The framework also provides uncertainty estimates. This paper presents a brief model evaluation and demonstrates that the TIER algorithm is functioning as expected. Several variations in model parameters and changes in the distributed variables are described. A key conclusion is that seemingly small changes in a model parameter result in large changes to the final distributed fields and their associated uncertainty estimates.", "authors": [ "Newman, Andrew J.", "Clark, Martyn P." ], "keywords": [ "" ], "year": "2020", "source": "GEOSCIENTIFIC MODEL DEVELOPMENT", "publication_type": "J", "point2d": [ -45.87765121459961, -51.5007438659668 ], "cluster": 14.0 }, { "idx": 639, "title": "Probabilistic Spatial Meteorological Estimates for Alaska and the Yukon", "abstract": "It is challenging to develop observationally based spatial estimates of meteorology in Alaska and the Yukon. Complex topography, frozen precipitation undercatch, and extremely sparse in situ observations all limit our capability to produce accurate spatial estimates of meteorological conditions. In this Arctic environment, it is necessary to develop probabilistic estimates of precipitation and temperature that explicitly incorporate spatiotemporally varying uncertainty and bias corrections. In this paper we exploit the recently developed ensemble Climatologically Aided Interpolation (eCAI) system to produce daily historical estimates of precipitation and temperature across Alaska and the Yukon Territory at a 2 km grid spacing for the time period 1980-2013. We extend the previous eCAI method to address precipitation gauge undercatch and wetting loss, which is of high importance for this high-latitude region where much of the precipitation falls as snow. Leave-one-out cross-validation shows our ensemble has little bias in daily precipitation and mean temperature at the station locations, with an overestimate in the daily standard deviation of precipitation. The ensemble is statistically reliable compared to climatology and can discriminate precipitation events across different precipitation thresholds. Long-term mean loss adjusted precipitation is up to 36% greater than the unadjusted estimate in windy areas that receive a large fraction of frozen precipitation, primarily due to wind induced undercatch. Comparing the ensemble mean climatology of precipitation and temperature to PRISM and Daymet v3 shows large interproduct differences, particularly in precipitation across the complex terrain of southeast and northern Alaska.", "authors": [ "Newman, Andrew J.", "Clark, Martyn P.", "Wood, Andrew W.", "Arnold, Jeffrey R." ], "keywords": [ "precipitation", "Arctic", "hydrometeorology", "temperature", "spatial interpolation", "climatology" ], "year": "2020", "source": "JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES", "publication_type": "J", "point2d": [ -41.77245330810547, 6.121466636657715 ], "cluster": 8.0 }, { "idx": 640, "title": "Hydroclimatic changes in Alaska portrayed by a high-resolution regional climate simulation", "abstract": "The Arctic has been warming faster than the global average during recent decades, and trends are projected to continue through the twenty-first century. Analysis of climate change impacts across the Arctic using dynamical models has almost exclusively been limited to outputs from global climate models or coarser regional climate models. Coarse resolution simulations limit the representation of physical processes, particularly in areas of complex topography and high land-surface heterogeneity. Here, current climate reference and future regional climate model simulations based on the RCP8.5 scenario over Alaska at 4 km grid spacing are compared to identify changes in snowfall and snowpack. In general, results show increases in total precipitation, large decreases in snowfall fractional contribution over 30% in some areas, decreases in snowpack season length by 50-100 days in lower elevations and along the southern Alaskan coastline, and decreases in snow water equivalent. However, increases in snowfall and snowpack of sometimes greater than 20% are evident for some colder northern areas and at the highest elevations in southern Alaska. The most significant changes in snow cover and snowfall fractional contributions occur during the spring and fall seasons. Finally, the spatial pattern of winter temperatures above freezing has small-scale spatial features tied to the topography. Such areas would not be resolved with coarser resolution regional or global climate model simulations.", "authors": [ "Newman, Andrew J.", "Monaghan, Andrew J.", "Clark, Martyn P.", "Ikeda, Kyoko", "Xue, Lulin", "Gutmann, Ethan D.", "Arnold, Jeffrey R." ], "keywords": [ "Hydroclimate", "Regional climate simulation", "Snow water equivalent", "Precipitation partitioning", "Pseudo global warming" ], "year": "2021", "source": "CLIMATIC CHANGE", "publication_type": "J", "point2d": [ -41.062782287597656, 7.248515605926514 ], "cluster": 12.0 }, { "idx": 641, "title": "How Well Can Land-Surface Models Represent the Diurnal Cycle of Turbulent Heat Fluxes?", "abstract": "The diurnal cycle of solar radiation represents the strongest energetic forcing and dominates the exchange of heat and mass of the land surface with the atmosphere. This diurnal heat redistribution represents a core of land-atmosphere coupling that should be accurately represented in land surface models (LSMs), which are critical parts of weather and climate models. We employ a diagnostic model evaluation approach using a signature-based metric that describes the diurnal variation of heat fluxes. The metric is obtained by decomposing the diurnal variation of surface heat fluxes into their direct response and the phase lag to incoming solar radiation. We employ the output of 13 different LSMs driven with meteorological forcing of 20 FLUXNET sites (PLUMBER dataset). All LSMs show a poor representation of the evaporative fraction and thus the diurnal magnitude of the sensible and latent heat flux under cloud-free conditions. In addition, we find that the diurnal phase of both heat fluxes is poorly represented. The best performing model only reproduces 33% of the evaluated evaporative conditions across the sites. The poor performance of the diurnal cycle of turbulent heat exchange appears to be linked to how models solve for the surface energy balance and redistribute heat into the subsurface. We conclude that a systematic evaluation of diurnal signatures is likely to help to improve the simulated diurnal cycle, better represent land-atmosphere interactions, and therefore improve simulations of the near-surface climate.", "authors": [ "Renner, Maik", "Kleidon, Axel", "Clark, Martyn", "Nijssen, Bart", "Heidkamp, Marvin", "Best, Martin", "Abramowitz, Gab" ], "keywords": [ "Atmosphere-land interaction", "Heat budgets/fluxes", "Land surface model", "Model comparison", "Model evaluation/performance", "Diurnal effects" ], "year": "2021", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -64.66156768798828, -55.46928024291992 ], "cluster": 17.0 }, { "idx": 642, "title": "How Well Can Land-Surface Models Represent the Diurnal Cycle of Turbulent Heat Fluxes?", "abstract": "The diurnal cycle of solar radiation represents the strongest energetic forcing and dominates the exchange of heat and mass of the land surface with the atmosphere. This diurnal heat redistribution represents a core of land-atmosphere coupling that should be accurately represented in land surface models (LSMs), which are critical parts of weather and climate models. We employ a diagnostic model evaluation approach using a signature-based metric that describes the diurnal variation of heat fluxes. The metric is obtained by decomposing the diurnal variation of surface heat fluxes into their direct response and the phase lag to incoming solar radiation. We employ the output of 13 different LSMs driven with meteorological forcing of 20 FLUXNET sites (PLUMBER dataset). All LSMs show a poor representation of the evaporative fraction and thus the diurnal magnitude of the sensible and latent heat flux under cloud-free conditions. In addition, we find that the diurnal phase of both heat fluxes is poorly represented. The best performing model only reproduces 33% of the evaluated evaporative conditions across the sites. The poor performance of the diurnal cycle of turbulent heat exchange appears to be linked to how models solve for the surface energy balance and redistribute heat into the subsurface. We conclude that a systematic evaluation of diurnal signatures is likely to help to improve the simulated diurnal cycle, better represent land-atmosphere interactions, and therefore improve simulations of the near-surface climate.", "authors": [ "Renner, Maik", "Kleidon, Axel", "Clark, Martyn", "Nijssen, Bart", "Heidkamp, Marvin", "Best, Martin", "Abramowitz, Gab" ], "keywords": [ "Atmosphere-land interaction", "Heat budgets/fluxes", "Land surface model", "Model comparison", "Model evaluation/performance", "Diurnal effects" ], "year": "2021", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -64.66156768798828, -55.46928024291992 ], "cluster": 17.0 }, { "idx": 645, "title": "Deep Learning Neural Network Approach for Predicting the Sorption of Ionizable and Polar Organic Pollutants to a Wide Range of Carbonaceous Materials", "abstract": "Most contaminants of emerging concern are polar and/or ionizable organic compounds, whose removal from engineered and environmental systems is difficult. Carbonaceous sorbents include activated carbon, biochar, fullerenes, and carbon nanotubes, with applications such as drinking water filtration, wastewater treatment, and contaminant remediation. Tools for predicting sorption of many emerging contaminants to these sorbents are lacking because existing models were developed for neutral compounds. A method to select the appropriate sorbent for a given contaminant based on the ability to predict sorption is required by researchers and practitioners alike. Here, we present a widely applicable deep learning neural network approach that excellently predicted the conventionally used Freundlich isotherm fitting parameters log K-F and n (R-2 > 0.98 for log K-F, and R-2 > 0.91 for n). The neural network models are based on parameters generally available for carbonaceous sorbents and/or parameters freely available from online databases. A freely accessible graphical user interface is provided.", "authors": [ "Sigmund, Gabriel", "Gharasoo, Mehdi", "Hueffer, Thorsten", "Hofmann, Thilo" ], "keywords": [ "" ], "year": "2020", "source": "ENVIRONMENTAL SCIENCE & TECHNOLOGY", "publication_type": "J", "point2d": [ 57.65582275390625, 43.04189682006836 ], "cluster": 6.0 }, { "idx": 646, "title": "Deep Learning Neural Network Approach for Predicting the Sorption of Ionizable and Polar Organic Pollutants to a Wide Range of Carbonaceous Materials", "abstract": "Most contaminants of emerging concern are polar and/or ionizable organic compounds, whose removal from engineered and environmental systems is difficult. Carbonaceous sorbents include activated carbon, biochar, fullerenes, and carbon nanotubes, with applications such as drinking water filtration, wastewater treatment, and contaminant remediation. Tools for predicting sorption of many emerging contaminants to these sorbents are lacking because existing models were developed for neutral compounds. A method to select the appropriate sorbent for a given contaminant based on the ability to predict sorption is required by researchers and practitioners alike. Here, we present a widely applicable deep learning neural network approach that excellently predicted the conventionally used Freundlich isotherm fitting parameters log K-F and n (R-2 > 0.98 for log K-F, and R-2 > 0.91 for n). The neural network models are based on parameters generally available for carbonaceous sorbents and/or parameters freely available from online databases. A freely accessible graphical user interface is provided.", "authors": [ "Sigmund, Gabriel", "Gharasoo, Mehdi", "Hueffer, Thorsten", "Hofmann, Thilo" ], "keywords": [ "" ], "year": "2020", "source": "ENVIRONMENTAL SCIENCE & TECHNOLOGY", "publication_type": "J", "point2d": [ 58.121829986572266, 43.19282913208008 ], "cluster": 6.0 }, { "idx": 647, "title": "Simulating river regulation and reservoir performance in a continental-scale hydrologic model", "abstract": "This study develops a novel reservoir regulation routine, incorporated into a continental-scale hydrologic model in the Nelson, Churchill, Yenisey, Ob, and Lena basins. This regulation routine is integrated into the Hydrological Predictions for the Environment (HYPE) hydrologic model, used for continental-scale applications. Applying this daily timestep regulation routine at 19 reservoirs in the Arctic Ocean watershed, performance is shown to improve upon the reservoir regulation currently available in the HYPE model when testing outflow and storage Nash Sutcliffe Efficiencies (NSEs). Improvements stem from intra-annually variable storage rule curves and a variety of stage-dependent outflow functions, improving simulation skill (median NSE increases of 0.18 over 21 reservoir outflow records and 0.49 over 19 reservoir storage records). This new, reservoir regulation routine is suitable for continental-scale modelling by deriving varying, rather than fixed, threshold water surface levels and associated outflow rules in a programmatic way for multiple reservoirs.", "authors": [ "Tefs, A. A. G.", "Stadnyk, T. A.", "Koenig, K. A.", "Dery, S. J.", "MacDonald, M. K.", "Slota, P.", "Crawford, J.", "Hamilton, M." ], "keywords": [ "Hydrologic modelling", "Hydroelectric regulation", "Hudson bay" ], "year": "2021", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 13.242044448852539, -60.11317443847656 ], "cluster": 16.0 }, { "idx": 648, "title": "Simulating river regulation and reservoir performance in a continental-scale hydrologic model", "abstract": "This study develops a novel reservoir regulation routine, incorporated into a continental-scale hydrologic model in the Nelson, Churchill, Yenisey, Ob, and Lena basins. This regulation routine is integrated into the Hydrological Predictions for the Environment (HYPE) hydrologic model, used for continental-scale applications. Applying this daily timestep regulation routine at 19 reservoirs in the Arctic Ocean watershed, performance is shown to improve upon the reservoir regulation currently available in the HYPE model when testing outflow and storage Nash Sutcliffe Efficiencies (NSEs). Improvements stem from intra-annually variable storage rule curves and a variety of stage-dependent outflow functions, improving simulation skill (median NSE increases of 0.18 over 21 reservoir outflow records and 0.49 over 19 reservoir storage records). This new, reservoir regulation routine is suitable for continental-scale modelling by deriving varying, rather than fixed, threshold water surface levels and associated outflow rules in a programmatic way for multiple reservoirs.", "authors": [ "Tefs, A. A. G.", "Stadnyk, T. A.", "Koenig, K. A.", "Dery, S. J.", "MacDonald, M. K.", "Slota, P.", "Crawford, J.", "Hamilton, M." ], "keywords": [ "Hydrologic modelling", "Hydroelectric regulation", "Hudson bay" ], "year": "2021", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 13.242044448852539, -60.11317443847656 ], "cluster": 16.0 }, { "idx": 649, "title": "Assessing Water Balance Closure Using Multiple Data Assimilation- and Remote Sensing-Based Datasets for Canada", "abstract": "Obtaining reliable water balance estimates remains a major challenge in Canada for large regions with scarce in situ measurements. Various remote sensing products can be used to complement observation-based datasets and provide an estimate of the water balance at river basin or regional scales. This study provides an assessment of the water balance using combinations of various remote sensing- and data assimilation-based products and quantifies the nonclosure errors for river basins across Canada, ranging from 90 900 to 1 679 100 km(2), for the period from 2002 to 2015. A water balance equation combines the following to estimate the monthly water balance closure: multiple sources of data for each water budget component, including two precipitation products-the global product WATCH Forcing Data ERA-Interim (WFDEI), and the Canadian Precipitation Analysis (CaPA); two evapotranspiration products-MODIS, and Global Land surface Evaporation: The Amsterdam Methodology (GLEAM); one source of water storage data-GRACE from three different centers; and observed discharge data from hydrometric stations (HYDAT). The nonclosure error is attributed to the different data products using a constrained Kalman filter. Results show that the combination of CaPA, GLEAM, and the JPL mascon GRACE product tended to outperform other combinations across Canadian river basins. Overall, the error attributions of precipitation, evapotranspiration, water storage change, and runoff were 36.7%, 33.2%, 17.8%, and 12.2%, which corresponded to 8.1, 7.9, 4.2, and 1.4 mm month(-1), respectively. In particular, the nonclosure error from precipitation dominated in Western Canada, whereas that from evapotranspiration contributed most in the Mackenzie River basin.", "authors": [ "Wong, Jefferson S.", "Zhang, Xuebin", "Gharari, Shervan", "Shrestha, Rajesh R.", "Wheater, Howard S.", "Famiglietti, James S." ], "keywords": [ "North America", "Watersheds", "Hydrometeorology", "Water budget", "balance", "Error analysis", "Kalman filters", "Uncertainty" ], "year": "2021", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -34.64291763305664, -21.933664321899414 ], "cluster": 1.0 }, { "idx": 650, "title": "Assessing Water Balance Closure Using Multiple Data Assimilation- and Remote Sensing-Based Datasets for Canada", "abstract": "Obtaining reliable water balance estimates remains a major challenge in Canada for large regions with scarce in situ measurements. Various remote sensing products can be used to complement observation-based datasets and provide an estimate of the water balance at river basin or regional scales. This study provides an assessment of the water balance using combinations of various remote sensing- and data assimilation-based products and quantifies the nonclosure errors for river basins across Canada, ranging from 90 900 to 1 679 100 km(2), for the period from 2002 to 2015. A water balance equation combines the following to estimate the monthly water balance closure: multiple sources of data for each water budget component, including two precipitation products-the global product WATCH Forcing Data ERA-Interim (WFDEI), and the Canadian Precipitation Analysis (CaPA); two evapotranspiration products-MODIS, and Global Land surface Evaporation: The Amsterdam Methodology (GLEAM); one source of water storage data-GRACE from three different centers; and observed discharge data from hydrometric stations (HYDAT). The nonclosure error is attributed to the different data products using a constrained Kalman filter. Results show that the combination of CaPA, GLEAM, and the JPL mascon GRACE product tended to outperform other combinations across Canadian river basins. Overall, the error attributions of precipitation, evapotranspiration, water storage change, and runoff were 36.7%, 33.2%, 17.8%, and 12.2%, which corresponded to 8.1, 7.9, 4.2, and 1.4 mm month(-1), respectively. In particular, the nonclosure error from precipitation dominated in Western Canada, whereas that from evapotranspiration contributed most in the Mackenzie River basin.", "authors": [ "Wong, Jefferson S.", "Zhang, Xuebin", "Gharari, Shervan", "Shrestha, Rajesh R.", "Wheater, Howard S.", "Famiglietti, James S." ], "keywords": [ "North America", "Watersheds", "Hydrometeorology", "Water budget", "balance", "Error analysis", "Kalman filters", "Uncertainty" ], "year": "2021", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -34.75080871582031, -22.365673065185547 ], "cluster": 1.0 }, { "idx": 651, "title": "Assessing the hydrological and geomorphic behaviour of a landscape evolution model within a limits-of-acceptability uncertainty analysis framework", "abstract": "Landscape evolution models (LEMs) have the capability to characterize key aspects of geomorphological and hydrological processes. However, their usefulness is hindered by model equifinality and paucity of available calibration data. Estimating uncertainty in the parameter space and resultant model predictions is rarely achieved as this is computationally intensive and the uncertainties inherent in the observed data are large. Therefore, a limits-of-acceptability (LoA) uncertainty analysis approach was adopted in this study to assess the value of uncertain hydrological and geomorphic data. These were used to constrain simulations of catchment responses and to explore the parameter uncertainty in model predictions. We applied this approach to the River Derwent and Cocker catchments in the UK using a LEM CAESAR-Lisflood. Results show that the model was generally able to produce behavioural simulations within the uncertainty limits of the streamflow. Reliability metrics ranged from 24.4% to 41.2% and captured the high-magnitude low-frequency sediment events. Since different sets of behavioural simulations were found across different parts of the catchment, evaluating LEM performance, in quantifying and assessing both at-a-point behaviour and spatial catchment response, remains a challenge. Our results show that evaluating LEMs within uncertainty analyses framework while taking into account the varying quality of different observations constrains behavioural simulations and parameter distributions and is a step towards a full-ensemble uncertainty evaluation of such models. We believe that this approach will have benefits for reflecting uncertainties in flooding events where channel morphological changes are occurring and various diverse (and yet often sparse) data have been collected over such events.", "authors": [ "Wong, Jefferson S.", "Freer, Jim E.", "Bates, Paul D.", "Warburton, Jeff", "Coulthard, Tom J." ], "keywords": [ "CAESAR‐", "Lisflood", "GLUE", "landscape evolution models", "limits of acceptability", "observational uncertainty", "parameter uncertainty", "uncertainty analysis" ], "year": "2021", "source": "EARTH SURFACE PROCESSES AND LANDFORMS", "publication_type": "J", "point2d": [ -0.264959454536438, -63.23368835449219 ], "cluster": 16.0 }, { "idx": 652, "title": "Assessing the hydrological and geomorphic behaviour of a landscape evolution model within a limits-of-acceptability uncertainty analysis framework", "abstract": "Landscape evolution models (LEMs) have the capability to characterize key aspects of geomorphological and hydrological processes. However, their usefulness is hindered by model equifinality and paucity of available calibration data. Estimating uncertainty in the parameter space and resultant model predictions is rarely achieved as this is computationally intensive and the uncertainties inherent in the observed data are large. Therefore, a limits-of-acceptability (LoA) uncertainty analysis approach was adopted in this study to assess the value of uncertain hydrological and geomorphic data. These were used to constrain simulations of catchment responses and to explore the parameter uncertainty in model predictions. We applied this approach to the River Derwent and Cocker catchments in the UK using a LEM CAESAR-Lisflood. Results show that the model was generally able to produce behavioural simulations within the uncertainty limits of the streamflow. Reliability metrics ranged from 24.4% to 41.2% and captured the high-magnitude low-frequency sediment events. Since different sets of behavioural simulations were found across different parts of the catchment, evaluating LEM performance, in quantifying and assessing both at-a-point behaviour and spatial catchment response, remains a challenge. Our results show that evaluating LEMs within uncertainty analyses framework while taking into account the varying quality of different observations constrains behavioural simulations and parameter distributions and is a step towards a full-ensemble uncertainty evaluation of such models. We believe that this approach will have benefits for reflecting uncertainties in flooding events where channel morphological changes are occurring and various diverse (and yet often sparse) data have been collected over such events.", "authors": [ "Wong, Jefferson S.", "Freer, Jim E.", "Bates, Paul D.", "Warburton, Jeff", "Coulthard, Tom J." ], "keywords": [ "CAESAR‐", "Lisflood", "GLUE", "landscape evolution models", "limits of acceptability", "observational uncertainty", "parameter uncertainty", "uncertainty analysis" ], "year": "2021", "source": "EARTH SURFACE PROCESSES AND LANDFORMS", "publication_type": "J", "point2d": [ -0.12932920455932617, -62.81898880004883 ], "cluster": 16.0 }, { "idx": 653, "title": "Understanding Uncertainty in Probabilistic Floodplain Mapping in the Time of Climate Change", "abstract": "An integrated framework was employed to develop probabilistic floodplain maps, taking into account hydrologic and hydraulic uncertainties under climate change impacts. To develop the maps, several scenarios representing the individual and compounding effects of the models' input and parameters uncertainty were defined. Hydrologic model calibration and validation were performed using a Dynamically Dimensioned Search algorithm. A generalized likelihood uncertainty estimation method was used for quantifying uncertainty. To draw on the potential benefits of the proposed methodology, a flash-flood-prone urban watershed in the Greater Toronto Area, Canada, was selected. The developed floodplain maps were updated considering climate change impacts on the input uncertainty with rainfall Intensity-Duration-Frequency (IDF) projections of RCP8.5. The results indicated that the hydrologic model input poses the most uncertainty to floodplain delineation. Incorporating climate change impacts resulted in the expansion of the potential flood area and an increase in water depth. Comparison between stationary and non-stationary IDFs showed that the flood probability is higher when a non-stationary approach is used. The large inevitable uncertainty associated with floodplain mapping and increased future flood risk under climate change imply a great need for enhanced flood modeling techniques and tools. The probabilistic floodplain maps are beneficial for implementing risk management strategies and land-use planning.", "authors": [ "Zahmatkesh, Zahra", "Han, Shasha", "Coulibaly, Paulin" ], "keywords": [ "probabilistic floodplain mapping", "uncertainty quantification", "model calibration", "climate change" ], "year": "2021", "source": "WATER", "publication_type": "J", "point2d": [ -6.671682357788086, -54.807010650634766 ], "cluster": 16.0 }, { "idx": 654, "title": "Understanding Uncertainty in Probabilistic Floodplain Mapping in the Time of Climate Change", "abstract": "An integrated framework was employed to develop probabilistic floodplain maps, taking into account hydrologic and hydraulic uncertainties under climate change impacts. To develop the maps, several scenarios representing the individual and compounding effects of the models' input and parameters uncertainty were defined. Hydrologic model calibration and validation were performed using a Dynamically Dimensioned Search algorithm. A generalized likelihood uncertainty estimation method was used for quantifying uncertainty. To draw on the potential benefits of the proposed methodology, a flash-flood-prone urban watershed in the Greater Toronto Area, Canada, was selected. The developed floodplain maps were updated considering climate change impacts on the input uncertainty with rainfall Intensity-Duration-Frequency (IDF) projections of RCP8.5. The results indicated that the hydrologic model input poses the most uncertainty to floodplain delineation. Incorporating climate change impacts resulted in the expansion of the potential flood area and an increase in water depth. Comparison between stationary and non-stationary IDFs showed that the flood probability is higher when a non-stationary approach is used. The large inevitable uncertainty associated with floodplain mapping and increased future flood risk under climate change imply a great need for enhanced flood modeling techniques and tools. The probabilistic floodplain maps are beneficial for implementing risk management strategies and land-use planning.", "authors": [ "Zahmatkesh, Zahra", "Han, Shasha", "Coulibaly, Paulin" ], "keywords": [ "probabilistic floodplain mapping", "uncertainty quantification", "model calibration", "climate change" ], "year": "2021", "source": "WATER", "publication_type": "J", "point2d": [ -7.087752819061279, -54.66086196899414 ], "cluster": 16.0 }, { "idx": 655, "title": "Dataset of O-18 and H-2 in streamflow across Canada: A national resource for tracing water sources, water balance and predictive modelling", "abstract": "Oxygen-18 and deuterium were measured in streamflow samples collected from 331 gauging stations across Canada during 2013 to 2019. This dataset includes 9206 isotopic analyses made on 4603 individual water samples, and an additional 1259 analysis repeats for quality assurance/quality control. We also include arithmetic and flow-weighted averages, and other basic statistics for stations where adequate data were available. Station data are provided including station code, name, province, latitude, longitude and drainage area. Flow data were extracted from the historical database of the Water Survey of Canada. Details on the preliminary application of these data are provided in O-18 and H-2 in streamflow across Canada[1]. Overall, these data are expected to be useful when combined with precipitation datasets and analytical or numerical models for water resource management and planning, including tracing streamflow source, water balance, evapotranspiration partitioning, residence time analysis, and early detection of climate and land use changes in Canada. Crown Copyright (c) 2021 Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)", "authors": [ "Gibson, J. J.", "Eby, P.", "Stadnyk, T. A.", "Holmes, T.", "Birks, S. J.", "Pietroniro, A." ], "keywords": [ "Stable isotopes", "Oxygen-18", "Deuterium", "Isotope mass balance", "Streamflow", "Watershed", "Canada" ], "year": "2021", "source": "DATA IN BRIEF", "publication_type": "J", "point2d": [ -2.408782482147217, 17.441781997680664 ], "cluster": 18.0 }, { "idx": 656, "title": "O-18 and H-2 in streamflow across Canada", "abstract": "Study region: Water samples for isotopic analysis were collected during 2013-2019 at 331 gauging stations across Canada in representative watersheds ranging from the Atlantic to the Pacific to the Arctic Oceans. Drainage area coverage of the network included 56 % of Canada's landmass (9,984,670 km(2)) and was representative of 91 % of Canada's annual water yield. Study focus: Baseline data, including 4603 O-18 and H-2 analyses, are described to assess potential for process studies and predictive model calibration. New hydrological insights for the region: While similar patterns are noted between isotopes in streamflow and precipitation across Canada, systematic evaporative enrichment in streamflow occurs in lake- and wetland-rich areas, and systematic depletion occurs in some mountainous and/or cold-regions watersheds. The latter are attributed to uncertainty in precipitation isotope records, glacial melt and/or permafrost thaw. In delta O-18-delta H-2 space, streamflow characteristically plotted on or below the Canadian Meteoric Water Line (CMWL) (delta H-2 = 8.6(18)O+8.5) along imbricated Regional River Lines (RRL) displaying a range of regression slopes (4.34-9.31) and intercepts (-54 to +24), reflecting regional variations in isotopic composition of input sources, evaporative enrichment, and tributary mixing. We define the Canadian Rivers Line (CRL) based on the linear regression of flow-weighted mean values of station data (delta H-2 = 7.89.delta O-18+0.45, r(2) = 0.962; n = 161).", "authors": [ "Gibson, J. J.", "Holmes, T.", "Stadnyk, T. A.", "Birks, S. J.", "Eby, P.", "Pietroniro, A." ], "keywords": [ "Stable isotopes", "Streamflow", "Hydrology", "Water sources", "Water balance", "Evaporation", "Transpiration" ], "year": "2020", "source": "JOURNAL OF HYDROLOGY-REGIONAL STUDIES", "publication_type": "J", "point2d": [ -1.7978203296661377, 17.533756256103516 ], "cluster": 18.0 }, { "idx": 657, "title": "Regional Calibration With Isotope Tracers Using a Spatially Distributed Model: A Comparison of Methods", "abstract": "Accurate representation of flow sources in process-based hydrologic models remains challenging for remote, data-scarce regions. This study applies stable isotope tracers (O-18 and(2)H) in water as auxiliary data for the calibration of the isoWATFLOOD((TM))model. The most efficient method of those evaluated for introducing isotope data into model calibration was the PA-DDS multiobjective search algorithm. The compromise solutions incorporating isotope data performed slightly inferior in terms of streamflow simulation compared to the calibrated solution using streamflow data only. However, the former solution outperformed the latter one in terms of isotope simulation. Approximation of the model parameter uncertainty into internal flow path partitioning was explored. Inclusion of isotope error facilitated a broader examination of the total parameter space, resulting in significant differences in internal storage and flow paths, most significantly for soil storage and evapotranspiration loss. Isotope-optimized calibration reduced evaporation rates and increased soil moisture content within the model, impacting soil water velocity but not streamflow celerity. Flow-only calibration resulted in artificially narrow model prediction bounds, significantly underestimating the propagation of parameter uncertainty, while isotope-informed calibrations yielded more reliable and robust bound on model predictions. Our findings demonstrate that the accuracy of a complex, spatially distributed, and process-based model cannot be judged from one summative flow-based model performance evaluation metric alone.", "authors": [ "Holmes, Tegan", "Stadnyk, Tricia A.", "Kim, Su Jin", "Asadzadeh, Masoud" ], "keywords": [ "hydrologic modeling", "flow tracers", "calibration", "flow partitioning", "stable isotopes", "parameterization" ], "year": "2020", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -4.201729774475098, 12.39247989654541 ], "cluster": 16.0 }, { "idx": 658, "title": "On the value of isotope-enabled hydrological model calibration", "abstract": "Calibration of hydrological models is challenging in high-latitude regions where hydrometric data are minimal. Process-based models are needed to predict future changes in water supply, yet often with high amounts of uncertainty, in part, from poor calibrations. We demonstrate the utility of stable isotopes (O-18, H-2) as data employed for improving the amount and type of information available for model calibration using the isoWATFLOOD(TM) model. We show that additional information added to calibration does not hurt model performance and can improve simulation of water volume. Isotope-enabled calibration improves long-term validation over traditional flow-only calibrated models and offers additional feedback on internal flowpaths and hydrological storages that can be useful for informing internal water distribution and model parameterization. The inclusion of isotope data in model calibration reduces the number of realistic parameter combinations, resulting in more constrained model parameter ranges and improved long-term simulation of large-scale water balance.", "authors": [ "Stadnyk, Tricia A.", "Holmes, T. L." ], "keywords": [ "hydrological modelling", "calibration", "flow tracers", "parameterization", "stable isotopes" ], "year": "2020", "source": "HYDROLOGICAL SCIENCES JOURNAL-JOURNAL DES SCIENCES HYDROLOGIQUES", "publication_type": "J", "point2d": [ -3.49169921875, 12.264054298400879 ], "cluster": 16.0 }, { "idx": 659, "title": "Extreme rainfall drives early onset cyanobacterial bloom", "abstract": "The increasing prevalence of cyanobacteria-dominated harmful algal blooms is strongly associated with nutrient loading and changing climatic patterns. Changes to precipitation frequency and intensity, as predicted by current climate models, are likely to affect bloom development and composition through changes in nutrient fluxes and water column mixing. However, few studies have directly documented the effects of extreme precipitation events on cyanobacterial composition, biomass, and toxin production. We tracked changes in a eutrophic reservoir following an extreme precipitation event, describing an atypically early toxin-producing cyanobacterial bloom and successional progression of the phytoplankton community, toxins, and geochemistry. An increase in bioavailable phosphorus by more than 27-fold in surface waters preceded notable increases in Aphanizomenon floc-aquae throughout the reservoir approximately 2 weeks postevent and -5 weeks before blooms typically occur. Anabaenopeptin-A and three microcystin congeners (microcystin-LR, -YR, and -RR) were detected at varying levels across sites during the bloom period, which lasted between 3 and 5 weeks. These findings suggest extreme rainfall can trigger early cyanobacterial bloom initiation, effectively elongating the bloom season period of potential toxicity. However, effects will vary depending on factors including the timing of rainfall and reservoir physical structure.", "authors": [ "Larsen, Megan L.", "Baulch, Helen M.", "Schiff, Sherry L.", "Simon, Dana F.", "Sauve, Sebastien", "Venkiteswaran, Jason J." ], "keywords": [ "cyanobacterial bloom", "extreme rainfall", "phosphorus", "reservoir", "cyanotoxins" ], "year": "2020", "source": "FACETS", "publication_type": "J", "point2d": [ 59.398826599121094, 14.198827743530273 ], "cluster": 19.0 }, { "idx": 660, "title": "Low sediment redox promotes cyanobacteria blooms across a trophic range: implications for management", "abstract": "Molot LA, Schiff SL, Venkiteswaran JJ, Baulch HM, Higgins SN, Zastepa A, Verschoor MJ, Walters D. 2021. Low sediment redox promotes cyanobacteria blooms across a trophic range: implications for management. Lake Reserv Manage. XX:XXX-XXX. Field observations and experimental manipulations with different oxidizing agents including nitrate demonstrate that high sediment redox prevents cyanobacteria blooms in eutrophic freshwaters. Conversely, low sediment redox caused by depletion of dissolved oxygen and nitrate allows blooms to form. This explains why bloom risk increases with phosphorus levels: Higher productivity increases the spatial and temporal extent of low sediment redox. The intermediate link between low redox and cyanobacteria blooms appears to be internal loading of ferrous iron (Fe2+) from reduced sediments with diffusion to depths accessible to migrating cyanobacteria, providing a source for their high iron demand. Regardless of whether Fe2+ release is the intermediate link, the concept of low sediment redox as promoter has major potential to improve bloom management if managers consider the impact of their nutrient management choices, nutrient targets, and in-lake methods on sediment redox. Phosphorus input targets can be adjusted as climate change alters the extent of anoxia, and short-term bloom prediction models that incorporate the sediment redox concept could predict onset of blooms earlier than current models that depend on detection of photosynthetic pigments associated with blooms.", "authors": [ "Molot, Lewis A.", "Schiff, Sherry L.", "Venkiteswaran, Jason J.", "Baulch, Helen M.", "Higgins, Scott N.", "Zastepa, Arthur", "Verschoor, Mark J.", "Walters, Daniel" ], "keywords": [ "Bloom management", "climate change", "cyanobacteria blooms", "iron", "nitrogen", "phosphorus", "sediment anoxia" ], "year": "2021", "source": "LAKE AND RESERVOIR MANAGEMENT", "publication_type": "J", "point2d": [ 61.077789306640625, 10.71467399597168 ], "cluster": 19.0 }, { "idx": 661, "title": "Low sediment redox promotes cyanobacteria blooms across a trophic range: implications for management", "abstract": "Molot LA, Schiff SL, Venkiteswaran JJ, Baulch HM, Higgins SN, Zastepa A, Verschoor MJ, Walters D. 2021. Low sediment redox promotes cyanobacteria blooms across a trophic range: implications for management. Lake Reserv Manage. XX:XXX-XXX. Field observations and experimental manipulations with different oxidizing agents including nitrate demonstrate that high sediment redox prevents cyanobacteria blooms in eutrophic freshwaters. Conversely, low sediment redox caused by depletion of dissolved oxygen and nitrate allows blooms to form. This explains why bloom risk increases with phosphorus levels: Higher productivity increases the spatial and temporal extent of low sediment redox. The intermediate link between low redox and cyanobacteria blooms appears to be internal loading of ferrous iron (Fe2+) from reduced sediments with diffusion to depths accessible to migrating cyanobacteria, providing a source for their high iron demand. Regardless of whether Fe2+ release is the intermediate link, the concept of low sediment redox as promoter has major potential to improve bloom management if managers consider the impact of their nutrient management choices, nutrient targets, and in-lake methods on sediment redox. Phosphorus input targets can be adjusted as climate change alters the extent of anoxia, and short-term bloom prediction models that incorporate the sediment redox concept could predict onset of blooms earlier than current models that depend on detection of photosynthetic pigments associated with blooms.", "authors": [ "Molot, Lewis A.", "Schiff, Sherry L.", "Venkiteswaran, Jason J.", "Baulch, Helen M.", "Higgins, Scott N.", "Zastepa, Arthur", "Verschoor, Mark J.", "Walters, Daniel" ], "keywords": [ "Bloom management", "climate change", "cyanobacteria blooms", "iron", "nitrogen", "phosphorus", "sediment anoxia" ], "year": "2021", "source": "LAKE AND RESERVOIR MANAGEMENT", "publication_type": "J", "point2d": [ 61.38737869262695, 11.021739959716797 ], "cluster": 19.0 }, { "idx": 663, "title": "CliGAN: A Structurally Sensitive Convolutional Neural Network Model for Statistical Downscaling of Precipitation from Multi-Model Ensembles", "abstract": "Despite numerous studies in statistical downscaling methodologies, there remains a lack of methods that can downscale from precipitation modeled in global climate models to regional level high resolution gridded precipitation. This paper reports a novel downscaling method using a Generative Adversarial Network (GAN), CliGAN, which can downscale large-scale annual maximum precipitation given by simulation of multiple atmosphere-ocean global climate models (AOGCM) from Coupled Model Inter-comparison Project 6 (CMIP6) to regional-level gridded annual maximum precipitation data. This framework utilizes a convolution encoder-dense decoder network to create a generative network and a similar network to create a critic network. The model is trained using an adversarial training approach. The critic uses the Wasserstein distance loss function and the generator is trained using a combination of adversarial loss Wasserstein distance, structural loss with the multi-scale structural similarity index (MSSIM), and content loss with the Nash-Sutcliff Model Efficiency (NS). The MSSIM index allowed us to gain insight into the model's regional characteristics and shows that relying exclusively on point-based error functions, widely used in statistical downscaling, may not be enough to reliably simulate regional precipitation characteristics. Further use of structural loss functions within CNN-based downscaling methods may lead to higher quality downscaled climate model products.", "authors": [ "Chaudhuri, Chiranjib", "Robertson, Colin" ], "keywords": [ "statistical downscaling", "generative adversarial network", "combination of errors", "convolutional neural network", "multi-scale structural similarity index", "Wasserstein GAN" ], "year": "2020", "source": "WATER", "publication_type": "J", "point2d": [ -41.438663482666016, -55.58708190917969 ], "cluster": 14.0 }, { "idx": 664, "title": "InundatEd-v1.0: a height above nearest drainage (HAND)-based flood risk modeling system using a discrete global grid system", "abstract": "Despite the high historical losses attributed to flood events, Canadian flood mitigation efforts have been hindered by a dearth of current, accessible flood extent/risk models and maps. Such resources often entail large datasets and high computational requirements. This study presents a novel, computationally efficient flood inundation modeling framework (InundatEd) using the height above nearest drainage (HAND)-based solution for Manning's equation, implemented in a big-data discrete global grid system (DGGS)-based architecture with a web-GIS (Geographic Information Systems) platform. Specifically, this study aimed to develop, present, and validate InundatEd through binary classification comparisons to recently observed flood events. The framework is divided into multiple swappable modules including GIS pre-processing; regional regression; inundation models; and web-GIS visualization. Extent testing and processing speed results indicate the value of a DGGS-based architecture alongside a simple conceptual inundation model and a dynamic user interface.", "authors": [ "Chaudhuri, Chiranjib", "Gray, Annie", "Robertson, Colin" ], "keywords": [ "" ], "year": "2021", "source": "GEOSCIENTIFIC MODEL DEVELOPMENT", "publication_type": "J", "point2d": [ 3.857477903366089, -15.193648338317871 ], "cluster": 16.0 }, { "idx": 665, "title": "Fluctuating water levels influence access to critical habitats for threatened Cowichan Lake lamprey", "abstract": "Cowichan Lake lamprey (Entosphenus macrostomus) is a threatened species resident to Mesachie Lake, Cowichan Lake, and adjoining Bear Lake and their major tributaries in British Columbia. Decreases in trapping success have created concerns that the population is declining. Some potential threats include water use, climate change, and management actions. Owing to the absence of long-term data on population trends, little information is available to estimate habitat quality and factors that influence it. We sought to fill this gap by examining associations between habitat area and variables representing suspected key drivers of habitat availability. Critical habitat areas were imaged using an unmanned aerial vehicle over a period of three years at three sites at Cowichan Lake and a subsequent habitat area was classified. Meteorological and anthropogenic controls on habitat area were investigated through automatic relevance detection regression models. The major driver of habitat area during the critical spawning period was water level during the storage season, which also depends on the meteorological variables and anthropogenic control. It is recommended that regulation of the weir should aim to ensure that the water level remains above the 1 m mark, which roughly equates to the 67% coverage of water on the habitat area used for spawning.", "authors": [ "Chaudhuri, Chiranjib", "Wade, Joy", "Robertson, Colin" ], "keywords": [ "anthropogenic effects on habitat", "automatic relevance detection", "conservation of species", "Cowichan lamprey", "critical habitat mapping", "drone survey" ], "year": "2020", "source": "FACETS", "publication_type": "J", "point2d": [ 59.294918060302734, -1.9859675168991089 ], "cluster": 19.0 }, { "idx": 666, "title": "CWDAT-An Open-Source Tool for the Visualization and Analysis of Community-Generated Water Quality Data", "abstract": "Citizen science initiatives span a wide range of topics, designs, and research needs. Despite this heterogeneity, there are several common barriers to the uptake and sustainability of citizen science projects and the information they generate. One key barrier often cited in the citizen science literature is data quality. Open-source tools for the analysis, visualization, and reporting of citizen science data hold promise for addressing the challenge of data quality, while providing other benefits such as technical capacity-building, increased user engagement, and reinforcing data sovereignty. We developed an operational citizen science tool called the Community Water Data Analysis Tool (CWDAT)-a R/Shiny-based web application designed for community-based water quality monitoring. Surveys and facilitated user-engagement were conducted among stakeholders during the development of CWDAT. Targeted recruitment was used to gather feedback on the initial CWDAT prototype's interface, features, and potential to support capacity building in the context of community-based water quality monitoring. Fourteen of thirty-two invited individuals (response rate 44%) contributed feedback via a survey or through facilitated interaction with CWDAT, with eight individuals interacting directly with CWDAT. Overall, CWDAT was received favourably. Participants requested updates and modifications such as water quality thresholds and indices that reflected well-known barriers to citizen science initiatives related to data quality assurance and the generation of actionable information. Our findings support calls to engage end-users directly in citizen science tool design and highlight how design can contribute to users' understanding of data quality. Enhanced citizen participation in water resource stewardship facilitated by tools such as CWDAT may provide greater community engagement and acceptance of water resource management and policy-making.", "authors": [ "Gray, Annie", "Robertson, Colin", "Feick, Rob" ], "keywords": [ "citizen science", "data quality", "web application", "water quality", "community-based monitoring" ], "year": "2021", "source": "ISPRS INTERNATIONAL JOURNAL OF GEO-INFORMATION", "publication_type": "J", "point2d": [ 50.54360580444336, -28.399303436279297 ], "cluster": 4.0 }, { "idx": 667, "title": "Decentralized geoprivacy: leveraging social trust on the distributed web", "abstract": "Despite several high-profile data breaches and business models that commercialize user data, participation in social media networks continues to require users to trust corporations to safeguard their personal data. Since these data increasingly contain geographic references that allude to individuals' locations and movements, the need for new approaches to geoprivacy and data sovereignty has grown. We develop a geoprivacy framework that couples two emerging technologies - decentralized data storage and discrete global grid systems - to facilitate fine-grained user control over the ownership of, access to and map-based representation of their data. The framework is illustrated with a dynamic k-anonymity model that links the geographic precision of shared data to social trust within in a social network. In this framework, users' spatio-temporal data are shared through a decentralized system and are represented on a discrete global grid data model at spatial resolutions that correspond to varying degrees of trust between individuals who are exchanging information. Our framework has several advantages over centralized geoprivacy approaches, namely trust in a third-party entity is not required and geoprivacy is dynamic and context-dependent with users maintaining autonomy. As the distributed web begins to emerge, so too can the next generation of geographic information sharing tools.", "authors": [ "Hojati, Majid", "Farmer, Carson", "Feick, Rob", "Robertson, Colin" ], "keywords": [ "Socio-spatial networks", "decentralized geoprivacy", "distributed spatial data sharing", "discrete global grid systems" ], "year": "2021", "source": "INTERNATIONAL JOURNAL OF GEOGRAPHICAL INFORMATION SCIENCE", "publication_type": "J", "point2d": [ 30.88234519958496, -38.65556716918945 ], "cluster": 4.0 }, { "idx": 668, "title": "Reconstruction of past backyard skating seasons in the Original Six NHL cities from citizen science data", "abstract": "This study conducted linear and change-point analyses of historical trends since 1942 in the length and number of days suitable for skating on backyard rinks in the Original Six National Hockey League cities of Boston, Chicago, Detroit, Montreal, New York, and Toronto. Analysis is based on the relationship between ambient air temperatures and the probability of skating, using thresholds identified through the RinkWatch citizen science project. In all cities, coefficient estimates suggest the number of high-probability skating days per winter is declining, with easternmost cities displaying notable declines and growing inter-annual variability in skating days in recent decades. Linear analysis shows a statistically significant decline in Toronto, with a step-change emerging in 1980, after which there is on average one-third fewer skating days compared with preceding decades. The outdoor skating season trends towards later start dates in Boston, Montreal, New York, and Toronto. Future monitoring of outdoor rinks provides an opportunity for engaging the public in identification of winter warming trends that might otherwise be imperceptible, and for raising awareness of the impacts of climate change.", "authors": [ "Malik, Karim", "McLeman, Robert", "Robertson, Colin", "Lawrence, Haydn" ], "keywords": [ "outdoor skating", "backyard rinks", "hockey", "winter climate" ], "year": "2020", "source": "CANADIAN GEOGRAPHER-GEOGRAPHE CANADIEN", "publication_type": "J", "point2d": [ -40.691593170166016, -30.693307876586914 ], "cluster": 8.0 }, { "idx": 669, "title": "Exploring the Use of Computer Vision Metrics for Spatial Pattern Comparison", "abstract": "Detection of changes in spatial processes has long been of interest to quantitative geographers seeking to test models, validate theories, and anticipate change. Given the current data-rich environment of today, it may be time to reconsider the methodological approaches used for quantifying change in spatial processes. New tools emerging from computer vision research may hold particular potential to make significant advances in quantifying changes in spatial processes. In this article, two comparative indices from computer vision, the structural similarity (SSIM) index, and the complex wavelet structural similarity (CWSSIM) index were examined for their utility in the comparison of real and simulated spatial data sets. Gaussian Markov random fields were simulated and compared with both metrics. A case study into comparison of snow water equivalent spatial patterns over northern Canada was used to explore the properties of these indices on real-world data. CWSSIM was found to be less sensitive than SSIM to changing window dimension. The CWSSIM appears to have significant potential in characterizing change and/or similarity; distinguishing between map pairs that possess subtle structural differences. Further research is required to explore the utility of these approaches for empirical comparison cases of different forms of landscape change and in comparison to human judgments of spatial pattern differences.", "authors": [ "Malik, Karim", "Robertson, Colin" ], "keywords": [ "" ], "year": "2020", "source": "GEOGRAPHICAL ANALYSIS", "publication_type": "J", "point2d": [ -40.5138053894043, -44.04011154174805 ], "cluster": 8.0 }, { "idx": 670, "title": "An integrated environmental analytics system (IDEAS) based on a DGGS", "abstract": "Discrete global grid systems (DGGS) have been proposed as a data model for a digital earth framework. We introduce a new data model and analytics system called IDEAS - integrated discrete environmental analysis system to create an operational DGGS-based GIS which is suitable for large scale environmental modelling and analysis. Our analysis demonstrates that DGGS-based GIS is feasible within a relational database environment incorporating common data analytics tools. Common GIS operations implemented in our DGGS data model outperformed the same operations computed using traditional geospatial data types. A case study into wildfire modelling demonstrates the capability for data integration and supporting big data geospatial analytics. These results indicate that DGGS data models have significant capability to solve some of the key outstanding problems related to geospatial data analytics, providing a common representation upon which fast and scalable algorithms can be built.", "authors": [ "Robertson, Colin", "Chaudhuri, Chiranjib", "Hojati, Majid", "Roberts, Steven A." ], "keywords": [ "DGGS", "Data model", "Big data", "Spatial data", "Analytics", "Environment" ], "year": "2020", "source": "ISPRS JOURNAL OF PHOTOGRAMMETRY AND REMOTE SENSING", "publication_type": "J", "point2d": [ 28.848527908325195, -39.56361389160156 ], "cluster": 16.0 }, { "idx": 671, "title": "The impacts of changing climate and streamflow on nutrient speciation in a large Prairie reservoir", "abstract": "Climate mediated warming water temperature, drought and extreme flooding are projected to shift the phenology of nutrients in receiving lakes and reservoirs further intensifying eutrophication and algal blooms, especially in temperate reservoirs. An emerging issue in reservoir management is the prediction of climate change impacts, a necessity for sound decision making and sustainable management. Lake Diefenbaker is a large multipurpose reservoir in the Canadian Prairies. In this study, the impact of climate change on nutrient speciation in Lake Diefenbaker is examined using loosely linked SpAtially Referenced Regression On Watershed attributes (SPARROW) and CE-QUAL-W2 models. Two climate mediated scenarios, RCP 8.5 representing the most extreme climate change, and climate induced streamflow were modelled. Nutrient levels are anticipated to double under the climate change and streamflow scenarios. Winter and spring were identified as hot moments for nitrogen pollution with a plausible saturation of nitrous oxides in the future. Of concern is a plausible recycling of nitrate through dissimilatory nitrate reduction to ammonium. Summer and fall on the other hand represent the period for phosphorus enrichment and internal loading with a probable succession of cyanobacteria in the summer.", "authors": [ "Akomeah, E.", "Morales-Marin, L. A.", "Carr, M.", "Sadeghian, A.", "Lindenschmidt, K. E." ], "keywords": [ "Climate change", "CE-QUAL-W2", "Large multi-purpose reservoir", "Eutrophication" ], "year": "2021", "source": "JOURNAL OF ENVIRONMENTAL MANAGEMENT", "publication_type": "J", "point2d": [ 35.66499328613281, -8.998371124267578 ], "cluster": 10.0 }, { "idx": 672, "title": "Data assimilation of satellite-based terrestrial water storage changes into a hydrology land-surface model", "abstract": "Accurate estimation of snow mass or snow water equivalent (SWE) over space and time is required for global and regional predictions of the effects of climate change. This work investigates whether integration of remotely sensed terrestrial water storage (TWS) information, which is derived from the Gravity Recovery and Climate Experiment (GRACE), can improve SWE and streamflow simulations within a semi-distributed hydrology land surface model. A data assimilation (DA) framework was developed to combine TWS observations with the MESH (Modelisation Environnementale Communautaire - Surface Hydrology) model using an ensemble Kalman smoother (EnKS). The snow-dominated Liard Basin was selected as a case study. The proposed assimilation methodology reduced bias of monthly SWE simulations at the basin scale by 17.5% and improved unbiased root-mean-square difference (ubRMSD) by 23%. At the grid scale, the DA method improved ubRMSD values and correlation coefficients for 85% and 97% of the grid cells, respectively. Effects of GRACE DA on streamflow simulations were evaluated against observations from three river gauges, where it effectively improved the simulation of high flows during snowmelt season from April to June. The influence of GRACE DA on the total flow volume and low flows was found to be variable. In general, the use of GRACE observations in the assimilation framework not only improved the simulation of SWE, but also effectively influenced streamflow simulations.", "authors": [ "Bahrami, Ala", "Goita, Kalifa", "Magagi, Ramata", "Davison, Bruce", "Razavi, Saman", "Elshamy, Mohamed", "Princz, Daniel" ], "keywords": [ "GRACE", "MESH", "Data assimilation", "EnKS", "Snow water equivalent", "Terrestrial water storage" ], "year": "2021", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -36.582923889160156, -21.337324142456055 ], "cluster": 8.0 }, { "idx": 673, "title": "Time Variant Sensitivity Analysis of Hydrological Model Parameters in a Cold Region Using Flow Signatures", "abstract": "The complex terrain, seasonality, and cold region hydrology of the Nelson Churchill River Basin (NCRB) presents a formidable challenge for hydrological modeling, which complicates the calibration of model parameters. Seasonality leads to different hydrological processes dominating at different times of the year, which translates to time variant sensitivity in model parameters. In this study, Hydrological Predictions for the Environment model (HYPE) is set up in the NCRB to analyze the time variant sensitivity analysis (TVSA) of model parameters using a Global Sensitivity Analysis technique known as Variogram Analysis of Response Surfaces (VARS). TVSA can identify parameters that are highly influential in a short period but relatively uninfluential over the whole simulation period. TVSA is generally effective in identifying model's sensitivity to event-based parameters related to cold region processes such as snowmelt and frozen soil. This can guide event-based calibration, useful for operational flood forecasting. In contrast to residual based metrics, flow signatures, specifically the slope of the mid-segment of the flow duration curve, allows VARS to detect the influential parameters throughout the timescale of analysis. The results are beneficial for the calibration process in complex and multi-dimensional models by targeting the informative parameters, which are associated with the cold region hydrological processes.", "authors": [ "Bajracharya, Ajay", "Awoye, Herve", "Stadnyk, Tricia", "Asadzadeh, Masoud" ], "keywords": [ "hydrological modeling", "cold region processes", "non-stationarity", "variogram analysis of response surfaces", "time variant sensitivity analysis" ], "year": "2020", "source": "WATER", "publication_type": "J", "point2d": [ 3.51613450050354, -68.16339111328125 ], "cluster": 16.0 }, { "idx": 674, "title": "Improved modelling of a Prairie catchment using a progressive two-stage calibration strategy with in situ soil moisture and streamflow data", "abstract": "Dynamic contributing areas, various fill-and-spill mechanisms and cold-region processes make the hydrological modelling of the Prairies very challenging. Several models (from simple conceptual to advanced process-based) are available, but the focus has been largely in reproducing streamflow. Few studies have assimilated soil moisture and other hydrological fluxes for improved simulation, but the emphasis has been predominately on simulating contributing areas. However, previous research has shown that the contributing areas are dynamic, and can vary from one year to the next, depending on hydro-meteorological conditions. Therefore, the areas deemed non-contributing can also occasionally contribute to streamflow. In this study, we introduce a progressive two-stage calibration strategy to constrain soil moisture in non-contributing areas. We demonstrate that constraining soil moisture in non-contributing areas can result in improved hydrological simulations and more realistic process representations. The Nash-Sutcliffe efficiency (NSE) values for simulated soil moisture in contributing areas increased by 68% at 20 cm and 25% at 50 cm soil depths during validation when non-contributing areas were constrained. This further led to increases in NSE values in streamflow simulation during calibration (6%) and validation (12%). Our findings suggest that soil moisture in non-contributing areas should be properly constrained for improved modelling of Prairie catchments.", "authors": [ "Budhathoki, Sujata", "Rokaya, Prabin", "Lindenschmidt, Karl-Erich" ], "keywords": [ "contributing areas", "hydrological modelling", "model fidelity", "multi-objective calibration", "Prairie", "soil moisture" ], "year": "2020", "source": "HYDROLOGY RESEARCH", "publication_type": "J", "point2d": [ 17.32228660583496, -54.68207550048828 ], "cluster": 16.0 }, { "idx": 675, "title": "Current status and advancement suggestions of ice-jam flood hazard and risk assessment", "abstract": "In many northern rivers, ice-jam flooding can be more severe than open-water flooding, leading to human casualties, damages to property and infrastructure, and adverse impacts on the ecology. Consequently, ice jam related flooding is a major concern for many riverside communities, water authorities, insurance companies, and government agencies. Ice-jam flood hazard delineation and risk analysis are important measures for flood preparation, mitigation, and management strategies. Although methodologies and techniques for open-water flood hazard and risk assessment are well established, methodologies and techniques for ice-jam flood hazard and risk assessment are often unavailable or less developed. In addition to this, a considerable number of studies have been conducted in the context of flood management, but a very limited number of studies have been carried out in real-time flood risk analysis during operational flood forecasting. In this paper, the current status of ice-jam flood hazard delineation and risk analysis is discussed. A framework for real-time risk analysis for operational flood forecasting is also discussed. Finally, current limitations and future requirements for developing effective ice-jam flood hazard delineation and risk analysis methodologies are provided.", "authors": [ "Das, Apurba", "Lindenschmidt, Karl-Erich" ], "keywords": [ "ice jam", "flood hazard", "flood risk", "model systems" ], "year": "2020", "source": "ENVIRONMENTAL REVIEWS", "publication_type": "J", "point2d": [ -2.5595920085906982, -36.458797454833984 ], "cluster": 16.0 }, { "idx": 676, "title": "Evaluation of the implications of ice-jam flood mitigation measures", "abstract": "Ice-jam flood risk management requires new approaches to reduce flood damages. Although many structural and non-structural measures are implemented to reduce the impacts of ice-jam flooding, there are still many challenges in identifying appropriate strategies to reduce the ice-jam flood risk along northern rivers. The main purpose of this study is to provide a novel methodological framework to assess the feasibility of various ice-jam flood mitigation measures based on risk analysis. A total of three ice-jam flood mitigation measures (artificial breakup, sediment dredging and dike installation) were examined using a stochastic modelling framework for the potential to reduce the ice-jam flood risk along the Athabasca River at Fort McMurray. An ensemble of hundreds of backwater level profiles was used to construct ice-jam flood hazard maps to estimate expected annual damages, using depth-damage curves for structural and content damages, within the downtown area of Fort McMurray. The results show that, while sediment dredging may be able to reduce a certain level of expected annual damages in the town, and artificial breakup and a dike with a crest elevation of 250 m a.s.l. can be the most effective measures to reduce the amount of expected annual damages.", "authors": [ "Das, Apurba", "Lindenschmidt, Karl-Erich" ], "keywords": [ "Athabasca River", "expected annual damages", "flood mitigation", "Fort McMurray", "ice jams", "Monte-Carlo", "risk analysis", "stochastic framework" ], "year": "2021", "source": "JOURNAL OF FLOOD RISK MANAGEMENT", "publication_type": "J", "point2d": [ -0.6007740497589111, -36.290287017822266 ], "cluster": 16.0 }, { "idx": 677, "title": "Evaluation of the implications of ice-jam flood mitigation measures", "abstract": "Ice-jam flood risk management requires new approaches to reduce flood damages. Although many structural and non-structural measures are implemented to reduce the impacts of ice-jam flooding, there are still many challenges in identifying appropriate strategies to reduce the ice-jam flood risk along northern rivers. The main purpose of this study is to provide a novel methodological framework to assess the feasibility of various ice-jam flood mitigation measures based on risk analysis. A total of three ice-jam flood mitigation measures (artificial breakup, sediment dredging and dike installation) were examined using a stochastic modelling framework for the potential to reduce the ice-jam flood risk along the Athabasca River at Fort McMurray. An ensemble of hundreds of backwater level profiles was used to construct ice-jam flood hazard maps to estimate expected annual damages, using depth-damage curves for structural and content damages, within the downtown area of Fort McMurray. The results show that, while sediment dredging may be able to reduce a certain level of expected annual damages in the town, and artificial breakup and a dike with a crest elevation of 250 m a.s.l. can be the most effective measures to reduce the amount of expected annual damages.", "authors": [ "Das, Apurba", "Lindenschmidt, Karl-Erich" ], "keywords": [ "Athabasca River", "expected annual damages", "flood mitigation", "Fort McMurray", "ice jams", "Monte-Carlo", "risk analysis", "stochastic framework" ], "year": "2021", "source": "JOURNAL OF FLOOD RISK MANAGEMENT", "publication_type": "J", "point2d": [ -0.5945066213607788, -35.761199951171875 ], "cluster": 16.0 }, { "idx": 678, "title": "Evaluation of the sensitivity of hydraulic model parameters, boundary conditions and digital elevation models on ice-jam flood delineation", "abstract": "Model parameters and boundary conditions characterizing flood domains in riverine flood modelling play an important role in the delineation of flood hazard along rivers. Since the digital elevation model (DEM) is an integral part of the delineation of flood hazard, it is necessary to determine the relative sensitivity of the DEM alongside the hydraulic model parameters and boundary conditions. This study provides a novel framework to examine the relative sensitivity of a river ice hydraulic model and various DEMs on ice-jam flood delineation. The Athabasca River at Fort McMurray in Canada is presented as a test site. The study found that ice-jam flood delineation is highly sensitive to DEMs. While flood hazard delineation is low to moderate sensitive to all the model parameters, it is highly sensitive to almost all the boundary conditions.", "authors": [ "Das, Apurba", "Lindenschmidt, Karl-Erich" ], "keywords": [ "River ice", "Flood hazard", "DEM", "Sensitivity analysis", "RIVICE" ], "year": "2021", "source": "COLD REGIONS SCIENCE AND TECHNOLOGY", "publication_type": "J", "point2d": [ 0.9862005710601807, -40.37104415893555 ], "cluster": 16.0 }, { "idx": 679, "title": "Ice-Jam Flood Risk Assessment and Hazard Mapping under Future Climate", "abstract": "In cold-region environments, ice-jam floods (IJFs) can result in high water levels in rivers to overtop levees, leading to devastating floods. Since climatic conditions play an important role in ice-jam flooding, there is a growing concern among property developers, insurance companies, government agencies, and communities on future IJF probabilities, especially in the context of changing climate. This study presents a stochastic framework for future IJF risk assessment and hazard mapping. Future hydrological conditions derived from a physically based hydrological model (forced with meteorological inputs from the Canadian regional climate model driven by two atmospheric-ocean general circulation climate models) were coupled to a fully dynamic hydraulic river-ice model to evaluate ice-jam scenarios and subsequent backwater-level profiles for the 2041-2070 period along the Athabasca River at Fort McMurray in Alberta, Canada. The modeling results show that future IJF risk will be lower and flood inundations less severe due to projected changes in climate, hydrology, and ice phenology in the 2041-2070 period compared to the baseline period of 1971-2000. However, extreme IJF events are still probable and can flood a considerable area of the town.", "authors": [ "Das, Apurba", "Rokaya, Prabin", "Lindenschmidt, Karl-Erich" ], "keywords": [ "Climate", "Ice-jam flood", "Risk assessment", "Hazard mapping", "Athabasca River" ], "year": "2020", "source": "JOURNAL OF WATER RESOURCES PLANNING AND MANAGEMENT", "publication_type": "J", "point2d": [ -1.3409497737884521, -39.20980453491211 ], "cluster": 16.0 }, { "idx": 680, "title": "Diagnosis of future changes in hydrology for a Canadian Rockies headwater basin", "abstract": "Climate change is anticipated to impact the hydrology of the Saskatchewan River, which originates in the Canadian Rockies mountain range. To better understand the climate change impacts in the mountain headwaters of this basin, a physically based hydrological model was developed for this basin using the Cold Regions Hydrological Modelling platform (CRHM) for Marmot Creek Research Basin (similar to 9.4 km(2)), located in the Front Ranges of the Canadian Rockies. Marmot Creek is composed of ecozones ranging from montane forests to alpine tundra and alpine exposed rock and includes both large and small clearcuts. The model included blowing and intercepted snow redistribution, sublimation, energy-balance snowmelt, slope and canopy effects on melt, Penman-Monteith evapotranspiration, infiltration to frozen and unfrozen soils, hillslope hydrology, streamflow routing, and groundwater components and was parameterised without calibration from streamflow. Near-surface outputs from the 4 km Weather Research and Forecasting (WRF) model were bias-corrected using the quantile delta mapping method with respect to meteorological data from five stations located from low-elevation montane forests to alpine ridgetops and running over October 2005-September 2013. The bias-corrected WRF outputs during a current period (2005-2013) and a future pseudo global warming period (PGW, 2091-2099) were used to drive model simulations to assess changes in Marmot Creek's hydrology. Under a business-as-usual forcing scenario, Representative Concentration Pathway 8.5 (RCP8.5) in PGW, the basin will warm up by 4.7 degrees C and receive 16% more precipitation, which will lead to a 40 mm decline in seasonal peak snowpack, 84 mm decrease in snowmelt volume, 0.2 mm d(-1) slower melt rate, and 49 d shorter snow-cover duration. The alpine snow season will be shortened by almost 1.5 months, but at some lower elevations there will be large decreases in peak snowpack (similar to 45 %) in addition to a shorter snow season. Declines in the peak snowpack will be much greater in clearcuts than under mature forest canopies. In alpine and treeline ecozones, blowing snow transport and sublimation will be suppressed by higher-threshold wind speeds for transport, in forest ecozones, sublimation losses from intercepted snow will decrease due to faster unloading and drip, and throughout the basin, evapotranspiration will increase due to a longer snow-free season and more rainfall. Runoff will begin earlier in all ecozones, but, as a result of variability in surface and subsurface hydrology, forested and alpine ecozones will generate the greatest runoff volumetric increases, ranging from 12% to 25 %, whereas the treeline ecozone will have a small (2 %) decrease in runoff volume due to decreased melt volumes from smaller snowdrifts. The shift in timing in streamflow will be notable, with 236% higher flows in spring months and 12% lower flows in summer and 13% higher flows in early fall. Overall, Marmot Creek's annual streamflow discharge will increase by 18% with PGW, without a change in its streamflow generation efficiency, despite its basin shifting from primarily snowmelt runoff towards rainfall-dominated runoff generation.", "authors": [ "Fang, Xing", "Pomeroy, John W." ], "keywords": [ "" ], "year": "2020", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -27.777450561523438, -10.914928436279297 ], "cluster": 12.0 }, { "idx": 681, "title": "Understanding human adaptation to drought: agent-based agricultural water demand modeling in the Bow River Basin, Canada", "abstract": "The farmers in the Bow River Basin (BRB), Canada, have adopted water conservation strategies to reduce water needs. This reduction, however, encouraged the expansion of irrigation, which may rebound agricultural water demands. This paradox requires an understanding of human adaptation to drought by mapping individual farmers' water conservation decisions to the dynamics of the basin-wide water demand. We develop an agent-based agricultural water demand (ABAD) model, simulating farmers' behavior in adopting new on-farm irrigation systems and/or changing crop patterns in response to drought conditions in the BRB. ABAD demonstrates (1) how farmers' attitude toward profits, risk aversion, environmental protection, social interaction, and irrigation expansion explains the dynamics of the water demand and (2) how the conservation program may paradoxically lead to the rebound phenomenon. ABAD, subject to its conceptualization limitations, can be used for exploration and scenario analysis of future agricultural water demand in response to water conservation programs in the BRB.", "authors": [ "Ghoreishi, Mohammad", "Razavi, Saman", "Elshorbagy, Amin" ], "keywords": [ "rebound phenomenon", "socio-hydrology", "agent-based modeling", "agricultural water demand modeling", "Bow River Basin" ], "year": "2021", "source": "HYDROLOGICAL SCIENCES JOURNAL", "publication_type": "J", "point2d": [ 46.37895202636719, -56.526126861572266 ], "cluster": 11.0 }, { "idx": 683, "title": "Energy stores and mercury concentrations in a common minnow (spottail shiner, Notropis hudsonius) associated with a peaking hydroelectric dam", "abstract": "Peaking hydroelectric facilities release water from dams to match energy production with demand, often on a daily cycle. These fluctuating flows downstream can exert several potential stressors on organisms that may inhibit their growth, indirectly causing higher contaminant concentrations through reduced growth dilution. We collected spottail shiner (Notropis hudsonius) at two sites upstream and two sites downstream of a peaking hydroelectric dam in east-central Saskatchewan, Canada, and compared their body condition, triglyceride concentrations, and mercury concentrations. Condition decline was observed in one of two downstream sites from August to September, and the lowest triglyceride concentrations were consistently found downstream of the dam where hydropeaking had the most perceptible effects on the shoreline. Mercury concentrations were significantly greater at both downstream sites relative to upstream. Despite these results, inconsistencies in response parameters across sites and time limited our ability to isolate the effects of hydropeaking as a causative agent and suggest indirect effects such as shifts in algal and macroinvertebrate communities may be responsible for our observations. These results suggest that hydroelectric power generation may indirectly increase mercury concentrations in downstream fish, but more research will be required to determine the specific mechanisms by which this occurs. The results and data also provide useful insights into the physiology of wild spottail shiner populations, which can help to inform the development of these fish as a North American sentinel species.", "authors": [ "Green, Derek J.", "Jardine, Timothy D.", "Weber, Lynn P.", "Janz, David M." ], "keywords": [ "fish", "native species", "North America", "river", "stress" ], "year": "2020", "source": "RIVER RESEARCH AND APPLICATIONS", "publication_type": "J", "point2d": [ 66.85537719726562, -3.279329299926758 ], "cluster": 0.0 }, { "idx": 684, "title": "Using big data analytics to synthesize research domains and identify emerging fields in urban climatology", "abstract": "The growing concerns over urbanization and climate change have resulted in an exponential growth in publications on urban climatology in recent decades. However, an advanced synthesis that characterizes the existing studies is lacking. In this review, we used citation network analysis and a text mining approach to identify research trends and extract common research topics and the emerging domains in urban climatology. Based on the clustered networks, we found that aerosols and ozone, and urban heat island are the most popular topics. Together with other clusters, four emerging topical fields were identified: secondary organic aerosols, urban precipitation, flood risk and adaptation, and greenhouse gas emissions. The city case studies' geographical information was analyzed to explore the spatial-temporal patterns, especially in the emerging topical fields. Interdisciplinary research grew in recent years as the field of urban climatology expanded to interact with urban hydrology, health, energy issues, and social sciences. A few knowledge gaps were proposed: the lack of long-term high-temporal-resolution observational data of organic aerosols for model validation and improvements, the need for predictions of urban effects on precipitation and extreme flooding events under climate change, and the lack of a framework for cooperation between physical sciences and social sciences under urban settings. To fill these gaps, we call for more observational data with high spatial and temporal resolution, using high-resolution models that adequately represent urban processes to conduct scenario analyses for urban planning, and the development of intellectual frameworks for better integration of urban climatology and social-economical systems in cities. This article is categorized under: Climate, History, Society, Culture > Disciplinary Perspectives", "authors": [ "Huo, Fei", "Xu, Li", "Li, Yanping", "Famiglietti, James S.", "Li, Zhenhua", "Kajikawa, Yuya", "Chen, Fei" ], "keywords": [ "citation analysis", "knowledge mapping", "text mining", "thematic synthesis", "urban climate" ], "year": "2021", "source": "WILEY INTERDISCIPLINARY REVIEWS-CLIMATE CHANGE", "publication_type": "J", "point2d": [ -41.348419189453125, -64.14964294433594 ], "cluster": 14.0 }, { "idx": 685, "title": "Socio-technical scales in socio-environmental modeling: Managing a system-of-systems modeling approach", "abstract": "System-of-systems approaches for integrated assessments have become prevalent in recent years. Such approaches integrate a variety of models from different disciplines and modeling paradigms to represent a socioenvironmental (or social-ecological) system aiming to holistically inform policy and decision-making processes. Central to the system-of-systems approaches is the representation of systems in a multi-tier framework with nested scales. Current modeling paradigms, however, have disciplinary-specific lineage, leading to inconsistencies in the conceptualization and integration of socio-environmental systems. In this paper, a multidisciplinary team of researchers, from engineering, natural and social sciences, have come together to detail socio-technical practices and challenges that arise in the consideration of scale throughout the socioenvironmental modeling process. We identify key paths forward, focused on explicit consideration of scale and uncertainty, strengthening interdisciplinary communication, and improvement of the documentation process. We call for a grand vision (and commensurate funding) for holistic system-of-systems research that engages researchers, stakeholders, and policy makers in a multi-tiered process for the co-creation of knowledge and solutions to major socio-environmental problems.", "authors": [ "Iwanaga, Takuya", "Wang, Hsiao-Hsuan", "Hamilton, Serena H.", "Grimm, Volker", "Koralewski, Tomasz E.", "Salado, Alejandro", "Elsawah, Sondoss", "Razavi, Saman", "Yang, Jing", "Glynn, Pierre", "Badham, Jennifer", "Voinov, Alexey", "Chen, Min", "Grant, William E.", "Peterson, Tarla Rai", "Frank, Karin", "Shenk, Gary", "Barton, C. Michael", "Jakeman, Anthony J.", "Little, John C." ], "keywords": [ "Social-ecological modeling", "Interdisciplinary modeling", "Integrated modeling", "Scale issues", "System-of-systems approach" ], "year": "2021", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 56.03441619873047, -26.866600036621094 ], "cluster": 4.0 }, { "idx": 686, "title": "Assessment and projection of the water budget over western Canada using convection-permitting weather research and forecasting simulations", "abstract": "Water resources in cold regions in western Canada face severe risks posed by anthropogenic global warming as evapotranspiration increases and precipitation regimes shift. Although understanding the water cycle is key for addressing climate change issues, it is difficult to obtain high spatial- and temporal-resolution observations of hydroclimatic processes, especially in remote regions. Climate models are useful tools for dissecting and diagnosing these processes, especially the convection-permitting (CP) high-resolution regional climate simulation, which provides advantages over lower-resolution models by explicitly representing convection. In addition to better representing convective systems, higher spatial resolution also better represents topography, mountain meteorology, and highly heterogeneous geophysical features. However, there is little work with convection-permitting regional climate models conducted over western Canada. Focusing on the Mackenzie River and Saskatchewan River basins, this study investigated the surface water budget and atmospheric moisture balance in historical and representative concentration pathway (RCP8.5) projections using 4 km CP Weather Research and Forecasting (WRF). We compared the high-resolution 4 km CP WRF and three common reanalysis datasets, namely the North American Regional Reanalysis (NARR), the Japanese 55-year Reanalysis (JRA-55), and European Centre for Medium-Range Weather Forecasts reanalysis interim dataset (ERA-Interim). High-resolution WRF outperforms the reanalyses in balancing the surface water budget in both river basins with much lower residual terms. For the pseudo-global-warming scenario at the end of the 21st century with representative concentration pathway (RCP8.5) radiative forcing, both the Mackenzie River and Saskatchewan River basins show increases in the amplitude for precipitation and evapotranspiration and a decrease in runoff. The Saskatchewan River basin (SRB) shows a moderate increase in precipitation in the west and a small decrease in the east. Combined with a significant increase in evapotranspiration in a warmer climate, the Saskatchewan River basin would have a larger deficit of water resources than in the current climate based on the pseudo-global-warming (PGW) simulation. The high-resolution simulation also shows that the difference of atmospheric water vapour balance in the two river basins is due to flow orientation and topography differences at the western boundaries of the two basins. The sensitivity of water vapour balance to fine-scale topography and atmospheric processes shown in this study demonstrates that high-resolution dynamical downscaling is important for large-scale water balance and hydrological cycles.", "authors": [ "Kurkute, Sopan", "Li, Zhenhua", "Li, Yanping", "Huo, Fei" ], "keywords": [ "" ], "year": "2020", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -33.3809928894043, -31.3572940826416 ], "cluster": 1.0 }, { "idx": 687, "title": "Object-based tracking of precipitation systems in western Canada: the importance of temporal resolution of source data", "abstract": "Object-based algorithm provides additional spatiotemporal information of precipitation, besides traditional aspects such as amount and intensity. Using the Method for Object-based Diagnostic Evaluation with Time Dimension (MODE-TD, or MTD), precipitation features in western Canada have been analyzed comprehensively based on the Canadian Precipitation Analysis, North American Regional Reanalysis, Multi-Source Weighted-Ensemble Precipitation, and a convection-permitting climate model. We found light precipitation occurs frequently in the interior valleys of western Canada while moderate to heavy precipitation is rare there. The size of maritime precipitation system near the coast is similar to the continental precipitation system on the Prairies for moderate to heavy precipitation while light precipitation on the Prairies is larger in size than that occurs near the coast. For temporal features, moderate to heavy precipitation lasts longer than light precipitation over the Pacific coast, and precipitation systems on the Prairies generally move faster than the coastal precipitation. For annual cycle, the west coast has more precipitation events in cold seasons while more precipitation events are identified in warm seasons on the Prairies due to vigorous convection activities. Using two control experiments, the way how the spatiotemporal resolution of source data influences the MTD results has been examined. Overall, the spatial resolution of source data has little influence on MTD results. However, MTD driven by dataset with coarse temporal resolution tend to identify precipitation systems with relatively large size and slow propagation speed. This kind of precipitation systems normally have short track length and relatively long lifetime. For a typical precipitation system (0.7 similar to 2 x 10(4) km(2)in size) in western Canada, the maximum propagation speed that can be identified by 6-h data is approximately 25 km h(-1), 33 km h(-1) for 3-h, and 100 km h(-1) for hourly dataset. Since the propagation speed of precipitation systems in North America is basically between 0 and 80 km h(-1), we argue that precipitation features can be identified properly by MTD only when dataset with hourly or higher temporal resolution is used.", "authors": [ "Li, Lintao", "Li, Yanping", "Li, Zhenhua" ], "keywords": [ "Precipitation feature", "MODE-TD", "Source data", "Temporal resolution", "Western Canada" ], "year": "2020", "source": "CLIMATE DYNAMICS", "publication_type": "J", "point2d": [ -47.99396896362305, -39.63308334350586 ], "cluster": 1.0 }, { "idx": 688, "title": "Freeze-Thaw Changes of Seasonally Frozen Ground on the Tibetan Plateau from 1960 to 2014", "abstract": "The freeze-thaw changes of seasonally frozen ground (SFG) are an important indicator of climate change. Based on observed daily freeze depth of SFG from meteorological stations on the Tibetan Plateau (TP) from 1960 to 2014, the spatial-temporal characteristics and trends in SFG were analyzed, and the relationships between them and climatic and geographical factors were explored. Freeze-thaw changes of SFG on a regional scale were assessed by multiple regression functions. Results showed multiyear mean maximum freeze depth, freeze-thaw duration, freeze start date, and thaw end date that demonstrate obvious distribution characteristics of climatic zones. A decreasing trend in maximum freeze depth and freeze-thaw duration occurred on the TP from 1960 to 2014. The freeze start date has been later, and the thaw end date has been significantly earlier. The freeze-thaw changes of SFG significantly affected by soil hydrothermal conditions on the TP could be assessed by elevation and latitude or by air temperature and precipitation, due to their high correlations. The regional average of maximumfreeze depth and freeze-thaw duration caused by climatic and geographical factors were larger than those averaged using meteorological station data because most stations are located at lower altitudes. Maximum freeze depth and freeze-thaw duration have decreased sharply since 2000 on the entire TP. Warming and wetting conditions of the soil resulted in a significant decrease in maximum freeze depth and freeze-thaw duration in the most area of the TP, while drying soil results in a slight increase of them in the southeast of the TP.", "authors": [ "Luo, Siqiong", "Wang, Jingyuan", "Pomeroy, John W.", "Lyu, Shihua" ], "keywords": [ "" ], "year": "2020", "source": "JOURNAL OF CLIMATE", "publication_type": "J", "point2d": [ -39.05210876464844, 27.28936767578125 ], "cluster": 2.0 }, { "idx": 689, "title": "Multi-criteria, time dependent sensitivity analysis of an event-oriented, physically-based, distributed sediment and runoff model", "abstract": "Runoff and sediment yield predictions using rainfall-runoff modeling systems play a significant role in developing sustainable rangeland and water resource management strategies. To characterize the behavior and predictive uncertainty of the KINEROS2 physically-based distributed hydrologic model, we assessed model parameters importance at the event-scale for small nested semi-arid subwatersheds in southeastern Arizona using the Variogram Analysis of Response Surfaces (VARS) methodology. A two-pronged approach using time-aggregate and time-variant parameter importance analysis was adopted to improve understanding of the control and behavior of models. The time-aggregate analysis looks at several signature responses, including runoff volume, sediment yield, peak runoff, runoff duration, time to peak, lag time, and recession duration, to investigate the influence of parameter and input on the model predictions. The time-variant analysis looks at the dynamical influence of parameters on the simulation of flow and sediment rates at every simulation time step using the different forcing inputs. This investigation was able to address Simpson's paradox-type issues where the analysis across the different objective functions and full data set vs. its subsets (i.e., different events and/or time steps) could yield inconsistent and potentially misleading results. The results indicated the uncertainties in the flow responses are primarily due to the saturated hydraulic conductivity, the Manning's coefficient, the soil capillary coefficient, and the cohesion in sediment and flow-related responses. The level of influence of K2 parameters depends on the type of the model response surface, the rainfall, and the watershed size.", "authors": [ "Meles, Menberu B.", "Goodrich, Dave C.", "Gupta, Hoshin, V", "Burns, I. Shea", "Unkrich, Carl L.", "Razavi, Saman", "Guertin, D. Phillip" ], "keywords": [ "Walnut Gulch", "KINEROS2", "Global sensitivity", "Uncertainty", "Parameter importance", "Response surfaces", "VARS", "Rainfall intensity" ], "year": "2021", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ 2.1053545475006104, -67.6680679321289 ], "cluster": 16.0 }, { "idx": 690, "title": "Scientific and Human Errors in a Snow Model Intercomparison", "abstract": "Twenty-seven models participated in the Earth System Model-Snow Model Intercomparison Project (ESM-SnowMIP), the most data-rich MIP dedicated to snow modeling. Our findings do not support the hypothesis advanced by previous snow MIPs: evaluating models against more variables and providing evaluation datasets extended temporally and spatially does not facilitate identification of key new processes requiring improvement to model snow mass and energy budgets, even at point scales. In fact, the same modeling issues identified by previous snow MIPs arose: albedo is a major source of uncertainty, surface exchange parameterizations are problematic, and individual model performance is inconsistent. This lack of progress is attributed partly to the large number of human errors that led to anomalous model behavior and to numerous resubmissions. It is unclear how widespread such errors are in our field and others; dedicated time and resources will be needed to tackle this issue to prevent highly sophisticated models and their research outputs from being vulnerable because of avoidable human mistakes. The design of and the data available to successive snow MIPs were also questioned. Evaluation of models against bulk snow properties was found to be sufficient for some but inappropriate for more complex snow models whose skills at simulating internal snow properties remained untested. Discussions between the authors of this paper on the purpose of MIPs revealed varied, and sometimes contradictory, motivations behind their participation. These findings started a collaborative effort to adapt future snow MIPs to respond to the diverse needs of the community.", "authors": [ "Menard, Cecile B.", "Essery, Richard", "Krinner, Gerhard", "Arduini, Gabriele", "Bartlett, Paul", "Boone, Aaron", "Brutel-Vuilmet, Claire", "Burke, Eleanor", "Cuntz, Matthias", "Dai, Yongjiu", "Decharme, Bertrand", "Dutra, Emanuel", "Fang, Xing", "Fierz, Charles", "Gusev, Yeugeniy", "Hagemann, Stefan", "Haverd, Vanessa", "Kim, Hyungjun", "Lafaysse, Matthieu", "Marke, Thomas", "Nasonova, Olga", "Nitta, Tomoko", "Niwano, Masashi", "Pomeroy, John", "Schaedler, Gerd", "Semenov, Vladimir A.", "Smirnova, Tatiana", "Strasser, Ulrich", "Swenson, Sean", "Turkov, Dmitry", "Wever, Nander", "Yuan, Hua" ], "keywords": [ "Snow", "Snowpack", "Model comparison", "Model evaluation", "performance" ], "year": "2021", "source": "BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY", "publication_type": "J", "point2d": [ -46.568233489990234, -12.99005126953125 ], "cluster": 8.0 }, { "idx": 691, "title": "Scientific and Human Errors in a Snow Model Intercomparison", "abstract": "Twenty-seven models participated in the Earth System Model-Snow Model Intercomparison Project (ESM-SnowMIP), the most data-rich MIP dedicated to snow modeling. Our findings do not support the hypothesis advanced by previous snow MIPs: evaluating models against more variables and providing evaluation datasets extended temporally and spatially does not facilitate identification of key new processes requiring improvement to model snow mass and energy budgets, even at point scales. In fact, the same modeling issues identified by previous snow MIPs arose: albedo is a major source of uncertainty, surface exchange parameterizations are problematic, and individual model performance is inconsistent. This lack of progress is attributed partly to the large number of human errors that led to anomalous model behavior and to numerous resubmissions. It is unclear how widespread such errors are in our field and others; dedicated time and resources will be needed to tackle this issue to prevent highly sophisticated models and their research outputs from being vulnerable because of avoidable human mistakes. The design of and the data available to successive snow MIPs were also questioned. Evaluation of models against bulk snow properties was found to be sufficient for some but inappropriate for more complex snow models whose skills at simulating internal snow properties remained untested. Discussions between the authors of this paper on the purpose of MIPs revealed varied, and sometimes contradictory, motivations behind their participation. These findings started a collaborative effort to adapt future snow MIPs to respond to the diverse needs of the community.", "authors": [ "Menard, Cecile B.", "Essery, Richard", "Krinner, Gerhard", "Arduini, Gabriele", "Bartlett, Paul", "Boone, Aaron", "Brutel-Vuilmet, Claire", "Burke, Eleanor", "Cuntz, Matthias", "Dai, Yongjiu", "Decharme, Bertrand", "Dutra, Emanuel", "Fang, Xing", "Fierz, Charles", "Gusev, Yeugeniy", "Hagemann, Stefan", "Haverd, Vanessa", "Kim, Hyungjun", "Lafaysse, Matthieu", "Marke, Thomas", "Nasonova, Olga", "Nitta, Tomoko", "Niwano, Masashi", "Pomeroy, John", "Schaedler, Gerd", "Semenov, Vladimir A.", "Smirnova, Tatiana", "Strasser, Ulrich", "Swenson, Sean", "Turkov, Dmitry", "Wever, Nander", "Yuan, Hua" ], "keywords": [ "Snow", "Snowpack", "Model comparison", "Model evaluation", "performance" ], "year": "2021", "source": "BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY", "publication_type": "J", "point2d": [ -46.568233489990234, -12.99005126953125 ], "cluster": 8.0 }, { "idx": 692, "title": "The Future of Sensitivity Analysis: An essential discipline for systems modeling and policy support", "abstract": "Sensitivity analysis (SA) is en route to becoming an integral part of mathematical modeling. The tremendous potential benefits of SA are, however, yet to be fully realized, both for advancing mechanistic and data-driven modeling of human and natural systems, and in support of decision making. In this perspective paper, a multidisciplinary group of researchers and practitioners revisit the current status of SA, and outline research challenges in regard to both theoretical frameworks and their applications to solve real-world problems. Six areas are discussed that warrant further attention, including (1) structuring and standardizing SA as a discipline, (2) realizing the untapped potential of SA for systems modeling, (3) addressing the computational burden of SA, (4) progressing SA in the context of machine learning, (5) clarifying the relationship and role of SA to uncertainty quantification, and (6) evolving the use of SA in support of decision making. An outlook for the future of SA is provided that underlines how SA must underpin a wide variety of activities to better serve science and society.", "authors": [ "Razavi, Saman", "Jakeman, Anthony", "Saltelli, Andrea", "Prieur, Clementine", "Iooss, Bertrand", "Borgonovo, Emanuele", "Plischke, Elmar", "Lo Piano, Samuele", "Iwanaga, Takuya", "Becker, William", "Tarantola, Stefano", "Guillaume, Joseph H. A.", "Jakeman, John", "Gupta, Hoshin", "Melillo, Nicola", "Rabitti, Giovanni", "Chabridon, Vincent", "Duan, Qingyun", "Sun, Xifu", "Smith, Stefan", "Sheikholeslami, Razi", "Hosseini, Nasim", "Asadzadeh, Masoud", "Puy, Arnald", "Kucherenko, Sergei", "Maier, Holger R." ], "keywords": [ "Sensitivity analysis", "Mathematical modeling", "Machine learning", "Uncertainty quantification", "Decision making", "Model validation and verification", "Model robustness", "Policy support" ], "year": "2021", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 6.167178630828857, -77.44768524169922 ], "cluster": 16.0 }, { "idx": 693, "title": "A physically-based modelling framework for operational forecasting of river ice breakup", "abstract": "Forecasting river ice breakup is critical for supporting emergency responses to river ice-related flooding along rivers in the northern hemisphere. However, due to complex river ice processes, forecasting river ice breakup is more challenging than predicting open-water flood conditions. Although considerable progress has been made in understanding the mechanisms and characteristics of breakup processes and in forecasting breakup timing using empirical methods at the local scale, fewer advances have been made in understanding and forecasting breakup using physically-based models, particularly at the catchment scale. In this study, we present a physically-based coupled hydrological and water temperature modelling framework for breakup prediction in cold region catchments in real time. The modelling framework was applied for operational forecasting of the 2019 breakup event along the Athabasca River at Fort McMurray in Alberta. Further model validation was performed by hindcasting the 2016, 2017 and 2018 breakup events. The model shows promising results for predicting the ice cover breakup with an average error of about 5 days, demonstrating its usefulness in real-time operational forecasting. Importantly, the model generates breakup progression at the catchment scale, providing an advantage over existing site specific breakup prediction methods.", "authors": [ "Rokaya, Prabin", "Morales-Marin, Luis", "Lindenschmidt, Karl-Erich" ], "keywords": [ "Forecasting", "Operational water management", "River ice", "Flood risk", "Hydroclimatic extremes", "Cold region" ], "year": "2020", "source": "ADVANCES IN WATER RESOURCES", "publication_type": "J", "point2d": [ -7.899050712585449, -42.0217399597168 ], "cluster": 16.0 }, { "idx": 694, "title": "A Fresh Look at Variography: Measuring Dependence and Possible Sensitivities Across Geophysical Systems From Any Given Data", "abstract": "Sensitivity analysis in Earth and environmental systems modeling typically demands an onerous computational cost. This issue coexists with the reliance of these algorithms on ad hoc designs of experiments, which hampers making the most out of the existing data sets. We tackle this problem by introducing a method for sensitivity analysis, based on the theory of variogram analysis of response surfaces (VARS), that works on any sample of input-output data or pre-computed model evaluations. Called data-driven VARS (D-VARS), this method characterizes the relationship strength between inputs and outputs by investigating their covariograms. We also propose a method to assess robustness of the results against sampling variability and numerical methods' imperfectness. Using two hydrologic modeling case studies, we show that D-VARS is highly efficient and statistically robust, even when the sample size is small. Therefore, D-VARS can provide unique opportunities to investigate geophysical systems whose models are computationally expensive or available data is scarce. Plain Language Summary Sensitivity analysis (SA) is about assessing how the properties of a system are influenced by different factors. It can also help us better understand the behavior of a mathematical model and the underlying real-world system that it mimics. Almost always, classic SA estimates the sensitivities by sampling the entire problem space in a specific manner. They are incapable of using a pre-existing set of input-output data or pre-computed model evaluations. Hence, classic SA becomes useless in cases where a sample of input-output data, obtained from physical experiments or computationally expensive simulations, is already available. We propose a purely data-driven method that can effectively be used in such situations. Based on the principles of variography, our method measures dependence and possible sensitivities across a system from any given data. Here, we illustrate our method in the context of hydrologic modeling, but it can potentially be applied to study other geophysical systems models.", "authors": [ "Sheikholeslami, Razi", "Razavi, Saman" ], "keywords": [ "" ], "year": "2020", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ 5.52916955947876, -73.23090362548828 ], "cluster": 16.0 }, { "idx": 695, "title": "Sensitivity of boundary data in a shallow prairie lake model", "abstract": "A good water quality model needs sufficient data to characterise the waterbody, yet monitoring resources are often limited. Inadequate boundary data often contribute to model uncertainty and error. In these situations, the same water quality model can also be used to determine where sampling efforts are best concentrated for improving model reliability. A sensitivity analysis using a one-at-a-time approach on a shallow, eutrophic, Prairie reservoir model investigates which boundary conditions are contributing most to variability in the model. The model results show the lake model has greater sensitivity to its catchment processes than to its in-lake processes. Flows are shown to have the greatest influence on model predictions for all water quality variables tested, followed by air temperature. The lake is facing pressure from climate change, and water management decisions. Results indicate defining the water balance accurately will be a crucial factor in future monitoring programs and modelling efforts.", "authors": [ "Terry, Julie A.", "Lindenschmidt, Karl-Erich" ], "keywords": [ "" ], "year": "2020", "source": "CANADIAN WATER RESOURCES JOURNAL", "publication_type": "J", "point2d": [ 31.205724716186523, -11.30654239654541 ], "cluster": 16.0 }, { "idx": 696, "title": "Automatic clustering-based surrogate-assisted genetic algorithm for groundwater remediation system design", "abstract": "Simulation-optimization techniques in support of groundwater management are computationally expensive. To tackle such computational burden, a variety of surrogate modeling-frameworks have been proposed, where a cheaper-to-run model referred to as a surrogate is used in lieu of a computationally intensive model. These frameworks are generally based on what referred herein to as 'global surrogate modelling' where a single surrogate approximates the underlying response surface of a model. Such classic frameworks, however, are suboptimal when the response surface is complex and/or high-dimensional. This paper proposes a novel 'local surrogate modelling' framework that simultaneously builds and evolves multiple local surrogates, guided by an automatic clustering method. Unlike traditional clustering methods that select the number of clusters a priori, the proposed automatic clustering method concurrently determines the optimum number of clusters and the clustering scheme itself. To serve as the surrogate, Artificial Neural Networks (ANNs) are used. The proposed framework is applied to solve a computationally intensive groundwater remediation optimization problem. This study shows that the proposed automatic clustering-based local surrogate modeling is effective and reliable while reducing at least 60 percent of the computational burden.", "authors": [ "Vali, Majid", "Zare, Mohammad", "Razavi, Saman" ], "keywords": [ "Simulation-optimization", "Local surrogate modeling", "Automatic clustering", "Davis-Bouldin cluster validity index", "Groundwater remediation" ], "year": "2021", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ 9.76620864868164, -79.53720092773438 ], "cluster": 16.0 }, { "idx": 697, "title": "Assessing the factors governing the ability to predict late-spring flooding in cold-region mountain basins", "abstract": "From 19 to 22 June 2013, intense rainfall and concurrent snowmelt led to devastating floods in the Canadian Rockies, foothills and downstream areas of southern Alberta and southeastern British Columbia, Canada. Such an event is typical of late-spring floods in cold-region mountain headwater, combining intense precipitation with rapid melting of late-lying snowpack, and represents a challenge for hydrological forecasting systems. This study investigated the factors governing the ability to predict such an event. Three sources of uncertainty, other than the hydrological model processes and parameters, were considered: (i) the resolution of the atmospheric forcings, (ii) the snow and soil moisture initial conditions (ICs) and (iii) the representation of the soil texture. The Global Environmental Multiscale hydrological modeling platform (GEM-Hydro), running at a 1 km grid spacing, was used to simulate hydrometeorological conditions in the main headwater basins of southern Alberta during this event. The GEM atmospheric model and the Canadian Precipitation Analysis (CaPA) system were combined to generate atmospheric forcing at 10, 2.5 and 1 km over southern Alberta. Gridded estimates of snow water equivalent (SWE) from the Snow Data Assimilation System (SNODAS) were used to replace the model SWE at peak snow accumulation and generate alternative snow and soil moisture ICs before the event. Two global soil texture datasets were also used. Overall 12 simulations of the flooding event were carried out. Results show that the resolution of the atmospheric forcing affected primarily the flood volume and peak flow in all river basins due to a more accurate estimation of intensity and total amount of precipitation during the flooding event provided by CaPA analysis at convection-permitting scales (2.5 and 1 km). Basin-averaged snowmelt also changed with the resolution due to changes in near-surface wind and resulting turbulent fluxes contributing to snowmelt. Snow ICs were the main sources of uncertainty for half of the headwater basins. Finally, the soil texture had less impact and only affected peak flow magnitude and timing for some stations. These results highlight the need to combine atmospheric forcing at convection-permitting scales with high-quality snow ICs to provide accurate streamflow predictions during late-spring floods in cold-region mountain river basins. The predictive improvement by inclusion of high-elevation weather stations in the precipitation analysis and the need for accurate mountain snow information suggest the necessity of integrated observation and prediction systems for forecasting extreme events in mountain river basins.", "authors": [ "Vionnet, Vincent", "Fortin, Vincent", "Gaborit, Etienne", "Roy, Guy", "Abrahamowicz, Maria", "Gasset, Nicolas", "Pomeroy, John W." ], "keywords": [ "" ], "year": "2020", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -42.78110885620117, -21.299711227416992 ], "cluster": 12.0 }, { "idx": 698, "title": "Measuring the skill of an operational ice jam flood forecasting system", "abstract": "Though mitigation measures and research have increased over the last few decades, ice jams and associated flooding continue to be one of the most underestimated disasters in many northern countries. Operational ice jam flood forecasting systems are becoming one of the more prominent tools used in mitigating ice-related flood risk within Canada. Several forecasting systems have been adopted across the country and forecasters are constantly looking to improve the accuracy and consistency of their systems. The Lower Red River in Manitoba has been the subject in discussion of many ice jam related studies, and a data-driven ice-jam hazard forecasting system is currently in use at this site. This system differs from hydrologic model driven forecasting systems used for other ice jam prone rivers across Canada. This study focuses on identifying the methodology of the data driven ice jam flood forecasting system, along with the methodology of the forecasting procedures. Furthermore, the effectiveness of the data driven forecasting system is measured and assessed for the Lower Red River's 2020 breakup season.", "authors": [ "Williams, Brandon S.", "Das, Apurba", "Johnston, Peter", "Luo, Bin", "Lindenschmidt, Karl-Erich" ], "keywords": [ "Ice jam", "Operational flood forecasting", "Data-driven model", "Stochastic modelling", "Red river" ], "year": "2021", "source": "INTERNATIONAL JOURNAL OF DISASTER RISK REDUCTION", "publication_type": "J", "point2d": [ -1.9236233234405518, -42.85274887084961 ], "cluster": 16.0 }, { "idx": 699, "title": "An ice jam flood hazard assessment of a lowland river and its terminus inland delta", "abstract": "Flooding is one of the most frequent and most costly natural disasters that occur throughout Canada, and although there is ongoing work to update and improve flood hazard assessments and mapping of high flood risk rivers throughout the country, most studies only delve into open water flooding. However, many rivers in Canada experience higher peak water levels due to ice jamming, resulting in severe flooding of surrounding areas. Hence, there is an urgency to expand current flood hazard assessments to include ice jam flooding for better flood management practices. One area that is often plagued with ice jam flooding is the lowest reach of Manitoba's Red River. The Lower Red River is a low-lying river with a terminus inland delta where water levels are governed by Lake Winnipeg. Ice jam floods often divert water into the lower Red River's floodplain that is continually being encroached by development. RIVICE, Environment Canada's one-dimensional ice hydraulic model, was set up within a Monte Carlo framework to simulate an envelope of backwater level profiles that result from ice jams within the study site. Non-exceedance probability profiles were created from the envelope of backwater level profiles to assess ice jam flood hazard.", "authors": [ "Williams, Brandon", "Das, Apurba", "Luo, Bin", "Lindenschmidt, Karl-Erich" ], "keywords": [ "Ice jam", "Flooding", "Hazard assessment" ], "year": "2021", "source": "NATURAL HAZARDS", "publication_type": "J", "point2d": [ -0.47257670760154724, -39.72574996948242 ], "cluster": 16.0 }, { "idx": 700, "title": "A generic approach to evaluate costs and effectiveness of agricultural Beneficial Management Practices to improve water quality management", "abstract": "Nutrient export from agricultural areas is among the main contributors to water pollution in various watersheds. Agricultural Beneficial Management Practices (BMPs) are commonly used to reduce excessive nutrient runoff and improve water quality. The successful uptake of BMPs not only depends on their effectiveness but also on their costs of implementation. This study conducts a set of cost-effectiveness analyses to help stakeholders identify their preferred combinations of BMPs in the Qu?Appelle River Basin, a typical watershed in the Canadian Prairies. The considered BMPs are related to cattle and cropping farms and are initially selected by agricultural producers in this region. The analyses use a water quality model to estimate the impact of implementing BMPs on nutrient export, and the cost estimation model to approximate the cost of implementing BMPs at tributary and watershed scales. Our results show that BMPs? effectiveness, total costs of implementation and costs per kilogram of nutrient abatement vary between tributaries. However, wetland conservation is among the optimal practices to improve water quality across the watershed. It is also found that the rates of BMP adoption by stakeholders can influence the effectiveness of practices in a large watershed scale, which highlights the importance of stakeholder engagement in water quality management. This type of analyses can help stakeholders choose single or a combination of BMPs according to their available budget and acceptable levels of reduction in nutrients.", "authors": [ "Zammali, Mohamed Khalil", "Hassanzadeh, Elmira", "Shupena-Soulodre, Etienne", "Lindenschmidt, Karl-Erich" ], "keywords": [ "Water quality management", "Beneficial management practices", "Agricultural lands", "Cost-effectiveness analyses", "System dynamics" ], "year": "2021", "source": "JOURNAL OF ENVIRONMENTAL MANAGEMENT", "publication_type": "J", "point2d": [ 48.55302429199219, -37.70932388305664 ], "cluster": 11.0 }, { "idx": 701, "title": "Assessment of the cascade of uncertainty in future snow depth projections across watersheds of mountainous, foothill, and plain areas in northern latitudes", "abstract": "Snowmelt is a major driver of the hydrological cycle in cold regions, as such, its accurate representation in hydrological models is key to both regional snow depth and streamflow prediction. The choice of a proper method for snowmelt representation is often improvised; however, a thorough characterization of uncertainty in such process representations particularly in the context of climate change has remained essential. To fill this gap, this study revisits and characterizes performance and uncertainty around the two general approaches to snowmelt representation, namely Energy-Balance Modules (EBMs) and Temperature-Index Modules (TIMs). To account for snow depth simulation and projection, two common Snow Density formulations (SNDs) are implemented that map snow water equivalent (SWE) to snow depth. The major research questions we address are two-fold. First, we examine the dominant controls of uncertainty in snow depth and streamflow simulations across scales and in different climates. Second, we evaluate the cascade of uncertainty of snow depth projections resulting from impact model parameters, greenhouse gas emission scenarios, climate models and their internal variability, and downscaling processes. We enable the Soil and Water Assessment Tool (SWAT) by coupling EBM, TIM, and two SND modules for examination of different snowmelt representation methods, and Analysis of Variance (ANOVA) for uncertainty decomposition and attribution. These analyses are implemented in mountainous, foothill, and plain regions in a large snow-dominated watershed in western Canada. Results show, rather counter-intuitively, that the choice of SND is a major control of performance and uncertainty of snow depth simulation rather than the choice between TIMs and EBMs and of their uncertain parameters. Also, analysis of streamflow simulations suggest that EBMs generally overestimate streamflow on main tributaries. Finally, uncertainty decompositions show that parameter uncertainty related to snowmelt modules dominantly controls uncertainty in future snow depth projections under climate change, particularly in mountainous regions. However, in plain regions, the uncertainty contribution of model parameters becomes more variable with time and less dominant compared with the other sources of uncertainty. Overall, it is shown that the hydro-climatic and topographic conditions of different regions, as well as input data availability, have considerable effect on reproduction of snow depth, snowmelt and resulting streamflow, and on the share of different uncertainty sources when projecting regional snow depth.", "authors": [ "Zaremehrjardy, Majid", "Razavi, Saman", "Faramarzi, Monireh" ], "keywords": [ "Regional hydrology", "Uncertainty decomposition", "Snowmelt projection", "Energy Balance", "Temperature Index", "SWAT" ], "year": "2021", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -38.323055267333984, -9.957620620727539 ], "cluster": 12.0 }, { "idx": 702, "title": "Modeling groundwater responses to climate change in the Prairie Pothole Region", "abstract": "Shallow groundwater in the Prairie Pothole Region (PPR) is predominantly recharged by snowmelt in the spring and supplies water for evapotranspiration through the summer and fall. This two-way exchange is underrepresented in current land surface models. Furthermore, the impacts of climate change on the groundwater recharge rates are uncertain. In this paper, we use a coupled land-groundwater model to investigate the hydrological cycle of shallow groundwater in the PPR and study its response to climate change at the end of the 21st century. The results show that the model does a reasonably good job of simulating the timing of recharge. The mean water table depth (WTD) is well simulated, except for the fact that the model predicts a deep WTD in northwestern Alberta. The most significant change under future climate conditions occurs in the winter, when warmer temperatures change the rain/snow partitioning, delaying the time for snow accumulation/soil freezing while advancing early melting/thawing. Such changes lead to an earlier start to a longer recharge season but with lower recharge rates. Different signals are shown in the eastern and western PPR in the future summer, with reduced precipitation and drier soils in the east but little change in the west. The annual recharge increased by 25% and 50% in the eastern and western PPR, respectively. Additionally, we found that the mean and seasonal variation of the simulated WTD are sensitive to soil properties; thus, fine-scale soil information is needed to improve groundwater simulation on the regional scale.", "authors": [ "Zhang, Zhe", "Li, Yanping", "Barlage, Michael", "Chen, Fei", "Miguez-Macho, Gonzalo", "Ireson, Andrew", "Li, Zhenhua" ], "keywords": [ "" ], "year": "2020", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -8.377846717834473, -20.41425323486328 ], "cluster": 12.0 }, { "idx": 703, "title": "The need to integrate legacy nitrogen storage dynamics and time lags into policy and practice", "abstract": "Increased fluxes of reactive nitrogen (N-r), often associated with N fertilizer use in agriculture, have resulted in negative environmental consequences, including eutrophication, which cost billions of dollars per year globally. To address this, best management practices (BMPs) to reduce N-r loading to the environment have been introduced in many locations. However, improvements in water quality associated with BMP implementation have not always been realised over expected timescales. There is a now a significant body of scientific evidence showing that the dynamics of legacy Nr storage and associated time lags invalidate the assumptions of many models used by policymakers for decision making regarding N-r BMPs. Building on this evidence, we believe that the concepts of legacy N-r storage dynamics and time lags need to be included in these models. We believe the biogeochemical research community could play a more proactive role in advocating for this change through both awareness raising and direct collaboration with policymakers to develop improved datasets and models. We anticipate that this will result in more realistic expectations of timescales for water quality improvements associated with BMPs. Given the need for multi-nutrient policy responses to tackle challenges such as eutrophication, integration of N stores will have the further benefit of aligning both researchers and policymakers in the N community with the phosphorus and carbon communities, where estimation of stores is more widespread. Ultimately, we anticipate that integrating legacy N-r storage dynamics and time lags into policy frameworks will better meet the needs of human and environmental health. (C) 2021 The Authors. Published by Elsevier B.V.", "authors": [ "Ascott, Matthew J.", "Gooddy, Daren C.", "Fenton, Owen", "Vero, Sara", "Ward, Rob S.", "Basu, Nandita B.", "Worrall, Fred", "Van Meter, Kimberly", "Surridge, Ben W. J." ], "keywords": [ "Nitrogen", "Legacy pollution", "Water pollution", "Time lag" ], "year": "2021", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 31.962966918945312, 2.043856620788574 ], "cluster": 10.0 }, { "idx": 704, "title": "Long-Term Shifts in US Nitrogen Sources and Sinks Revealed by the New TREND-Nitrogen Data Set (1930-2017)", "abstract": "Reactive nitrogen (N) fluxes have increased tenfold over the last century, driven by increases in population, shifting diets, and increased use of commercial N fertilizers. Runoff of excess N from intensively managed landscapes threatens drinking water quality and disrupts aquatic ecosystems. Excess N is also a major source of greenhouse gas emissions from agricultural soils. While N emissions from agricultural landscapes are known to originate from not only current-year N input but also legacy N accumulation in soils and groundwater, there has been limited access to fine-scale, long-term data regarding N inputs and outputs over decades of intensive agricultural land use. In the present work, we synthesize population, agricultural, and atmospheric deposition data to develop a comprehensive, 88-year (1930-2017) data set of county-scale components of the N mass balance across the contiguous United States (Trajectories Nutrient Dataset for nitrogen [TREND-nitrogen]). Using a machine-learning algorithm, we also develop spatially explicit typologies for components of the N mass balance. Our results indicate a large range of N trajectory behaviors across the United States due to differences in land use and management and particularly due to the very different drivers of N dynamics in densely populated urban areas compared with intensively managed agricultural zones. Our analysis of N trajectories also demonstrates a widespread functional homogenization of agricultural landscapes. This newly developed typology of N trajectories improves our understanding of long-term N dynamics, and the underlying data set provides a powerful tool for modeling the impacts of legacy N on past, present, and future water quality. Plain Language Summary Over the last century, people have increasingly used nitrogen fertilizer to increase crop yields. The nitrogen not taken up by crops in agricultural areas runs off of the land and pollutes rivers, lakes, and coastal areas. This excess nitrogen also forms a powerful greenhouse gas that contributes to climate change. Excess nitrogen can build up in the environment over time and pollute our water for decades. It is therefore necessary for us to know how much extra nitrogen has been applied over many decades to better understand current risks to the environment. In our study, we have used multiple data sources to calculate how much nitrogen has been added to the landscape, how much nitrogen has been removed through crop production, and how much human waste is produced, for every county in the contiguous United States from 1930 to 2017. We show that the main sources of nitrogen can be different in different areas of the country. We also show that high levels of nitrogen use can make landscapes in very different climates look very similar. This new data set will be very important for creating models that can predict how decades of high nitrogen inputs impact water quality and future changes in climate.", "authors": [ "Byrnes, D. K.", "Van Meter, K. J.", "Basu, N. B." ], "keywords": [ "budget", "fertilizer", "homogenization", "landscape", "manure", "nitrogen" ], "year": "2020", "source": "GLOBAL BIOGEOCHEMICAL CYCLES", "publication_type": "J", "point2d": [ 31.381370544433594, 3.7985079288482666 ], "cluster": 10.0 }, { "idx": 705, "title": "Maximizing US nitrate removal through wetland protection and restoration", "abstract": "Analysis of US continental wetland inventory data combined with model simulations indicate that a spatially targeted 10% increase in wetland area could double wetland nitrogen removal. Growing populations and agricultural intensification have led to raised riverine nitrogen (N) loads, widespread oxygen depletion in coastal zones (coastal hypoxia)(1) and increases in the incidence of algal blooms.Although recent work has suggested that individual wetlands have the potential to improve water quality(2-9), little is known about the current magnitude of wetland N removal at the landscape scale. Here we use National Wetland Inventory data and 5-kilometre grid-scale estimates of N inputs and outputs to demonstrate that current N removal by US wetlands (about 860 +/- 160 kilotonnes of nitrogen per year) is limited by a spatial disconnect between high-density wetland areas and N hotspots. Our model simulations suggest that a spatially targeted increase in US wetland area by 10 per cent (5.1 million hectares) would double wetland N removal. This increase would provide an estimated 54 per cent decrease in N loading in nitrate-affected watersheds such as the Mississippi River Basin. The costs of this increase in area would be approximately 3.3 billion US dollars annually across the USA-nearly twice the cost of wetland restoration on non-agricultural, undeveloped land-but would provide approximately 40 times more N removal. These results suggest that water quality improvements, as well as other types of ecosystem services such as flood control and fish and wildlife habitat, should be considered when creating policy regarding wetland restoration and protection.", "authors": [ "Cheng, F. Y.", "Van Meter, K. J.", "Byrnes, D. K.", "Basu, N. B." ], "keywords": [ "" ], "year": "2020", "source": "NATURE", "publication_type": "J", "point2d": [ 36.60983657836914, 2.8736298084259033 ], "cluster": 10.0 }, { "idx": 706, "title": "Curbing the Summer Surge: Permanent Outdoor Water Use Restrictions in Humid and Semiarid Cities", "abstract": "As urban droughts make headlines across the globe, it is increasingly relevant to critically evaluate the long-term sustainability of both water supply and demand in the world's cities. This is the case even in water-rich regions, where upward swings in water demands during periods of hot, dry weather can aggravate already strained water supplies and increase cities' vulnerability to water shortage. Summer spikes in water demand have motivated several cities to impose permanent restrictions on outdoor water uses; however, little is yet known about their effectiveness. This paper examines daily water production data from 15 Canadian cities to (1) quantify how overall and seasonal demands are evolving over time across humid and semiarid settings and (2) determine whether permanent water use restrictions have been effective in curbing summer water demands both seasonally and during specific hot and dry periods. Results show that while per-capita water demand is declining in all cities studied, the seasonal distribution of that demand has remained largely stable in all but a few cases. While average demands in the summer months remain largely unaffected by the imposition of permanent restrictions, cities that enforce stringent limits on outdoor water use have seen a reduction in the variability of daily demands and a decline in peak demands following their implementation. During short-term periods of exceptionally hot and dry weather when vulnerability to water shortage is most acute, cities with strict restrictions also see smaller surges in demand than those with weaker or no restrictions in place.", "authors": [ "Finley, Sara L.", "Basu, Nandita B." ], "keywords": [ "urban water use", "peak water demands", "drought vulnerability", "water use restrictions", "resilience", "climate change" ], "year": "2020", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -39.44001007080078, -33.668556213378906 ], "cluster": 4.0 }, { "idx": 707, "title": "A multiregional input-output optimization model to assess impacts of water supply disruptions under climate change on the Great Lakes economy", "abstract": "This paper presents a water-restricted multi-regional input-output model to evaluate the economic impacts of water supply reductions in the Canadian Great Lakes Basin (GLB), one of the largest freshwater reservoirs in the world. The proposed model, first of its kind applied to the GLB, aims to minimize the impact of water supply disruptions on the GLB-economy, measured by the loss of GDP. A new flexible economic optimization procedure is introduced, capable of imposing resource constraints and ensuring minimal supply levels for intermediate and final consumption at the same time. The model accounts for inter-regional trade between different lake regions. The impacts of two climate change scenarios on water security and the economy are investigated, with and without additional food and energy security restrictions. The proposed economic optimization model holds promise as a new tool for resource-restricted Input-Output analyses.", "authors": [ "Garcia-Hernandez, Jorge A.", "Brouwer, Roy" ], "keywords": [ "Input-output model", "nonlinear optimization", "water scarcity", "Great Lakes" ], "year": "2021", "source": "ECONOMIC SYSTEMS RESEARCH", "publication_type": "J", "point2d": [ 40.82782745361328, -56.667518615722656 ], "cluster": 11.0 }, { "idx": 708, "title": "Comparison of freshwater monitoring approaches: strengths, opportunities, and recommendations", "abstract": "This review identifies strengths and weaknesses of water monitoring programs selected by Canadian water managers. We used 22 criteria, guided by outcomes of an exploratory study and supported by 21 semi-structured key informant interviews. The highest-scoring programs include the Slave Watershed Environmental Effects Program (Canada), the Government of Canada's Environmental Effects Monitoring Program, and Healthy Land and Water (Australia). We describe five recommendations for improving future freshwater monitoring frameworks: (1) recognize different knowledge approaches (especially Indigenous), (2) use multiple reporting formats, (3) clarify monitoring and management roles, (4) apply a whole-watershed approach, and (5) link monitoring to management and decision-making.", "authors": [ "Ho, Elaine", "Trant, Andrew J.", "Gray, Michelle A.", "Courtenay, Simon C." ], "keywords": [ "Monitoring", "Water management", "Cumulative effects", "Freshwater" ], "year": "2020", "source": "ENVIRONMENTAL MONITORING AND ASSESSMENT", "publication_type": "J", "point2d": [ 57.38957214355469, -24.389482498168945 ], "cluster": 4.0 }, { "idx": 709, "title": "Is the River a Chemostat?: Scale Versus Land Use Controls on Nitrate Concentration-Discharge Dynamics in the Upper Mississippi River Basin", "abstract": "The Upper Mississippi River Basin is the largest source of reactive nitrogen (N) to the Gulf of Mexico. Concentration-discharge (C-Q) relationships offer a means to understand both the terrestrial sources that generate this reactive N and the in-stream processes that transform it. Progress has been made on identifying land use controls on C-Q dynamics. However, the impact of basin size and river network structure on C-Q relationships is not well characterized. Here, we show, using high-resolution nitrate concentration data, that tile drainage is a dominant control on C-Q dynamics, with increasing drainage density contributing to more chemostatic C-Q behavior. We further find that concentration variability increases, relative to discharge variability, with increasing basin size across six orders of magnitude, and this pattern is attributed to different spatial correlation structures for C and Q. Our results show how land use and river network structure jointly control riverine N export.", "authors": [ "Marinos, Richard E.", "Van Meter, Kimberly J.", "Basu, Nandita B." ], "keywords": [ "concentration-discharge", "nitrate", "agriculture", "Mississippi river", "tile drainage", "scaling" ], "year": "2020", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ 26.997146606445312, 2.7489254474639893 ], "cluster": 10.0 }, { "idx": 710, "title": "Changes in Sedimentary Phosphorus Burial Following Artificial Eutrophication of Lake 227, Experimental Lakes Area, Ontario, Canada", "abstract": "Lake 227 of the Experimental Lakes Area (ELA) in Ontario, Canada, has been fertilized with phosphorus (P) since 1969, which resulted in a rapid transition from oligotrophic to eutrophic conditions. Sediment cores collected from the oxygenated epilimnion, and the mostly anoxic hypolimnion of this unique lake contain a historical record of the changes in sediment P speciation and burial rates across the trophic transition. To elucidate these changes, results of chemical extractions were combined with Pb-210 sediment dating, and with P-31 NMR, Mossbauer, and XANES spectroscopies. Prior to 1969, organic P (P-Org) was the major sedimentary P sink in Lake 227. Eutrophication of the lake coincided with marked increases in the burial rate of total P (TP), as well as in the relative contribution of the NaHCO3-extractable P pool (humic-bound P, P-Hum). Together, P-Hum and P-Org account for >= 70% of total P burial in the sediments deposited since artificial fertilization started. The P-Hum fraction likely comprises phosphate complexes with humic substances. The strong linear correlation between P and iron (Fe) extracted by NaHCO3 implies a close association of the two elements in the humic fraction. Mossbauer and XANES spectra further indicate that most Fe in the post-1969 sediments remained in the Fe (III) oxidation state, which is attributed to the stabilization of reducible Fe by organic matter, in part via the formation of phosphate-Fe (III)-humic complexes. Importantly, our results show that the eutrophication experimentation of Lake 227 caused the accumulation of a large reservoir of reactive sediment P, which may continue to fuel internal P loading to the water column once artificial fertilization is terminated.", "authors": [ "O'Connell, D. W.", "Ansems, N.", "Kukkadapu, R. K.", "Jaisi, D.", "Orihel, D. M.", "Cade-Menun, B. J.", "Hu, Y.", "Wiklund, J.", "Hall, R., I", "Chessell, H.", "Behrends, T.", "Van Cappellen, P." ], "keywords": [ "" ], "year": "2020", "source": "JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES", "publication_type": "J", "point2d": [ 54.312286376953125, 10.057269096374512 ], "cluster": 19.0 }, { "idx": 711, "title": "An analysis of the sample size requirements for acceptable statistical power in water quality monitoring for improvement detection", "abstract": "Many water quality managers seek to demonstrate reductions in pollutants after a remedial program or policy change of some sort is implemented, but there is little information in the literature to help guide the extent of water quality sampling that is required to be confident that a change has occurred. Statistical power refers to the likelihood of avoiding a Type II error in hypothesis testing. It is critical to examine statistical power levels to ensure results are not unduly influenced by insufficient quantity of data. This study presents the first published record, to the best of our knowledge, on sample size requirements to achieve acceptable levels of statistical power in hypothesis testing of annual water quality (nutrients) in streams. We examined 13 temperate agricultural watersheds spanning a gradient of size from 11 to 16,000 km(2) using data synthesized from long-term flow and water quality records. We found that achieving commonly accepted levels of statistical power (0.8) after reductions of 20% in load or flow-weighted mean concentration (FWMC) required an inordinate quantity of data (50-250 years for load, 10-120 years for FWMC), while achieving statistical power of 0.8 after reductions of 80% of load or FWMC required very little data (2-4 years for FWMC, 2-7 years for load). Load reductions of 40% required a range of 8-50 years of data depending on analyte, while FWMC reductions of 40% required 3-10 years of total phosphorus (TP) data, 5-25 years for soluble reactive phosphorus (SRP), and 2-6 years for nitrate (NO3). We examined relationships among times to achieve statistical power and a number of common landscape descriptors (discharge, baseflow index, basin size, concentration-discharge slope) and found no discernable relationships for either TP or SRP, whereas catchments with higher baseflow indices were found to have lower data requirements for achieving statistical power of 0.8 for NO3. We also show through subsampling experiments that higher frequency sampling tended to reduce data requirements to achieve acceptable statistical power, though these gains diminish as the sample frequency increases. The information presented will help those tasked with watershed monitoring to design appropriate sampling regimes to ensure adequate data are obtained to detect change.", "authors": [ "Wellen, Christopher", "Van Cappellen, Philippe", "Gospodyn, Larissa", "Thomas, Janis L.", "Mohamed, Mohamed N." ], "keywords": [ "Statistical power", "Phosphorus", "Nitrogen", "SRP", "Hypothesis test", "Water quality" ], "year": "2020", "source": "ECOLOGICAL INDICATORS", "publication_type": "J", "point2d": [ 38.973793029785156, 7.203161716461182 ], "cluster": 10.0 }, { "idx": 712, "title": "Unique surface density layers promote formation of harmful algal blooms in the Pengxi River, Three Gorges Reservoir", "abstract": "The Three Gorges Reservoir (TGR), China, is the largest man-made reservoir in the world. Harmful algal blooms (HABs) have become common since the reservoir's impoundment in 2003. To investigate the mechanisms of HAB formation in the reservoir and to determine possible mitigation measures, we conducted surveys over a range of spatial scales and temporal resolutions over a 2-y period (March 2013-December 2014). The large-scale survey (the portion of the reservoir on the main stem of the Yangtze River and 22 tributaries) revealed that cyanobacteria blooms were restricted to the upper reaches of the tributaries. The medium-scale survey (1 tributary: Pengxi River) showed that cyanobacteria blooms were confined to the early-spring period with the initiation of thermal stratification in the deep-water column. The small-scale survey (a local, backwater lake in the Pengxi River), which was of higher-temporal resolution than the other 2 surveys, demonstrated that the bloom occurred at the same time as the formation of a surface-density layer unique to the geomorphology and water-control management of the reservoir. The vertical distributions of the bloom and surface-density layer appeared to be related, although the density layer persisted beyond the duration of the HABs. We hypothesized that limited nutrient diffusion into these density layers could result in nutrient limitation despite the hyper-eutrophic conditions that generally characterize the TGR basin. In the main stem of the Yangtze River and lower reaches of the tributaries in the TGR, algal blooms were not observed because of continuous, deep mixing throughout the year. We conclude that the hydrological stability and geomorphological characteristics of the TGR play critical roles in regulating the temporal and spatial patterns of algal blooms and that artificial mixing of the water column is currently the best option to limit HAB formation, especially in upper tributaries.", "authors": [ "Zhang, Lei", "Xia, Zhiqiang", "Zhou, Chuan", "Fu, Li", "Yu, Jianjun", "Taylor, William D.", "Hamilton, Paul B.", "Van Cappellen, Philippe", "Ji, Daobin", "Liu, Defu", "Xie, Deti", "Zeng, Bo", "McLeod, Anne M.", "Haffner, G. Douglas" ], "keywords": [ "Three Gorges Reservoir", "geomorphology", "harmful algal blooms", "surface-density layers", "nutrients" ], "year": "2020", "source": "FRESHWATER SCIENCE", "publication_type": "J", "point2d": [ 55.68207550048828, 18.966100692749023 ], "cluster": 19.0 }, { "idx": 713, "title": "Endocrine Disruptor Impacts on Fish From Chile: The Influence of Wastewaters", "abstract": "Industrial wastewaters and urban discharges contain complex mixtures of chemicals capable of impacting reproductive performance in freshwater fish, called endocrine-disrupting compounds (EDCs). In Chile, the issue was highlighted by our group beginning over 15 years ago, by analyzing the impacts of pulp and paper mill effluents (PPME) in the Biobio, Itata, and Cruces River basins. All of the rivers studied are important freshwater ecosystems located in the Mediterranean region of Central Chile, each with a unique fish biodiversity. Sequentially, we developed a strategy based on laboratory assays, semicontrolled-field experiments (e.g., caging) and wild fish population assessments to explore the issue of reproductive impacts on both introduced and native fish in Chile. The integration of watershed, field, and laboratory studies was effective at understanding the endocrine responses in Chilean freshwater systems. The studies demonstrated that regardless of the type of treatment, pulp mill effluents can contain compounds capable of impacting endocrine systems. Urban wastewater treatment plant effluents (WWTP) were also investigated using the same integrated strategy. Although not directly compared, PPME and WWTP effluent seem to cause similar estrogenic effects in fish after waterborne exposure, with differing intensities. This body of work underscores the urgent need for further studies on the basic biology of Chilean native fish species, and an improved understanding on reproductive development and variability across Chilean ecosystems. The lack of knowledge of the ontogeny of Chilean fish, especially maturation and sexual development, with an emphasis on associated habitats and landscapes, are impediment factors for their conservation and protection against the threat of EDCs. The assessment of effects on native species in the receiving environment is critical for supporting and designing protective regulations and remediation strategies, and for conserving the unique Chilean fish biodiversity.", "authors": [ "Barra, Ricardo O.", "Chiang, Gustavo", "Saavedra, Maria Fernanda", "Orrego, Rodrigo", "Servos, Mark R.", "Hewitt, L. Mark", "McMaster, Mark E.", "Bahamonde, Paulina", "Tucca, Felipe", "Munkittrick, Kelly R." ], "keywords": [ "pulp mill effluents", "urban treated discharges", "Biobio River", "Itata River", "Native fish Chile" ], "year": "2021", "source": "FRONTIERS IN ENDOCRINOLOGY", "publication_type": "J", "point2d": [ 74.4783935546875, -4.418674945831299 ], "cluster": 0.0 }, { "idx": 714, "title": "Improved biodegradation of pharmaceuticals after mild photocatalytic pretreatment", "abstract": "The combination of photocatalysis and biodegradation was investigated for the removal of nine selected pharmaceuticals as a means to reduce loadings into the environment. The combined process, consisting of a resource-efficient mild photocatalysis and a subsequent biological treatment, was compared to single processes of intensive photocatalysis and biological treatment. The UV-TiO(2)based photocatalysis effectively removed atorvastatin, atenolol and fluoxetine (>80%). Biological treatment after mild photocatalytic pretreatment removed diclofenac effectively (>99%), while it persisted during the single biological treatment (<50%). Moreover, the biodegradation of atorvastatin, caffeine, gemfibrozil and ibuprofen was enhanced after mild photocatalytic pretreatment compared to biological treatment alone. The enhanced biodegradation of these pharmaceuticals appeared to be triggered by the biodegradation of photocatalytic products. Mild photocatalysis followed by biological treatment is an effective and resource-efficient combination for pharmaceutical removal that could substantially reduce the loading of pharmaceuticals into the environment.", "authors": [ "de Wilt, Arnoud", "Arlos, Maricor J.", "Servos, Mark R.", "Rijnaarts, Huub H. M.", "Langenhoff, Alette A. M.", "Parker, Wayne J." ], "keywords": [ "biodegradation", "combined treatment", "pharmaceuticals", "photocatalysis", "pretreatment" ], "year": "2020", "source": "WATER AND ENVIRONMENT JOURNAL", "publication_type": "J", "point2d": [ 50.60132598876953, 36.7952766418457 ], "cluster": 6.0 }, { "idx": 715, "title": "Impacts on Metabolism and Gill Physiology of Darter Species (Etheostoma spp.) That Are Attributed to Wastewater Effluent in the Grand River", "abstract": "The effluent from municipal wastewater treatment plants is a major point source of contamination in Canadian waterways. The improvement of effluent quality to reduce contaminants, such as pharmaceuticals and personal care products, before being released into the environment is necessary to reduce the impacts on organisms that live in the river downstream. Here, we aimed to characterize the metabolic and gill physiological responses of rainbow (Etheostoma caeruleum), fantail (Etheostoma flabellare), and greenside (Etheostoma blennioides) darters to the effluent in the Grand River from the recently upgraded Waterloo municipal wastewater treatment plant. The routine metabolism of darters was not affected by effluent exposure, but some species had increased maximum metabolic rates, leading to an increased aerobic scope. The rainbow darter aerobic scope increased by 2.2 times and the fantail darter aerobic scope increased by 2.7 times compared to the reference site. Gill samples from effluent-exposed rainbow darters and greenside darters showed evidence of more pathologies and variations in morphology. These results suggest that darters can metabolically adjust to effluent-contaminated water and may also be adapting to the urban and agricultural inputs. The modification and damage to the gills provide a useful water quality indicator but does not necessarily reflect how well acclimated the species is to the environment due to a lack of evidence of poor fish health.", "authors": [ "Hodgson, Rhiannon", "Bragg, Leslie", "Dhiyebi, Hadi A.", "Servos, Mark R.", "Craig, Paul M." ], "keywords": [ "Etheostoma species", "wastewater effluent", "field metabolic rate", "gill pathology", "respirometry", "pharmaceuticals" ], "year": "2020", "source": "APPLIED SCIENCES-BASEL", "publication_type": "J", "point2d": [ 72.28663635253906, -0.8995609879493713 ], "cluster": 0.0 }, { "idx": 716, "title": "Rock glaciers and related cold rocky landforms: Overlooked climate refugia for mountain biodiversity", "abstract": "Mountains are global biodiversity hotspots where cold environments and their associated ecological communities are threatened by climate warming. Considerable research attention has been devoted to understanding the ecological effects of alpine glacier and snowfield recession. However, much less attention has been given to identifying climate refugia in mountain ecosystems where present-day environmental conditions will be maintained, at least in the near-term, as other habitats change. Around the world, montane communities of microbes, animals, and plants live on, adjacent to, and downstream of rock glaciers and related cold rocky landforms (CRL). These geomorphological features have been overlooked in the ecological literature despite being extremely common in mountain ranges worldwide with a propensity to support cold and stable habitats for aquatic and terrestrial biodiversity. CRLs are less responsive to atmospheric warming than alpine glaciers and snowfields due to the insulating nature and thermal inertia of their debris cover paired with their internal ventilation patterns. Thus, CRLs are likely to remain on the landscape after adjacent glaciers and snowfields have melted, thereby providing longer-term cold habitat for biodiversity living on and downstream of them. Here, we show that CRLs will likely act as key climate refugia for terrestrial and aquatic biodiversity in mountain ecosystems, offer guidelines for incorporating CRLs into conservation practices, and identify areas for future research.", "authors": [ "Brighenti, Stefano", "Hotaling, Scott", "Finn, Debra S.", "Fountain, Andrew G.", "Hayashi, Masaki", "Herbst, David", "Saros, Jasmine E.", "Tronstad, Lusha M.", "Millar, Constance I." ], "keywords": [ "alpine stream", "biodiversity monitoring", "climate adaptation", "climate change ecology", "debris-covered glacier", "icy seeps", "mountain hydrology", "talus slope" ], "year": "2021", "source": "GLOBAL CHANGE BIOLOGY", "publication_type": "J", "point2d": [ -20.149898529052734, 48.3853759765625 ], "cluster": 13.0 }, { "idx": 717, "title": "Hydrogeological characterization of an alpine aquifer system in the Canadian Rocky Mountains", "abstract": "Groundwater storage in alpine regions is essential for maintaining baseflows in mountain streams. Recent studies have shown that common alpine landforms (e.g., talus and moraine) have substantial groundwater storage capacity, but the hydrogeological connectivity between individual landforms has not been understood. This study characterizes the hydrogeology of an alpine cirque basin in the Canadian Rocky Mountains that contains typical alpine landforms (talus, meadow, moraines) and hydrological features (tarn, streams, and springs). Geological, hydrological, and hydrochemical observations were used to understand the overall hydrogeological setting of the study basin, and three different geophysical methods (electrical resistivity tomography, seismic refraction tomography, and ground penetrating radar) were used to characterize the subsurface structure and connectivity, and to develop a hydrogeological conceptual model. Geophysical imaging shows that the talus is typically 20-40 m thick and highly heterogeneous. The meadow sediments are only up to 11 m thick but are part of a 30-40-m-thick accumulation of unconsolidated material that fills a bedrock overdeepening (i.e. a closed, subglacial basin). A minor, shallow groundwater system feeds springs on the talus and streams on the meadow, whereas a deep system in the moraine supplies most of the water to the basin outlet springs, thereby serving as a 'gate keeper' of the basin. Although the hydrologic functions of the talus in this study are substantially different from other locations, primarily due to differences in bedrock lithology and geomorphic processes, the general conceptual framework developed in this study is expected to be applicable to other alpine regions.", "authors": [ "Christensen, Craig William", "Hayashi, Masaki", "Bentley, Laurence R." ], "keywords": [ "Geophysical methods", "Geomorphology", "Talus", "Moraine", "Canada" ], "year": "2020", "source": "HYDROGEOLOGY JOURNAL", "publication_type": "J", "point2d": [ -4.088881015777588, -3.187952995300293 ], "cluster": 18.0 }, { "idx": 718, "title": "Icefield Breezes: Mesoscale Diurnal Circulation in the Atmospheric Boundary Layer Over an Outlet of the Columbia Icefield, Canadian Rockies", "abstract": "Atmospheric boundary layer (ABL) dynamics over glaciers mediate the response of glacier mass balance to large-scale climate forcing. Despite this, very few ABL observations are available over mountain glaciers in complex terrain. An intensive field campaign was conducted in June 2015 at the Athabasca Glacier outlet of Columbia Icefield in the Canadian Rockies. Observations of wind and temperature profiles with novel kite and radio-acoustic sounding systems showed a well-defined mesoscale circulation developed between the glacier and snow-free valley in fair weather. The typical vertical ABL structure above the glacier differed from that expected for glacier winds; strong daytime down-glacier winds extended through the lowest 200 m with no up-valley return flow aloft. This structure suggests external forcing at mesoscale scales or greater and is provisionally termed an icefield breeze. A wind speed maximum near the surface, characteristic of a glacier wind, was only observed during night-time and one afternoon. Lapse rates of air temperature down the glacier centerline show the interaction of down-glacier cooling driven by sensible heat loss into the ice, entrainment and periodic disruption and warming. Down-glacier cooling was weaker in icefield breeze conditions, while in glacier wind conditions, stronger down-glacier cooling enabled large increases in near-surface temperature on the lower glacier during periods of surface boundary layer (SBL) disruption. These results raise several questions, including the impact of Columbia Icefield on the ABL and melt of Athabasca Glacier. Future work should use these observations as a testbed for modeling spatio-temporal variations in the ABL and SBL within complex glaciated terrain.", "authors": [ "Conway, J. P.", "Helgason, W. D.", "Pomeroy, J. W.", "Sicart, J. E." ], "keywords": [ "atmospheric boundary layer", "complex terrain", "diurnal winds", "glacier surface boundary layer", "surface lapse rates" ], "year": "2021", "source": "JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES", "publication_type": "J", "point2d": [ -51.78230667114258, -19.714031219482422 ], "cluster": 1.0 }, { "idx": 720, "title": "Snow cover duration trends observed at sites and predicted by multiple models", "abstract": "The 30-year simulations of seasonal snow cover in 22 physically based models driven with bias-corrected meteorological reanalyses are examined at four sites with long records of snow observations. Annual snow cover durations differ widely between models, but interannual variations are strongly correlated because of the common driving data. No significant trends are observed in starting dates for seasonal snow cover, but there are significant trends towards snow cover ending earlier at two of the sites in observations and most of the models. A simplified model with just two parameters controlling solar radiation and sensible heat contributions to snowmelt spans the ranges of snow cover durations and trends. This model predicts that sites where snow persists beyond annual peaks in solar radiation and air temperature will experience rapid decreases in snow cover duration with warming as snow begins to melt earlier and at times of year with more energy available for melting.", "authors": [ "Essery, Richard", "Kim, Hyungjun", "Wang, Libo", "Bartlett, Paul", "Boone, Aaron", "Brutel-Vuilmet, Claire", "Burke, Eleanor", "Cuntz, Matthias", "Decharme, Bertrand", "Dutra, Emanuel", "Fang, Xing", "Gusev, Yeugeniy", "Hagemann, Stefan", "Haverd, Vanessa", "Kontu, Anna", "Krinner, Gerhard", "Lafaysse, Matthieu", "Lejeune, Yves", "Marke, Thomas", "Marks, Danny", "Marty, Christoph", "Menard, Cecile B.", "Nasonova, Olga", "Nitta, Tomoko", "Pomeroy, John", "Schaedler, Gerd", "Semenov, Vladimir", "Smirnova, Tatiana", "Swenson, Sean", "Turkov, Dmitry", "Wever, Nander", "Yuan, Hua" ], "keywords": [ "" ], "year": "2020", "source": "CRYOSPHERE", "publication_type": "J", "point2d": [ -45.13961410522461, -10.074159622192383 ], "cluster": 8.0 }, { "idx": 721, "title": "Alpine Hydrogeology: The Critical Role of Groundwater in Sourcing the Headwaters of the World", "abstract": "Groundwater discharge in alpine headwaters sustains baseflow in rivers originating in mountain ranges of the world, which is critically important for aquatic habitats, run-of-river hydropower generation, and downstream water supply. Groundwater storage in alpine watersheds was long considered negligible, but recent field-based studies have shown that aquifers are ubiquitous in the alpine zone with no soil and vegetation. Talus, moraine, and rock glacier aquifers are common in many alpine regions of the world, although bedrock aquifers occur in some geological settings. Alpine aquifers consisting of coarse sediments have a fast recession of discharge after the recharge season (e.g., snowmelt) or rainfall events, followed by a slow recession that sustains discharge over a long period. The two-phase recession is likely controlled by the internal structure of the aquifers. Spatial extent and distribution of individual aquifers determine the groundwater storage-discharge characteristics in first- and second-order watersheds in the alpine zone, which in turn govern baseflow characteristics in major rivers. Similar alpine landforms appear to have similar hydrogeological characteristics in many mountain ranges across the world, suggesting that a common conceptual framework can be used to understand alpine aquifers based on geological and geomorphological settings. Such a framework will be useful for parameterizing storage-discharge characteristics in large river hydrological models.", "authors": [ "Hayashi, Masaki" ], "keywords": [ "" ], "year": "2020", "source": "GROUNDWATER", "publication_type": "J", "point2d": [ -3.8028364181518555, -3.768688917160034 ], "cluster": 18.0 }, { "idx": 722, "title": "Accelerated global glacier mass loss in the early twenty-first century", "abstract": "Glaciers distinct from the Greenland and Antarctic ice sheets are shrinking rapidly, altering regional hydrology(1), raising global sea level(2) and elevating natural hazards(3). Yet, owing to the scarcity of constrained mass loss observations, glacier evolution during the satellite era is known only partially, as a geographic and temporal patchwork(4,5). Here we reveal the accelerated, albeit contrasting, patterns of glacier mass loss during the early twenty-first century. Using largely untapped satellite archives, we chart surface elevation changes at a high spatiotemporal resolution over all of Earth's glaciers. We extensively validate our estimates against independent, high-precision measurements and present a globally complete and consistent estimate of glacier mass change. We show that during 2000-2019, glaciers lost a mass of 267 +/- 16 gigatonnes per year, equivalent to 21 +/- 3 per cent of the observed sea-level rise(6). We identify a mass loss acceleration of 48 +/- 16 gigatonnes per year per decade, explaining 6 to 19 per cent of the observed acceleration of sea-level rise. Particularly, thinning rates of glaciers outside ice sheet peripheries doubled over the past two decades. Glaciers currently lose more mass, and at similar or larger acceleration rates, than the Greenland or Antarctic ice sheets taken separately(7-9). By uncovering the patterns of mass change in many regions, we find contrasting glacier fluctuations that agree with the decadal variability in precipitation and temperature. These include a North Atlantic anomaly of decelerated mass loss, a strongly accelerated loss from northwestern American glaciers, and the apparent end of the Karakoram anomaly of mass gain(10). We anticipate our highly resolved estimates to advance the understanding of drivers that govern the distribution of glacier change, and to extend our capabilities of predicting these changes at all scales. Predictions robustly benchmarked against observations are critically needed to design adaptive policies for the local- and regional-scale management of water resources and cryospheric risks, as well as for the global-scale mitigation of sea-level rise. Analysis of satellite stereo imagery uncovers two decades of mass change for all of Earth's glaciers, revealing accelerated glacier shrinkage and regionally contrasting changes consistent with decadal climate variability.", "authors": [ "Hugonnet, Romain", "McNabb, Robert", "Berthier, Etienne", "Menounos, Brian", "Nuth, Christopher", "Girod, Luc", "Farinotti, Daniel", "Huss, Matthias", "Dussaillant, Ines", "Brun, Fanny", "Kaab, Andreas" ], "keywords": [ "" ], "year": "2021", "source": "NATURE", "publication_type": "J", "point2d": [ -43.393463134765625, 11.991597175598145 ], "cluster": 8.0 }, { "idx": 723, "title": "Subalpine forest water use behaviour and evapotranspiration during two hydrologically contrasting growing seasons in the Canadian Rockies", "abstract": "Hydrological processes in mountain headwater basins are changing as climate and vegetation change. Interactions between hydrological processes and subalpine forest ecological function are important to mountain water supplies due to their control on evapotranspiration (ET). Improved understanding of the sensitivity of these interactions to seasonal and interannual changes in snowmelt and summer rainfall is needed as these interactions can impact forest growth, succession, health, and susceptibility to wildfire. To better understand this sensitivity, this research examined ET for a sub-alpine forest in the Canadian Rockies over two contrasting growing seasons and quantified the contribution of transpiration (T) from the younger tree population to overall stand ET. The younger population was focused on to permit examination of trees that have grown under the effect of recent climate change and will contribute to treeline migration, and subalpine forest densification and succession. Research sites were located at Fortress Mountain Research Basin, Kananaskis, Alberta, where the subalpine forest examined is composed of Abies lasiocarpa (Subalpine fir) and Picea engelmannii (Engelmann spruce). Seasonal changes in water availability from snowmelt, precipitation, soil moisture reserves yielded stark differences in T and ET between 2016 and 2017. ET was higher in the drier year (2017), which had late snowmelt and lower summer rainfall than in the wetter year (2016) that had lower snowmelt and a rainy summer, highlighting the importance of spring snowmelt recharge of soil moisture. However, stand T of the younger trees (73% of forest population) was greater (64 mm) in 2016 (275 mm summer rainfall) than 2017 (39 mm T, 147 mm summer rainfall), and appears to be sensitive to soil moisture decreases in fall, which are largely a function of summer period rainfall. Relationships between subalpine forest water use and different growing season and antecedent (snowmelt period) hydrological conditions clarify the interactions between forest water use and alpine hydrology, which can lead to better anticipation of the hydrological response of subalpine forest-dominated basins to climate variability and change.", "authors": [ "Langs, Lindsey E.", "Petrone, Richard M.", "Pomeroy, John W." ], "keywords": [ "Canadian Rocky Mountains", "eddy covariance", "evapotranspiration", "forest health", "sap flow", "subalpine forest", "transpiration", "water use" ], "year": "2021", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -21.839569091796875, 10.17426872253418 ], "cluster": 13.0 }, { "idx": 724, "title": "A delta O-18 and delta H-2 stable water isotope analysis of subalpine forest water sources under seasonal and hydrological stress in the Canadian Rocky Mountains", "abstract": "Subalpine forests are hydrologically important to the function and health of mountain basins. Identifying the specific water sources and the proportions used by subalpine forests is necessary to understand potential impacts to these forests under a changing climate. The recent Two Water Worlds hypothesis suggests that trees can favour tightly bound soil water instead of readily available free-flowing soil water. Little is known about the specific sources of water used by subalpine trees Abies lasiocarpa (Subalpine fir) and Picea engelmannii (Engelmann spruce) in the Canadian Rocky Mountains. In this study, stable water isotope (delta O-18 and delta H-2) samples were obtained from S. fir and Engelmann spruce trees at three points of the growing season in combination with water sources available at time of sampling (snow, vadose zone water, saturated zone water, precipitation). Using the Bayesian Mixing Model, MixSIAR, relative source water proportions were calculated. In the drought summer examined, there was a net loss of water via evapotranspiration from the system. Results highlighted the importance of tightly vadose zone, or bound soil water, to subalpine forests, providing insights of future health under sustained years of drought and net loss in summer growing seasons. This work builds upon concepts from the Two Water Worlds hypothesis, showing that subalpine trees can draw from different water sources depending on season and availability. In our case, water use was largely driven by a tension gradient within the soil allowing trees to utilize vadose zone water and saturated zone water at differing points of the growing season.", "authors": [ "Langs, Lindsey E.", "Petrone, Richard M.", "Pomeroy, John W." ], "keywords": [ "Canadian Rocky Mountains", "evapotranspiration", "forest health", "subalpine forest", "transpiration", "water use" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -11.72923469543457, 20.28310775756836 ], "cluster": 3.0 }, { "idx": 725, "title": "Beaver dam analogue configurations influence stream and riparian water table dynamics of a degraded spring-fed creek in the Canadian Rockies", "abstract": "Beaver dam analogues (BDAs) are intended to simulate natural beaver dam ecohydrological functions including modifying stream hydrology and enhancing stream-riparian hydrological connectivity. River restoration practitioners are proactively deploying BDAs in thousands of degraded streams. How various BDAs or their configurations impact stream hydrology and the riparian water table remains poorly understood. We investigated three types of BDA configurations (single, double and triple) in a spring-fed Canadian Rocky Mountain stream over three study seasons (April-October; 2017-2019). All three BDA configurations significantly elevated the upstream stage. The deepest pools occurred upstream of the triple-configuration BDAs (0.46 m) and the shallowest pools occurred upstream of the single-configuration (0.36 m). Further, the single-BDA configuration lowered stream stage and flow peaks below it but raised low flows. The double-BDA configuration modulated flow peaks but had little influence on low flows. Unexpectedly, higher flow peaks and low flows were recorded below the triple-BDA configuration, owing to groundwater seep. Similar to the natural beaver dam function, we observed an immediate water table rise in the riparian area after installation of the BDAs. The water table rise was greatest 2 m from the stream (0.14 m) and diminished with increasing lateral distance from the stream. Also noted was a reversal in the direction of flow between the stream and riparian area after BDA installation. Future research should further explore the dynamics of stream-riparian hydrological connections under various BDA configurations and spacings, with the goal of identifying best practices for simulating the ecohydrological functions of natural beaver dams.", "authors": [ "Munir, Tariq M.", "Westbrook, Cherie J." ], "keywords": [ "BDA", "beaver dam analogues", "Castor canadensis", "ecohydrology", "mountain creek", "riparian area", "stream" ], "year": "2021", "source": "RIVER RESEARCH AND APPLICATIONS", "publication_type": "J", "point2d": [ 11.637959480285645, -2.349691152572632 ], "cluster": 13.0 }, { "idx": 726, "title": "Beaver dam analogue configurations influence stream and riparian water table dynamics of a degraded spring-fed creek in the Canadian Rockies", "abstract": "Beaver dam analogues (BDAs) are intended to simulate natural beaver dam ecohydrological functions including modifying stream hydrology and enhancing stream-riparian hydrological connectivity. River restoration practitioners are proactively deploying BDAs in thousands of degraded streams. How various BDAs or their configurations impact stream hydrology and the riparian water table remains poorly understood. We investigated three types of BDA configurations (single, double and triple) in a spring-fed Canadian Rocky Mountain stream over three study seasons (April-October; 2017-2019). All three BDA configurations significantly elevated the upstream stage. The deepest pools occurred upstream of the triple-configuration BDAs (0.46 m) and the shallowest pools occurred upstream of the single-configuration (0.36 m). Further, the single-BDA configuration lowered stream stage and flow peaks below it but raised low flows. The double-BDA configuration modulated flow peaks but had little influence on low flows. Unexpectedly, higher flow peaks and low flows were recorded below the triple-BDA configuration, owing to groundwater seep. Similar to the natural beaver dam function, we observed an immediate water table rise in the riparian area after installation of the BDAs. The water table rise was greatest 2 m from the stream (0.14 m) and diminished with increasing lateral distance from the stream. Also noted was a reversal in the direction of flow between the stream and riparian area after BDA installation. Future research should further explore the dynamics of stream-riparian hydrological connections under various BDA configurations and spacings, with the goal of identifying best practices for simulating the ecohydrological functions of natural beaver dams.", "authors": [ "Munir, Tariq M.", "Westbrook, Cherie J." ], "keywords": [ "BDA", "beaver dam analogues", "Castor canadensis", "ecohydrology", "mountain creek", "riparian area", "stream" ], "year": "2021", "source": "RIVER RESEARCH AND APPLICATIONS", "publication_type": "J", "point2d": [ 11.637959480285645, -2.349691152572632 ], "cluster": 13.0 }, { "idx": 727, "title": "Thermal Characteristics of a Beaver Dam Analogues Equipped Spring-Fed Creek in the Canadian Rockies", "abstract": "Beaver dam analogues (BDAs) are becoming an increasingly popular stream restoration technique. One ecological function BDAs might help restore is suitable habitat conditions for fish in streams where loss of beaver dams and channel incision has led to their decline. A critical physical characteristic for fish is stream temperature. We examined the thermal regime of a spring-fed Canadian Rocky Mountain stream in relation to different numbers of BDAs installed in series over three study periods (April-October; 2017-2019). While all BDA configurations significantly influenced stream and pond temperatures, single- and double-configuration BDAs incrementally increased stream temperatures. Single and double configuration BDAs warmed the downstream waters of mean maxima of 9.9, 9.3 degrees C by respective mean maxima of 0.9 and 1.0 degrees C. Higher pond and stream temperatures occurred when ponding and discharge decreased, and vice versa. In 2019, variation in stream temperature below double-configuration BDAs was lower than the single-configuration BDA. The triple-configuration BDA, in contrast, cooled the stream, although the mean maximum stream temperature was the highest below these structures. Ponding upstream of BDAs increased discharge and resulted in cooling of the stream. Rainfall events sharply and transiently reduced stream temperatures, leading to a three-way interaction between BDA configuration, rainfall and stream discharge as factors co-influencing the stream temperature regime. Our results have implications for optimal growth of regionally important and threatened bull and cutthroat trout fish species.", "authors": [ "Munir, Tariq M.", "Westbrook, Cherie J." ], "keywords": [ "stream temperature", "stream restoration", "BDA", "ecohydrology", "cutthroat trout", "bull trout" ], "year": "2021", "source": "WATER", "publication_type": "J", "point2d": [ 4.523911952972412, -1.314307451248169 ], "cluster": 13.0 }, { "idx": 728, "title": "Thermal Characteristics of a Beaver Dam Analogues Equipped Spring-Fed Creek in the Canadian Rockies", "abstract": "Beaver dam analogues (BDAs) are becoming an increasingly popular stream restoration technique. One ecological function BDAs might help restore is suitable habitat conditions for fish in streams where loss of beaver dams and channel incision has led to their decline. A critical physical characteristic for fish is stream temperature. We examined the thermal regime of a spring-fed Canadian Rocky Mountain stream in relation to different numbers of BDAs installed in series over three study periods (April-October; 2017-2019). While all BDA configurations significantly influenced stream and pond temperatures, single- and double-configuration BDAs incrementally increased stream temperatures. Single and double configuration BDAs warmed the downstream waters of mean maxima of 9.9, 9.3 degrees C by respective mean maxima of 0.9 and 1.0 degrees C. Higher pond and stream temperatures occurred when ponding and discharge decreased, and vice versa. In 2019, variation in stream temperature below double-configuration BDAs was lower than the single-configuration BDA. The triple-configuration BDA, in contrast, cooled the stream, although the mean maximum stream temperature was the highest below these structures. Ponding upstream of BDAs increased discharge and resulted in cooling of the stream. Rainfall events sharply and transiently reduced stream temperatures, leading to a three-way interaction between BDA configuration, rainfall and stream discharge as factors co-influencing the stream temperature regime. Our results have implications for optimal growth of regionally important and threatened bull and cutthroat trout fish species.", "authors": [ "Munir, Tariq M.", "Westbrook, Cherie J." ], "keywords": [ "stream temperature", "stream restoration", "BDA", "ecohydrology", "cutthroat trout", "bull trout" ], "year": "2021", "source": "WATER", "publication_type": "J", "point2d": [ 4.65978479385376, -0.8430898785591125 ], "cluster": 13.0 }, { "idx": 729, "title": "Meteorological drivers of interannual variation in transparency of mountain lakes", "abstract": "In mountain lakes, water transparency is regulated primarily by materials loaded from the surrounding catchment. Consequently, transparency within a lake can vary over time due to meteorological conditions that affect hydrologic inputs. Furthermore, lake responses to these inputs may depend on catchment characteristics. We examined the relationships between meteorological conditions and interannual variation in transparency over thirteen years in a set of four lakes in Yoho National Park, British Columbia, Canada. We measured mid-summer transparency as the attenuation coefficient of 320 nm and collected meteorological data daily with an automatic weather station located near the study lakes. Despite their close proximity, lakes varied in the strength of associations between transparency and cumulative precipitation across a range of durations. Specifically, transparency in non-glacially fed Lake Hungabee was most strongly correlated with cumulative precipitation in the fifteen days preceding sampling, whereas glacially fed Lakes Opabin and Oesa were most strongly affected by longer periods of cumulative precipitation. Consequently, there was relatively little temporal synchrony in interannual transparency variation among lakes. Our results suggest that both the timing and amount of precipitation as well local hydrology must be considered when predicting effects of climate change on mountain lake ecosystems even within a single region.", "authors": [ "Olson, Mark H.", "Fischer, Janet M.", "Hayashi, Masaki", "Williamson, Craig E." ], "keywords": [ "Canadian Rocky Mountains", "water transparency", "turbidity", "chromophoric dissolved organic matter", "limnology" ], "year": "2020", "source": "ARCTIC ANTARCTIC AND ALPINE RESEARCH", "publication_type": "J", "point2d": [ 3.825840473175049, 9.939838409423828 ], "cluster": 13.0 }, { "idx": 730, "title": "Contrasting storage-flux-age interactions revealed by catchment inter-comparison using a tracer-aided runoff model", "abstract": "Water storage dynamics modulate fluxes within catchments, control the rainfall-runoff response and regulate the velocity of water particles through mixing associated processes. Tracer-aided models are useful tools for tracking the interactions between catchment storage and fluxes, as they can capture both the celerity of the runoff response and the velocity of water particles revealed by tracer dynamics. The phase-space reconstruction of modelled systems can help in this regard; it traces the evolution of a dynamic system from a known initial state as phase trajectories in response to inputs. In this study, we compared the modelled storage-flux dynamics obtained from the application of a spatially distributed tracer-aided hydrological model (STARR) in five contrasting long-term research catchments with varying degrees of snow influence. The models were calibrated using a consistent multivariate methodology based on discharge, isotope composition and snowpack water equivalent. Analysis of extracted modelled storage dynamics gave insights into the system functioning. Large volumes of total stored water needed to be invoked at most sites to reconcile celerity and travel times to match observe discharge and isotope responses. This is because changes in dynamic storage from water balance considerations are small when compared to volume of storage necessary for observed tracer dampening. In the phase-space diagrams, the rates of storage change gave insights into the relative storage volume and seasonal catchment functioning. The storage increase was dominated by hydroclimatic inputs; thus, it presented a stochastic response. Furthermore, depending on the dominance of snow or rainfall inputs, catchments had different seasonal responses in storage dynamics. Decreases in storage were more predictable and reflected the efficiency of catchment drainage, yet at lower storages the influence of ET was also evident. Activation of flow paths due to overland and near-surface flows resulted in non-linearity of catchment functioning largely at high storage states. The storage-discharge relationships generally showed a non-linear distribution, with more scattered states during wettest condition. In turn, all the catchments exhibited an inverse storage effect, with modelled water ages decreasing with increasing storage as lateral flow paths were activated. Insights from this inter-comparison of storage-flux-age dynamics show the benefits of tracer-aided hydrological models in exploring their interactions at well-instrumented sites to better understand hydrological functioning of contrasting catchments.", "authors": [ "Piovano, T.", "Tetzlaff, D.", "Maneta, M.", "Buttle, J. M.", "Carey, S. K.", "Laudon, H.", "McNamara, J.", "Soulsby, C." ], "keywords": [ "Storage", "Water ages", "Storage-discharge", "Hydroclimatic forces", "Phase-space", "Non-linearity" ], "year": "2020", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -5.944707870483398, 13.064580917358398 ], "cluster": 12.0 }, { "idx": 731, "title": "The Role of Basin Geometry in Mountain Snowpack Responses to Climate Change", "abstract": "Snowmelt contributions to streamflow in mid-latitude mountain basins typically dominate other runoff sources on annual and seasonal timescales. Future increases in temperature and changes in precipitation will affect both snow accumulation and seasonal runoff timing and magnitude, but the underlying and fundamental roles of mountain basin geometry and hypsometry on snowmelt sensitivity have received little attention. To investigate the role of basin geometry in snowmelt sensitivity, a linear snow accumulation model and the Cold Regions Hydrological Modeling (CRHM) platform driven are used to estimate how hypsometry affects basin-wide snow volumes and snowmelt runoff. Area-elevation distributions for fifty basins in western Canada were extracted, normalized according to their elevation statistics, and classified into three clusters that represent top-heavy, middle, and bottom-heavy basins. Prescribed changes in air temperature alter both the snow accumulation gradient and the total snowmelt energy, leading to snowpack volume reductions (10-40%), earlier melt onsets (1-4 weeks) and end of melt season (3 weeks), increases in early spring melt rates and reductions in seasonal areal melt rates (up to 50%). Basin hypsometry controls the magnitude of the basin response. The most sensitive basins are bottom-heavy, and have a greater proportion of their area at low elevations. The least sensitive basins are top-heavy, and have a greater proportion of their area at high elevations. Basins with similar proportional areas at high and low elevations fall in between the others in terms of sensitivity and other metrics. This work provides context for anticipating the impacts of ongoing hydrological change due to climate change, and provides guidance for both monitoring networks and distributed modeling efforts.", "authors": [ "Shea, Joseph M.", "Whitfield, Paul H.", "Fang, Xing", "Pomeroy, John W." ], "keywords": [ "mountain", "snowpack", "hydrology", "elevation", "climate change" ], "year": "2021", "source": "FRONTIERS IN WATER", "publication_type": "J", "point2d": [ -37.792755126953125, -11.932645797729492 ], "cluster": 12.0 }, { "idx": 732, "title": "Stable isotopes of water reveal differences in plant - soil water relationships across northern environments", "abstract": "We compared stable isotopes of water in plant stem (xylem) water and soil collected over a complete growing season from five well-known long-term study sites in northern/cold regions. These spanned a decreasing temperature gradient from Bruntland Burn (Scotland), Dorset (Canadian Shield), Dry Creek (USA), Krycklan (Sweden), to Wolf Creek (northern Canada). Xylem water was isotopically depleted compared to soil waters, most notably for deuterium. The degree to which potential soil water sources could explain the isotopic composition of xylem water was assessed quantitatively using overlapping polygons to enclose respective data sets when plotted in dual isotope space. At most sites isotopes in xylem water from angiosperms showed a strong overlap with soil water; this was not the case for gymnosperms. In most cases, xylem water composition on a given sampling day could be better explained if soil water composition was considered over longer antecedent periods spanning many months. Xylem water at most sites was usually most dissimilar to soil water in drier summer months, although sites differed in the sequence of change. Open questions remain on why a significant proportion of isotopically depleted water in plant xylem cannot be explained by soil water sources, particularly for gymnosperms. It is recommended that future research focuses on the potential for fractionation to affect water uptake at the soil-root interface, both through effects of exchange between the vapour and liquid phases of soil water and the effects of mycorrhizal interactions. Additionally, in cold regions, evaporation and diffusion of xylem water in winter may be an important process.", "authors": [ "Tetzlaff, Doerthe", "Buttle, James", "Carey, Sean K.", "Kohn, Matthew J.", "Laudon, Hjalmar", "McNamara, James P.", "Smith, Aaron", "Sprenger, Matthias", "Soulsby, Chris" ], "keywords": [ "cold regions", "critical zone", "northern environments", "stable isotopes", "soil isotopes", "xylem isotopes" ], "year": "2021", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -11.25796127319336, 25.230815887451172 ], "cluster": 3.0 }, { "idx": 733, "title": "Hydrological functioning of a beaver dam sequence and regional dam persistence during an extreme rainstorm", "abstract": "It is becoming increasingly popular to reintroduce beaver to streams with the hopes of restoring riparian ecosystem function or reducing some of the hydrological impacts of climate change. One of the risks of relying on beaver to enhance ecosystem water storage is that their dams are reportedly more apt to fail during floods which can exacerbate flood severity. Missing are observations of beaver dam persistence and water storage capacity during floods, information needed to evaluate the risk of relying on beaver as a nature-based flood solution. A June rainstorm in 2013 triggered the largest recorded flood in the Canadian Rocky Mountains west of Calgary, Alberta. We opportunistically recorded hydrometric data during the rainfall event at a beaver-occupied peatland that has been studied for more than a decade. We supplemented these observations with a post-event regional analysis of beaver dam persistence. Results do not support two long-held hypotheses-that beaver ponds have limited flood attenuation capacity and commonly fail during large flood events. Instead we found that 68% of the beaver dam cascade systems across the region were intact or partially intact after the event. Pond fullness, in addition to the magnitude of the water-sediment surge, emerged as important factors in determining the structural fate of dam cascade sequences. Beaver ponds at the instrumented site quickly filled in the first few hours of the rain event and levels were dynamic during the event. Water storage offered by the beaver ponds, even ones that failed, delayed downstream floodwater transmission. Study findings have important implications for reintroducing beaver as part of nature-based restoration and climate change adaptation strategies.", "authors": [ "Westbrook, Cherie J.", "Ronnquist, Amanda", "Bedard-Haughn, Angela" ], "keywords": [ "2013 Alberta flood", "beaver dams", "Canadian Rockies", "Castor canadensis", "nature-based flood solutions", "surface hydrology" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 10.537687301635742, -0.4395493268966675 ], "cluster": 13.0 }, { "idx": 734, "title": "Using zooplankton metabarcoding to assess the efficacy of different techniques to clean-up an oil-spill in a boreal lake", "abstract": "Regulators require adequate information to select best practices with less ecosystem impacts for remediation of freshwater ecosystems after oil spills. Zooplankton are valuable indicators of aquatic ecosystem health as they play pivotal roles in biochemical cycles while stabilizing food webs. Compared with morphological identification, metabarcoding holds promise for cost-effective, high-throughput, and benchmarkable biomonitoring of zooplankton communities. The objective of this study was to apply DNA and RNA metabarcoding of zooplankton for ecotoxicological assessment and compare it with traditional morphological identification in experimental shoreline enclosures in a boreal lake. These identification methods were also applied in context of assessing response of the zooplankton community exposed to simulated spills of diluted bitumen (dilbit), with experimental remediation practices (enhanced monitored natural recovery and shoreline cleaner application). Metabarcoding detected boreal zooplankton taxa up to the genus level, with a total of 24 shared genera, and while metabarcoding-based relative abundance served as an acceptable proxy for biomass inferred by morphological identification (rho >= 0.52). Morphological identification determined zooplankton community composition changes due to treatments at 11 days post-spill (PERMANOVA, p = 0.0143) while metabarcoding methods indicated changes in zooplankton richness and communities at 38 days post-spill (T-test, p < 0.05; PERMANOVA, p <= 0.0429). Shoreline cleaner application overall seemed to have the largest impact on zooplankton communities relative to enhanced monitored natural recovery, regardless of zooplankton identification method. Both metabarcoding and morphological identification were able to discern the differences between the two experimental remediation practices. Metabarcoding of zooplankton could provide informative results for ecotoxicological assessment of the remediation practices of dilbit, advancing our knowledge of best practices for remediating oilimpacted aquatic ecosystems while serving to accelerate the assessment of at-risk freshwater ecosystems.", "authors": [ "Ankley, Phillip J.", "Xie, Yuwei", "Black, Tyler A.", "DeBofsky, Abigail", "Perry, McKenzie", "Paterson, Michael J.", "Hanson, Mark", "Higgins, Scott", "Giesy, John P.", "Palace, Vince" ], "keywords": [ "Next-generation sequencing", "Mitochondrial COI", "Ecogenomics", "Freshwater", "Canada", "Ecotoxicology" ], "year": "2021", "source": "AQUATIC TOXICOLOGY", "publication_type": "J", "point2d": [ 76.43639373779297, 9.06386947631836 ], "cluster": 0.0 }, { "idx": 735, "title": "Comparison of approaches to quantify SARS-CoV-2 in wastewater using RT-qPCR: Results and implications from a collaborative inter-laboratory study in Canada", "abstract": "Detection of SARS-CoV-2 RNA in wastewater is a promising tool for informing public health decisions during the COVID-19 pandemic. However, approaches for its analysis by use of reverse transcription quantitative polymerase chain reaction (RT-qPCR) are still far from standardized globally. To characterize inter- and intra-laboratory variability among results when using various methods deployed across Canada, aliquots from a real wastewater sample were spiked with surrogates of SARS-CoV-2 (gamma-radiation inactivated SARS-CoV-2 and human coronavirus strain 229E [HCoV-229E]) at low and high levels then provided blind to eight laboratories. Concentration estimates reported by individual laboratories were consistently within a 1.0-log(10) range for aliquots of the same spiked condition. All laboratories distinguished between low- and high-spikes for both surrogates. As expected, greater variability was observed in the results amongst laboratories than within individual laboratories, but SARS-CoV-2 RNA concentration estimates for each spiked condition remained mostly within 1.0-log(10) ranges. The no-spike wastewater aliquots provided yielded non-detects or trace levels (<20 gene copies/mL) of SARS-CoV-2 RNA. Detections appear linked to methods that included or focused on the solids fraction of the wastewater matrix and might represent in-situ SARS-CoV-2 to the wastewater sample. HCoV-229E RNA was not detected in the no-spike aliquots. Overall, all methods yielded comparable results at the conditions tested. Partitioning behavior of SARS-CoV-2 and spiked surrogates in wastewater should be considered to evaluate method effectiveness. A consistent method and laboratory to explore wastewater SARS-CoV-2 temporal trends for a given system, with appropriate quality control protocols and documented in adequate detail should succeed. (c) 2021 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.", "authors": [ "Chik, Alex H. S.", "Glier, Melissa B.", "Servos, Mark", "Mangat, Chand S.", "Pang, Xiao-Li", "Qiu, Yuanyuan", "D'Aoust, Patrick M.", "Burnet, Jean-Baptiste", "Delatolla, Robert", "Dorner, Sarah", "Geng, Qiudi", "Giesy, John P., Jr.", "McKay, Robert Mike", "Mulvey, Michael R.", "Prystajecky, Natalie", "Srikanthan, Nivetha", "Xie, Yuwei", "Conant, Bernadette", "Hrudey, Steve E." ], "keywords": [ "COVID-19", "Wastewater surveillance", "Public health", "Quality assurance", "Quality control" ], "year": "2021", "source": "JOURNAL OF ENVIRONMENTAL SCIENCES", "publication_type": "J", "point2d": [ 74.5398178100586, 25.605606079101562 ], "cluster": 19.0 }, { "idx": 737, "title": "Quantitative analysis of SARS-CoV-2 RNA from wastewater solids in communities with low COVID-19 incidence and prevalence", "abstract": "In the absence of an effective vaccine to prevent COVID-19 it is important to be able to track community infections to inform public health interventions aimed at reducing the spread and therefore reduce pressures on health-care, improve health outcomes and reduce economic uncertainty. Wastewater surveillance has rapidly emerged as a potential tool to effectively monitor community infections through measuring trends of RNA signal in wastewater systems. In this study SARS-CoV-2 viral RNA N1 and N2 gene regions are quantified in solids collected from influent post grit solids (PGS) and primary clarified sludge (PCS) in two water resource recovery facilities (WRRF) serving Canada's national capital region, i.e., the City of Ottawa, ON (pop. approximate to 1.1M) and the City of Gatineau, QC (pop. approximate to 280K). PCS samples show signal inhibition using RT-ddPCR compared to RT-qPCR, with PGS samples showing similar quantifiable concentrations of RNA using both assays. RT-qPCR shows higher frequency of detection of N1 and N2 gene regions in PCS (92.7, 90.6%, n = 6) as compared to PGS samples (79.2, 82.3%, n = 5). Sampling of PCS may therefore be an effective approach for SARS-CoV-2 viral quantification, especially during periods of declining and low COVID-19 incidence in the community. The pepper mild mottle virus (PMMoV) is determined to have a less variable RNA signal in PCS over a three month period for two WRRFs, regardless of environmental conditions, compared to Bacteroides 16S rRNA or human 18S rRNA, making PMMoV a potentially useful biomarker for normalization of SARS-CoV-2 signal. PMMoV-normalized PCS RNA signal from WRRFs of two cities correlated with the regional public health epidemiological metrics, identifying PCS normalized to a fecal indicator (PMMoV) as a potentially effective tool for monitoring trends during decreasing and low-incidence of infection of SARS-Cov-2 in communities. (C) 2020 Elsevier Ltd. All rights reserved.", "authors": [ "D'Aoust, Patrick M.", "Mercier, Elisabeth", "Montpetit, Danika", "Jia, Jian-Jun", "Alexandrov, Ilya", "Neault, Nafisa", "Baig, Aiman Tariq", "Mayne, Janice", "Zhang, Xu", "Alain, Tommy", "Langlois, Marc-Andre", "Servos, Mark R.", "MacKenzie, Malcolm", "Figeys, Daniel", "MacKenzie, Alex E.", "Graber, Tyson E.", "Delatolla, Robert" ], "keywords": [ "COVID-19", "SARS-CoV-2", "Wastewater", "Primary clarified sludge", "Solids", "Virus" ], "year": "2021", "source": "WATER RESEARCH", "publication_type": "J", "point2d": [ 74.0315933227539, 24.801103591918945 ], "cluster": 19.0 }, { "idx": 738, "title": "Differential responses of gut microbiota of male and female fathead minnow (Pimephales promelas) to a short-term environmentally-relevant, aqueous exposure to benzo[a]pyrene", "abstract": "In addition to aiding in digestion of food and uptake of nutrients, microbiota in guts of vertebrates are responsible for regulating several beneficial functions, including development of an organism and maintaining homeostasis. However, little is known about effects of exposures to chemicals on structure and function of gut microbiota of fishes. To assess effects of exposure to polycyclic aromatic hydrocarbons (PAHs) on gut microbiota, male and female fathead minnows (Pimephales promelas) were exposed to environmentally-relevant concentrations of the legacy PAH benzo[a]pyrene (BaP) in water. Measured concentrations of BaP ranged from 2.3 x 10(-3) to 1.3 mu g L-1. The community of microbiota in the gut were assessed by use of 16S rRNA metagenetics. Exposure to environmentally-relevant aqueous concentrations of BaP did not alter expression levels of mRNA for cyp1a1, a classic biomarker of exposure to BaP, but resulted in shifts in relative compositions of gut microbiota in females rather than males. Results presented here illustrate that in addition to effects on more well-studied molecular endpoints, relative compositions of the microbiota in guts of fish can also quickly respond to exposure to chemicals, which can provide additional mechanisms for adverse effects on individuals. (C) 2020 Elsevier Ltd. All rights reserved.", "authors": [ "DeBofsky, Abigail", "Xie, Yuwei", "Grimard, Chelsea", "Alcaraz, Alper James", "Brinkmann, Markus", "Hecker, Markus", "Giesy, John P." ], "keywords": [ "Homeostasis", "Next generation sequencing", "Freshwater fish", "Persistence organics pollution", "Molecular ecology" ], "year": "2020", "source": "CHEMOSPHERE", "publication_type": "J", "point2d": [ 79.11720275878906, 1.5767326354980469 ], "cluster": 0.0 }, { "idx": 741, "title": "High Throughput Sequencing of MicroRNA in Rainbow Trout Plasma, Mucus, and Surrounding Water Following Acute Stress", "abstract": "Circulating plasma microRNAs (miRNAs) are well established as biomarkers of several diseases in humans and have recently been used as indicators of environmental exposures in fish. However, the role of plasma miRNAs in regulating acute stress responses in fish is largely unknown. Tissue and plasma miRNAs have recently been associated with excreted miRNAs; however, external miRNAs have never been measured in fish. The objective of this study was to identify the altered plasma miRNAs in response to acute stress in rainbow trout (Oncorhynchus mykiss), as well as altered miRNAs in fish epidermal mucus and the surrounding ambient water. Small RNA was extracted and sequenced from plasma, mucus, and water collected from rainbow trout pre- and 1 h-post a 3-min air stressor. Following small RNA-Seq and pathway analysis, we identified differentially expressed plasma miRNAs that targeted biosynthetic, degradation, and metabolic pathways. We successfully isolated miRNA from trout mucus and the surrounding water and detected differences in miRNA expression 1-h post air stress. The expressed miRNA profiles in mucus and water were different from the altered plasma miRNA profile, which indicated that the plasma miRNA response was not associated with or immediately reflected in external samples, which was further validated through qPCR. This research expands understanding of the role of plasma miRNA in the acute stress response of fish and is the first report of successful isolation and profiling of miRNA from fish mucus or samples of ambient water. Measurements of miRNA from plasma, mucus, or water can be further studied and have potential to be applied as non-lethal indicators of acute stress in fish.", "authors": [ "Ikert, Heather", "Lynch, Michael D. J.", "Doxey, Andrew C.", "Giesy, John P.", "Servos, Mark R.", "Katzenback, Barbara A.", "Craig, Paul M." ], "keywords": [ "microRNA", "high throughput sequencing", "acute stress", "non-lethal", "blood plasma", "mucus", "water", "Oncorhynchus mykiss" ], "year": "2021", "source": "FRONTIERS IN PHYSIOLOGY", "publication_type": "J", "point2d": [ 76.3772201538086, -1.630474328994751 ], "cluster": 0.0 }, { "idx": 742, "title": "Integrated assessment of west coast of South Korea by use of benthic bacterial community structure as determined by eDNA, concentrations of contaminants, and in vitro bioassays", "abstract": "During the past few decades, contamination of sediments by persistent toxic substances (PTSs) has been observed in estuarine and coastal areas on the west coast of South Korea. The contaminants are suspected to cause toxicities in aquatic biota, but little is known about their ecological effects, particularly on benthic microbial communities. In this study, an eDNA-based assessment was applied along with classic assessments of exposure, such as chemistry and in vitro bioassays, to evaluate condition of benthic bacterial communities subjected to PTSs. Two strategies were adopted for the study. One was to conduct a comprehensive assessment in space (by comparing seawater and freshwater sites at five coastal regions) and in time (by following change over a 5-y period). Although we found that bacterial composition varied among and within years, some phyla, such as Proteobacteria (28.7%), Actinobacteria (13.1%), Firmicutes (12.7%), and Chloroflexi (12.5%) were consistently dominated across the study regions. Certain bacterial groups, such as Firmicutes and Verrucomicrobia have been linked to contamination at some sites in the study area and at specific points in time. Bacterial communities were not significantly correlated with salinity or AhR- and ER-mediated potencies, whereas concentrations of PAHs, APs, and certain metals (Cd and Hg) exhibited significant associations to the structure of bacterial communities at the phylum level. In fact, the relative abundance of microbes in the phylum Planctomycetes was significantly and negatively correlated with concentrations of PAHs and metals. Thus, the relative abundance of Planctomycetes could be used as an indicator of sedimentary contamination by PAHs and/or metals. Based on our correlation analyses, Cd and ER-mediated potencies were associated more with bacterial abundances at the class taxonomic level than were other PTSs and metals. Overall, the eDNA-based assessment was useful by augmenting more traditional measures of exposure and responses in a sediment triad approach and has potential as a more rapid screening tool.", "authors": [ "Lee, Aslan Hwanhwi", "Lee, Junghyun", "Hong, Seongjin", "Kwon, Bong-Oh", "Xie, Yuwei", "Giesy, John P.", "Zhang, Xiaowei", "Khim, Jong Seong" ], "keywords": [ "eDNA", "In situ microbial community", "Next generation sequencing", "Persistent toxic substances", "In vitro bioassay", "Sediment pollution" ], "year": "2020", "source": "ENVIRONMENT INTERNATIONAL", "publication_type": "J", "point2d": [ 76.73733520507812, 13.433005332946777 ], "cluster": 0.0 }, { "idx": 743, "title": "Remodeling of Arctic char (Salvelinus alpinus) lipidome under a stimulated scenario of Arctic warming", "abstract": "Arctic warming associated with global climate change poses a significant threat to populations of wildlife in the Arctic. Since lipids play a vital role in adaptation of organisms to variations in temperature, high-resolution mass-spectrometry-based lipidomics can provide insights into adaptive responses of organisms to a warmer environment in the Arctic and help to illustrate potential novel roles of lipids in the process of thermal adaption. In this study, we studied an ecologically and economically important species-Arctic char (Salvelinus alpinus)-with a detailed multi-tissue analysis of the lipidome in response to chronic shifts in temperature using a validated lipidomics workflow. In addition, dynamic alterations in the hepatic lipidome during the time course of shifts in temperature were also characterized. Our results showed that early life stages of Arctic char were more susceptible to variations in temperature. One-year-old Arctic char responded to chronic increases in temperature with coordinated regulation of lipids, including headgroup-specific remodeling of acyl chains in glycerophospholipids (GP) and extensive alterations in composition of lipids in membranes, such as less lyso-GPs, and more ether-GPs and sphingomyelin. Glycerolipids (e.g., triacylglycerol, TG) also participated in adaptive responses of the lipidome of Arctic char. Eight-week-old Arctic char exhibited rapid adaptive alterations of the hepatic lipidome to stepwise decreases in temperature while showing blunted responses to gradual increases in temperature, implying an inability to adapt rapidly to warmer environments. Three common phosphatidylethanolamines (PEs) (PE 36:6|PE 16:1_20:5, PE 38:7|PE 16:1_22:6, and PE 40:7|PE 18:1_22:6) were finally identified as candidate lipid biomarkers for temperature shifts via machine learning approach. Overall, this work provides additional information to a better understanding of underlying regulatory mechanisms of the lipidome of Arctic organisms in the face of near-future warming.", "authors": [ "Wang, Chao", "Gong, Yufeng", "Deng, Fuchang", "Ding, Enmin", "Tang, Jie", "Codling, Garry", "Challis, Jonathan K.", "Green, Derek", "Wang, Jing", "Chen, Qiliang", "Xie, Yuwei", "Su, Shu", "Yang, Zilin", "Raine, Jason", "Jones, Paul D.", "Tang, Song", "Giesy, John P." ], "keywords": [ "Arctic warming", "chronic temperature shifts", "dynamic alterations", "glycerolipids", "glycerophospholipids", "lipidomics", "machine learning" ], "year": "2021", "source": "GLOBAL CHANGE BIOLOGY", "publication_type": "J", "point2d": [ 78.31397247314453, -9.904626846313477 ], "cluster": 0.0 }, { "idx": 744, "title": "Multitemporal terrestrial laser scanning point clouds for thaw subsidence observation at Arctic permafrost monitoring sites", "abstract": "This paper investigates different methods for quantifying thaw subsidence using terrestrial laser scanning (TLS) point clouds. Thaw subsidence is a slow (millimetre to centimetre per year) vertical displacement of the ground surface common in ice-rich permafrost-underlain landscapes. It is difficult to quantify thaw subsidence in tundra areas as they often lack stable reference frames. Also, there is no solid ground surface to serve as a basis for elevation measurements, due to a continuous moss-lichen cover. We investigate how an expert-driven method improves the accuracy of benchmark measurements at discrete locations within two sites using multitemporal TLS data of a 1-year period. Our method aggregates multiple experts' determination of the ground surface in 3D point clouds, collected in a web-based tool. We then compare this to the performance of a fully automated ground surface determination method. Lastly, we quantify ground surface displacement by directly computing multitemporal point cloud distances, thereby extending thaw subsidence observation to an area-based assessment. Using the expert-driven quantification as reference, we validate the other methods, including in-situ benchmark measurements from a conventional field survey. This study demonstrates that quantifying the ground surface using 3D point clouds is more accurate than the field survey method. The expert-driven method achieves an accuracy of 0.1 +/- 0.1 cm. Compared to this, in-situ benchmark measurements by single surveyors yield an accuracy of 0.4 +/- 1.5 cm. This difference between the two methods is important, considering an observed displacement of 1.4 cm at the sites. Thaw subsidence quantification with the fully automatic benchmark-based method achieves an accuracy of 0.2 +/- 0.5 cm and direct point cloud distance computation an accuracy of 0.2 +/- 0.9 cm. The range in accuracy is largely influenced by properties of vegetation structure at locations within the sites. The developed methods enable a link of automated quantification and expert judgement for transparent long-term monitoring of permafrost subsidence. (c) 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd", "authors": [ "Anders, Katharina", "Marx, Sabrina", "Boike, Julia", "Herfort, Benjamin", "Wilcox, Evan James", "Langer, Moritz", "Marsh, Philip", "Hoefle, Bernhard" ], "keywords": [ "change analysis", "3D geoinformation", "ground surface displacement", "permafrost monitoring", "multitemporal LiDAR" ], "year": "2020", "source": "EARTH SURFACE PROCESSES AND LANDFORMS", "publication_type": "J", "point2d": [ -56.895938873291016, 3.02881121635437 ], "cluster": 8.0 }, { "idx": 745, "title": "No beating around the bush: the impact of projected high-latitude vegetation transitions on soil and ecosystem respiration", "abstract": "", "authors": [ "Baltzer, Jennifer L.", "Sonnentag, Oliver" ], "keywords": [ "carbon allocation", "climate change", "land-cover change", "latitudinal gradient", "soil respiration", "tree girdling" ], "year": "2020", "source": "NEW PHYTOLOGIST", "publication_type": "J", "point2d": [ -34.53532409667969, 52.237586975097656 ], "cluster": 17.0 }, { "idx": 747, "title": "Linking testate amoeba assemblages to paleohydrology and ecosystem function in Holocene peat records from the Hudson Bay Lowlands, Ontario, Canada", "abstract": "Peat cores from boreal bog and fen sites in the Hudson Bay Lowlands of Northern Ontario, Canada, were analysed to calculate Holocene carbon accumulation rates, and to show how testate amoeba taxonomic assemblages, inferred depths to water table, and four morpho-traits that may be linked to function (mixotrophy, aperture size, aperture position, and biovolume) changed since peatland initiation. Carbon accumulation rates were on average higher for the Holocene in the fen record (19.4 g C m(-2) yr(-1)) in comparison with the bog record (15.7 g C m(-2) yr(-1)), which underwent a fen-to-bog transition around 6900 cal yr BP. Changes in rates of carbon accumulation were most strongly driven by changes in rates of peat vertical accretion, with more rapid rates in the fen record. Carbon accumulation rates were highest following peatland initiation when reconstructed water tables were highest, and in the late Holocene, when water table positions were variable. Taxa with larger biovolumes and apertures were generally more abundant when reconstructed water tables were higher, most notably following peatland initiation. Mixotrophic taxa were more prevalent in drier conditions and in the bog record. Changing frequencies of morpho-traits suggest that testate amoebae may occupy a higher trophic position in the microbial food web during wetter periods, signaling the possibility of internal feedbacks between peatland ecohydrology and critical ecosystem functions including long-term carbon accumulation.", "authors": [ "Bysouth, David", "Finkelstein, Sarah A." ], "keywords": [ "boreal", "functional traits", "paleoecology", "peatlands", "soil carbon sequestration", "testate amoebae" ], "year": "2021", "source": "HOLOCENE", "publication_type": "J", "point2d": [ -10.631856918334961, 61.805519104003906 ], "cluster": 9.0 }, { "idx": 748, "title": "Substantial hysteresis in emergent temperature sensitivity of global wetland CH4 emissions", "abstract": "Wetland methane (CH4) emissions (FCH4) are important in global carbon budgets and climate change assessments. Currently, FCH4 projections rely on prescribed static temperature sensitivity that varies among biogeochemical models. Meta-analyses have proposed a consistent FCH4 temperature dependence across spatial scales for use in models; however, site-level studies demonstrate that FCH4 are often controlled by factors beyond temperature. Here, we evaluate the relationship between FCH4 and temperature using observations from the FLUXNET-CH4 database. Measurements collected across the globe show substantial seasonal hysteresis between FCH4 and temperature, suggesting larger FCH4 sensitivity to temperature later in the frost-free season (about 77% of site-years). Results derived from a machine-learning model and several regression models highlight the importance of representing the large spatial and temporal variability within site-years and ecosystem types. Mechanistic advancements in biogeochemical model parameterization and detailed measurements in factors modulating CH4 production are thus needed to improve global CH4 budget assessments. Wetland methane emissions contribute to global warming, and are oversimplified in climate models. Here the authors use eddy covariance measurements from 48 global sites to demonstrate seasonal hysteresis in methane-temperature relationships and suggest the importance of microbial processes.", "authors": [ "Chang, Kuang-Yu", "Riley, William J.", "Knox, Sara H.", "Jackson, Robert B.", "McNicol, Gavin", "Poulter, Benjamin", "Aurela, Mika", "Baldocchi, Dennis", "Bansal, Sheel", "Bohrer, Gil", "Campbell, David, I", "Cescatti, Alessandro", "Chu, Housen", "Delwiche, Kyle B.", "Desai, Ankur R.", "Euskirchen, Eugenie", "Friborg, Thomas", "Goeckede, Mathias", "Helbig, Manuel", "Hemes, Kyle S.", "Hirano, Takashi", "Iwata, Hiroki", "Kang, Minseok", "Keenan, Trevor", "Krauss, Ken W.", "Lohila, Annalea", "Mammarella, Ivan", "Mitra, Bhaskar", "Miyata, Akira", "Nilsson, Mats B.", "Noormets, Asko", "Oechel, Walter C.", "Papale, Dario", "Peichl, Matthias", "Reba, Michele L.", "Rinne, Janne", "Runkle, Benjamin R. K.", "Ryu, Youngryel", "Sachs, Torsten", "Schaefer, Karina V. R.", "Schmid, Hans Peter", "Shurpali, Narasinha", "Sonnentag, Oliver", "Tang, Angela C., I", "Torn, Margaret S.", "Trotta, Carlo", "Tuittila, Eeva-Stiina", "Ueyama, Masahito", "Vargas, Rodrigo", "Vesala, Timo", "Windham-Myers, Lisamarie", "Zhang, Zhen", "Zona, Donatella" ], "keywords": [ "" ], "year": "2021", "source": "NATURE COMMUNICATIONS", "publication_type": "J", "point2d": [ -32.70213317871094, 64.25704193115234 ], "cluster": 17.0 }, { "idx": 749, "title": "Identifying Functional Impacts of Heat-Resistant Fungi on Boreal Forest Recovery After Wildfire", "abstract": "Fungi play key roles in carbon (C) dynamics of ecosystems: saprotrophs decompose organic material and return C in the nutrient cycle, and mycorrhizal species support plants that accumulate C through photosynthesis. The identities and functions of extremophile fungi present after fire can influence C dynamics, particularly because plant-fungal relationships are often species-specific. However, little is known about the function and distribution of fungi that survive fires. We aim to assess the distribution of heat-resistant soil fungi across burned stands of boreal forest in the Northwest Territories, Canada, and understand their functions in relation to decomposition and tree seedling growth. We cultured and identified fungi from heat-treated soils and linked sequences from known taxa with high throughput sequencing fungal data (Illumina MiSeq, ITS1) from soils collected in 47 plots. We assessed functions under controlled conditions by inoculating litter and seedlings with heat-resistant fungi to assess decomposition and effects on seedling growth, respectively, for black spruce (Picea mariana), birch (Betula papyrifera), and jack pine (Pinus banksiana). We also measured litter decomposition rates and seedling densities in the field without inoculation. We isolated seven taxa of heat-resistant fungi and found their relative abundances were not associated with environmental or fire characteristics. Under controlled conditions,Fayodia gracilipesandPenicillium arenicoladecomposed birch, but no taxa decomposed black spruce litter significantly more than the control treatment. Seedlings showed reduced biomass and/or mortality when inoculated with at least one of the fungal taxa.Penicillium turbatumreduced growth and/or caused mortality of all three species of seedlings. In the field, birch litter decomposed faster in stands with greater pre-fire proportion of black spruce, while black spruce litter decomposed faster in stands experiencing longer fire-free intervals. Densities of seedlings that had germinated since fire were positively associated with ectomycorrhizal richness while there were fewer conifer seedlings with greater heat-resistant fungal abundance. Overall, our study suggests that extremophile fungi present after fires have multiple functions and may have unexpected negative effects on forest functioning and regeneration. In particular, heat-resistant fungi after fires may promote shifts away from conifer dominance that are observed in these boreal forests.", "authors": [ "Day, Nicola J.", "Cumming, Steven G.", "Dunfield, Kari E.", "Johnstone, Jill F.", "Mack, Michelle C.", "Reid, Kirsten A.", "Turetsky, Merritt R.", "Walker, Xanthe J.", "Baltzer, Jennifer L." ], "keywords": [ "mycorrhiza", "saprotroph", "Taiga plains", "boreal", "Northwest Territories", "seedlings", "litter decomposition", "extremophile" ], "year": "2020", "source": "FRONTIERS IN FORESTS AND GLOBAL CHANGE", "publication_type": "J", "point2d": [ -21.21221160888672, 76.53343200683594 ], "cluster": 15.0 }, { "idx": 751, "title": "Unexpected greening in a boreal permafrost peatland undergoing forest loss is partially attributable to tree species turnover", "abstract": "Time series of vegetation indices derived from satellite imagery are useful in measuring vegetation response to climate warming in remote northern regions. These indices show that productivity is generally declining in the boreal forest, but it is unclear which components of boreal vegetation are driving these trends. We aimed to compare trends in the normalized difference vegetation index (NDVI) to forest growth and demographic data taken from a 10 ha mapped plot located in a spruce-dominated boreal peatland. We used microcores to quantify recent growth trends and tree census data to characterize mortality and recruitment rates of the three dominant tree species. We then compared spatial patterns in growth and demography to patterns in Landsat-derived maximum NDVI trends (1984-2019) in 78 pixels that fell within the plot. We found that NDVI trends were predominantly positive (i.e., greening) in spite of the ongoing loss of black spruce (the dominant species; 80% of stems) from the plot. The magnitude of these trends correlated positively with black spruce growth trends, but was also governed to a large extent by tree mortality and recruitment. Greening trends were weaker (lower slope) in areas with high larch mortality, and high turnover of spruce and birch, but stronger (higher slope) in areas with high larch recruitment. Larch dominance is currently low (similar to 11% of stems), but it is increasing in abundance as permafrost thaw progresses and will likely have a substantial influence on future NDVI trends. Our results emphasize that NDVI trends in boreal peatlands can be positive even when the forest as a whole is in decline, and that the magnitude of trends can be strongly influenced by the demographics of uncommon species.", "authors": [ "Dearborn, Katherine D.", "Baltzer, Jennifer L." ], "keywords": [ "boreal", "forest demography", "Landsat", "NDVI", "peatland", "permafrost", "tree growth" ], "year": "2021", "source": "GLOBAL CHANGE BIOLOGY", "publication_type": "J", "point2d": [ -24.831552505493164, 51.09269714355469 ], "cluster": 15.0 }, { "idx": 752, "title": "Permafrost thaw in boreal peatlands is rapidly altering forest community composition", "abstract": "Boreal peatlands are frequently underlain by permafrost, which is thawing rapidly. A common ecological response to thaw is the conversion of raised forested plateaus to treeless wetlands, but unexplained spatial variation in responses, combined with a lack of stand-level data, make it difficult to predict future trajectories of boreal forest composition and structure. We sought to characterize patterns and identify drivers of forest structure, composition, mortality and recruitment in a boreal peatland experiencing permafrost thaw. To do this, we established a large (10 ha) permanent forest plot (completed in 2014), located in the Northwest Territories, Canada, that includes 40,584 mapped and measured trees. In 2018, we conducted a comprehensive mortality and recruitment recensus. We also measured frost table depth, soil moisture, soil humification and organic layer thickness within the plot between 2012 and 2018, and used habitat association tests to link these variables to forest characteristics and dynamics. Forest composition and structure varied markedly throughout the plot and were strongly governed by patterns in permafrost presence and organic layer thickness. Overall, there was a net loss of trees from the plot at a rate of 0.7% year(-1). Mortality of black spruce, the dominant tree species, was more than double that of recruitment and was strongly associated with permafrost thaw. In contrast, recruitment of larch was over four times greater than mortality, and occurred primarily in low-lying, permafrost-free wetlands with mineral soil near the surface. Synthesis. The trends in tree demography and underlying drivers suggest that spruce-dominated permafrost plateaus will be converted into larch-dominated wetlands as permafrost thaw progresses in boreal peatlands, particularly in areas where mineral soil is near the surface. In the longer term, thaw could increase the hydrologic connectivity of the landscape, resulting in widespread drainage and re-vegetation by spruce, but we did not find evidence that this is occurring yet. Given the increasing rates of permafrost thaw, and positive feedbacks between thaw and forest change, we predict that larch abundance will continue to increase in boreal peatlands over the coming decades, leading to shifts in ecosystem function, wildlife habitat, albedo and snow dynamics.", "authors": [ "Dearborn, Katherine D.", "Wallace, Cory A.", "Patankar, Rajit", "Baltzer, Jennifer L." ], "keywords": [ "active layer", "black spruce", "boreal forest", "eastern larch", "ForestGEO", "organic layer thickness", "peatland", "permafrost" ], "year": "2021", "source": "JOURNAL OF ECOLOGY", "publication_type": "J", "point2d": [ -25.948389053344727, 50.693450927734375 ], "cluster": 9.0 }, { "idx": 753, "title": "Human biomonitoring results of contaminant and nutrient biomarkers in Old Crow, Yukon, Canada", "abstract": "Several large-scale human biomonitoring projects have been conducted in Canada, including the Canadian Health Measures Survey (CHMS) and the First Nations Biomonitoring Initiative (FNBI). However, neither of these studies included participants living in the Yukon. To address this data gap, a human biomonitoring project was implemented in Old Crow, a fly-in Gwich'in community in the northern Yukon. The results of this project provide baseline levels of contaminant and nutrient biomarkers from Old Crow in 2019. Samples of hair, blood, and/or urine were collected from approximately 44% of community residents (77 of 175 adults). These samples were analyzed for contaminants (including heavy metals and persistent organic pollutants (POPs)), and nutrients (including trace elements and omega-3 fatty acids). Levels of these analytes were compared to healthbased guidance values, when available, and results from other human biomonitoring projects in Canada. Levels of lead (GM 0.64 mu g/g creatinine in urine/24 mu g/L blood), cadmium (GM 0.32 mu g/g creatinine in urine/0.85 mu g/L blood), and mercury (GM < LOD in urine/0.76 mu g/L blood/0.31 mu g/g hair) were below select health-based guidance values formore than 95% of participants. However, compared to the general Canadian population, elevated levels of some contaminants, including lead (approximately 2x higher), cobalt (approximately 1.5x higher), manganese (approximately 1.3x higher), and hexachlorobenzene (approximately 1.5x higher) were observed. In contrast, levels of other POPs, including insecticides such as dichlorodiphenyltrichloroethane (DDT), its metabolite, dichlorodiphenyldichloroethylene (DDE), and polychlorinated biphenyls (PCBs) were similar to, or lower than, those reported in the general Canadian population. This study can be used along with future biomonitoring programs to evaluate the effectiveness of international initiatives designed to reduce the contaminant burden in the Arctic, including the Stockholm Convention and the Minamata Convention. Regionally, this project complements environmental monitoring being conducted in the region, informing local and regional traditional food consumption advisories. (C) 2020 Elsevier B.V. All rights reserved.", "authors": [ "Drysdale, Mallory", "Ratelle, Mylene", "Skinner, Kelly", "Garcia-Barrios, Joshua", "Gamberg, Mary", "Williams, Megan", "Majowicz, Shannon", "Bouchard, Michele", "Stark, Ken", "Chalil, Dan", "Laird, Brian D." ], "keywords": [ "Exposure", "Indigenous", "Arctic", "Biomarker", "Lead", "Organochlorine" ], "year": "2021", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 77.87149047851562, -16.358156204223633 ], "cluster": 7.0 }, { "idx": 754, "title": "The distribution and dynamics of aufeis in permafrost regions", "abstract": "Aufeis, also known as an icing or naled, is an accumulation of ice that forms primarily during winter when water is expelled onto frozen ground or ice surfaces and freezes in layers. Process-oriented aufeis research initially expanded in the 20(th) century, but recent interest in changing hydrological conditions in permafrost regions has rejuvenated this field. Despite its societal relevance, the controls on aufeis distribution and dynamics are not well defined and this impedes projections of variation in aufeis size and distribution expected to accompany climate change. This paper reviews the physical controls on aufeis development, current broad-scale aufeis distribution and anticipated change, and approaches to aufeis investigation. We propose an adjustment to terminology to better distinguish between the formation process and resulting ice bodies, a clarification of the aufeis classification approach based on source water, and a size threshold for broad-scale aufeis inventory to facilitate collaborative research. We identify additional objectives for future research including advancing process knowledge at fine spatial scales, describing broad-scale distribution using current remote sensing capabilities, and improving our understanding and predictive capacity over the interactions between aufeis and landscape-scale permafrost, hydrogeological, geotectonic, and climate conditions.", "authors": [ "Ensom, Timothy", "Makarieva, Olga", "Morse, Peter", "Kane, Douglas", "Alekseev, Vladimir", "Marsh, Philip" ], "keywords": [ "aufeis", "climate change", "groundwater", "icing", "naled", "taryn" ], "year": "2020", "source": "PERMAFROST AND PERIGLACIAL PROCESSES", "publication_type": "J", "point2d": [ -28.63190269470215, 39.244964599609375 ], "cluster": 2.0 }, { "idx": 755, "title": "Mapping and understanding the vulnerability of northern peatlands to permafrost thaw at scales relevant to community adaptation planning", "abstract": "Developing spatially explicit permafrost datasets and climate assessments at scales relevant to northern communities is increasingly important as land users and decision makers incorporate changing permafrost conditions in community and adaptation planning. This need is particularly strong within the discontinuous permafrost zone of the Northwest Territories (NWT) Canada where permafrost peatlands are undergoing rapid thaw due to a warming climate. Current data products for predicting landscapes at risk of thaw are generally built at circumpolar scales and do not lend themselves well to fine-scale regional interpretations. Here, we present a new permafrost vulnerability dataset that assesses the degree of permafrost thaw within peatlands across a 750 km latitudinal gradient in the NWT. This updated dataset provides spatially explicit estimates of where peatland thermokarst potential exists, thus making it much more suitable for local, regional or community usage. Within southern peatland complexes, we show that permafrost thaw affects up to 70% of the peatland area and that thaw is strongly mediated by both latitude and elevation, with widespread thaw occuring particularly at low elevations. At the northern end of our latitudinal gradient, peatland permafrost remains climate-protected with relatively little thaw. Collectively these results demonstrate the importance of scale in permafrost analyses and mapping if research is to support northern communities and decision makers in a changing climate. This study offers a more scale-appropriate approach to support community adaptative planning under scenarios of continued warming and widespread permafrost thaw.", "authors": [ "Gibson, C.", "Cottenie, K.", "Gingras-Hill, T.", "Kokelj, S., V", "Baltzer, J. L.", "Chasmer, L.", "Turetsky, M. R." ], "keywords": [ "thermokarst", "peramfrost thaw", "community adaptation", "spatial dataset" ], "year": "2021", "source": "ENVIRONMENTAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -25.597543716430664, 46.7475700378418 ], "cluster": 13.0 }, { "idx": 756, "title": "Identifying groundwater discharge zones in the Central Mackenzie Valley using remotely sensed optical and thermal imagery", "abstract": "Landsat 4-5 Thematic Mapper, Landsat 8 Operational Land Imager, and RapidEye-3 data sets were used to identify potential groundwater discharge zones, via icings, in the Central Mackenzie Valley (CMV) of the Northwest Territories. Given that this area is undergoing active shale oil exploration and climatic changes, identification of groundwater discharge zones is of great importance both for pinpointing potential contaminant transport pathways and for characterizing the hydrologic system. Following the work of Morse and Wolfe (2015), a series of image algorithms were applied to imagery for the entire CMV and for the Bogg Creek watershed (a sub watershed of the CMV) for selected years between 2004 and 2017. Icings were statistically examined for all of the selected years to determine whether a significant difference in their spatial occurrence existed. It was concluded that there was a significant difference in the spatial distribution of icings from year to year (alpha = 0.05), but that there were several places where icings were recurring. During the summer of 2018, these recurrent icings, which are expected to be spring sourced, were verified using a thermal camera aboard a helicopter, as well as in situ measurements of hydraulic gradient, groundwater geochemistry, and electroconductivity. Strong agreement was found between the mapped icings and summer field data, making them ideal field monitoring locations. Furthermore, identifying these discharge points remotely is expected to have drastically reduced the field efforts that would have been required to find them in situ. This work demonstrates the value of remote sensing methods for hydrogeological applications, particularly in remote northern locations.", "authors": [ "Glass, Brittney K.", "Rudolph, David L.", "Duguay, Claude", "Wicke, Andrew" ], "keywords": [ "icings", "aufeis", "permafrost", "climate change", "groundwater discharge" ], "year": "2021", "source": "CANADIAN JOURNAL OF EARTH SCIENCES", "publication_type": "J", "point2d": [ -24.480323791503906, 4.124087333679199 ], "cluster": 2.0 }, { "idx": 757, "title": "Predicting patterns of terrestrial lichen biomass recovery following boreal wildfires", "abstract": "Increased fire activity due to climate change may impact the successional dynamics of boreal forests, with important consequences for caribou habitat. Early successional forests have been shown to support lower quantities of caribou forage lichens, but geographic variation in, and controls on, the rates of lichen recovery has been largely unexplored. In this study, we sampled across a broad region in northwestern Canada to compare lichen biomass accumulation in ecoprovinces, including the Saskatchewan Boreal Shield, the Northwest Territories Taiga Shield, and Northwest Territories Taiga Plains, divided into North and South. We focused on the most valuable Cladonia species for boreal and barren-ground caribou: Cladonia mitis and C. arbuscula, C. rangiferina and C. stygia, and C. stellaris and C. uncialis. We developed new allometric equations to estimate lichen biomass from field measurements of lichen cover and height; allometries were consistent among ecoprovinces, suggesting generalizability. We then used estimates of lichen biomass to quantify patterns of lichen recovery in different stand types, ecoprovinces, and with time following stand-replacing fire. We used a hurdle model to account both for the heterogeneous nature of lichen presence (zero inflation) and for the range of abundance in stands where lichen was present. The first component of the hurdle model, a generalized linear model, identified stand age, stand type, and ecoprovince as significant predictors of lichen presence. With a logistic growth model, a measure of lichen recovery (time to 50% asymptotic value) varied from 28 to 73 yr, dependent on stand type and ecoprovince. The combined predictions of the hurdle model suggest the most rapid recovery of lichen biomass across our study region occurred in jack pine in the Boreal Shield (30 yr), while stands located in the Taiga Plains (North and South) required a longer recovery period (approximately 75 yr). These results provide a basis for estimating future caribou habitat that encompasses some of the large variation in fire effects on lichen abundance and vegetation types across the range of boreal and barren-ground caribou in North America.", "authors": [ "Greuel, Ruth J.", "Degre-Timmons, Genevieve E.", "Baltzer, Jennifer L.", "Johnstone, Jill F.", "McIntire, Eliot J. B.", "Day, Nicola J.", "Hart, Sarah J.", "McLoughlin, Philip D.", "Schmiegelow, Fiona K. A.", "Turetsky, Merritt R.", "Truchon-Savard, Alexandre", "van Telgen, Mario D.", "Cumming, Steven G." ], "keywords": [ "Caribou forage", "chronosequence", "Cladonia", "hurdle model", "natural disturbance", "nonlinear mixed‐", "effects models", "Rangifer", "wildfire", "zero‐", "inflated distribution" ], "year": "2021", "source": "ECOSPHERE", "publication_type": "J", "point2d": [ -9.070979118347168, 52.019691467285156 ], "cluster": 15.0 }, { "idx": 758, "title": "Linking tundra vegetation, snow, soil temperature, and permafrost", "abstract": "Connections between vegetation and soil thermal dynamics are critical for estimating the vulnerability of permafrost to thaw with continued climate warming and vegetation changes. The interplay of complex biophysical processes results in a highly heterogeneous soil temperature distribution on small spatial scales. Moreover, the link between topsoil temperature and active layer thickness remains poorly constrained. Sixty-eight temperature loggers were installed at 1-3 cm depth to record the distribution of topsoil temperatures at the Trail Valley Creek study site in the northwestern Canadian Arctic. The measurements were distributed across six different vegetation types characteristic for this landscape. Two years of topsoil temperature data were analysed statistically to identify temporal and spatial characteristics and their relationship to vegetation, snow cover, and active layer thickness. The mean annual topsoil temperature varied between -3.7 and 0.1 degrees C within 0.5 km(2). The observed variation can, to a large degree, be explained by variation in snow cover. Differences in snow depth are strongly related with vegetation type and show complex associations with late-summer thaw depth. While cold winter soil temperature is associated with deep active layers in the following summer for lichen and dwarf shrub tundra, we observed the opposite beneath tall shrubs and tussocks. In contrast to winter observations, summer topsoil temperature is similar below all vegetation types with an average summer topsoil temperature difference of less than 1 degrees C. Moreover, there is no significant relationship between summer soil temperature or cumulative positive degree days and active layer thickness. Altogether, our results demonstrate the high spatial variability of topsoil temperature and active layer thickness even within specific vegetation types. Given that vegetation type defines the direction of the relationship between topsoil temperature and active layer thickness in winter and summer, estimates of permafrost vulnerability based on remote sensing or model results will need to incorporate complex local feedback mechanisms of vegetation change and permafrost thaw.", "authors": [ "Gruenberg, Inge", "Wilcox, Evan J.", "Zwieback, Simon", "Marsh, Philip", "Boike, Julia" ], "keywords": [ "" ], "year": "2020", "source": "BIOGEOSCIENCES", "publication_type": "J", "point2d": [ -31.791975021362305, 43.60541534423828 ], "cluster": 13.0 }, { "idx": 759, "title": "Increasing contribution of peatlands to boreal evapotranspiration in a warming climate", "abstract": "Climate warming increases evapotranspiration (ET) more in boreal peatlands than in forests. Observations show that peatland ET can exceed forest ET by up to 30%, indicating a stronger warming response in peatlands. Earth system models do not fully account for peatlands and hence may underestimate future boreal ET. The response of evapotranspiration (ET) to warming is of critical importance to the water and carbon cycle of the boreal biome, a mosaic of land cover types dominated by forests and peatlands. The effect of warming-induced vapour pressure deficit (VPD) increases on boreal ET remains poorly understood because peatlands are not specifically represented as plant functional types in Earth system models. Here we show that peatland ET increases more than forest ET with increasing VPD using observations from 95 eddy covariance tower sites. At high VPD of more than 2 kPa, peatland ET exceeds forest ET by up to 30%. Future (2091-2100) mid-growing season peatland ET is estimated to exceed forest ET by over 20% in about one-third of the boreal biome for RCP4.5 and about two-thirds for RCP8.5. Peatland-specific ET responses to VPD should therefore be included in Earth system models to avoid biases in water and carbon cycle projections.", "authors": [ "Helbig, Manuel", "Waddington, James Michael", "Alekseychik, Pavel", "Amiro, Brian D.", "Aurela, Mika", "Barr, Alan G.", "Black, T. Andrew", "Blanken, Peter D.", "Carey, Sean K.", "Chen, Jiquan", "Chi, Jinshu", "Desai, Ankur R.", "Dunn, Allison", "Euskirchen, Eugenie S.", "Flanagan, Lawrence B.", "Forbrich, Inke", "Friborg, Thomas", "Grelle, Achim", "Harder, Silvie", "Heliasz, Michal", "Humphreys, Elyn R.", "Ikawa, Hiroki", "Isabelle, Pierre-Erik", "Iwata, Hiroki", "Jassal, Rachhpal", "Korkiakoski, Mika", "Kurbatova, Juliya", "Kutzbach, Lars", "Lindroth, Anders", "Lofvenius, Mikaell Ottosson", "Lohila, Annalea", "Mammarella, Ivan", "Marsh, Philip", "Maximov, Trofim", "Melton, Joe R.", "Moore, Paul A.", "Nadeau, Daniel F.", "Nicholls, Erin M.", "Nilsson, Mats B.", "Ohta, Takeshi", "Peichl, Matthias", "Petrone, Richard M.", "Petrov, Roman", "Prokushkin, Anatoly", "Quinton, William L.", "Reed, David E.", "Roulet, Nigel T.", "Runkle, Benjamin R. K.", "Sonnentag, Oliver", "Strachan, Ian B.", "Taillardat, Pierre", "Tuittila, Eeva-Stiina", "Tuovinen, Juha-Pekka", "Turner, Jessica", "Ueyama, Masahito", "Varlagin, Andrej", "Wilmking, Martin", "Wofsy, Steven C.", "Zyrianov, Vyacheslav" ], "keywords": [ "" ], "year": "2020", "source": "NATURE CLIMATE CHANGE", "publication_type": "J", "point2d": [ -20.218278884887695, 59.90595626831055 ], "cluster": 9.0 }, { "idx": 760, "title": "The biophysical climate mitigation potential of boreal peatlands during the growing season", "abstract": "Peatlands and forests cover large areas of the boreal biome and are critical for global climate regulation. They also regulate regional climate through heat and water vapour exchange with the atmosphere. Understanding how land-atmosphere interactions in peatlands differ from forests may therefore be crucial for modelling boreal climate system dynamics and for assessing climate benefits of peatland conservation and restoration. To assess the biophysical impacts of peatlands and forests on peak growing season air temperature and humidity, we analysed surface energy fluxes and albedo from 35 peatlands and 37 evergreen needleleaf forests-the dominant boreal forest type-and simulated air temperature and vapour pressure deficit (VPD) over hypothetical homogeneous peatland and forest landscapes. We ran an evapotranspiration model using land surface parameters derived from energy flux observations and coupled an analytical solution for the surface energy balance to an atmospheric boundary layer (ABL) model. We found that peatlands, compared to forests, are characterized by higher growing season albedo, lower aerodynamic conductance, and higher surface conductance for an equivalent VPD. This combination of peatland surface properties results in a similar to 20% decrease in afternoon ABL height, a cooling (from 1.7 to 2.5 degrees C) in afternoon air temperatures, and a decrease in afternoon VPD (from 0.4 to 0.7 kPa) for peatland landscapes compared to forest landscapes. These biophysical climate impacts of peatlands are most pronounced at lower latitudes (similar to 45 degrees N) and decrease toward the northern limit of the boreal biome (similar to 70 degrees N). Thus, boreal peatlands have the potential to mitigate the effect of regional climate warming during the growing season. The biophysical climate mitigation potential of peatlands needs to be accounted for when projecting the future climate of the boreal biome, when assessing the climate benefits of conserving pristine boreal peatlands, and when restoring peatlands that have experienced peatland drainage and mining.", "authors": [ "Helbig, Manuel", "Waddington, James M.", "Alekseychik, Pavel", "Amiro, Brian", "Aurela, Mika", "Barr, Alan G.", "Black, T. Andrew", "Carey, Sean K.", "Chen, Jiquan", "Chi, Jinshu", "Desai, Ankur R.", "Dunn, Allison", "Euskirchen, Eugenie S.", "Flanagan, Lawrence B.", "Friborg, Thomas", "Garneau, Michelle", "Grelle, Achim", "Harder, Silvie", "Heliasz, Michal", "Humphreys, Elyn R.", "Ikawa, Hiroki", "Isabelle, Pierre-Erik", "Iwata, Hiroki", "Jassal, Rachhpal", "Korkiakoski, Mika", "Kurbatova, Juliya", "Kutzbach, Lars", "Lapshina, Elena", "Lindroth, Anders", "Lofvenius, Mikaell Ottosson", "Lohila, Annalea", "Mammarella, Ivan", "Marsh, Philip", "Moore, Paul A.", "Maximov, Trofim", "Nadeau, Daniel F.", "Nicholls, Erin M.", "Nilsson, Mats B.", "Ohta, Takeshi", "Peichl, Matthias", "Petrone, Richard M.", "Prokushkin, Anatoly", "Quinton, William L.", "Roulet, Nigel", "Runkle, Benjamin R. K.", "Sonnentag, Oliver", "Strachan, Ian B.", "Taillardat, Pierre", "Tuittila, Eeva-Stiina", "Tuovinen, Juha-Pekka", "Turner, Jessica", "Ueyama, Masahito", "Varlagin, Andrej", "Vesala, Timo", "Wilmking, Martin", "Zyrianov, Vyacheslav", "Schulze, Christopher" ], "keywords": [ "peatlands", "boreal forest", "climate mitigation", "regional climate", "energy balance" ], "year": "2020", "source": "ENVIRONMENTAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -19.316669464111328, 59.90944290161133 ], "cluster": 9.0 }, { "idx": 761, "title": "Impact of wildfire on permafrost landscapes: A review of recent advances and future prospects", "abstract": "Changes in the frequency and extent of wildfires are expected to lead to substantial and irreversible alterations to permafrost landscapes under a warming climate. Here we review recent publications (2010-2019) that advance our understanding of the effects of wildfire on surface and ground temperatures, on active layer thickness and, where permafrost is ice-rich, on ground subsidence and the development of thermokarst features. These thermal and geomorphic changes are initiated immediately following wildfire and alter the hydrology and biogeochemistry of permafrost landscapes, including the release of previously frozen carbon. In many locations, permafrost has been resilient, with key characteristics such as active layer thickness returning to pre-fire conditions after several decades. However, permafrost near its southern limit is losing this resiliency as a result of ongoing climate warming and increasingly common vegetation state changes. Shifts in fire return intervals, severity and extent are expected to alter the trajectories of wildfire impacts on permafrost, and to enlarge spatial impacts to more regularly include the burning of tundra areas. Modeling indicates some lowland boreal forest and tundra environments will remain resilient while uplands and areas with thin organic layers and dry soils will experience rapid and irreversible permafrost degradation. More work is needed to relate modeling to empirical studies, particularly incorporating dynamic variables such as soil moisture, snow and thermokarst development, and to identify post-fire permafrost responses for different landscape types and regions. Future progress requires further collaboration among geocryologists, ecologists, hydrologists, biogeochemists, modelers and remote sensing specialists.", "authors": [ "Holloway, Jean E.", "Lewkowicz, Antoni G.", "Douglas, Thomas A.", "Li, Xiaoying", "Turetsky, Merritt R.", "Baltzer, Jennifer L.", "Jin, Huijun" ], "keywords": [ "active layer", "carbon cycling", "climate change", "permafrost", "thermokarst", "wildfire" ], "year": "2020", "source": "PERMAFROST AND PERIGLACIAL PROCESSES", "publication_type": "J", "point2d": [ -28.42376708984375, 47.932010650634766 ], "cluster": 15.0 }, { "idx": 762, "title": "L-band vegetation optical depth as an indicator of plant water potential in a temperate deciduous forest stand", "abstract": "Vegetation optical depth (VOD) retrieved from microwave radiometry correlates with the total amount of water in vegetation, based on theoretical and empirical evidence. Because the total amount of water in vegetation varies with relative water content (as well as with biomass), this correlation further suggests a possible relationship between VOD and plant water potential, a quantity that drives plant hydraulic behavior. Previous studies have found evidence for that relationship on the scale of satellite pixels tens of kilometers across, but these comparisons suffer from significant scaling error. Here we used small-scale remote sensing to test the link between remotely sensed VOD and plant water potential. We placed an L-band radiometer on a tower above the canopy looking down at red oak forest stand during the 2019 growing season in central Massachusetts, United States. We measured stem xylem and leaf water potentials of trees within the stand and retrieved VOD with a single-channel algorithm based on continuous radiometer measurements and measured soil moisture. VOD exhibited a diurnal cycle similar to that of leaf and stem water potential, with a peak at approximately 05:00 eastern daylight time (UTC -4). VOD was also positively correlated with both the measured dielectric constant and water potentials of stem xylem over the growing season. The presence of moisture on the leaves did not affect the observed relationship between VOD and stem water potential. We used our observed VOD-waterpotential relationship to estimate stand-level values for a radiative transfer parameter and a plant hydraulic parameter, which compared well with the published literature. Our findings support the use of VOD for plant hydraulic studies in temperate forests.", "authors": [ "Holtzman, Nataniel M.", "Anderegg, Leander D. L.", "Kraatz, Simon", "Mavrovic, Alex", "Sonnentag, Oliver", "Pappas, Christoforos", "Cosh, Michael H.", "Langlois, Alexandre", "Lakhankar, Tarendra", "Tesser, Derek", "Steiner, Nicholas", "Colliander, Andreas", "Roy, Alexandre", "Konings, Alexandra G." ], "keywords": [ "" ], "year": "2021", "source": "BIOGEOSCIENCES", "publication_type": "J", "point2d": [ -69.21021270751953, 27.03396987915039 ], "cluster": 3.0 }, { "idx": 763, "title": "Representativeness of Eddy-Covariance flux footprints for areas surrounding AmeriFlux sites", "abstract": "Large datasets of greenhouse gas and energy surface-atmosphere fluxes measured with the eddy-covariance technique (e.g., FLUXNET2015, AmeriFlux BASE) are widely used to benchmark models and remote-sensing products. This study addresses one of the major challenges facing model-data integration: To what spatial extent do flux measurements taken at individual eddy-covariance sites reflect model- or satellite-based grid cells? We evaluate flux footprints-the temporally dynamic source areas that contribute to measured fluxes-and the representativeness of these footprints for target areas (e.g., within 250-3000 m radii around flux towers) that are often used in flux-data synthesis and modeling studies. We examine the land-cover composition and vegetation characteristics, represented here by the Enhanced Vegetation Index (EVI), in the flux footprints and target areas across 214 AmeriFlux sites, and evaluate potential biases as a consequence of the footprint-to-target-area mismatch. Monthly 80% footprint climatologies vary across sites and through time ranging four orders of magnitude from 10(3) to 10(7) m(2) due to the measurement heights, underlying vegetation- and ground-surface characteristics, wind directions, and turbulent state of the atmosphere. Few eddy-covariance sites are located in a truly homogeneous landscape. Thus, the common model-data integration approaches that use a fixed-extent target area across sites introduce biases on the order of 4%-20% for EVI and 6%-20% for the dominant land cover percentage. These biases are site-specific functions of measurement heights, target area extents, and land-surface characteristics. We advocate that flux datasets need to be used with footprint awareness, especially in research and applications that benchmark against models and data products with explicit spatial information. We propose a simple representativeness index based on our evaluations that can be used as a guide to identify site-periods suitable for specific applications and to provide general guidance for data use.", "authors": [ "Chu, Housen", "Luo, Xiangzhong", "Ouyang, Zutao", "Chan, W. Stephen", "Dengel, Sigrid", "Biraud, Sebastien C.", "Torn, Margaret S.", "Metzger, Stefan", "Kumar, Jitendra", "Arain, M. Altaf", "Arkebauer, Tim J.", "Baldocchi, Dennis", "Bernacchi, Carl", "Billesbach, Dave", "Black, T. Andrew", "Blanken, Peter D.", "Bohrer, Gil", "Bracho, Rosvel", "Brown, Shannon", "Brunsell, Nathaniel A.", "Chen, Jiquan", "Chen, Xingyuan", "Clark, Kenneth", "Desai, Ankur R.", "Duman, Tomer", "Durden, David", "Fares, Silvano", "Forbrich, Inke", "Gamon, John A.", "Gough, Christopher M.", "Griffis, Timothy", "Helbig, Manuel", "Hollinger, David", "Humphreys, Elyn", "Ikawa, Hiroki", "Iwata, Hiroki", "Ju, Yang", "Knowles, John F.", "Knox, Sara H.", "Kobayashi, Hideki", "Kolb, Thomas", "Law, Beverly", "Lee, Xuhui", "Litvak, Marcy", "Liu, Heping", "Munger, J. William", "Noormets, Asko", "Novick, Kim", "Oberbauer, Steven F.", "Oechel, Walter", "Oikawa, Patty", "Papuga, Shirley A.", "Pendall, Elise", "Prajapati, Prajaya", "Prueger, John", "Quinton, William L.", "Richardson, Andrew D.", "Russell, Eric S.", "Scott, Russell L.", "Starr, Gregory", "Staebler, Ralf", "Stoy, Paul C.", "Stuart-Haentjens, Ellen", "Sonnentag, Oliver", "Sullivan, Ryan C.", "Suyker, Andy", "Ueyama, Masahito", "Vargas, Rodrigo", "Wood, Jeffrey D.", "Zona, Donatella" ], "keywords": [ "Flux footprint", "Spatial representativeness", "Landsat EVI", "Land cover", "Sensor location bias", "Model-data benchmarking" ], "year": "2021", "source": "AGRICULTURAL AND FOREST METEOROLOGY", "publication_type": "J", "point2d": [ -49.31897735595703, 53.85867691040039 ], "cluster": 17.0 }, { "idx": 764, "title": "Refining the role of phenology in regulating gross ecosystem productivity across European peatlands", "abstract": "The role of plant phenology as a regulator for gross ecosystem productivity (GEP) in peatlands is empirically not well constrained. This is because proxies to track vegetation development with daily coverage at the ecosystem scale have only recently become available and the lack of such data has hampered the disentangling of biotic and abiotic effects. This study aimed at unraveling the mechanisms that regulate the seasonal variation in GEP across a network of eight European peatlands. Therefore, we described phenology with canopy greenness derived from digital repeat photography and disentangled the effects of radiation, temperature and phenology on GEP with commonality analysis and structural equation modeling. The resulting relational network could not only delineate direct effects but also accounted for possible effect combinations such as interdependencies (mediation) and interactions (moderation). We found that peatland GEP was controlled by the same mechanisms across all sites: phenology constituted a key predictor for the seasonal variation in GEP and further acted as a distinct mediator for temperature and radiation effects on GEP. In particular, the effect of air temperature on GEP was fully mediated through phenology, implying that direct temperature effects representing the thermoregulation of photosynthesis were negligible. The tight coupling between temperature, phenology and GEP applied especially to high latitude and high altitude peatlands and during phenological transition phases. Our study highlights the importance of phenological effects when evaluating the future response of peatland GEP to climate change. Climate change will affect peatland GEP especially through changing temperature patterns during plant phenologically sensitive phases in high latitude and high altitude regions.", "authors": [ "Koebsch, Franziska", "Sonnentag, Oliver", "Jarveoja, Jarvi", "Peltoniemi, Mikko", "Alekseychik, Pavel", "Aurela, Mika", "Arslan, Ali Nadir", "Dinsmore, Kerry", "Gianelle, Damiano", "Helfter, Carole", "Jackowicz-Korczynski, Marcin", "Korrensalo, Aino", "Leith, Fraser", "Linkosalmi, Maiju", "Lohila, Annalea", "Lund, Magnus", "Maddison, Martin", "Mammarella, Ivan", "Mander, Ulo", "Minkkinen, Kari", "Pickard, Amy", "Pullens, Johannes W. M.", "Tuittila, Eeva-Stiina", "Nilsson, Mats B.", "Peichl, Matthias" ], "keywords": [ "canopy greenness", "commonality analysis", "mediation", "moderation", "peatland C cycle", "photosynthesis", "structural equation modeling" ], "year": "2020", "source": "GLOBAL CHANGE BIOLOGY", "publication_type": "J", "point2d": [ -22.671424865722656, 62.40420150756836 ], "cluster": 17.0 }, { "idx": 765, "title": "Shallow soils are warmer under trees and tall shrubs across Arctic and Boreal ecosystems", "abstract": "Soils are warming as air temperatures rise across the Arctic and Boreal region concurrent with the expansion of tall-statured shrubs and trees in the tundra. Changes in vegetation structure and function are expected to alter soil thermal regimes, thereby modifying climate feedbacks related to permafrost thaw and carbon cycling. However, current understanding of vegetation impacts on soil temperature is limited to local or regional scales and lacks the generality necessary to predict soil warming and permafrost stability on a pan-Arctic scale. Here we synthesize shallow soil and air temperature observations with broad spatial and temporal coverage collected across 106 sites representing nine different vegetation types in the permafrost region. We showed ecosystems with tall-statured shrubs and trees (>40 cm) have warmer shallow soils than those with short-statured tundra vegetation when normalized to a constant air temperature. In tree and tall shrub vegetation types, cooler temperatures in the warm season do not lead to cooler mean annual soil temperature indicating that ground thermal regimes in the cold-season rather than the warm-season are most critical for predicting soil warming in ecosystems underlain by permafrost. Our results suggest that the expansion of tall shrubs and trees into tundra regions can amplify shallow soil warming, and could increase the potential for increased seasonal thaw depth and increase soil carbon cycling rates and lead to increased carbon dioxide loss and further permafrost thaw.", "authors": [ "Kropp, Heather", "Loranty, Michael M.", "Natali, Susan M.", "Kholodov, Alexander L.", "Rocha, Adrian, V", "Myers-Smith, Isla", "Abbot, Benjamin W.", "Abermann, Jakob", "Blanc-Betes, Elena", "Blok, Daan", "Blume-Werry, Gesche", "Boike, Julia", "Breen, Amy L.", "Cahoon, Sean M. P.", "Christiansen, Casper T.", "Douglas, Thomas A.", "Epstein, Howard E.", "Frost, Gerald, V", "Goeckede, Mathias", "Hoye, Toke T.", "Mamet, Steven D.", "O'Donnell, Jonathan A.", "Olefeldt, David", "Phoenix, Gareth K.", "Salmon, Verity G.", "Sannel, A. Britta K.", "Smith, Sharon L.", "Sonnentag, Oliver", "Vaughn, Lydia Smith", "Williams, Mathew", "Elberling, Bo", "Gough, Laura", "Hjort, Jan", "Lafleur, Peter M.", "Euskirchen, Eugenie S.", "Heijmans, Monique M. P. D.", "Humphreys, Elyn R.", "Iwata, Hiroki", "Jones, Benjamin M.", "Jorgenson, M. Torre", "Gruenberg, Inge", "Kim, Yongwon", "Laundre, James", "Mauritz, Marguerite", "Michelsen, Anders", "Schaepman-Strub, Gabriela", "Tape, Ken D.", "Ueyama, Masahito", "Lee, Bang-Yong", "Langley, Kirsty", "Lund, Magnus" ], "keywords": [ "Arctic", "boreal forest", "soil temperature", "vegetation change", "permafrost" ], "year": "2021", "source": "ENVIRONMENTAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -34.680091857910156, 49.651668548583984 ], "cluster": 17.0 }, { "idx": 766, "title": "Drivers and health implications of the dietary transition among Inuit in the Canadian Arctic: a scoping review", "abstract": "Objective: The current study undertook a systematic scoping review on the drivers and implications of dietary changes among Inuit in the Canadian Arctic. Design: A keyword search of peer-reviewed articles was performed using PubMed, Web of Science, CINAHL, Academic Search Premier, Circumpolar Health Bibliographic Database and High North Research Documents. Eligibility criteria included all full-text articles of any design reporting on research on food consumption, nutrient intake, dietary adequacy, dietary change, food security, nutrition-related chronic diseases or traditional food harvesting and consumption among Inuit populations residing in Canada. Articles reporting on in vivo and in vitro experiments or on health impacts of environmental contaminants were excluded. Results: A total of 162 studies were included. Studies indicated declining country food (CF) consumption in favour of market food (MF). Drivers of this transition include colonial processes, poverty and socio-economic factors, changing food preferences and knowledge, and climate change. Health implications of the dietary transition are complex. Micro-nutrient deficiencies and dietary inadequacy are serious concerns and likely exacerbated by increased consumption of non-nutrient dense MF. Food insecurity, overweight, obesity and related cardiometabolic health outcomes are growing public health concerns. Meanwhile, declining CF consumption is entangled with shifting culture and traditional knowledge, with potential implications for psychological, spiritual, social and cultural health and well-being. Conclusions: By exploring and synthesising published literature, this review provides insight into the complex factors influencing Inuit diet and health. Findings may be informative for future research, decision-making and intersectoral actions around risk assessment, food policy and innovative community programmes.", "authors": [ "Little, Matthew", "Hagar, Hilary", "Zivot, Chloe", "Dodd, Warren", "Skinner, Kelly", "Kenny, Tiff-Annie", "Caughey, Amy", "Gaupholm, Josephine", "Lemire, Melanie" ], "keywords": [ "Nutrition transition", "Indigenous health", "Inuit health", "Food security", "Food environments" ], "year": "2021", "source": "PUBLIC HEALTH NUTRITION", "publication_type": "J", "point2d": [ 75.39857482910156, -22.805740356445312 ], "cluster": 7.0 }, { "idx": 767, "title": "Increased high-latitude photosynthetic carbon gain offset by respiration carbon loss during an anomalous warm winter to spring transition", "abstract": "Arctic and boreal ecosystems play an important role in the global carbon (C) budget, and whether they act as a future net C sink or source depends on climate and environmental change. Here, we used complementary in situ measurements, model simulations, and satellite observations to investigate the net carbon dioxide (CO2) seasonal cycle and its climatic and environmental controls across Alaska and northwestern Canada during the anomalously warm winter to spring conditions of 2015 and 2016 (relative to 2010-2014). In the warm spring, we found that photosynthesis was enhanced more than respiration, leading to greater CO2 uptake. However, photosynthetic enhancement from spring warming was partially offset by greater ecosystem respiration during the preceding anomalously warm winter, resulting in nearly neutral effects on the annual net CO2 balance. Eddy covariance CO2 flux measurements showed that air temperature has a primary influence on net CO2 exchange in winter and spring, while soil moisture has a primary control on net CO2 exchange in the fall. The net CO2 exchange was generally more moisture limited in the boreal region than in the Arctic tundra. Our analysis indicates complex seasonal interactions of underlying C cycle processes in response to changing climate and hydrology that may not manifest in changes in net annual CO2 exchange. Therefore, a better understanding of the seasonal response of C cycle processes may provide important insights for predicting future carbon-climate feedbacks and their consequences on atmospheric CO2 dynamics in the northern high latitudes.", "authors": [ "Liu, Zhihua", "Kimball, John S.", "Parazoo, Nicholas C.", "Ballantyne, Ashley P.", "Wang, Wen J.", "Madani, Nima", "Pan, Caleb G.", "Watts, Jennifer D.", "Reichle, Rolf H.", "Sonnentag, Oliver", "Marsh, Philip", "Hurkuck, Miriam", "Helbig, Manuel", "Quinton, William L.", "Zona, Donatella", "Ueyama, Masahito", "Kobayashi, Hideki", "Euskirchen, Eugenie S." ], "keywords": [ "ABoVE", "boreal", "carbon cycle", "climate change", "productivity", "respiration", "SMAP L4C", "soil moisture", "tundra" ], "year": "2020", "source": "GLOBAL CHANGE BIOLOGY", "publication_type": "J", "point2d": [ -40.647789001464844, 54.99468994140625 ], "cluster": 17.0 }, { "idx": 768, "title": "Expert assessment of future vulnerability of the global peatland carbon sink", "abstract": "Peatlands are impacted by climate and land-use changes, with feedback to warming by acting as either sources or sinks of carbon. Expert elicitation combined with literature review reveals key drivers of change that alter peatland carbon dynamics, with implications for improving models. The carbon balance of peatlands is predicted to shift from a sink to a source this century. However, peatland ecosystems are still omitted from the main Earth system models that are used for future climate change projections, and they are not considered in integrated assessment models that are used in impact and mitigation studies. By using evidence synthesized from the literature and an expert elicitation, we define and quantify the leading drivers of change that have impacted peatland carbon stocks during the Holocene and predict their effect during this century and in the far future. We also identify uncertainties and knowledge gaps in the scientific community and provide insight towards better integration of peatlands into modelling frameworks. Given the importance of the contribution by peatlands to the global carbon cycle, this study shows that peatland science is a critical research area and that we still have a long way to go to fully understand the peatland-carbon-climate nexus.", "authors": [ "Loisel, J.", "Gallego-Sala, A., V", "Amesbury, M. J.", "Magnan, G.", "Anshari, G.", "Beilman, D. W.", "Benavides, J. C.", "Blewett, J.", "Camill, P.", "Charman, D. J.", "Chawchai, S.", "Hedgpeth, A.", "Kleinen, T.", "Korhola, A.", "Large, D.", "Mansilla, C. A.", "Muller, J.", "van Bellen, S.", "West, J. B.", "Yu, Z.", "Bubier, J. L.", "Garneau, M.", "Moore, T.", "Sannel, A. B. K.", "Page, S.", "Valiranta, M.", "Bechtold, M.", "Brovkin, V", "Cole, L. E. S.", "Chanton, J. P.", "Christensen, T. R.", "Davies, M. A.", "De Vleeschouwer, F.", "Finkelstein, S. A.", "Frolking, S.", "Galka, M.", "Gandois, L.", "Girkin, N.", "Harris, L., I", "Heinemeyer, A.", "Hoyt, A. M.", "Jones, M. C.", "Joos, F.", "Juutinen, S.", "Kaiser, K.", "Lacourse, T.", "Lamentowicz, M.", "Larmola, T.", "Leifeld, J.", "Lohila, A.", "Milner, A. M.", "Minkkinen, K.", "Moss, P.", "Naafs, B. D. A.", "Nichols, J.", "O'Donnell, J.", "Payne, R.", "Philben, M.", "Piilo, S.", "Quillet, A.", "Ratnayake, A. S.", "Roland, T. P.", "Sjogersten, S.", "Sonnentag, O.", "Swindles, G. T.", "Swinnen, W.", "Talbot, J.", "Treat, C.", "Valach, A. C.", "Wu, J." ], "keywords": [ "" ], "year": "2021", "source": "NATURE CLIMATE CHANGE", "publication_type": "J", "point2d": [ -19.158924102783203, 63.54164505004883 ], "cluster": 9.0 }, { "idx": 769, "title": "Empowering small-scale, community-based fisheries through a food systems framework", "abstract": "In the context of the growing climate emergency and the negative social and environmental impacts of the industrial food system, significant attention is focused on the question of how we will feed ourselves sustainably. Small-scale fisheries are receiving more attention and communities are increasingly resisting a resourcist perspective that treats fish as a commodity by engaging in efforts to (re)envision fisheries as part of food systems. This paper presents four case studies from freshwater and marine fisheries across Canada to demonstrate ways of using food systems as an organizing concept to protect small-scale fisheries, build sustainable communities, and influence fisheries governance and policy. Insights are shared from the lobster fishery in Shelburne County, Nova Scotia; fish and country foods harvesting in Kakisa, Northwest Territories; traditional fisheries of Batchewana First Nation on Lake Superior, Ontario; and the national sustainable seafood partnership program, SeaChoice. We conclude by providing our collective ideas for how governance and policy may better support sustainability at the nexus of fisheries and food systems, emphasizing a need for structures and policies that are better adapted to the contexts of small-scale fisheries and that empower community participation in decision-making.", "authors": [ "Lowitt, Kristen", "Levkoe, Charles Z.", "Spring, Andrew", "Turlo, Colleen", "Williams, Patricia L.", "Bird, Sheila", "Sayers, Chief Dean", "Simba, Melaine" ], "keywords": [ "Small-scale fisheries", "Governance", "Food security", "Food systems", "Canada" ], "year": "2020", "source": "MARINE POLICY", "publication_type": "J", "point2d": [ 71.84580993652344, -28.927139282226562 ], "cluster": 4.0 }, { "idx": 770, "title": "The Retail Food Environment, Store Foods, and Diet and Health among Indigenous Populations: a Scoping Review", "abstract": "Purpose of the Review Describe the state of knowledge on how the retail food environment contributes to diet-related health and obesity among Indigenous populations, and assess how the literature incorporates Indigenous perspectives, methodologies and engagement throughout the research process. Outcomes included dietary behaviour (purchasing, intakes and diet quality) and diet-related health outcomes (weight-related outcomes, non-communicable diseases and holistic health or definitions of health as defined by Indigenous populations involved in the study). Recent Findings Of fifty included articles (1996-2019), the largest proportions described Indigenous communities in Canada (20 studies, 40%), the USA (16, 32%) and Australia (9, 18%). Among articles that specified the Indigenous population of focus (42 studies, 84%), the largest proportion (11 studies, 26%) took place in Inuit communities, followed by Aboriginal and Torres Strait Islander communities (8 studies, 19%). The included literature encompassed four main study designs: type A, dietary intakes of store foods (14 studies, 28%), and type B, store food environments (16, 32%), comprised the greatest proportion of articles; the remainder were type C, store food environments and diet (7, 14%), and type D, store food environment interventions (13, 26%). Of the studies that assessed diet or health outcomes (36, 72%), 22 (61%) assessed dietary intakes; 16 (44%) sales/purchasing; and 8 (22%) weight-related outcomes. Store foods tended to contribute the greatest amount of dietary energy to the diets of Indigenous peoples and increased non-communicable disease risk as compared to traditional foods. Multi-pronged interventions appeared to have positive impacts on dietary behaviours, food purchasing and nutrition knowledge; promotion and nutrition education alone had more mixed effects. Of the nine studies which were found to have strong engagement with Indigenous populations, eight had moderate or high methodological quality. Eighteen studies (36%) did not mention any engagement with Indigenous populations. The literature confirmed the importance of store foods to the total energy intake of the contemporary diets of Indigenous people, the gaps in accessing both retail food environments and traditional foods and the potential for both new dietary assessment research and retail food environment intervention strategies to better align with and privilegeIndigenous Ways of Knowing.", "authors": [ "Luongo, Gabriella", "Skinner, Kelly", "Phillipps, Breanna", "Yu, Ziwa", "Martin, Debbie", "Mah, Catherine L." ], "keywords": [ "Food", "Retail", "Environment", "Indigenous populations", "Review" ], "year": "2020", "source": "CURRENT OBESITY REPORTS", "publication_type": "J", "point2d": [ 74.70498657226562, -23.471540451049805 ], "cluster": 7.0 }, { "idx": 771, "title": "Use of pre-industrial baselines to monitor anthropogenic enrichment of metals concentrations in recently deposited sediment of floodplain lakes in the Peace-Athabasca Delta (Alberta, Canada)", "abstract": "Well-designed monitoring approaches are needed to assess effects of industrial development on downstream aquatic environments and guide environmental stewardship. Here, we develop and apply a monitoring approach to detect potential enrichment of metals concentrations in surficial lake sediments of the Peace-Athabasca Delta (PAD), northern Alberta, Canada. Since the ecological integrity of the PAD is strongly tied to river floodwaters that replenish lakes in the delta, and the PAD is located downstream of the Alberta oil sands, concerns have been raised over the potential transport of industry-supplied metals to the PAD via the Athabasca River. Surface sediment samples were collected in September 2017 from 61 lakes across the delta, and again in July 2018 from 20 of the same lakes that had received river floodwaters 2 months earlier, to provide snapshots of metals concentrations (Be, Cd, Cr, Cu, Ni, Pb, V, and Zn) that have recently accumulated in these lakes. To assess for anthropogenic enrichment, surficial sediment metals concentrations were normalized to aluminum and compared to pre-industrial baseline (i.e., reference) metal-aluminum linear relations for the Athabasca and Peace sectors of the PAD developed from pre-1920 measurements in lake sediment cores. Numerical analysis demonstrates no marked enrichment of these metals concentrations above pre-1920 baselines despite strong ability (> 99% power) to detect enrichment of 10%. Measurements of river sediment collected by the Regional Aquatics- and Oil Sands-Monitoring Programs (RAMP/OSM) also did not exceed pre-1920 concentrations. Thus, results presented here show no evidence of substantial oil sands-derived metals enrichment of sediment supplied by the Athabasca River to lakes in the PAD and demonstrate the usefulness of these methods as a monitoring framework.", "authors": [ "Owca, Tanner J.", "Kay, Mitchell L.", "Faber, Jelle", "Remmer, Casey R.", "Zabel, Nelson", "Wiklund, Johan A.", "Wolfe, Brent B.", "Hall, Roland I." ], "keywords": [ "Wood Buffalo National Park", "River sediment quality", "Alberta oil sands", "Aquatic ecosystem monitoring", "Environmental impact assessment", "Paleolimnology" ], "year": "2020", "source": "ENVIRONMENTAL MONITORING AND ASSESSMENT", "publication_type": "J", "point2d": [ 49.27702331542969, -3.0269887447357178 ], "cluster": 19.0 }, { "idx": 772, "title": "Aboveground tree growth is a minor and decoupled fraction of boreal forest carbon input", "abstract": "The boreal biome accounts for approximately one third of the terrestrial carbon (C) sink. However, estimates of its individual C pools remain uncertain. Here, focusing on the southern boreal forest, we quantified the magnitude and temporal dynamics of C allocation to aboveground tree growth at a mature black spruce (Picea mariana)-dominated forest stand in Saskatchewan, Canada. We reconstructed aboveground tree biomass increments (AGBi) using a biometric approach, i.e., species-specific allometry combined with forest stand characteristics and tree ring widths collected with a C-oriented sampling design. We explored the links between boreal tree growth and ecosystem C input by comparing AGBi with eddy-covariance-derived ecosystem C fluxes from 1999 to 2015 and we synthesized our findings with a refined meta-analysis of published values of boreal forest C use efficiency (CUE). Mean AGBi at the study site was decoupled from ecosystem C input and equal to 71 +/- 7 g C m(-2) (1999-2015), which is only a minor fraction of gross ecosystem production (GEP; i.e., AGBi / GEP approximate to 9 %). Moreover, C allocation to AGBi remained stable over time (AGBi / GEP; -0.0001 yr(-1) ; p-value = 0.775), contrary to significant trends in GEP ( + 5.72 g C m(-2) yr(-2) ; p-value = 0.02) and CUE (-0.0041 yr(-1), p-value =0.007). CUE was estimated as 0.50 +/- 0.03 at the study area and 0.41 +/- 0.12 across the reviewed boreal forests. These findings highlight the importance of belowground tree C investments, together with the substantial contribution of understory, ground cover and soil to the boreal forest C balance. Our quantitative insights into the dynamics of aboveground boreal tree C allocation offer additional observational constraints for terrestrial ecosystem models that are often biased in converting C input to biomass, and can guide forest-management strategies for mitigating carbon dioxide emissions.", "authors": [ "Pappas, Christoforos", "Maillet, Jason", "Rakowski, Sharon", "Baltzer, Jennifer L.", "Barr, Alan G.", "Black, T. Andrew", "Fatichi, Simone", "Laroque, Colin P.", "Matheny, Ashley M.", "Roy, Alexandre", "Sonnentag, Oliver", "Zha, Tianshan" ], "keywords": [ "Carbon use efficiency (CUE)", "Forest inventories", "Larix laricina (eastern larch, tamarack), Picea mariana (black spruce)", "Southern old black spruce (SOBS)", "Terrestrial carbon sink" ], "year": "2020", "source": "AGRICULTURAL AND FOREST METEOROLOGY", "publication_type": "J", "point2d": [ -47.93046188354492, 65.32337951660156 ], "cluster": 17.0 }, { "idx": 773, "title": "Advancing Field-Based GNSS Surveying for Validation of Remotely Sensed Water Surface Elevation Products", "abstract": "To advance monitoring of surface water resources, new remote sensing technologies including the forthcoming Surface Water and Ocean Topography (SWOT) satellite (expected launch 2022) and its experimental airborne prototype AirSWOT are being developed to repeatedly map water surface elevation (WSE) and slope (WSS) of the world's rivers, lakes, and reservoirs. However, the vertical accuracies of these novel technologies are largely unverified; thus, standard and repeatable field procedures to validate remotely sensed WSE and WSS are needed. To that end, we designed, engineered, and operationalized a Water Surface Profiler (WaSP) system that efficiently and accurately surveys WSE and WSS in a variety of surface water environments using Global Navigation Satellite Systems (GNSS) time-averaged measurements with Precise Point Positioning corrections. Here, we present WaSP construction, deployment, and a data processing workflow. We demonstrate WaSP data collections from repeat field deployments in the North Saskatchewan River and three prairie pothole lakes near Saskatoon, Saskatchewan, Canada. We find that WaSP reproducibly measures WSE and WSS with vertical accuracies similar to standard field survey methods [WSE root mean squared difference (RMSD) similar to 8 cm, WSS RMSD similar to 1.3 cm/km] and that repeat WaSP deployments accurately quantify water level changes (RMSD similar to 3 cm). Collectively, these results suggest that WaSP is an easily deployed, self-contained system with sufficient accuracy for validating the decimeter-level expected accuracies of SWOT and AirSWOT. We conclude by discussing the utility of WaSP for validating airborne and spaceborne WSE mappings, present 63 WaSP in situ lake WSE measurements collected in support of NASA's Arctic-Boreal and Vulnerability Experiment, highlight routine deployment in support of the Lake Observation by Citizen Scientists and Satellites project, and explore WaSP utility for validating a novel GNSS interferometric reflectometry LArge Wave Warning System.", "authors": [ "Pitcher, Lincoln H.", "Smith, Laurence C.", "Cooley, Sarah W.", "Zaino, Annie", "Carlson, Robert", "Pettit, Joseph", "Gleason, Colin J.", "Minear, J. Toby", "Fayne, Jessica V.", "Willis, Michael J.", "Hansen, Jasmine S.", "Easterday, Kelly J.", "Harlan, Merritt E.", "Langhorst, Theodore", "Topp, Simon N.", "Dolan, Wayana", "Kyzivat, Ethan D.", "Pietroniro, Al", "Marsh, Philip", "Yang, Daqing", "Carter, Tom", "Onclin, Cuyler", "Hosseini, Nasim", "Wilcox, Evan", "Moreira, Daniel", "Berge-Nguyen, Muriel", "Cretaux, Jean-Francois", "Pavelsky, Tamlin M." ], "keywords": [ "ABoVE", "SWOT", "GNSS", "water surface elevation", "water surface slope" ], "year": "2020", "source": "FRONTIERS IN EARTH SCIENCE", "publication_type": "J", "point2d": [ -75.43379974365234, 4.3521928787231445 ], "cluster": 2.0 }, { "idx": 774, "title": "Factors influencing the structure of macroinvertebrate communities in subarctic lakes affected by wildfires", "abstract": "Fires are a natural phenomenon in the boreal forest, but their frequency is expected to increase over the coming century. Fires may affect water quality and invertebrates in lakes, but there have been few studies in the northern boreal forest to describe these impacts. We collected data on water quality, macrophytes, and invertebrates from 20 lakes in the Salmi Settlement Area of the Northwest Territories. Nine lakes were affected by fires in their catchments 4-5 years before data collection, while eleven were not. Our results showed that few water quality variables were associated with fires. However, remote sensing and field observations suggested that macrophyte biomass was higher in lakes affected by burns, and this variable was a significant predictor of invertebrate composition. Burn history was an important predictor of the richness and abundance of invertebrates, but natural variability in lake properties was more important for explaining differences among lakes. Our results suggest that a better understanding of the effects of wildfires might be gained by examining how postfire changes in macrophytes affect other trophic levels.", "authors": [ "Pretty, Thomas J.", "Chanyi, Charles-Matthew", "Kuhn, Catherine", "Gray, Derek K." ], "keywords": [ "" ], "year": "2021", "source": "CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES", "publication_type": "J", "point2d": [ 18.90694808959961, -24.48550796508789 ], "cluster": 13.0 }, { "idx": 775, "title": "Virtual barriers: unpacking the sustainability implications of online food spaces and the Yellowknife Farmers Market's response to COVID-19", "abstract": "BackgroundThrough their support of local agriculture, relationships, and healthy diets, farmers markets can contribute to a sustainable food system. Markets like the Yellowknife Farmers Market (YKFM) are social spaces that support local food, yet the COVID-19 pandemic has forced changes to their current model. We explore the potential of online marketplaces to contribute to a resilient, sustainable food system through a case study of the YKFM.MethodsIn 2019, a collaborative mixed-method evaluation was initiated by the YKFM and university partners in the Northwest Territories (NWT), Canada. The evaluation included an in-person Rapid Market Assessment dot survey and questionnaire of market patrons from two YKFM dates prior to the pandemic. Due to COVID-19, a vendor survey and interviews were deferred. Data collected from the two patron surveys, alongside researcher observations, available literature, public announcements, and informal email and phone discussions, inform the discussion.ResultsFor the patron surveys, 59 dot survey and 31 questionnaire participants were recruited. The top motivators for attendance were eating dinner, atmosphere, and supporting local businesses, and most patrons attended as couples and spent over half of their time talking to others. The YKFM did not move online; instead, they proposed and implemented a Shop, don't stop market. Informal conversations suggested the small scale of the market and technology challenges were perceived barriers to moving online. The physically-distanced market was well-attended and featured in local media.ConclusionsNWT food strategies rely on farmers markets to nurture a local food system. Data suggest a potential incongruence between an online model and important market characteristics such as the event-like atmosphere. Available literature suggests online markets can support local food by facilitating purchasing and knowledge-sharing, yet they do not replicate the open-air or social experience. The decision not to move online for the YKFM reflects market patron characteristics and current food context in Yellowknife and the NWT. While online adaptation does not fit into the YKFM plan today, online markets may prove useful as a complementary strategy for future emerging stressors to enhance the resiliency of local systems.", "authors": [ "Radcliffe, Josalyn", "Skinner, Kelly", "Spring, Andrew", "Picard, Lise", "Benoit, France", "Dodd, Warren" ], "keywords": [ "Farmers markets", "Sustainability", "Food system", "COVID-19", "Yellowknife", "Northwest Territories" ], "year": "2021", "source": "NUTRITION JOURNAL", "publication_type": "J", "point2d": [ 70.45773315429688, -31.568998336791992 ], "cluster": 4.0 }, { "idx": 776, "title": "Game bird consumption in Dene communities of the Northwest Territories, Canada", "abstract": "Objective: Game bird consumption is an important part of the diet of Indigenous populations in Canada and, as part of country food consumption, is associated with improved nutritional status. The objective of this project was to document the consumption of game birds for Dene First Nations in the Northwest Territories (NWT), Canada. Design: Participants were invited to complete a FFQ using an iPad to document the types of country foods consumed, as well as consumption frequency and preparation methods, including thirteen types of game birds. Setting: The project was implemented in nine communities in the Dehcho and Sahtu regions of the NWT, Canada. Participants: A total of 237 children and adult participants from Dene First Nations in the Mackenzie Valley region of the NWT took part in the current study. Results: FFQ findings indicated that game birds were frequently consumed in both Dehcho and Sahtu communities. Canada goose and mallard were found to be consumed by the largest number of participants. Five different species (including Canada goose and mallard) were found to be consumed by at least 25 % of participants over the last year. When consuming game birds, most participants reported consuming the meat as well as most, if not all, other parts of the bird. Conclusions: Differences were observed since the last country food assessment in the 1990s in the same regions. These findings increase knowledge of the current Dene diet patterns and support the understanding of diet transition.", "authors": [ "Ratelle, Mylene", "Haig, Laurie", "Laird, Brian D.", "Skinner, Kelly" ], "keywords": [ "Monitoring and surveillance", "Country food", "Dietary patterns", "Game birds", "Food Frequency Questionnaire", "Dene", "Northwest Territories" ], "year": "2021", "source": "PUBLIC HEALTH NUTRITION", "publication_type": "J", "point2d": [ 76.84680938720703, -23.75262451171875 ], "cluster": 7.0 }, { "idx": 777, "title": "Human biomonitoring of metals in sub-Arctic Dene communities of the Northwest Territories, Canada", "abstract": "A human biomonitoring project investigating environmental exposures to metals from hair, blood and urine samples was implemented in the Northwest Territories, Canada, between January 2016 and March 2018. This study reports the metal biomarker levels from nine Dene communities located in the Dehcho and Sahtti regions to identify contaminants of interest. Levels of metals in the urine (n = 198), blood (n = 276) and hair (n = 443) samples were generally similar to those seen in other biomonitoring studies in Canada, but lead levels in blood (GM = 16 mu g/L; 95th percentile = 71 mu g/L) and urine (GM = 0.59 mu g/L, 0.69 mu g/g of creatinine; 95th percentile = 4.2 mu g/L, 4.0 mu g/g of creatinine) were higher than those observed in the Canadian Health Measure Survey (CHMS, cycles 2 and 5). Hair mercury (but not blood mercury) appeared higher than observed in participants from the CHMS cycle 5. The vast majority of participants had biomarker levels below the biomonitoring guidance values established for mercury and lead. Based on a comparative analysis of biomarker statistics relative to a nationally-representative survey, metals and essential trace elements of particular interest for follow-up research include: lead, manganese, mercury, and selenium. This project provided baseline biomarker levels in participating regions, which is essential to track changes in the future, and identify the contaminants to prioritize for further investigation of exposure determinants.", "authors": [ "Ratelle, Mylene", "Packull-McCormick, Sara", "Bouchard, Michele", "Majowicz, Shannon", "Laird, Brian" ], "keywords": [ "Metals", "Exposure", "Contaminants", "Risk assessment", "Northwest territories" ], "year": "2020", "source": "ENVIRONMENTAL RESEARCH", "publication_type": "J", "point2d": [ 76.8377685546875, -16.04857635498047 ], "cluster": 7.0 }, { "idx": 778, "title": "Food frequency questionnaire assessing traditional food consumption in Dene/Metis communities, Northwest Territories, Canada", "abstract": "Food Frequency Questionnaires (FFQ) can be used to document food consumption and to estimate the intake of contaminants for Indigenous populations. The objective of this project was to refine and implement an FFQ to estimate the consumption of traditional locally harvested foods for Dene/Metis in the Northwest Territories, Canada. The strategy consisted of: 1) refining the FFQ through three focus groups and, 2) implementing the FFQ in Indigenous communities. Participants were asked to complete the FFQ using an iPad to document the types of traditional foods consumed over the past 12 months, as well as the consumption frequency, the portion size, and the preparation methods. Focus groups supported the refinement of the FFQ on the format, the list of foods, and the preparation methods listed in the questionnaire. The refined FFQ was then implemented with participants (n = 237). Findings indicated that the traditional foods most frequently consumed were moose, whitefish and lake trout. Participants who consumed fish and land animals reported, on average, a portion size for one serving of between 126 and 143 g, depending on age and sex. These findings increase knowledge of the current traditional food consumption of Dene/Metis communities and will support the assessment of contaminant exposure.", "authors": [ "Ratelle, Mylene", "Skinner, Kelly", "Packull-McCormick, Sara", "Laird, Brian" ], "keywords": [ "Indigenous", "food Frequency Questionnaire", "contaminants", "traditional foods", "Northwest Territories", "Dene", "country foods" ], "year": "2020", "source": "INTERNATIONAL JOURNAL OF CIRCUMPOLAR HEALTH", "publication_type": "J", "point2d": [ 76.2096939086914, -21.355192184448242 ], "cluster": 7.0 }, { "idx": 779, "title": "Polycyclic aromatic hydrocarbons (PAHs) levels in urine samples collected in a subarctic region of the Northwest Territories, Canada", "abstract": "Traditional food consumption for Indigenous peoples is associated with improved nutrition and health but can also pose potential risks via exposure to contaminants. Polycyclic aromatic hydrocarbons (PAHs) are compounds of interest due to their widespread presence (e.g., their metabolites are detected in up to 100% of the Canadian population) and their toxicological potential. To better understand the range of exposures faced by Indigenous populations in northern Canada and to address a contaminant of emerging concern identified by the Arctic Monitoring and Assessment Programme, a multi-year biomonitoring study investigated levels of PAH exposure in subarctic First Nations communities of the Northwest Territories, Canada. Secondary data analysis of banked samples from a subset of the cross-sectional study was done. PAHs and cotinine markers in the urine samples (n = 97) of participants from two regions from the Mackenzie Valley (Dehcho and Sahtii) was completed by liquid and gas chromatography coupled with mass spectrometry. Also, participants completed a 24-hr recall food survey. When compared according to age/sex categories, the GM of several biomarkers (1-hydroxypyrene, 1-naphthol, 2-hydroxyfluorene, 2-hydroxyphenanthrene, 2-naphthol, 3-hydroxyfluorene, 3-hydroxyphenanthrene, 4-hydroxyphenanthrene, 9-hydroxyfluorene, 9-hydroxyphenanthrene) appeared higher than observed for the general Canadian population. The PAHs levels observed were, however, below clinical levels associated with adverse health outcomes. Altogether, these elevated biomarkers are metabolites of pyrene, naphthalene, fluorene and phenanthrene. Statistically significant non-parametric associations were observed between several biomarkers and i) the consumption of cooked meat in the last 24 h; and, ii) smoking status (self-reported status and adjusted on urine cotinine level). This work is the first to report PAH levels in a northern Canadian population and provides local baseline data for monitoring the effects of changes to climate and lifestyle over time. These findings will support regional and territorial decision makers in identifying environmental health priorities.", "authors": [ "Ratelle, Mylene", "Khoury, Cheryl", "Adlard, Bryan", "Laird, Brian" ], "keywords": [ "Polycyclic aromatic hydrocarbons (PAHs)", "Cotinine", "Smoking", "Biomonitoring", "Northwest territories" ], "year": "2020", "source": "ENVIRONMENTAL RESEARCH", "publication_type": "J", "point2d": [ 79.7373046875, -16.97884178161621 ], "cluster": 7.0 }, { "idx": 780, "title": "Multi-year isoscapes of lake water balances across a dynamic northern freshwater delta", "abstract": "Sustainable approaches capable of tracking status, trends and drivers of lake water balances in complex, remote landscapes are needed to inform ecosystem stewardship and water-security actions. At the Peace-Athabasca Delta (Alberta, Canada), a globally recognized freshwater floodplain landscape, concerns about water-level drawdown and multiple potential stressors have prompted need to improve knowledge of lake water balances and establish a lake monitoring program. Yet, the delta's remoteness and dynamic nature present challenges to these goals. Here we use over 1000 measurements of water isotope composition at similar to 60 lakes and 9 river sites during the spring, summer and fall of five consecutive years (2015-2019) to elucidate patterns in lake water balance over time and space, the influential roles of evaporation and river floodwaters, and relations with meteorological conditions and river water levels. Calculation of evaporation-to-inflow ratios using a coupled-isotope tracer approach, displayed via generalized additive models and geospatial 'isoscapes', reveal strongly varying lake water balances. Results identify distinct areas vulnerable to lake-level drawdown, given the likelihood of continued decline in ice-jam flood frequency, longer ice-free season duration and reduced snowmelt runoff. Results also demarcate areas of the delta where lakes are more resilient to factors that cause drawdown. The former defines the Peace sector, which is influenced by floodwaters from the Peace River during episodic ice-jam flood events, whereas the latter describes portions of the active floodplain environment of the Athabasca sector which receives more frequent contributions of Athabasca River floodwaters during both spring ice-jam and open-water seasons. Efficiency of water isotope tracers to capture the marked temporal and spatial heterogeneity in lake water balances during this 5 year time span, and their diagnostic responses to key hydrological processes, serves as a foundation for ongoing lake monitoring, an approach readily transferable to other remote and dynamic lake-rich landscapes.", "authors": [ "Remmer, Casey R.", "Neary, Laura K.", "Kay, Mitchell L.", "Wolfe, Brent B.", "Hall, Roland, I" ], "keywords": [ "lake water balance", "isotope hydrology", "freshwater landscapes", "long-term studies", "Peace-Athabasca Delta", "aquatic ecosystem monitoring" ], "year": "2020", "source": "ENVIRONMENTAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ 3.028280258178711, 12.868882179260254 ], "cluster": 19.0 }, { "idx": 781, "title": "L-Band response to freeze/thaw in a boreal forest stand from ground- and tower-based radiometer observations", "abstract": "The extent, timing and duration of seasonal freeze/thaw (FT) state exerts dominant control on boreal forest carbon, water and energy cycle processes. Recent and on-going L-Band (approximate to 1.4 GHz) spaceborne missions have the potential to provide enhanced information on FT state over large geographic regions with rapid revisit time. However, the low spatial resolution of these spaceborne observations ( 45 km) makes it difficult to isolate the primary contributions (soil, vegetation, snow) to the FT signal in boreal forest. To better quantify these controls, two L-Band radiometers were deployed (September 2016 to July 2017) at a black spruce (Picea mariana) dominated boreal forest site; one unit above and one unit on the ground surface below the canopy to disentangle the microwave contributions of overstory canopy, and the ground surface on the FT brightness temperature (TB) signal. Bi-weekly multi-angular measurements from both units were combined in order to estimate effective scattering albedo (omega) and the microwave vegetative optical depth (tau), using the tau-omega microwave vegetation radiative transfer model. Soil moisture probes were inserted in the trunk of two black spruce and one larch (Larix laricina) trunks located in the footprint of the above-canopy radiometer to measure tree trunk relative dielectric constant (RDCtree). Results showed a strong relationship between RDCtree and tree skin temperature (Thee) under freezing temperature conditions, which led to a gradual decrease of tau in winter. During the spring thawing period in April and May, tau remained relatively stable. In contrast, it increased substantially in June, most likely in relation to the growing season onset. Overall, tau was related to the seasonal RDCtree cycle (r = 0.76). Regarding omega, a value of 0.086 (+/- 0.029) was obtained, but no dependency on T-tree or RDCtree was observed. Despite the observed impact of FT on vegetation L-Band signals, results from continuous TB observations spanning from 14 September 2016 to 25 May 2017, indicated that the main contribution to the observed L-Band TB freeze-up signal in the fall originated from the ground surface. The above-canopy unit showed some sensitivity to overstory canopy FT, yet the sensitivity was lower compared to the signal induced by the ground FT. In April and May, L-Band radiometer FT retrieval agreed closely to the melt onset detection using ADC, but it was likely related to the coincident presence of liquid water in the snow. Our findings have important applications to L-Band spaceborne FT algorithm development and validation across the boreal forest. More specifically, our findings allow better quantification of the potential effect of frozen ground on various biogeophysical and biogeochemical processes in boreal forests.", "authors": [ "Roy, Alexandre", "Toose, Peter", "Mavrovic, Alex", "Pappas, Christoforos", "Royer, Alain", "Derksen, Chris", "Berg, Aaron", "Rowlandson, Tracy", "El-Amine, Mariam", "Barr, Alan", "Black, Andrew", "Langlois, Alexandre", "Sonnentag, Oliver" ], "keywords": [ "" ], "year": "2020", "source": "REMOTE SENSING OF ENVIRONMENT", "publication_type": "J", "point2d": [ -70.00286865234375, 26.228334426879883 ], "cluster": 17.0 }, { "idx": 782, "title": "The Baker Creek Research Watershed: Streamflow data highlighting the behaviour of an intermittent Canadian Shield stream through a wet-dry-wet cycle", "abstract": "Baker Creek drains water from subarctic Canadian Shield terrain comprised of a mix of exposed Precambrian bedrock, lakes, open black spruce forest and peat filled depressions. Research in the catchment has focused on hydrological processes at the hillslope and catchment scales. Streamflow is gauged from several diverse sub-catchments ranging in size from 9 to 155 km(2). The period of record (2003-2019) of streamflow from these sub-catchments extends from 12 to 17 years, and these data are the focus of this note. Such data are unique in this remote region. 2003-2019 was a period that included both historic wet and dry conditions. Observations during such a diversity of conditions are helping to improve understanding of how stream networks that drain this landscape expand and contract in response to short and long hydroclimatic cycles. These data from a distinctly cold and dry region of low relief, thin soils, exposed bedrock and permafrost are a valuable contribution to the global diversity of research catchment data.", "authors": [ "Spence, Christopher", "Hedstrom, Newell" ], "keywords": [ "permafrost", "Precambrian Shield", "research basin", "subarctic" ], "year": "2021", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -15.862916946411133, 2.0127103328704834 ], "cluster": 13.0 }, { "idx": 783, "title": "Hydrological resilience to forest fire in the subarctic Canadian shield", "abstract": "Understanding the role of forest fires on water budgets of subarctic Precambrian Shield catchments is important because of growing evidence that fire activity is increasing. Most research has focused on assessing impacts on individual landscape units, so it is unclear how changes manifest at the catchment scale enough to alter water budgets. The objective of this study was to determine the water budget impact of a forest fire that partially burned a similar to 450 km(2) subarctic Precambrian Shield basin. Water budget components were measured in a pair of catchments: one burnt and another unburnt. Burnt and unburnt areas had comparable net radiation, but thaw was deeper in burned areas. There were deeper snow packs in burns. Differences in streamflow between the catchments were within measurement uncertainty. Enhanced winter streamflow from the burned watershed was evident by icing growth at the streamflow gauge location, which was not observed in the unburned catchment. Wintertime water chemistry was also clearly elevated in dissolved organics, and organic-associated nutrients. Application of a framework to assess hydrological resilience of watersheds to wildfire reveal that watersheds with both high bedrock and open water fractions are more resilient to hydrological change after fire in the subarctic shield, and resilience decreases with increasingly climatically wet conditions. This suggests significant changes in runoff magnitude, timing and water chemistry of many Shield catchments following wildfire depend on pre-fire land cover distribution, the extent of the wildfire and climatic conditions that follow the fire.", "authors": [ "Spence, Christopher", "Hedstrom, Newell", "Tank, Suzanne E.", "Quinton, William L.", "Olefeldt, David", "Goodman, Stefan", "Dion, Nicole" ], "keywords": [ "Canadian shield", "evapotranspiration", "forest fire", "permafrost", "resilience", "streamflow", "talik", "water budget" ], "year": "2020", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -15.559253692626953, 0.6920549869537354 ], "cluster": 13.0 }, { "idx": 785, "title": "Building upon open-barrel corer and sectioning systems to foster the continuing legacy of John Glew", "abstract": "The late John Glew contributed valuable equipment to the paleolimnology community for successful collection and processing of cores of sediment from aquatic ecosystems. Unfortunately, tubes that fit his hammer-gravity corer design are no longer conveniently available for purchase and, with his sudden passing, Glew gravity and coring equipment is difficult or impossible to access. In some field-sampling situations, other commercially available equipment present limitations. Here, we provide an updated design of the Glew gravity corer which accommodates a hammer-percussion instrument and overcomes limitations we have encountered when coring lakes in remote locations from floats of a helicopter or small, inflatable watercraft. Our approach integrates the 'best of both worlds' provided by the Glew and commercially available Uwitec designs, using readily available components. We updated the Glew corer tube collar to be compatible with standard, commercially available 90-mm external diameter (86-mm internal diameter) PVC tubing that fits Uwitec components (e.g., Uwitec rubber 'piston' and 'stoppers'; using terminology of the Uwitec catalogue), and designed a spring-loaded gasket-style plunger that achieves greater suction than the standard Glew designs. We also updated the Glew vertical sectioner to be compatible with 90-mm-diameter core tubes typically ranging from 60-120 cm long. An outcome is consolidation of the Uwitec and Glew gravity coring systems, which has allowed for interchangeability and choice among use of original and hammer-driven Glew, Uwitec, and the new hybrid 'Uwi-Glew-ee' gravity corer and sectioner configurations, depending on logistical constraints of fieldwork and anticipated lake sediment composition. The parts and systems are available from University of Waterloo's Science Technical Services (https://uwaterloo.ca/science-technical-services/).", "authors": [ "Telford, James, V", "Kay, Mitchell L.", "Vander Heide, Harman", "Wiklund, Johan A.", "Owca, Tanner J.", "Faber, Jelle A.", "Wolfe, Brent B.", "Hall, Roland, I" ], "keywords": [ "Lake sediment", "Open-barrel corer", "Hammer-driven gravity corer", "Uwitec gravity corer", "Glew gravity corer", "Paleolimnology", "Extruder" ], "year": "2021", "source": "JOURNAL OF PALEOLIMNOLOGY", "publication_type": "J", "point2d": [ 53.647743225097656, -1.410743236541748 ], "cluster": 18.0 }, { "idx": 786, "title": "Satellite-Observed Soil Moisture as an Indicator of Wildfire Risk", "abstract": "Wildfires are a concerning issue in Canada due to their immediate impact on people's lives, local economy, climate, and environment. Studies have shown that the number of wildfires and affected areas in Canada has increased during recent decades and is a result of a warming and drying climate. Therefore, identifying potential wildfire risk areas is increasingly an important aspect of wildfire management. The purpose of this study is to investigate if remotely sensed soil moisture products from the Soil Moisture and Ocean Salinity (SMOS) satellite can be used to identify potential wildfire risk areas for better wildfire management. We used the National Fire Database (NFDB) fire points and polygons to group the wildfires according to ecozone classifications, as well as to analyze the SMOS soil moisture data over the wildfire areas, between 2010-2017, across fourteen ecozones in Canada. Timeseries of 3-day, 5-day, and 7-day soil moisture anomalies prior to the onset of each wildfire occurrence were examined over the ecozones individually. Overall, the results suggest, despite the coarse-resolution, SMOS soil moisture products are potentially useful in identifying soil moisture anomalies where wildfire hot-spots may occur.", "authors": [ "Ambadan, Jaison Thomas", "Oja, Matilda", "Gedalof, Ze'ev", "Berg, Aaron A." ], "keywords": [ "wildfire", "ecozone", "soil moisture", "Canada", "SMOS" ], "year": "2020", "source": "REMOTE SENSING", "publication_type": "J", "point2d": [ -5.366603851318359, 43.34619903564453 ], "cluster": 15.0 }, { "idx": 788, "title": "Nitrous oxide emissions from permafrost-affected soils", "abstract": "Soils are sources of the potent greenhouse gas nitrous oxide (N2O) globally, but emissions from permafrost-affected soils have been considered negligible owing to nitrogen (N) limitation. Recent measurements of N2O emissions have challenged this view, showing that vegetated soils in permafrost regions are often small but evident sources of N2O during the growing season (similar to 30 mu g N2O-N m(-2) day(-1)). Moreover, barren or sparsely vegetated soils, common in harsh climates, can serve as substantial sources of N2O (similar to 455 mu g N2O-N m(-2) day(-1)), demonstrating the importance of permafrost-affected soils in Earth's N2O budget. In this Review, we discuss N2O fluxes from subarctic, Arctic, Antarctic and alpine permafrost regions, including areas that likely serve as sources (such as peatlands) and as sinks (wetlands, dry upland soils), and estimate global permafrost-affected soil N2O emissions from previously published fluxes. We outline the below-ground N cycle in permafrost regions and examine the environmental conditions influencing N2O dynamics. Climate-change-related impacts on permafrost ecosystems and how these impacts could alter N2O fluxes are reviewed, and an outlook on the major questions and research needs to better constrain the global impact of permafrost N2O emissions is provided.", "authors": [ "Voigt, Carolina", "Marushchak, Maija E.", "Abbott, Benjamin W.", "Biasi, Christina", "Elberling, Bo", "Siciliano, Steven D.", "Sonnentag, Oliver", "Stewart, Katherine J.", "Yang, Yuanhe", "Martikainen, Pertti J." ], "keywords": [ "" ], "year": "2020", "source": "NATURE REVIEWS EARTH & ENVIRONMENT", "publication_type": "J", "point2d": [ -36.84100341796875, 55.66730499267578 ], "cluster": 9.0 }, { "idx": 789, "title": "Accuracy assessment of late winter snow depth mapping for tundra environments using Structure-from-Motion photogrammetry", "abstract": "Arctic tundra environments are characterized by a spatially heterogeneous end-of-winter snow depth resulting from wind transport and deposition. Traditional methods for measuring snow depth do not accurately capture such heterogeneity at catchment scales. In this study we address the use of high-resolution, spatially distributed, snow depth data for Arctic environments through the application of unmanned aerial systems (UASs). We apply Structure-from-Motion photogrammetry to images collected using a fixed-wing UAS to produce a 1 m resolution snow depth product across seven areas of interest (AOIs) within the Trail Valley Creek Research Watershed, Northwest Territories, Canada. We evaluated these snow depth products with in situ measurements of both the snow surface elevation (n = 8434) and snow depth (n = 7191). When all AOIs were averaged, the RMSE of the snow surface elevation models was 0.16 m (<0.01 m bias), similar to the snow depth product (UASSD) RMSE of 0.15 m (+0.04 m bias). The distribution of snow depth between in situ measurements and UASSD was similar along the transects where in situ snow depth was collected, although similarity varies by AOI. Finally, we provide a discussion of factors that may influence the accuracy of the snow depth products including vegetation, environmental conditions, and study design.", "authors": [ "Walker, Branden", "Wilcox, Evan J.", "Marsh, Philip" ], "keywords": [ "unmanned aerial system (UAS)", "snow depth", "Structure-from-Motion (SFM)", "tundra", "high resolution" ], "year": "2021", "source": "ARCTIC SCIENCE", "publication_type": "J", "point2d": [ -57.97624206542969, 1.8247191905975342 ], "cluster": 8.0 }, { "idx": 790, "title": "Patterns of Ecosystem Structure and Wildfire Carbon Combustion Across Six Ecoregions of the North American Boreal Forest", "abstract": "Increases in fire frequency, extent, and severity are expected to strongly impact the structure and function of boreal forest ecosystems. An important function of the boreal forest is its ability to sequester and store carbon (C). Increasing disturbance from wildfires, emitting large amounts of C to the atmosphere, may create a positive feedback to climate warming. Variation in ecosystem structure and function throughout the boreal forest is important for predicting the effects of climate warming and changing fire regimes on C dynamics. In this study, we compiled data on soil characteristics, stand structure, pre-fire C pools, C loss from fire, and the potential drivers of these C metrics from 527 sites distributed across six ecoregions of North America's western boreal forests. We assessed structural and functional differences between these fire-prone ecoregions using data from 417 recently burned sites (2004-2015) and estimated ecoregion-specific relationships between soil characteristics and depth from 167 of these sites plus an additional 110 sites (27 burned, 83 unburned). We found that northern boreal ecoregions were generally older, stored and emitted proportionally more belowground than aboveground C, and exhibited lower rates of C accumulation over time than southern ecoregions. We present ecoregion-specific estimates of depth-wise soil characteristics that are important for predicting C combustion from fire. As climate continues to warm and disturbance from wildfires increases, the C dynamics of these fire-prone ecoregions are likely to change with significant implications for the global C cycle and its feedbacks to climate change.", "authors": [ "Walker, Xanthe J.", "Baltzer, Jennifer L.", "Bourgeau-Chavez, Laura", "Day, Nicola J.", "Dieleman, Catherine M.", "Johnstone, Jill F.", "Kane, Evan S.", "Rogers, Brendan M.", "Turetsky, Merritt R.", "Veraverbeke, Sander", "Mack, Michelle C." ], "keywords": [ "boreal forest", "fire", "black spruce", "jack pine", "carbon", "organic soil", "bulk density" ], "year": "2020", "source": "FRONTIERS IN FORESTS AND GLOBAL CHANGE", "publication_type": "J", "point2d": [ -27.20172691345215, 73.13245391845703 ], "cluster": 15.0 }, { "idx": 791, "title": "Fuel availability not fire weather controls boreal wildfire severity and carbon emissions", "abstract": "Carbon (C) emissions from wildfires are a key terrestrial-atmosphere interaction that influences global atmospheric composition and climate. Positive feedbacks between climate warming and boreal wildfires are predicted based on top-down controls of fire weather and climate, but C emissions from boreal fires may also depend on bottom-up controls of fuel availability related to edaphic controls and overstory tree composition. Here we synthesized data from 417 field sites spanning six ecoregions in the northwestern North American boreal forest and assessed the network of interactions among potential bottom-up and top-down drivers of C emissions. Our results indicate that C emissions are more strongly driven by fuel availability than by fire weather, highlighting the importance of fine-scale drainage conditions, overstory tree species composition and fuel accumulation rates for predicting total C emissions. By implication, climate change-induced modification of fuels needs to be considered for accurately predicting future C emissions from boreal wildfires. Carbon emissions from fires are generally modelled and predicted from fire weather and climate. Fuel availability drives carbon emissions more strongly than fire weather in boreal forests, highlighting the importance of ecological dynamics for fire-climate feedbacks.", "authors": [ "Walker, X. J.", "Rogers, B. M.", "Veraverbeke, S.", "Johnstone, J. F.", "Baltzer, J. L.", "Barrett, K.", "Bourgeau-Chavez, L.", "Day, N. J.", "de Groot, W. J.", "Dieleman, C. M.", "Goetz, S.", "Hoy, E.", "Jenkins, L. K.", "Kane, E. S.", "Parisien, M. -A.", "Potter, S.", "Schuur, E. A. G.", "Turetsky, M.", "Whitman, E.", "Mack, M. C." ], "keywords": [ "" ], "year": "2020", "source": "NATURE CLIMATE CHANGE", "publication_type": "J", "point2d": [ -26.515939712524414, 73.74412536621094 ], "cluster": 15.0 }, { "idx": 795, "title": "Using the red chromatic coordinate to characterize the phenology of forest canopy photosynthesis", "abstract": "Vegetation phenology has received increasing attention in climate change research. Near-surface sensing using digital repeat photography has proven to be useful for ecosystem-scale monitoring of vegetation phenology. However, our understanding of the link between phenological metrics derived from digital repeat photography and the phenology of forest canopy photosynthesis is still incomplete, especially for evergreen plant species. Using 49 site-years of digital images from the PhenoCam Network from eight evergreen needleleaf forest (ENF) and six deciduous broadleaf forest (DBF) sites in North America, we explored the potential of the green chromatic (GCC) and red chromatic coordinates (RCC) in tracking forest canopy photosynthesis by comparing camera-derived start- and end-of-growing season (SOS and EOS, respectively) with corresponding estimates derived from eddy covariance-derived daily gross primary productivity (GPP). We found that for DBF sites, both GCC and RCC performed comparable in capturing SOS and EOS. However, similar to earlier studies, GCC had limited potential in capturing GPP-based SOS or EOS for ENF sites. In contrast, we found RCC was a better predictor of both GPP-based SOS and EOS for ENF sites. Environmental and ecological explanations were both provided that phenological transitions derived from RCC were highly correlated with spring and autumn meteorological conditions, as well as having overall higher correlations with phenology based on LAI, a critical variable for describing canopy development. Our results demonstrate that RCC is an underappreciated metric for tracking vegetation phenology, especially for ENF sites where GCC failed to provide reliable estimates for GPP-based SOS or EOS. Our results improve confidence in using digital repeat photography to characterize the phenology of canopy photosynthesis across forest types.", "authors": [ "Liu, Ying", "Wu, Chaoyang", "Sonnentag, Oliver", "Desai, Ankur R.", "Wang, Jian" ], "keywords": [ "Phenology", "PhenoCam", "Gross primary productivity", "GCC", "RCC", "DBF", "ENF" ], "year": "2020", "source": "AGRICULTURAL AND FOREST METEOROLOGY", "publication_type": "J", "point2d": [ -65.58079528808594, 63.35232925415039 ], "cluster": 17.0 }, { "idx": 796, "title": "Debris cover on thaw slumps and its insulative role in a warming climate", "abstract": "Thaw slumps in ice-rich permafrost can retreat tens of metres per summer, driven by the melt of subaerially exposed ground ice. However, some slumps retain an ice-veneering debris cover as they retreat. A quantitative understanding of the thermal regime and geomorphic evolution of debris-covered slumps in a warming climate is largely lacking. To characterize the thermal regime, we instrumented four debris-covered slumps in the Canadian Low Arctic and developed a numerical conduction-based model. The observed surface temperatures >20 degrees C and steep thermal gradients indicate that debris insulates the ice by shifting the energy balance towards radiative and turbulent losses. After the model was calibrated and validated with field observations, it predicted sub-debris ice melt to decrease four-fold from 1.9 to 0.5 mas the thickness of the fine-grained debris quadruples from 0.1 to 0.4 m. With warming temperatures, melt is predicted to increase most rapidly, in relative terms, for thick (similar to 0.5-1.0 m) debris covers. The morphology and evolution of the debris-covered slumps were characterized using field and remote sensing observations, which revealed differences in association with morphology and debris composition. Two low-angle slumps retreated continually despite their persistent fine-grained debris covers. The observed elevation losses decreased from similar to 1.0 m/yr where debris thickness similar to 0.2 mto 0.1 m/yr where thickness similar to 1.0 m. Conversely, a steep slump with a coarse-grained debris veneer underwent short-lived bursts of retreat, hinting at a complex interplay of positive and negative feedback processes. The insulative protection and behaviour of debris vary significantly with factors such as thickness, grain size and climate: debris thus exerts a fundamental, spatially variable influence on slump trajectories in a warming climate. (c) 2020 John Wiley & Sons, Ltd.", "authors": [ "Zwieback, S.", "Boike, J.", "Marsh, P.", "Berg, A." ], "keywords": [ "retrogressive thaw slump", "thermokarst", "debris", "climate sensitivity", "permafrost", "ground ice" ], "year": "2020", "source": "EARTH SURFACE PROCESSES AND LANDFORMS", "publication_type": "J", "point2d": [ -28.75899887084961, 41.23406219482422 ], "cluster": 8.0 }, { "idx": 797, "title": "Rethinking groundwater age", "abstract": "", "authors": [ "Ferguson, Grant", "Cuthbert, Mark O.", "Befus, Kevin", "Gleeson, Tom", "McIntosh, Jennifer C." ], "keywords": [ "" ], "year": "2020", "source": "NATURE GEOSCIENCE", "publication_type": "J", "point2d": [ 13.66874885559082, 24.48282814025879 ], "cluster": 18.0 }, { "idx": 798, "title": "Rethinking groundwater age", "abstract": "", "authors": [ "Ferguson, Grant", "Cuthbert, Mark O.", "Befus, Kevin", "Gleeson, Tom", "McIntosh, Jennifer C." ], "keywords": [ "" ], "year": "2020", "source": "NATURE GEOSCIENCE", "publication_type": "J", "point2d": [ 13.66874885559082, 24.48282814025879 ], "cluster": 18.0 }, { "idx": 799, "title": "Deep Meteoric Water Circulation in Earth's Crust", "abstract": "Deep meteoric waters comprise a key component of the hydrologic cycle, transferring water, energy, and life between the Earth's surface and deeper crustal environments, yet little is known about the nature and extent of meteoric water circulation. Using water stable isotopes, we show that maximum circulation depths of meteoric waters across North America vary considerably from <1 to 5 km, with the deepest circulation in Western North America in areas of greater topographic relief. Shallower circulation occurs in sedimentary and shield-type environments with subdued topography. The amount of topographic relief available to drive regional groundwater flow and flush saline fluids is an important control on the extent of meteoric water circulation, in addition to permeability. The presence of an active flow system in the upper few kilometers of the Earth's crust and stagnant brines trapped by negative buoyancy offers a new framework for understanding deep groundwater systems.", "authors": [ "McIntosh, Jennifer C.", "Ferguson, Grant" ], "keywords": [ "Critical Zone", "Groundwater hydrology", "Groundwater transport", "Stable isotope geochemistry" ], "year": "2021", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ 5.043734550476074, 25.734296798706055 ], "cluster": 18.0 }, { "idx": 800, "title": "Deep Meteoric Water Circulation in Earth's Crust", "abstract": "Deep meteoric waters comprise a key component of the hydrologic cycle, transferring water, energy, and life between the Earth's surface and deeper crustal environments, yet little is known about the nature and extent of meteoric water circulation. Using water stable isotopes, we show that maximum circulation depths of meteoric waters across North America vary considerably from <1 to 5 km, with the deepest circulation in Western North America in areas of greater topographic relief. Shallower circulation occurs in sedimentary and shield-type environments with subdued topography. The amount of topographic relief available to drive regional groundwater flow and flush saline fluids is an important control on the extent of meteoric water circulation, in addition to permeability. The presence of an active flow system in the upper few kilometers of the Earth's crust and stagnant brines trapped by negative buoyancy offers a new framework for understanding deep groundwater systems.", "authors": [ "McIntosh, Jennifer C.", "Ferguson, Grant" ], "keywords": [ "Critical Zone", "Groundwater hydrology", "Groundwater transport", "Stable isotope geochemistry" ], "year": "2021", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ 5.043734550476074, 25.734296798706055 ], "cluster": 18.0 }, { "idx": 801, "title": "Biochemical and Molecular Investigation of In Vitro Antioxidant and Anticancer Activity Spectrum of Crude Extracts of Willow Leaves Salix safsaf", "abstract": "Organic fractions and extracts of willow (Salix safsaf) leaves, produced by sequential solvent extraction as well as infusion and decoction, exhibited anticancer potencies in four cancerous cell lines, including breast (MCF-7), colorectal (HCT-116), cervical (HeLa) and liver (HepG2). Results of the MTT assay revealed that chloroform (CHCl3) and ethyl acetate (EtOAc)-soluble fractions exhibited specific anticancer activities as marginal toxicities were observed against two non-cancerous control cell lines (BJ-1 and MCF-12). Ultra-high-resolution mass spectrometry Q-Exactive (TM) HF Hybrid Quadrupole-Orbitrap (TM) coupled with liquid chromatography (UHPLC) indicated that both extracts are enriched in features belonging to major phenolic and purine derivatives. Fluorescence-activated cell sorter analysis (FACS), employing annexin V-FITC/PI double staining indicated that the observed cytotoxic potency was mediated via apoptosis. FACS analysis, monitoring the increase in fluorescence signal, associated with oxidation of DCFH to DCF, indicated that the mechanism of apoptosis is independent of reactive oxygen species (ROS). Results of immunoblotting and RT-qPCR assays showed that treatment with organic fractions under investigation resulted in significant up-regulation of pro-apoptotic protein and mRNA markers for Caspase-3, p53 and Bax, whereas it resulted in a significant reduction in amounts of both protein and mRNA of the anti-apoptotic marker Bcl-2. FACS analysis also indicated that pre-treatment and co-treatment of human amniotic epithelial (WISH) cells exposed to the ROS H2O2 with EtOAc fraction provide a cytoprotective and antioxidant capacity against generated oxidative stress. In conclusion, our findings highlight the importance of natural phenolic and flavonoid compounds with unparalleled and unique antioxidant and anticancer properties.", "authors": [ "Aboul-Soud, Mourad A. M.", "Ashour, Abdelkader E.", "Challis, Jonathan K.", "Ahmed, Atallah F.", "Kumar, Ashok", "Nassrallah, Amr", "Alahmari, Tariq A.", "Saquib, Quaiser", "Siddiqui, Maqsood A.", "Al-Sheikh, Yazeed", "El-Shemy, Hany A.", "Aboul-Enein, Ahmed M.", "Alghamdi, Khalid M.", "Jones, Paul D.", "Giesy, John P." ], "keywords": [ "Salix safsaf", "cytotoxicity", "polyphenols", "flavonoids", "mass spectrometry", "apoptosis", "natural products" ], "year": "2020", "source": "PLANTS-BASEL", "publication_type": "J", "point2d": [ 82.90845489501953, -5.155313968658447 ], "cluster": 6.0 }, { "idx": 802, "title": "Mechanisms of pH-Dependent Uptake of Ionizable Organic Chemicals by Fish from Oil Sands Process-Affected Water (OSPW)", "abstract": "Uptake and effects of ionizable organic chemicals (IOCs) that are weak acids in aqueous solution by fish can differ as a function of pH. While the pH-dependent behavior of select IOCs is well-understood, complex mixtures of IOCs, e.g., from oil sands process-affected water (OSPW), have not yet been studied systematically. Here, we established an in vitro screening method using the rainbow trout gill cell line, RTgill-W1, to investigate pH-dependent cytotoxicity and permeation of IOCs across cultured epithelia using ultra-high-performance liquid chromatography with high-resolution mass spectrometry (UPLC-HRMS). The assay was benchmarked using model chemicals and technical mixtures, and then used to characterize fractions and reconstituted extracts of field-collected OSPW. Significant pH-dependent cytotoxicity of individual IOCs, acidic fractions, and reconstituted extracts of OSPW was observed. In vitro data were in good agreement with data from a 96 h in vivo exposure experiment with juvenile rainbow trout. Permeation of some IOCs from OSPW was mediated by active transport, as revealed by studies in which inhibitors of these active transport mechanisms were applied. We conclude that the RTgill-W1 in vitro assay is useful for the screening of pH-dependent uptake of IOCs in fish, and has applications for in vitro-in vivo extrapolation, and prioritization of chemicals in nontarget screenings.", "authors": [ "Brinkmann, Markus", "Alharbi, Hattan", "Fuchylo, Ulyana", "Wiseman, Steve", "Morandi, Garrett", "Peng, Hui", "Giesy, John P.", "Jones, Paul D.", "Hecker, Markus" ], "keywords": [ "" ], "year": "2020", "source": "ENVIRONMENTAL SCIENCE & TECHNOLOGY", "publication_type": "J", "point2d": [ 83.83070373535156, 2.938880681991577 ], "cluster": 0.0 }, { "idx": 803, "title": "Towards indigenous community-led monitoring of fish in the oil sands region of Canada: Lessons at the intersection of cultural consensus and fish science", "abstract": "In the Oil Sands Regions of Alberta, Canada, Indigenous reassertion of rights and responsibilities has lead to a renewed leadership in monitoring the effects of industries on various environment receptors. This study, conducted with Cold Lake First Nations, Alberta (CLFN), sought to explore local concerns regarding fish consumption safety and population health in response to multiple anthropogenic stressors focusing upon oil extraction. We undertook this work using a novel research design comprised of two distinct approaches including a participatory fish health and toxicology study and a cultural consensus survey of CLFN members. The cultural consensus study assessed similarities and differences in knowledge and perceptions of CLFN members. The fish toxicology and health research involved implementing a co-designed protocol to collect and sample fish for toxicants and overall population health using scientific indicators. We discuss the results of each study as well as the tangible application of our work in achieving a Multiple Evidence Base approach. Our work highlights that complementarities between our studies as part of a negotiated research process can form a single cohesive narrative to better inform fisheries management while respecting community knowledge, culture and rights to access land, water and country foods.", "authors": [ "Brunet, Nicolas D.", "Jardine, Timothy D.", "Jones, Paul D.", "Macdermid, Findlay", "Reed, Graeme", "Bogdan, Ana-Maria", "Tchir, Devan R.", "Natcher, David C." ], "keywords": [ "Indicator", "Multiple Evidence Base", "Fish consumption", "Alberta", "Fish health" ], "year": "2020", "source": "EXTRACTIVE INDUSTRIES AND SOCIETY-AN INTERNATIONAL JOURNAL", "publication_type": "J", "point2d": [ 73.515625, -20.192087173461914 ], "cluster": 7.0 }, { "idx": 804, "title": "Ractopamine and Other Growth-Promoting Compounds in Beef Cattle Operations: Fate and Transport in Feedlot Pens and Adjacent Environments", "abstract": "The current study represents a comprehensive investigation of the occurrence and fates of trenbolone acetate (TBA) and metabolites 17 alpha-trenbolone (17 alpha-TBOH), 17 beta-TBOH, and trendione (TBO); melengesterol acetate (MGA); and the less commonly studied beta-andrenergic agonist ractopamine (RAC) in two 8 month cattle feeding trials and simulated rainfall runoff experiments. Cattle were administered TBA, MGA, or RAC, and their residues were measured in fresh feces, pen floor material, and simulated rainfall runoff from pen floor surfaces and manure-amended pasture. Concentrations of RAC ranged from 3600 ng g(-1), dry weight (dw), in pen floor to 58 000 ng g(-1) in fresh feces and were, on average, observed at 3-4 orders of magnitude greater than those of TBA and MGA. RAC persisted in pen floors (manure t(1/2) = 18-49 days), and contamination of adjacent sites was observed, likely via transport of windblown particulates. Concentrations in runoff water from pen floors extrapolated to larger-scale commercial feedlots revealed that a single rainfall event could result in mobilization of gram quantities of RAC. This is the first report of RAC occurrence and fate in cattle feedlot environments, and will help understand the risks posed by this chemical and inform appropriate manure-management practices.", "authors": [ "Challis, J. K.", "Sura, S.", "Cantin, J.", "Curtis, A. W.", "Shade, K. M.", "McAllister, T. A.", "Jones, P. D.", "Giesy, J. P.", "Larney, F. J." ], "keywords": [ "" ], "year": "2021", "source": "ENVIRONMENTAL SCIENCE & TECHNOLOGY", "publication_type": "J", "point2d": [ 70.4408187866211, -6.379347801208496 ], "cluster": 0.0 }, { "idx": 805, "title": "Responses of juvenile fathead minnow (Pimephales promelas) gut microbiome to a chronic dietary exposure of benzo[a]pyrene", "abstract": "The microbiome has been described as an additional host organ with well-established beneficial roles. However, the effects of exposures to chemicals on both structure and function of the gut microbiome of fishes are understudied. To determine effects of benzo[a]pyrene (BaP), a model persistent organic pollutant, on structural shifts of gut microbiome in juvenile fathead minnows (Pimephales promelas), fish were exposed ad libitum in the diet to concentrations of 1,10,100, or 1000 mg BaP g(-1) food, in addition to a vehicle control, for two weeks. To determine the link between exposure to BaP and changes in the microbial community, concentrations of metabolites of BaP were measured in fish bile and 16S rRNA amplicon sequencing was used to evaluate the microbiome. Exposure to BaP only reduced alpha diversity at the greatest exposure concentrations. However, it did alter community composition assessed as differential abundance of taxa and reduced network complexity of the microbial community in all exposure groups. Results presented here illustrate that environmentally-relevant concentrations of BaP can alter the diversity of the gut microbiome and community network connectivity. (C) 2021 Elsevier Ltd. All rights reserved.", "authors": [ "DeBofsky, Abigail", "Xie, Yuwei", "Challis, Jonathan K.", "Jain, Niteesh", "Brinkmann, Markus", "Jones, Paul D.", "Giesy, John P." ], "keywords": [ "Homeostasis", "Next-generation sequencing", "Persistent organic pollutants", "Fish", "Metagenomics", "16s rRNA metagenetics" ], "year": "2021", "source": "ENVIRONMENTAL POLLUTION", "publication_type": "J", "point2d": [ 79.20381927490234, 2.1298296451568604 ], "cluster": 0.0 }, { "idx": 806, "title": "Effects of the husky oil spill on gut microbiota of native fishes in the North Saskatchewan River, Canada", "abstract": "In July 2016, a Husky Energy pipeline spilled 225,000 L of diluted heavy crude oil, with a portion of the oil entering the North Saskatchewan River near Maidstone, SK, Canada. This event provided a unique opportunity to assess potential effects of a crude oil constituent (namely polycyclic aromatic hydrocarbons, PAHs) on a possible sensitive indicator of freshwater ecosystem health, the gut microbiota of native fishes. In summer 2017, goldeye (Hiodon alosoides), walleye (Sander vitreus), northern pike (Esox lucius), and shorthead redhorse (Moxostoma macrolepidotum) were collected at six locations upstream and downstream of the spill. Muscle and bile were collected from individual fish for quantification of PAHs and intestinal contents were collected for characterization of the microbial community of the gut. Results suggested that host species is a significant determinant of gut microbiota, with significant differences among the species across sites. Concentrations of PAHs in dorsal muscle were significantly correlated with gut community compositions of walleye, but not of the other fishes. Concentrations of PAHs in muscle were also correlated with abundances of several families of bacteria among fishes. This study represents one of the first to investigate the response of the gut microbiome of wild fishes to chemical stressors.", "authors": [ "DeBofsky, Abigail", "Xie, Yuwei", "Jardine, Timothy D.", "Hill, Janet E.", "Jones, Paul D.", "Giesy, John P." ], "keywords": [ "Ecotoxicology", "16S rRNA metagenetics", "Molecular ecology", "Freshwater fish", "Wild animal" ], "year": "2020", "source": "AQUATIC TOXICOLOGY", "publication_type": "J", "point2d": [ 78.55487060546875, 4.321232795715332 ], "cluster": 0.0 }, { "idx": 807, "title": "In vitro-in vivo and cross-life stage extrapolation of uptake and biotransformation of benzo [a] pyrene in the fathead minnow (Pimephales promelas)", "abstract": "Understanding internal dose metrics is integral to adequately assess effects environmental contaminants might have on aquatic wildlife, including fish. In silico toxicokinetic (TK) models are a leading approach for quantifying internal exposure metrics for fishes; however, they often do not adequately consider chemicals that are actively biotransformed and have not been validated against early-life stages (ELS) that are often considered the most sensitive to the exposure to contaminants. To address these uncertainties, TK models were parameterized for the rapidly biotransformed chemical benzo [al pyrene (13 [al P) in embryo-larval and adult life stages of fathead minnows. Biotransformation of B[a]P was determined through measurements of in vitro clearance. Using in vitro-in vivo extrapolation, in vitro clearance was integrated into a multi-compartment TK model for adult fish and a one-compartment model for ELS. Model predictions were validated using measurements of B[a]P metabolites from in vivo flow-through exposures to graded concentrations of water-borne B[a]P. Significantly greater amounts of B[a]P metabolites were observed with exposure to greater concentrations of parent compound in both life stages. However, when assessing biotransformation capacity, no differences in phase I or phase II biotransformation were observed with greater exposures to B[a]P. Results of modelling suggested that biotransformation of B[a]P can be successfully implemented into in silico models to accurately predict life stage-specific abundances of B[a]P metabolites in either whole-body larvae or the bile of adult fish. Models developed increase the scope of applications in which TK models can be used to support environmental risk assessments.", "authors": [ "Grimard, Chelsea", "Mangold-Doering, Annika", "Schmitz, Markus", "Alharbi, Hattan", "Jones, Paul D.", "Giesy, John P.", "Hecker, Markus", "Brinkmann, Markus" ], "keywords": [ "Benzo[a]pyrene", "Biotransformation", "Fathead minnow", "In vitro-in vivoextrapolation", "Life-Stage extrapolation", "TK models" ], "year": "2020", "source": "AQUATIC TOXICOLOGY", "publication_type": "J", "point2d": [ 80.2811508178711, -0.010970328003168106 ], "cluster": 0.0 }, { "idx": 808, "title": "Toxicokinetics of Brominated Azo Dyes in the Early Life Stages of Zebrafish (Danio rerio) Is Prone to Aromatic Substituent Changes", "abstract": "Brominated azo dyes (BADS) have been identified as predominant indoor brominated pollutants in daycare dust; thus, their potential health risk to children is of concern. However, the toxicities of BADs remain elusive. In this study, the toxicokinetics of two predominant BADS, Disperse Blue 373 (DB373) and Disperse Violet 93 (DV93), and their suspect metabolite 2-bromo-4,6-dinitroaniline (BDNA) was investigated in embryos of zebrafish (Danio rerio). The bioconcentration factor of DV93 at 120 hpf is 6.2-fold lower than that of DB373. The nontarget analysis revealed distinct metabolism routes between DB373 and DV93 by reducing nitro groups to nitroso (DB373) or amine (DV93), despite their similar structures. NAD(P)H quinone oxidoreductase 1 (NQO1) and pyruvate dehydrogenase were predicted as the enzymes responsible for the reduction of DB373 and DV93 by correlating time courses of the metabolites and enzyme development. Further in vitro recombinant enzyme and in vivo inhibition results validated NQO1 as the enzyme specifically reducing DB373, but not DV93. Global proteome profiling revealed that the expression levels of proteins from the apoptosis- induced DNA fragmentation pathway were significantly upregulated by all three BADs, supporting the bioactivation of BADs to mutagenic aromatic amines. This study discovered the bioactivation of BADs via distinct eukaryotic enzymes, implying their potential health risks.", "authors": [ "Han, Jiajun", "Yang, Diwen", "Hall, David Ross", "Liu, Jiabao", "Sun, Jianxian", "Gu, Wen", "Tang, Song", "Alharbi, Hattan A.", "Jones, Paul D.", "Krause, Henry M.", "Peng, Hui" ], "keywords": [ "" ], "year": "2020", "source": "ENVIRONMENTAL SCIENCE & TECHNOLOGY", "publication_type": "J", "point2d": [ 84.16117095947266, -2.7454159259796143 ], "cluster": 0.0 }, { "idx": 809, "title": "Prefertilization Exposure of Rainbow Trout Eggs to Per- and Polyfluoroalkyl Substances to Simulate Accumulation During Oogenesis", "abstract": "Aqueous film-forming foams (AFFFs) are used in firefighting and are sources of per- and polyfluoroalkyl substances (PFAS) to the environment through surface runoff and groundwater contamination at defense and transportation sites. Little is known regarding the toxicity and bioaccumulation of newer AFFF formulations containing novel PFAS. To mimic maternal transfer of PFAS, prefertilization rainbow trout eggs were exposed to three PFAS using novel methodologies. Batches of unfertilized oocytes were exposed for 3 h to 0, 0.01, 0.1, 1, or 10 mu g/ml separately to perfluorooctanoic acid, perfluorohexanoic acid, or perfluorooctanesulfonic acid in either coelomic fluid or Cortland's solution. After exposure, the gametes were fertilized and rinsed with dechlorinated water. Egg yolk was aspirated from a subset of fertilized eggs for PFAS quantification. Each PFAS was detected in yolks of eggs exposed to the respective PFAS, and yolk concentrations were directly proportional to concentrations in aqueous media to which they were exposed. Exposure in coelomic fluid or Cortland's solution resulted in similar concentrations of PFAS in egg yolks. Ratios of PFAS concentrations in oocytes to concentrations in exposure media (oocyte fluid ratios) were <0.99 when exposed from 0.01 to 10 mu g/ml and <0.45 when exposed from 0.1 to 10 mu g/ml for both media and all three PFAS, demonstrating that the water solubility of the chemicals was relatively great. Prefertilization exposure of eggs effectively introduced PFAS into unfertilized egg yolk. This method provided a means of mimicking maternal transfer to evaluate toxicity to developing embryos from an early stage. This method is more rapid and efficient than injection of individual fertilized eggs and avoids trauma from inserting needles into eggs. Environ Toxicol Chem 2021;00:1-7. (c) 2021 SETAC", "authors": [ "Raine, J. C.", "Su, S.", "Lin, E.", "Yang, Z. L.", "Giesy, J. P.", "Jones, P. D." ], "keywords": [ "Aqueous film-forming foams", "Oocytes", "Fish", "Salmonid", "Yolk", "Development" ], "year": "2021", "source": "ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY", "publication_type": "J", "point2d": [ 86.73329162597656, 0.3592805564403534 ], "cluster": 0.0 }, { "idx": 810, "title": "Evaluating transdisciplinary research practices: insights from social network analysis", "abstract": "Transdisciplinary researchers collaborate with diverse partners outside of academia to tackle sustainability problems. The patterns and practices of social interaction and the contextual nature of transdisciplinary research result in different performance expectations than traditional, curiosity-driven research. Documenting patterns of interaction can inform project success and affirm progress toward interim outcomes on the way to achieve sustainability impacts. Yet providing credible and robust indicators of research activity remains challenging. We provide quantitative and qualitative indicators for assessing transdisciplinary practices and patterns through social network analysis (SNA). Our assessment developed four criteria to reveal how SNA metrics provide insight into (1) diversity of participants; (2) whether and how integration and collaboration are occurring, (3) the relative degrees of network stability and fragility, and (4) how the network is structured to achieve its goals. These four key criteria can be used to help identify patterns of research activity and determine whether interim progress is occurring.", "authors": [ "Steelman, T.", "Bogdan, A.", "Mantyka-Pringle, C.", "Bradford, L.", "Reed, M. G.", "Baines, S.", "Fresque-Baxter, J.", "Jardine, T.", "Shantz, S.", "Abu, R.", "Staples, K.", "Andrews, Evan", "Bharadwaj, Lalita", "Strickert, G.", "Jones, Paul", "Lindenschmidt, K.", "Poelzer, G." ], "keywords": [ "Early career researchers", "Evaluation", "Knowledge co-production", "Social network analysis", "Transdisciplinarity" ], "year": "2021", "source": "SUSTAINABILITY SCIENCE", "publication_type": "J", "point2d": [ 57.49640655517578, -29.269447326660156 ], "cluster": 4.0 }, { "idx": 811, "title": "Effects of the brominated flame retardant, TBCO, on development of zebrafish (Danio rerio) embryos", "abstract": "Brominated flame retardants (BFRs) can enter aquatic environments where they can have adverse effects on organisms. The BFR, 1,2,5,6-Tetrabromocyclooctane (TBCO), has been introduced as a potential replacement for the major use BRF, Hexabromocyclododecane (HBCD). However, little is known about effects of TBCO on aquatic organisms. Using zebrafish (Danio rerio) as a model species, objectives of this study were to determine whether TBCO has adverse effects on early life-stages and to investigate the molecular and biochemical mechanisms of any effects on development. Exposure to TBCO caused a concentration dependant increase in mortality, decrease in heart rate, and increase in incidences of spinal curvature and uninflated swim bladders. Neither peroxidation of lipids or mRNA abundances of genes important for the response to oxidative stress were greater in embryos exposed to TBCO suggesting effects were not caused by oxidative stress. The mRNA abundance of cytochrome p4501a was not greater in embryos exposed to TBCO suggesting that effects were not caused by activation of the aryl hydrocarbon receptor. Finally, mRNA abundances of genes important for development and inflation of the swim bladder were not affected by TBCO. Overall, TBCO causes adverse effects on early life-stages of zebrafish, but mechanisms of effects require further investigation. (C) 2020 Elsevier Ltd. All rights reserved.", "authors": [ "Van Essen, Darren", "Devoy, Chloe", "Miller, Justin", "Jones, Paul D.", "Wiseman, Steve" ], "keywords": [ "Novel brominated flame retardant", "Embryotoxicity", "Spinal curvature", "Swim bladder", "Oxidative stress" ], "year": "2021", "source": "CHEMOSPHERE", "publication_type": "J", "point2d": [ 83.46041107177734, -1.7239210605621338 ], "cluster": 0.0 }, { "idx": 812, "title": "Climate Extremes and Compound Hazards in a Warming World", "abstract": "Climate extremes threaten human health, economic stability, and the wellbeing of natural and built environments (e.g., 2003 European heat wave). As the world continues to warm, climate hazards are expected to increase in frequency and intensity. The impacts of extreme events will also be more severe due to the increased exposure (growing population and development) and vulnerability (aging infrastructure) of human settlements. Climate models attribute part of the projected increases in the intensity and frequency of natural disasters to anthropogenic emissions and changes in land use and land cover. Here, we review the impacts, historical and projected changes, and theoretical research gaps of key extreme events (heat waves, droughts, wildfires, precipitation, and flooding). We also highlight the need to improve our understanding of the dependence between individual and interrelated climate extremes because anthropogenic-induced warming increases the risk of not only individual climate extremes but also compound (co-occurring) and cascading hazards. Climate hazards are expected to increase in frequency and intensity in a warming world. Anthropogenic-induced warming increases the risk of compound and cascading hazards. We need to improve our understanding of causes and drivers of compound and cascading hazards.", "authors": [ "AghaKouchak, Amir", "Chiang, Felicia", "Huning, Laurie S.", "Love, Charlotte A.", "Mallakpour, Iman", "Mazdiyasni, Omid", "Moftakhari, Hamed", "Papalexiou, Simon Michael", "Ragno, Elisa", "Sadegh, Mojtaba" ], "keywords": [ "compound events", "cascading hazards", "climate extremes", "climate change", "risk", "hydrology" ], "year": "2020", "source": "ANNUAL REVIEW OF EARTH AND PLANETARY SCIENCES, VOL 48, 2020", "publication_type": "S", "point2d": [ -35.85578918457031, -66.05509948730469 ], "cluster": 14.0 }, { "idx": 813, "title": "How Probable Is Widespread Flooding in the United States?", "abstract": "Widespread flooding can cause major damages and substantial recovery costs. Still, estimates of how susceptible a region is to widespread flooding are largely missing mainly because of the sparseness of widespread flood events in records. The aim of this study is to assess the seasonal susceptibility of regions in the United States to widespread flooding using a stochastic streamflow generator, which enables simulating a large number of spatially consistent flood events. Furthermore, we ask which factors influence the strength of regional flood susceptibilities. We show that susceptibilities to widespread flooding vary regionally and seasonally. They are highest in regions where catchments show regimes with a strong seasonality, that is, the Pacific Northwest, the Rocky Mountains, and the Northeast. In contrast, they are low in regions where catchments are characterized by a weak seasonality and intermittent regimes such as the Great Plains. Furthermore, susceptibility is found to be the highest in winter and spring when spatial flood dependencies are strongest because of snowmelt contributions and high soil moisture availability. We conclude that regional flood susceptibilities emerge in river basins with catchments sharing similar streamflow and climatic regimes.", "authors": [ "Brunner, Manuela, I", "Papalexiou, Simon", "Clark, Martyn P.", "Gilleland, Eric" ], "keywords": [ "flood", "stochastic simulation", "regional frequency analysis", "hazard assessment", "spatial dependence", "extreme events" ], "year": "2020", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -11.876790046691895, -63.832374572753906 ], "cluster": 16.0 }, { "idx": 814, "title": "A cross-scale framework for integrating multi-source data in Earth system sciences", "abstract": "Integration of Earth system data from various sources is a challenging task. Except for their qualitative heterogeneity, different data records exist for describing similar Earth system processes at different spatiotemporal scales. Data inter-comparison and validation are usually performed at a single spatial or temporal scale, which could hamper the identification of potential discrepancies in other scales. Here, we propose a simple, yet efficient, graphical method for synthesizing and comparing observed and modelled data across a range of spatiotemporal scales. Instead of focusing at specific scales, such as annual means or original grid resolution, we examine how their statistical properties change across spatiotemporal continuum. The proposed cross-scale framework for integrating multi-source data in Earth system sciences is already developed as a stand-alone R package that is freely available to download.", "authors": [ "Markonis, Yannis", "Pappas, Christoforos", "Hanel, Martin", "Papalexiou, Simon Michael" ], "keywords": [ "Dataset validation", "Multiscale statistics", "Earth system models", "Earth system observations", "Cross-scale analysis", "Multi-source data" ], "year": "2021", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ -43.40554428100586, -50.188560485839844 ], "cluster": 14.0 }, { "idx": 815, "title": "Seasonality, Intensity, and Duration of Rainfall Extremes Change in a Warmer Climate", "abstract": "Precipitation extremes are expected to intensify under climate change with consequent impacts in flooding and ecosystem functioning. Here we use station data and high-resolution simulations from the WRF convection permitting climate model (similar to 4 km, 1 h) over the US to assess future changes in hourly precipitation extremes. It is demonstrated that hourly precipitation extremes and storm depths are expected to intensify under climate change and what is now a 20-year rainfall will become a 7-year rainfall on average for similar to 75% of gridpoints over the US. This intensification is mostly expressed as an increase in rainfall tail heaviness. Statistically significant changes in the seasonality and duration of rainfall extremes are also exhibited over similar to 95% of the domain. Our results suggest more non-linear future precipitation extremes with shorter spell duration that are distributed more uniformly throughout the year.", "authors": [ "Moustakis, Yiannis", "Papalexiou, Simon Michael", "Onof, Christian J.", "Paschalis, Athanasios" ], "keywords": [ "climate change", "convection‐", "permitting models", "rainfall extremes", "rainfall intensification", "rainfall seasonality" ], "year": "2021", "source": "EARTHS FUTURE", "publication_type": "J", "point2d": [ -47.1988639831543, -63.83876419067383 ], "cluster": 14.0 }, { "idx": 816, "title": "Global-scale massive feature extraction from monthly hydroclimatic time series: Statistical characterizations, spatial patterns and hydrological similarity", "abstract": "Hydroclimatic time series analysis focuses on a few feature types (e.g., autocorrelations, trends, extremes), which describe a small portion of the entire information content of the observations. Aiming to exploit a larger part of the available information and, thus, to deliver more reliable results (e.g., in hydroclimatic time series dustering contexts), here we approach hydroclimatic time series analysis differently, i.e., by performing massive feature extraction. In this respect, we develop a big data framework for hydroclimatic variable behaviour characterization. This framework relies on approximately 60 diverse features and is completely automatic (in the sense that it does not depend on the hydroclimatic process at hand). We apply the new framework to characterize mean monthly temperature, total monthly precipitation and mean monthly river flow. The applications are conducted at the global scale by exploiting 40-year-long time series originating from over 13 000 stations. We extract interpretable knowledge on seasonality, trends, autocorrelation, long-range dependence and entropy, and on feature types that are met less frequently. We further compare the examined hydroclimatic variable types in terms of this knowledge and, identify patterns related to the spatial variability of the features. For this latter purpose, we also propose and exploit a hydroclimatic time series dustering methodology. This new methodology is based on Breiman's random forests. The descriptive and exploratory insights gained by the global-scale applications prove the usefulness of the adopted feature compilation in hydroclimatic contexts. Moreover, the spatially coherent patterns characterizing the clusters delivered by the new methodology build confidence in its future exploitation. Given this spatial coherence and the scale-independent nature of the delivered feature values (which makes them particularly useful in forecasting and simulation contexts), we believe that this methodology could also be beneficial within regionalization frameworks. in which knowledge on hydrological similarity is exploited in technical and operative terms. (C) 2021 Elsevier B.V.", "authors": [ "Papacharalampous, Georgia", "Tyralis, Hristos", "Papalexiou, Simon Michael", "Langousis, Andreas", "Khatami, Sina", "Volpi, Elena", "Grimaldi, Salvatore" ], "keywords": [ "Autocorrelation", "Entropy", "Hydroclimatic signatures", "Seasonality", "Statistical hydrology", "Trends" ], "year": "2021", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ -24.627918243408203, -60.80620193481445 ], "cluster": 14.0 }, { "idx": 817, "title": "Robustness of CMIP6 Historical Global Mean Temperature Simulations: Trends, Long-Term Persistence, Autocorrelation, and Distributional Shape", "abstract": "Multi-model climate experiments carried out as part of different phases of the Coupled Model Intercomparison Project (CMIP) are crucial to evaluate past and future climate change. The reliability of models' simulations is often gauged by their ability to reproduce the historical climate across many time scales. This study compares the global mean surface air temperature from 29 CMIP6 models with observations from three datasets. We examine (1) warming and cooling rates in five subperiods from 1880 to 2014, (2) autocorrelation and long-term persistence, (3) models' performance based on probabilistic and entropy metrics, and (4) the distributional shape of temperature. All models simulate the observed long-term warming trend from 1880 to 2014. The late twentieth century warming (1975-2014) and the hiatus (1942-1975) are replicated by most models. The post-1998 warming is overestimated in 90% of the simulations. Only six out of 29 models reproduce the observed long-term persistence. All models show differences in distributional shape when compared with observations. Varying performance across metrics reveals the challenge to determine the best model. Thus, we argue that models should be selected, based on case-specific metrics, depending on the intended use. Metrics proposed here facilitate a comprehensive assessment for various applications.", "authors": [ "Papalexiou, Simon Michael", "Rajulapati, Chandra Rupa", "Clark, Martyn P.", "Lehner, Flavio" ], "keywords": [ "climate models", "CMIP6", "global temperature", "evaluation" ], "year": "2020", "source": "EARTHS FUTURE", "publication_type": "J", "point2d": [ -41.31437301635742, -71.0252456665039 ], "cluster": 14.0 }, { "idx": 818, "title": "Assessment of Extremes in Global Precipitation Products: How Reliable Are They?", "abstract": "Global gridded precipitation products have proven essential for many applications ranging from hydrological modeling and climate model validation to natural hazard risk assessment. They provide a global picture of how precipitation varies across time and space, specifically in regions where ground-based observations are scarce. While the application of global precipitation products has become widespread, there is limited knowledge on how well these products represent the magnitude and frequency of extreme precipitation-the key features in triggering flood hazards. Here, five global precipitation datasets (MSWEP, CFSR, CPC, PERSIANN-CDR, and WFDEI) are compared to each other and to surface observations. The spatial variability of relatively high precipitation events (tail heaviness) and the resulting discrepancy among datasets in the predicted precipitation return levels were evaluated for the time period 1979-2017. The analysis shows that 1) these products do not provide a consistent representation of the behavior of extremes as quantified by the tail heaviness, 2) there is strong spatial variability in the tail index, 3) the spatial patterns of the tail heaviness generally match the Koppen-Geiger climate classification, and 4) the predicted return levels for 100 and 1000 years differ significantly among the gridded products. More generally, our findings reveal shortcomings of global precipitation products in representing extremes and highlight that there is no single global product that performs best for all regions and climates.", "authors": [ "Rajulapati, Chandra Rupa", "Papalexiou, Simon Michael", "Clark, Martyn P.", "Razavi, Saman", "Tang, Guoqiang", "Pomeroy, John W." ], "keywords": [ "Risk assessment", "Statistical techniques", "Statistics", "Diagnostics", "Reanalysis data" ], "year": "2020", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -33.140724182128906, -57.819183349609375 ], "cluster": 14.0 }, { "idx": 819, "title": "PMP and Climate Variability and Change: A Review", "abstract": "A state-of-the-art review on the probable maximum precipitation (PMP) as it relates to climate variability and change is presented. The review consists of an examination of the current practice and the various developments published in the literature. The focus is on relevant research where the effect of climate dynamics on the PMP are discussed, as well as statistical methods developed for estimating very large extreme precipitation including the PMP. The review includes interpretation of extreme events arising from the climate system, their physical mechanisms, and statistical properties, together with the effect of the uncertainty of several factors determining them, such as atmospheric moisture, its transport into storms and wind, and their future changes. These issues are examined as well as the underlying historical and proxy data. In addition, the procedures and guidelines established by some countries, states, and organizations for estimating the PMP are summarized. In doing so, attention was paid to whether the current guidelines and research published literature take into consideration the effects of the variability and change of climatic processes and the underlying uncertainties.", "authors": [ "Salas, Jose D.", "Anderson, Michael L.", "Papalexiou, Simon M.", "Frances, Felix" ], "keywords": [ "Probable maximum precipitation (PMP)", "Extreme precipitation", "Climate change", "Uncertainty", "Risk" ], "year": "2020", "source": "JOURNAL OF HYDROLOGIC ENGINEERING", "publication_type": "J", "point2d": [ -34.44322967529297, -60.690120697021484 ], "cluster": 14.0 }, { "idx": 821, "title": "SCDNA: a serially complete precipitation and temperature dataset for North America from 1979 to 2018", "abstract": "Station-based serially complete datasets (SCDs) of precipitation and temperature observations are important for hydrometeorological studies. Motivated by the lack of serially complete station observations for North America, this study seeks to develop an SCD from 1979 to 2018 from station data. The new SCD for North America (SCDNA) includes daily precipitation, minimum temperature (T-min), and maximum temperature (T-max) data for 27 276 stations. Raw meteorological station data were obtained from the Global Historical Climate Network Daily (GHCN-D), the Global Surface Summary of the Day (GSOD), Environment and Climate Change Canada (ECCC), and a compiled station database in Mexico. Stations with at least 8-year-long records were selected, which underwent location correction and were subjected to strict quality control. Outputs from three reanalysis products (ERA5, JRA-55, and MERRA-2) provided auxiliary information to estimate station records. Infilling during the observation period and reconstruction beyond the observation period were accomplished by combining estimates from 16 strategies (variants of quantile mapping, spatial interpolation, and machine learning). A sensitivity experiment was conducted by assuming that 30% of observations from stations were missing - this enabled independent validation and provided a reference for reconstruction. Quantile mapping and mean value corrections were applied to the final estimates. The median Kling-Gupta efficiency (KGE') values of the final SCDNA for all stations are 0.90, 0.98, and 0.99 for precipitation, T-min, and T-max, respectively. The SCDNA is closer to station observations than the four benchmark gridded products and can be used in applications that require either quality-controlled meteorological station observations or reconstructed long-term estimates for analysis and modeling. The dataset is available at https://doi.org/10.5281/zenodo.3735533 (Tang et al., 2020).", "authors": [ "Tang, Guoqiang", "Clark, Martyn P.", "Newman, Andrew J.", "Wood, Andrew W.", "Papalexiou, Simon Michael", "Vionnet, Vincent", "Whitfield, Paul H." ], "keywords": [ "" ], "year": "2020", "source": "EARTH SYSTEM SCIENCE DATA", "publication_type": "J", "point2d": [ -43.220558166503906, -54.58235168457031 ], "cluster": 14.0 }, { "idx": 824, "title": "Explanation and Probabilistic Prediction of Hydrological Signatures with Statistical Boosting Algorithms", "abstract": "Hydrological signatures, i.e., statistical features of streamflow time series, are used to characterize the hydrology of a region. A relevant problem is the prediction of hydrological signatures in ungauged regions using the attributes obtained from remote sensing measurements at ungauged and gauged regions together with estimated hydrological signatures from gauged regions. The relevant framework is formulated as a regression problem, where the attributes are the predictor variables and the hydrological signatures are the dependent variables. Here we aim to provide probabilistic predictions of hydrological signatures using statistical boosting in a regression setting. We predict 12 hydrological signatures using 28 attributes in 667 basins in the contiguous US. We provide formal assessment of probabilistic predictions using quantile scores. We also exploit the statistical boosting properties with respect to the interpretability of derived models. It is shown that probabilistic predictions at quantile levels 2.5% and 97.5% using linear models as base learners exhibit better performance compared to more flexible boosting models that use both linear models and stumps (i.e., one-level decision trees). On the contrary, boosting models that use both linear models and stumps perform better than boosting with linear models when used for point predictions. Moreover, it is shown that climatic indices and topographic characteristics are the most important attributes for predicting hydrological signatures.", "authors": [ "Tyralis, Hristos", "Papacharalampous, Georgia", "Langousis, Andreas", "Papalexiou, Simon Michael" ], "keywords": [ "catchment hydrology", "flow indices", "flow metrics", "hydrological processes", "hydrological uncertainty", "large sample hydrology", "prediction in ungauged basins", "quantile regression", "statistical boosting", "streamflow signatures" ], "year": "2021", "source": "REMOTE SENSING", "publication_type": "J", "point2d": [ -10.09624195098877, -60.45599365234375 ], "cluster": 16.0 }, { "idx": 825, "title": "Revisiting flood peak distributions: A pan-Canadian investigation", "abstract": "Safe and cost-effective design of infrastructures, such as dams, bridges, highways, often requires knowing the magnitude and frequency of peak floods. The Generalized Extreme Value distribution (G epsilon V) prevailed in flood frequency analysis along with distributions comprising location, scale, and shape parameters. Here we explore alternative models and propose power-type models, having one scale and two shape parameters. The Burr type III (BrIII) and XII (BrXII) distributions are compared against the G epsilon V in 1088 streamflow records of annual peaks across Canada. A generic L-moment algorithm is devised to fit the distributions, also applicable to distributions without analytical L-moment expressions. The analysis shows: (1) the models perform equally well when describing the observed annual peaks; (2) the right tail appears heavier in the BrIII and BrXII models leading to larger streamflow predictions when compared to those of G epsilon V; (3) the G epsilon V predicts upper streamflow limits in 39.1% of the records-these limits have realistic exceedance probabilities based on the other two models; (4) the tail heaviness estimation seems not robust in the G epsilon V case when compared to the BrIII and BrXII models and this could challenge G epsilon V's reliability in predicting streamflow at large return periods; and, (5) regional variation is observed in the behaviour of flood peaks across different climatic regions of Canada. The findings of this study reveal potential limitations in using the G epsilon V for flood frequency analysis and suggest the BrIII and BrXII as consistent alternatives worth exploring.", "authors": [ "Zaghloul, Mohanad", "Papalexiou, Simon Michael", "Elshorbagy, Amin", "Coulibaly, Paulin" ], "keywords": [ "Flood peaks", "Extreme value theory", "GEV distribution", "Burr type III distribution" ], "year": "2020", "source": "ADVANCES IN WATER RESOURCES", "publication_type": "J", "point2d": [ -27.354721069335938, -54.77056121826172 ], "cluster": 16.0 }, { "idx": 826, "title": "Sowing a way towards revitalizing Indigenous agriculture: creating meaning from a forum discussion in Saskatchewan, Canada", "abstract": "Agriculture is practiced on 3-4 million acres of First Nations reserve lands in the Saskatchewan Prairies-predominantly by non-Indigenous farmers. A confluence of factors including an increase in agricultural land holdings on reserve and greater autonomy in land management have renewed conversations on how First Nations can realize the full economic benefits and exert greater control over agricultural activities that affect the reserve land base. We hosted a Forum on Indigenous Agriculture to share current knowledge on the contemporary status of Indigenous agriculture and to co-formulate research, capacity building, and policy priorities. First Nations' roles in agriculture are diverse and were categorized in three broad contexts: as farmers, relying on traditional Indigenous or western practice, or a synergy of both; as landlords negotiating lease agreements; and as agribusiness entrepreneurs. Five themes emerged from the forum: centring Indigenous knowledge and traditional relationships to the land, capacity building, building respectful partnerships and relationships, financing farming and equitable economies, and translating research to policy and legislation. The forum provided foundational data to inform research and capacity building to meet community-defined goals in agriculture on reserve lands and by First Nations people.", "authors": [ "Arcand, Melissa M.", "Bradford, Lori", "Worme, Dale F.", "Strickert, Graham E. H.", "Bear, Ken", "Johnston, Anthony Blair Dreaver", "Wuttunee, Sheldon M.", "Gamble, Alfred", "Shewfelt, Debra" ], "keywords": [ "Indigenous agriculture", "First Nations", "land use", "food sovereignty", "Canadian Prairies" ], "year": "2020", "source": "FACETS", "publication_type": "J", "point2d": [ 67.49749755859375, -28.898744583129883 ], "cluster": 4.0 }, { "idx": 827, "title": "Synthesis of science: findings on Canadian Prairie wetland drainage", "abstract": "", "authors": [ "Baulch, Helen", "Whitfield, Colin", "Wolfe, Jared", "Basu, Nandita", "Bedard-Haughn, Angela", "Belcher, Kenneth", "Clark, Robert", "Ferguson, Grant", "Hayashi, Masaki", "Ireson, Andrew", "Lloyd-Smith, Patrick", "Loring, Phil", "Pomeroy, John W.", "Shook, Kevin", "Spence, Christopher" ], "keywords": [ "Wetland", "Canadian Prairies", "drainage", "ecosystem service", "water", "agriculture" ], "year": "2021", "source": "CANADIAN WATER RESOURCES JOURNAL", "publication_type": "J", "point2d": [ -11.021873474121094, -9.16602897644043 ], "cluster": 13.0 }, { "idx": 828, "title": "Synthesis of science: findings on Canadian Prairie wetland drainage", "abstract": "", "authors": [ "Baulch, Helen", "Whitfield, Colin", "Wolfe, Jared", "Basu, Nandita", "Bedard-Haughn, Angela", "Belcher, Kenneth", "Clark, Robert", "Ferguson, Grant", "Hayashi, Masaki", "Ireson, Andrew", "Lloyd-Smith, Patrick", "Loring, Phil", "Pomeroy, John W.", "Shook, Kevin", "Spence, Christopher" ], "keywords": [ "Wetland", "Canadian Prairies", "drainage", "ecosystem service", "water", "agriculture" ], "year": "2021", "source": "CANADIAN WATER RESOURCES JOURNAL", "publication_type": "J", "point2d": [ -10.85262680053711, -8.75937557220459 ], "cluster": 13.0 }, { "idx": 829, "title": "Predicting Variable Contributing Areas, Hydrological Connectivity, and Solute Transport Pathways for a Canadian Prairie Basin", "abstract": "In cold agricultural regions, seasonal snowmelt over frozen soils provides the primary source of runoff and transports large nutrient loads downstream. The postglacial landscape of the Canadian Prairies and Northern Plains of the United States creates challenges for hydrological and water quality modeling. Here, the application of conventional hydrological models is problematic because of cold regions hydrological and chemical processes, the lack of fluvially eroded drainage systems, large noncontributing areas to streamflow and level topography. A new hydrodynamic model was developed to diagnose overland flow from snowmelt in this situation. The model was used to calculate the effect of variable contributing areas on (1) hydrological connectivity and the development of (2) tipping points in streamflow generation and (3) predominant chemical transport pathways. The agricultural Steppler Basin in Manitoba, Canada, was used to evaluate the model and diagnose snowmelt runoff. Relationships were established between contributing area and (1) snowmelt runoff intensity, (2) seasonal snowmelt volumes and duration, and (3) inundated, active and connected areas. Variations in the contributing area depended on terrain and snowmelt characteristics including wind redistribution of snow. Predictors of hydrological response and the size of the contributing area were developed which can be used in larger scale hydrological models of similar regions", "authors": [ "Costa, Diogo", "Shook, Kevin", "Spence, Chris", "Elliott, Jane", "Baulch, Helen", "Wilson, Henry", "Pomeroy, John W." ], "keywords": [ "snowmelt", "flooding", "variable contributing areas", "prairies", "transport pathways", "hydrodynamic modeling" ], "year": "2020", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -21.707332611083984, -10.547052383422852 ], "cluster": 12.0 }, { "idx": 830, "title": "Spatio-Temporal Patterns of Crops and Agrochemicals in Canada Over 35 Years", "abstract": "In an effort to feed a growing world population, agriculture has rapidly intensified over the last six decades, relying heavily on agrochemicals (fertilizers, insecticides, fungicides, and herbicides) to increase and maintain desired crop yields. Despite environmental concerns in Canada's agricultural regions, long-term patterns of changing crops and the associated trends in the proportion of cropland treated with agrochemicals are poorly documented. Using the Canadian Census of Agriculture, we compiled historical data over 35 years (eight census periods: 1981-2016) on agrochemical applications, measured as the proportion of cropland treated with pesticides and fertilizers and the associated crop classes, to identify and interpret spatial and temporal trends in Canada's agricultural practices across 260 census units. Due to differences in agricultural practices, soil, and climatic conditions across the country, the Pacific (British Columbia), Prairie (Alberta, Saskatchewan, Manitoba), Central (Ontario, Quebec), and Atlantic (Nova Scotia, New Brunswick, Newfoundland/Labrador, Prince Edward Island) regions were analyzed separately. Most of the agrochemicals in Canada were applied in the Prairie and Central regions, which combined comprise 97% of the total cropland. Fertilizers were the dominant agrochemicals across Canada applied on 48% (Pacific) to 78% (Prairie) of the total cropland area, followed by herbicides, which were applied on 30% (Pacific) to 81% (Prairie) of the total cropland area in 2016. Notably, we observed significant changes between 1996 and 2016 in area treated with fungicides and insecticides, which increased by 412% and 50% in the Prairie region and by 291% and 149% in the Central region, respectively. The proportion and distribution of crops shifted in favor of more oilseeds and soybeans in the most intensive Prairie and Central regions, whereas cereals decreased over the same time period. Our analysis of past and current trends of agrochemicals and cropping patterns within Canada indicates a rapid and systemic increase in chemical use, and policies that promote a shift toward lower chemical reliance through sustainable agricultural practices are urgently needed.", "authors": [ "Malaj, Egina", "Freistadt, Levi", "Morrissey, Christy A." ], "keywords": [ "Canadian Census of Agriculture", "cropping system", "agricultural intensification", "sustainable agriculture", "land cover change", "fertilizers", "pesticides" ], "year": "2020", "source": "FRONTIERS IN ENVIRONMENTAL SCIENCE", "publication_type": "J", "point2d": [ 37.28213882446289, -21.611928939819336 ], "cluster": 10.0 }, { "idx": 831, "title": "Transforming conflict over natural resources: a socio-ecological systems analysis of agricultural drainage", "abstract": "Agricultural drainage is a complicated and often conflict-ridden natural resource management issue, impacting contested ecosystem services related to the retention of wetlands as well as the productivity of farmland. This research identifies opportunities to transform the conflict over agricultural drainage in Saskatchewan, Canada, towards collaboration. We report on ethnographic research informed by a conservation conflict-transformation framework to evaluate the nature of the conflict and whether drivers of the conflict operate principally at the level of disputes over discrete ecosystem services or if they reach deeper into local social circumstances and build on larger unresolved conflict(s) among groups in the region. In addition to the conflict-transformation framework, we apply the Social-Ecological Systems Framework to elicit details regarding the substantive, relational, and material dimensions of this conflict. Our research suggests that processes for governing natural resources, such as those in place for governing drainage in Saskatchewan, need to have mechanisms to facilitate relationship building and shared understandings, need to be adaptable to people's changing needs and concerns, and should focus on inclusivity and empowerment of actors to address conflict.", "authors": [ "Minnes, Sarah", "Gaspard, Valencia", "Loring, Philip A.", "Baulch, Helen", "Breen, Sarah-Patricia" ], "keywords": [ "social-ecological systems", "natural resource conflict", "wetlands", "conservation", "Canadian Prairies", "agricultural drainage" ], "year": "2020", "source": "FACETS", "publication_type": "J", "point2d": [ 55.49508285522461, -33.70049285888672 ], "cluster": 4.0 }, { "idx": 832, "title": "Dual-permeability modeling of preferential flow and snowmelt partitioning in frozen soils", "abstract": "The infiltrability of frozen soils modulates the partitioning of snowmelt between infiltration and runoff in cold regions. Preferential flow in macropores may enhance infiltration, but flow dynamics in frozen soil are complicated by soil heat transfer processes. We developed a dual-permeability model that considers the interacting effects of freeze-thaw and preferential flow on infiltration and runoff generation in structured soils. This formulation was incorporated into the fully integrated groundwater-surface water model HydroGeoSphere, to represent water-ice phase change in macropores such that porewater freezing is governed by macropore-matrix heat exchange. Model performance was evaluated against laboratory experiments and synthetic test cases designed to examine the effects of preferential flow on snowmelt partitioning between infiltration, runoff, and drainage. Simulations were able to reproduce experimental observations of rapid infiltration and drainage behavior due to macropores very well, and approximated soil thaw to an acceptable degree. Simulation of measured data highlighted the importance of macropore hydraulic conductivity, as well as macropore-matrix heat and water transfer, on controlling preferential flow dynamics. Test cases replicated a range of snowmelt partitioning behavior commonly observed in frozen soils, including subsurface conditions that produce rapid infiltration and deeper drainage, the contrast between limited vs. unlimited infiltration responses to snowmelt, and the temporal evolution of runoff generation. This study demonstrates the important influence that water freezing along preferential flowpaths can have on infiltrability and runoff characteristics in frozen soils and provides a physically based description of this mechanism that links infiltration behavior to hydraulic and thermal properties of structured soils.", "authors": [ "Mohammed, Aaron A.", "Cey, Edwin E.", "Hayashi, Masaki", "Callaghan, Michael, V", "Park, Young-Jin", "Miller, Killian L.", "Frey, Steven K." ], "keywords": [ "" ], "year": "2021", "source": "VADOSE ZONE JOURNAL", "publication_type": "J", "point2d": [ -36.44205856323242, 23.092792510986328 ], "cluster": 12.0 }, { "idx": 833, "title": "Quantifying the effects of Prairie depressional storage complexes on drainage basin connectivity", "abstract": "Runoff in many locations within the Canadian Prairies is dominated by intermittent fill-and-spill between depressions. As a result, many basins have varying fractions of their areas connected to their outlets, due to changing depressional storage. The objective of this research is to determine the causes of the relationships between water storage and the connected fraction of depression-dominated Prairie basins. It is hypothesized that the shapes of the relationship curves are influenced by both the spatial and frequency distributions of depressional storage. Three sets of numerical experiments are presented to test the hypothesis. The first set of experiments demonstrates that where the number of depressions is small, their size and spatial distributions are important in controlling the relationship between the volume of depressional storage and the connected fraction of a basin. As the number of depressions is increased, the areal fractions of the largest depressions decrease, which reduces the importance of the spatial distribution of depressions. The second set of experiments demonstrates that the curve enveloping the connected fraction of a basin can be derived from the frequency distribution of depression areas, and scaling relationships between the area, volume and catchment area of the depressions, when the area of the largest depression is no greater than approximately 5% of the total. The third set of experiments demonstrates that the presence of a single large depression can strongly influence the relationship between the depressional storage and the connected fraction of a basin, depending on the relative size of the large depression, and its location within the basin. A single depression containing 30% of the total depressional area located near the outlet was shown to cause a basin to be nearly endorheic. A similar depression near the top of a basin was demonstrated not to fill and was therefore unable to contribute flows. The implications of the findings for developing hydrological models of large Prairie drainage basins are discussed.", "authors": [ "Shook, Kevin", "Papalexiou, Simon", "Pomeroy, John W." ], "keywords": [ "Fill and spill runoff", "Depressional storage", "Wetlands", "Hysteresis", "Contributing area", "Canadian Prairies" ], "year": "2021", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -8.48680305480957, -12.790803909301758 ], "cluster": 10.0 }, { "idx": 834, "title": "Size-based characterization of freshwater dissolved organic matter finds similarities within a waterbody type across different Canadian ecozones", "abstract": "Dissolved organic matter (DOM) represents a mixture of organic molecules that vary due to different source materials and degree of processing. Characterizing how DOM composition evolves along the aquatic continuum can be difficult. Using a size-exclusion chromatography technique (liquid chromatography-organic carbon detection [LC-OCD]), we assessed the variability in DOM composition from both surface and groundwaters across a number of Canadian ecozones (mean annual temperature spanning -10 degrees C to +6 degrees C). A wide range in DOM concentration was found from 0.2 to 120 mg C L-1. Proportions of different size-based groupings across ecozones were variable, yet similarities between specific waterbody types, regardless of location, suggest commonality in the processes dictating DOM composition. A principal component analysis identified 70% of the variation in LC-OCD derived DOM compositions could be explained by the waterbody type. We find that DOM composition within a specific waterbody type is similar regardless of the differences in climate or surrounding vegetation where the sample originated from.", "authors": [ "Aukes, Pieter J. K.", "Schiff, Sherry L.", "Venkiteswaran, Jason J.", "Elgood, Richard J.", "Spoelstra, John" ], "keywords": [ "" ], "year": "2021", "source": "LIMNOLOGY AND OCEANOGRAPHY LETTERS", "publication_type": "J", "point2d": [ 34.5177001953125, 38.39158248901367 ], "cluster": 19.0 }, { "idx": 835, "title": "A reusable, reagent-less free chlorine sensor using gold thin film electrode", "abstract": "Free chlorine is widely used as a disinfectant in the water industry. Accurate monitoring of the residual free chlorine concentration in water cycles is critical to maintain public health safety. Here, we report on a thin gold film-based reusable and reagent-less free chlorine sensor. A gold thin film of 300 nm thickness was deposited on a polyimide tape, which was placed on a glass substrate and a simple Styrofoam adhesive tape was used to cover the film and expose 0.36 cm2 circular area as the sensing surface. The sensor showed a high sensitivity of 0.327 mu A ppm(-1), with a linear range of 0 to 6 ppm, and an accuracy of <0.1 ppm with high selectivity in the presence of commonly interfering ions. The sensor response time was 50 s with a negligible hysteresis of 0.06 ppm. The sensor showed very little change in output current in the pH range between 5.2 to 8.4, and temperature range of 20 to 30 degrees C. Therefore, the sensor operation is reagent-less, does not need frequent calibration, and showed consistent sensing performance with real water samples. The simple fabrication, ease-of-use and reliable sensing performance of the proposed sensor shows feasibility for mass-production and application in remote and resource-limited areas.", "authors": [ "Ul Alam, Arif", "Clyne, Dennis", "Lush, Will", "Deen, M. Jamal" ], "keywords": [ "" ], "year": "2021", "source": "ANALYST", "publication_type": "J", "point2d": [ 79.03681945800781, 46.248416900634766 ], "cluster": 6.0 }, { "idx": 836, "title": "A reusable, reagent-less free chlorine sensor using gold thin film electrode", "abstract": "Free chlorine is widely used as a disinfectant in the water industry. Accurate monitoring of the residual free chlorine concentration in water cycles is critical to maintain public health safety. Here, we report on a thin gold film-based reusable and reagent-less free chlorine sensor. A gold thin film of 300 nm thickness was deposited on a polyimide tape, which was placed on a glass substrate and a simple Styrofoam adhesive tape was used to cover the film and expose 0.36 cm2 circular area as the sensing surface. The sensor showed a high sensitivity of 0.327 mu A ppm(-1), with a linear range of 0 to 6 ppm, and an accuracy of <0.1 ppm with high selectivity in the presence of commonly interfering ions. The sensor response time was 50 s with a negligible hysteresis of 0.06 ppm. The sensor showed very little change in output current in the pH range between 5.2 to 8.4, and temperature range of 20 to 30 degrees C. Therefore, the sensor operation is reagent-less, does not need frequent calibration, and showed consistent sensing performance with real water samples. The simple fabrication, ease-of-use and reliable sensing performance of the proposed sensor shows feasibility for mass-production and application in remote and resource-limited areas.", "authors": [ "Ul Alam, Arif", "Clyne, Dennis", "Lush, Will", "Deen, M. Jamal" ], "keywords": [ "" ], "year": "2021", "source": "ANALYST", "publication_type": "J", "point2d": [ 78.53247833251953, 46.268150329589844 ], "cluster": 6.0 }, { "idx": 837, "title": "Fruit Quality Monitoring with Smart Packaging", "abstract": "Smart packaging of fresh produce is an emerging technology toward reduction of waste and preservation of consumer health and safety. Smart packaging systems also help to prolong the shelf life of perishable foods during transport and mass storage, which are difficult to regulate otherwise. The use of these ever-progressing technologies in the packaging of fruits has the potential to result in many positive consequences, including improved fruit quality, reduced waste, and associated improved public health. In this review, we examine the role of smart packaging in fruit packaging, current-state-of-the-art, challenges, and prospects. First, we discuss the motivation behind fruit quality monitoring and maintenance, followed by the background on the development process of fruits, factors used in determining fruit quality, and the classification of smart packaging technologies. Then, we discuss conventional freshness sensors for packaged fruits including direct and indirect freshness indicators. After that, we provide examples of possible smart packaging systems and sensors that can be used in monitoring fruits quality, followed by several strategies to mitigate premature fruit decay, and active packaging technologies. Finally, we discuss the prospects of smart packaging application for fruit quality monitoring along with the associated challenges and prospects.", "authors": [ "Alam, Arif U.", "Rathi, Pranali", "Beshai, Heba", "Sarabha, Gursimran K.", "Deen, M. Jamal" ], "keywords": [ "smart packaging", "intelligent packaging", "active packaging", "fresh produce", "fruit quality", "fruit processing", "fruit smart packaging", "fruit sensor", "RFID", "IoT" ], "year": "2021", "source": "SENSORS", "publication_type": "J", "point2d": [ 71.53294372558594, 40.45567321777344 ], "cluster": 6.0 }, { "idx": 838, "title": "Freshness Monitoring of Packaged Vegetables", "abstract": "Smart packaging is an emerging technology that has a great potential in solving conventional food packaging problems and in meeting the evolving packaged vegetables market needs. The advantages of using such a system lies in extending the shelf life of products, ensuring the safety and the compliance of these packages while reducing the food waste; hence, lessening the negative environmental impacts. Many new concepts were developed to serve this purpose, especially in the meat and fish industry with less focus on fruits and vegetables. However, making use of these evolving technologies in packaging of vegetables will yield in many positive outcomes. In this review, we discuss the new technologies and approaches used, or have the potential to be used, in smart packaging of vegetables. We describe the technical aspects and the commercial applications of the techniques used to monitor the quality and the freshness of vegetables. Factors affecting the freshness and the spoilage of vegetables are summarized. Then, some of the technologies used in smart packaging such as sensors, indicators, and data carriers that are integrated with sensors, to monitor and provide a dynamic output about the quality and safety of the packaged produce are discussed. Comparison between various intelligent systems is provided followed by a brief review of active packaging systems. Finally, challenges, legal aspects, and limitations facing this smart packaging industry are discussed together with outlook and future improvements.", "authors": [ "Beshai, Heba", "Sarabha, Gursimran K.", "Rathi, Pranali", "Alam, Arif U.", "Deen, M. Jamal" ], "keywords": [ "smart packaging", "intelligent systems", "active packaging", "sensors", "indicators", "RFID tags", "nanoparticles", "biosensors", "humidity", "oxygen", "carbon dioxide" ], "year": "2020", "source": "APPLIED SCIENCES-BASEL", "publication_type": "J", "point2d": [ 71.36250305175781, 40.00971603393555 ], "cluster": 6.0 }, { "idx": 839, "title": "Design and Development of Low-Cost, Portable, and Smart Chlorophyll-A Sensor", "abstract": "Chlorophyll-A concentration is one of the most commonly measured water quality parameters. It is an indicator of algal biomass and provides insight into stressors such as eutrophication and bloom risk. It is also a widely used metric in terrestrial ecosystems as an indicator of photosynthetic activity and nutrient limitation. Laboratory-based methods for measuring chlorophyll-A require expensive instrumentation. In this paper, we proposed a smart, low-cost, and portable smart sensor system to measure the concentration of chlorophyll-A in an extracted solution using two consumer-grade spectral sensors that read the reflectance at 12 discrete wavelengths in visible and near-infrared spectra. The system was tuned for an optimal distance from the sensors to the solution and an enclosure was printed to maintain the distance, as well as to avoid natural light interference. Extracted chlorophyll solutions of 51 different concentrations were prepared, and at least 100 readings per sample were taken using our smart sensor system. The ground truth values of the samples were measured in the laboratory using Thermo Nano 2000C. After cleaning the anomalous data, different machine learning models were trained to determine the significant wavelengths that contribute most towards chlorophyll-A measurement. Finally, a decision tree model with 5 important features was chosen based on the lowest Root Mean Square and Mean Absolute Error when it was tested on the validation set. Our final model resulted in a mean error of +/- 0.9 mu g/L when applied on our test set. The total cost was around $150.", "authors": [ "Chowdhury, Rakibul Islam", "Wahid, Khan Arif", "Nugent, Katy", "Baulch, Helen" ], "keywords": [ "Chlorophyll-A", "machine learning", "multispectral sensors", "spectrophotometer", "water quality monitoring" ], "year": "2020", "source": "IEEE SENSORS JOURNAL", "publication_type": "J", "point2d": [ 60.43741226196289, 23.921388626098633 ], "cluster": 6.0 }, { "idx": 840, "title": "Chemiresistive detection of silver ions in aqueous media", "abstract": "Silver is used as a water disinfectant in hospital settings as well as in purifiers for potable water. Although there are no strict regulations on the concentration of silver in water, adverse effects such as argyria and respiratory tract irritation have been correlated to excess silver consumption. Based on this, the levels of silver in water are recommended to be maintained below 100 ppb to ensure safety for human consumption. In this work, we present a silver sensor for use in aqueous media that utilizes bathocuproine, a silver selective chromophore, adsorbed onto few-layer graphene (FLG) flake networks for the chemiresistive detection of silver. Complexation of silver to bathocuproine modulates the conductivity of the FLG film, which can be probed by applying a small voltage bias. The decrease in resistance of the film correlates with the concentration of silver in solution between 3 ppb and 1 ppm. Exposing the sensor to a lower pH resets the sensor, allowing it to be reused and reset multiple times. This sensor demonstrates a new pathway to chemiresistive cation sensing using known selective complexing agents adsorbed onto graphitic thin films. This concept can be expanded to the detection of other relevant analytes in domestic, industrial and environmental water sources.", "authors": [ "Dalmieda, Johnson", "Zubiarrain-Laserna, Ana", "Ganepola, Devanjith", "Selvaganapathy, P. Ravi", "Kruse, Peter" ], "keywords": [ "Water quality", "Heavy metal sensing", "Silver", "Cation sensing", "Graphene", "Chemiresistive sensor" ], "year": "2021", "source": "SENSORS AND ACTUATORS B-CHEMICAL", "publication_type": "J", "point2d": [ 81.19237518310547, 42.05778884887695 ], "cluster": 6.0 }, { "idx": 841, "title": "Comparative Performance Analysis of Lightweight Cryptography Algorithms for IoT Sensor Nodes", "abstract": "The Internet of Things (IoT) has become an integral part of future solutions, ranging from industrial to everyday human life applications. Adding a new level of intelligence to objects and automating decisions make this new technology appealing to everyone. However, applications that involve data are more vulnerable to various types of attacks. As a result, researchers are constantly exploring secure connections between IoT edge nodes. On one hand, suitable IoT nodes should be cheap and require low power, which means lower computational performance. On the other hand, a secure connection layer is power hungry and requires powerful hardware resources. Lightweight cryptography (LWC) algorithms are a promising solution to reduce computation complexity while maintaining a desired level of security. In the presented work, we attempt to address the issue of adding security to the IoT network layer by comparing the performance of 32 LWC algorithms with currently well-known algorithms on multiple IoT platforms (Raspberry Pi 3, Raspberry Pi Zero W, and iMX233). These 32 authenticated encryption with associated data algorithms have been selected from the second round of the LWC standardization process conducted by the National Institute of Standards and Technology. Power consumption, random access memory usage, and execution time are measured for these algorithms using the targeted embedded platforms that are used as IoT sensor nodes. The results of this study will assist researchers in choosing a suitable platform and optimal LWC algorithm for IoT applications.", "authors": [ "Fotovvat, Amir", "Rahman, Gazi M. E.", "Vedaei, Seyed Shahim", "Wahid, Khan A." ], "keywords": [ "Encryption", "Ciphers", "Internet of Things", "Software algorithms", "Cryptography", "Security", "Hardware", "Authenticated encryption with associated data (AEAD) algorithms", "Internet of Things (IoT)", "lightweight cryptography (LWC)", "security" ], "year": "2021", "source": "IEEE INTERNET OF THINGS JOURNAL", "publication_type": "J", "point2d": [ 68.77974700927734, 35.80194091796875 ], "cluster": 6.0 }, { "idx": 842, "title": "Revised application of copper ion selective electrode (Cu-ISE) in marine waters: A new meta-calibration approach", "abstract": "Copper (Cu) is a bio-essential trace element that is of concerns due to its potential toxicity at concentrations commonly encountered in coastal waters. Here, we revisit the applicability of Cu(II) ion selective electrode (Cu-ISE) based on a jalpaite membrane for the measurement of Cu-free in seawater. At high total Cu concentration (>0.1 mM), (near)Nernstian slope was obtained and determination of Cu-free down to fM levels was possible. However, this slope decreases with decreasing total Cu concentration (e.g. 7 mV/decade at 15 nM total Cu) making the use of a common single calibration approach unreliable. To solve this problem, we carried out several calibrations at different levels of total Cu (15 nM - 1 mM) and ethylenediamine (EN: 5 mu M - 15 mM) and fitted the calibration parameters (slope and intercept) as a function of total Cu using the Gompertz function (a meta-calibration approach). The derived empirical equations allowed the determination of Cu-free at any total Cu concentration above 20 nM (determination of Cu-free at lower total Cu levels is prevented by the dissolution of the electrode). We successfully tested this meta-calibration approach in UV digested seawater in presence of a synthetic ligand (EN), isolated natural organic matter (humic acid, HA) and in a natural estuarine sample. In each case, our meta-calibration approach provided a good agreement with modeled speciation data (Visual MINTEQ), while standard single approach failed. We provide here a new method for the direct determination of the free Cu ion concentration in seawater at levels relevant for coastal waters.", "authors": [ "Marcinek, Sasa", "Chapoulie, Arnaud", "Salaun, Pascal", "Smith, Scott", "Omanovic, Dario" ], "keywords": [ "Copper ion selective electrode", "meta-Calibration", "Speciation", "Trace metals" ], "year": "2021", "source": "TALANTA", "publication_type": "J", "point2d": [ 80.45018768310547, 37.287540435791016 ], "cluster": 6.0 }, { "idx": 843, "title": "Solid State Sensors for Hydrogen Peroxide Detection", "abstract": "Hydrogen peroxide (H2O2) is a key molecule in numerous physiological, industrial, and environmental processes. H2O2 is monitored using various methods like colorimetry, luminescence, fluorescence, and electrochemical methods. Here, we aim to provide a comprehensive review of solid state sensors to monitor H2O2. The review covers three categories of sensors: chemiresistive, conductometric, and field effect transistors. A brief description of the sensing mechanisms of these sensors has been provided. All three sensor types are evaluated based on the sensing parameters like sensitivity, limit of detection, measuring range and response time. We highlight those sensors which have advanced the field by using innovative materials or sensor fabrication techniques. Finally, we discuss the limitations of current solid state sensors and the future directions for research and development in this exciting area.", "authors": [ "Patel, Vinay", "Kruse, Peter", "Selvaganapathy, Ponnambalam Ravi" ], "keywords": [ "solid state sensors", "field effect transistor", "chemiresisitive sensor", "conductometric sensor", "hydrogen peroxide", "biosensor and sensors" ], "year": "2021", "source": "BIOSENSORS-BASEL", "publication_type": "J", "point2d": [ 82.8974838256836, 51.07118606567383 ], "cluster": 6.0 }, { "idx": 844, "title": "LDAP: Lightweight Dynamic Auto-Reconfigurable Protocol in an IoT-Enabled WSN for Wide-Area Remote Monitoring", "abstract": "IoT (Internet of Things)-based remote monitoring and controlling applications are increasing in dimensions and domains day by day. Sensor-based remote monitoring using a Wireless Sensor Network (WSN) becomes challenging for applications when both temporal and spatial data from widely spread sources are acquired in real time. In applications such as environmental, agricultural, and water quality monitoring, the data sources are geographically distributed, and have little or no cellular connectivity. These applications require long-distance wireless or satellite connections for IoT connectivity. Present WSNs are better suited for densely populated applications and require a large number of sensor nodes and base stations for wider coverage but at the cost of added complexity in routing and network organization. As a result, real time data acquisition using an IoT connected WSN is a challenge in terms of coverage, network lifetime, and wireless connectivity. This paper proposes a lightweight, dynamic, and auto-reconfigurable communication protocol (LDAP) for Wide-Area Remote Monitoring (WARM) applications. It has a mobile data sink for wider WSN coverage, and auto-reconfiguration capability to cope with the dynamic network topology required for device mobility. The WSN coverage and lifetime are further improved by using a Long-Range (LoRa) wireless interface. We evaluated the performance of the proposed LDAP in the field in terms of the data delivery rate, Received Signal Strength (RSS), and Signal to Noise Ratio (SNR). All experiments were conducted in a field trial for a water quality monitoring application as a case study. We have used both static and mobile data sinks with static sensor nodes in an IoT-connected environment. The experimental results show a significant reduction (up to 80%) of the number of data sinks while using the proposed LDAP. We also evaluated the energy consumption to determine the lifetime of the WSN using the LDAP algorithm.", "authors": [ "Rahman, Gazi M. E.", "Wahid, Khan A." ], "keywords": [ "distributed wireless sensor network", "wide-area remote monitoring", "lightweight protocol", "internet of things", "dynamic protocol", "water quality monitoring" ], "year": "2020", "source": "REMOTE SENSING", "publication_type": "J", "point2d": [ 69.62979888916016, 36.56877136230469 ], "cluster": 6.0 }, { "idx": 845, "title": "Editors' Choice-Review-Conductive Forms of MoS(2)and Their Applications in Energy Storage and Conversion", "abstract": "Conductive forms of MoS(2)are important emerging 2D materials due to their unique combination of properties such as high electrical conductivity, availability of active sites in edge and basal planes for catalytic activity and expanded interlayer distances. Consequently, there has been a drive to find synthetic routes toward conductive forms of MoS2. Naturally occurring or synthetically grown semiconducting 2H-MoS(2)can either be converted into metallic 1T-MoS2, or various dopants may be introduced to modulate the electronic band gap of the 2H-MoS(2)phase and increase its conductivity. Chemical and electrochemical intercalation methods, hydrothermal and solvothermal processes, and chemical vapor deposition have all been developed to synthesize conductive MoS2. Conductive MoS(2)finds applications in energy storage devices, electrocatalytic reactions, and sensors. Here, we summarize a detailed understanding of the atomic structure and electronic properties of conductive MoS(2)which is crucial for its applications. We also discuss various fabrication methods that have been previously reported along with their advantages and disadvantages. Finally, we will give an overview of current trends in different applications in energy storage and electrocatalytic reactions in order to help researchers to further explore the applications of conductive MoS2.", "authors": [ "Saha, Dipankar", "Kruse, Peter" ], "keywords": [ "Electrocatalysis", "Dichalcogenide", "Energy Conversion", "Energy Storage", "Graphene", "Surface modification" ], "year": "2020", "source": "JOURNAL OF THE ELECTROCHEMICAL SOCIETY", "publication_type": "J", "point2d": [ 83.42662048339844, 55.32631301879883 ], "cluster": 6.0 }, { "idx": 846, "title": "Peroxide-Induced Tuning of the Conductivity of Nanometer-Thick MoS2 Films for Solid-State Sensors", "abstract": "Applications of molybdenum disulfide (MoS) in energy storage devices, solar cells, electrocatalysts, and sensors require good electrical conductivity. However, neither of the current ways to prepare conductive MoS (lithium intercalation and hydrothermal processes) is easily amenable to scale-up. A possible alternative pathway is the modulation of the electronic properties of the semiconducting form of MoS through structural defects. Here, we report the preparation of nanoscale conductive MoS2 flakes by treating exfoliated 2H-MoS with dilute aqueous hydrogen peroxide at room temperature. Sheet resistance measurements as well as Raman and photoelectron spectroscopy reveal the partial formation of hydrogen molybdenum bronze (H) and substoichiometric MoO, which help tune the conductivity of the nanometer-scale thin films without impacting the sulfur-to-molybdenum ratio. We have cast the material into thin film networks to fabricate highly stable chemiresistive pH sensors. Our work introduces a straightforward and safe way of preparing a conductive form of MoS style=color:red2 and its application as a low-cost solid-state sensor.", "authors": [ "Saha, Dipankar", "Selvaganapathy, Ponnambalam Ravi", "Kruse, Peter" ], "keywords": [ "2D materials", "conducting films", "MoS2", "chemiresistor", "pH sensor" ], "year": "2020", "source": "ACS APPLIED NANO MATERIALS", "publication_type": "J", "point2d": [ 83.61551666259766, 53.403812408447266 ], "cluster": 6.0 }, { "idx": 847, "title": "Developing understanding of the fate and behaviour of silver in fresh waters and waste waters", "abstract": "The Windermere Humic Aqueous Model (WHAM) is often used for risk assessment of metals; WHAM can be used to estimate the potential bioavailability of dissolved metals, where metals complexed to dissolved organic matter (DOM) are expected to be less toxic than ionic forms. Silver is a potential metal of concern but WHAM has not been rigorously tested against experimental measurements. This study compares WHAM predictions to measured ionic silver during fixed pH (4, 8 or 10) argentometric titrations of DOM from diverse origins. There were almost two orders of magnitude variation in free silver between sources but, within model uncertainty. WHAM captured this variability. This agreement, between measurements and models, suggests that WHAM is an appropriate tool for silver risk assessment in surface receiving waters when DOM is predominantly in the form of humic/fulvic acids. In sewage samples WHAM dramatically underestimated silver binding by approximately 3 orders of magnitude. Simulations with additional specific strong silver binding sulphide-like binding sites could explain Ag binding at low loadings, but not at higher loadings. This suggests the presence of additional intermediate strength binding sites. These additional ligands would represent components of the raw sewage largely absent in natural waters unimpacted by sewage effluents. A revised empirical model was proposed to account for these sewage-specific binding sites. Further, it is suspected that as sewage organic matter is degraded, either by natural attenuation or by engineered treatment, that sewage organic matter will degrade to a form more readily modelled by WHAM; i.e., humic-like substances. These ageing experiments were performed starting from raw sewage, and the material did in fact become more humic-like, but even after 30 days of aerobic incubation still showed greater Ag+ binding than WHAM predictions. In these incubation experiments it was found that silver (up to 1000 mu g/L) had minimal impact on ammonia oxidation kinetics. (C) 2020 Elsevier B.V. All rights reserved.", "authors": [ "Smith, D. Scott", "Nasir, R.", "Parker, Wayne", "Peters, A.", "Merrington, G.", "van Egmond, R.", "Lofts, S." ], "keywords": [ "Silver", "Windermere humic aqueous model (WHAM)", "Ion selective electrode", "Sulphide binding sites", "Risk assessment", "Metal bioavailability" ], "year": "2021", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 80.95233154296875, 34.1663932800293 ], "cluster": 6.0 }, { "idx": 848, "title": "A Systematic Study on Transit Time and Its Impact on Accuracy of Concentration Measured by Microfluidic Devices", "abstract": "Gating or threshold selection is very important in analyzing data from a microflow cytometer, which is especially critical in analyzing weak signals from particles/cells with small sizes. It has been reported that using the amplitude gating alone may result in false positive events in analyzing data with a poor signal-to-noise ratio. Transit time (tau) can be set as a gating threshold along with side-scattered light or fluorescent light signals in the detection of particles/cells using a microflow cytometer. In this study, transit time of microspheres was studied systematically when the microspheres passed through a laser beam in a microflow cytometer and side-scattered light was detected. A clear linear relationship between the inverse of the average transit time and total flow rate was found. Transit time was used as another gate (other than the amplitude of side-scattering signals) to distinguish real scattering signals from noise. It was shown that the relative difference of the measured microsphere concentration can be reduced significantly from the range of 3.43%-8.77% to the range of 8.42%-111.76% by employing both amplitude and transit time as gates in analysis of collected scattering data. By using optimized transit time and amplitude gate thresholds, a good correlation with the traditional hemocytometer-based particle counting was achieved (R-2 > 0.94). The obtained results suggest that the transit time could be used as another gate together with the amplitude gate to improve measurement accuracy of particle/cell concentration for microfluidic devices.", "authors": [ "Zhang, Yushan", "Guo, Tianyi", "Xu, Changqing" ], "keywords": [ "microfluidic", "transit time", "amplitude", "particle", "cell concentration counting", "accuracy of measurement" ], "year": "2020", "source": "SENSORS", "publication_type": "J", "point2d": [ 72.38912963867188, 30.395565032958984 ], "cluster": 6.0 }, { "idx": 849, "title": "Using Statistical and Dynamical Downscaling to Assess Climate Change Impacts on Mine Reclamation Cover Water Balances", "abstract": "The oil sands industry in Canada uses soil-vegetation-atmosphere-transfer (SVAT) water balance models, calibrated against short-term (1 L for DI-IRMS to yield a measurable amount of atmospheric CO2 gas. It has been determined that the integrity of vials and flasks for air sample storage can be compromised after 3 days of air collection for delta C-13 values and within 10 hours for delta O-18 values. Air samples must be purified after collection to remove constituents of air, such as Ar, O-2, N-2, N2O, and water vapor, to avoid isobaric interferences during mass spectrometric measurement. Purification is generally undertaken by utilizing commercial or custom-made preconcentration devices, the blanking method for CF-IRMS, or an offline/online cryogenic separation using a vacuum line for DI-IRMS. Ambient N2O is a component of air that may affect analytical results and thus must either be corrected for or be removed using a gas chromatographic column. In some cases, water is removed during air collection by using a common chemical desiccant, magnesium perchlorate (Mg(ClO4)(2)), or by a dry ice/alcohol mixture (-78 degrees C). Lastly, a linearity issue for IRMS due to the low amount of purified CO2 from a typical ambient air sample must be considered. In general, analytical precisions of 0.02-0.21 parts per thousand and 0.04-0.34 parts per thousand for CF-IRMS and 0.01-0.02 parts per thousand and 0.01-0.02 parts per thousand for DI-IRMS are expected for delta C-13 and delta O-18 measurements, respectively.", "authors": [ "Manaj, Savio", "Kim, Sang-Tae" ], "keywords": [ "" ], "year": "2021", "source": "RAPID COMMUNICATIONS IN MASS SPECTROMETRY", "publication_type": "J", "point2d": [ -2.9699490070343018, 22.019441604614258 ], "cluster": 17.0 }, { "idx": 869, "title": "Comparison of tree-ring growth and eddy covariance-based ecosystem productivities in three different-aged pine plantation forests", "abstract": "Key message This study utilized dendrochronology and long-term (2003-2017) eddy covariance (EC) carbon flux data to investigate the relationships between tree growth and gross ecosystem productivity (GEP(EC)) in different-age (15-, 42- and 78-year old) pine plantation forests in the Great Lakes region in eastern North America and found that tree-ring growth in these different-age pine forests was significantly (p < 0.05) correlated with observed annual GEP(EC) values. Forests play a major role in the global carbon cycle. Understanding the dynamics of the forest carbon cycle and its driving factors is challenging. This study utilized dendrochronology and long-term (2003-2017) eddy covariance (EC) carbon flux data to investigate the relationships between tree growth and gross and net ecosystem productivities (GEP(EC) and NEPEC) in different-age (15-, 42- and 78-year old) pine plantation forests in the Great Lakes region in eastern North America. Tree growth in these different-age pine forests was significantly (p < 0.05) correlated with observed annual GEP(EC) values, while coherence between tree growth and NEPEC was relatively poor. Current-year and 1-year lagged ring-width chronologies and climate variables, including spring (April-May) temperature (T-SPR) and Standardized Potential Evapotranspiration Index (SPEISUM) over the summer months (June-August) were used to test ten different linear regression models to simulate tree-ring-based GEP (GEP(TR)) values at all three sites. This analysis showed that current-year growth was the best predictor of GEP(TR) at all three sites, when compared to observed GEP(EC,) except during drought years, when GEP(TR) was underestimated. Current-year tree growth models were then used to reconstruct GEP(TR) over the life span of each stand. These reconstructions showed low GEP(TR) values from 1978 to 1988 and from 2002 to 2007. Low GEP(TR) in late 1970s occurred in response to below average temperatures when there were no major drought periods, while low GEP(TR) in early 2000s occurred following drought-like conditions in 2002. However, in recent years relatively higher GEP(TR) was observed at all three different-age forest sites. This interdisciplinary study will help to improve our understanding of carbon exchanges and the key environmental controls and associated uncertainties on tree growth in these different-age plantation stands in eastern North America. It will also help to determine how these forests may respond to climate change.", "authors": [ "McKenzie, Shawn M.", "Pisaric, Michael F. J.", "Arain, M. Altaf" ], "keywords": [ "Dendrochronology", "Tree-rings", "Eddy covariance", "Gross ecosystem productivity", "Net ecosystem productivity", "Temperate forest", "Forest carbon cycle" ], "year": "2021", "source": "TREES-STRUCTURE AND FUNCTION", "publication_type": "J", "point2d": [ -48.348453521728516, 63.39364242553711 ], "cluster": 17.0 }, { "idx": 870, "title": "The FLUXNET2015 dataset and the ONEFlux processing pipeline for eddy covariance data", "abstract": "The FLUXNET2015 dataset provides ecosystem-scale data on CO2, water, and energy exchange between the biosphere and the atmosphere, and other meteorological and biological measurements, from 212 sites around the globe (over 1500 site-years, up to and including year 2014). These sites, independently managed and operated, voluntarily contributed their data to create global datasets. Data were quality controlled and processed using uniform methods, to improve consistency and intercomparability across sites. The dataset is already being used in a number of applications, including ecophysiology studies, remote sensing studies, and development of ecosystem and Earth system models. FLUXNET2015 includes derived-data products, such as gap-filled time series, ecosystem respiration and photosynthetic uptake estimates, estimation of uncertainties, and metadata about the measurements, presented for the first time in this paper. In addition, 206 of these sites are for the first time distributed under a Creative Commons (CC-BY 4.0) license. This paper details this enhanced dataset and the processing methods, now made available as open-source codes, making the dataset more accessible, transparent, and reproducible.", "authors": [ "Pastorello, Gilberto", "Trotta, Carlo", "Canfora, Eleonora", "Chu, Housen", "Christianson, Danielle", "Cheah, You-Wei", "Poindexter, Cristina", "Chen, Jiquan", "Elbashandy, Abdelrahman", "Humphrey, Marty", "Isaac, Peter", "Polidori, Diego", "Ribeca, Alessio", "van Ingen, Catharine", "Zhang, Leiming", "Amiro, Brian", "Ammann, Christof", "Arain, M. Altaf", "Ardo, Jonas", "Arkebauer, Timothy", "Arndt, Stefan K.", "Arriga, Nicola", "Aubinet, Marc", "Aurela, Mika", "Baldocchi, Dennis", "Barr, Alan", "Beamesderfer, Eric", "Marchesini, Luca Belelli", "Bergeron, Onil", "Beringer, Jason", "Bernhofer, Christian", "Berveiller, Daniel", "Billesbach, Dave", "Black, Thomas Andrew", "Blanken, Peter D.", "Bohrer, Gil", "Boike, Julia", "Bolstad, Paul V.", "Bonal, Damien", "Bonnefond, Jean-Marc", "Bowling, David R.", "Bracho, Rosvel", "Brodeur, Jason", "Bruemmer, Christian", "Buchmann, Nina", "Burban, Benoit", "Burns, Sean P.", "Buysse, Pauline", "Cale, Peter", "Cavagna, Mauro", "Cellier, Pierre", "Chen, Shiping", "Chini, Isaac", "Christensen, Torben R.", "Cleverly, James", "Collalti, Alessio", "Consalvo, Claudia", "Cook, Bruce D.", "Cook, David", "Coursolle, Carole", "Cremonese, Edoardo", "Curtis, Peter S.", "D'Andrea, Ettore", "da Rocha, Humberto", "Dai, Xiaoqin", "Davis, Kenneth J.", "De Cinti, Bruno", "de Grandcourt, Agnes", "De Ligne, Anne", "De Oliveira, Raimundo C.", "Delpierre, Nicolas", "Desai, Ankur R.", "Di Bella, Carlos Marcelo", "di Tommasi, Paul", "Dolman, Han", "Domingo, Francisco", "Dong, Gang", "Dore, Sabina", "Duce, Pierpaolo", "Dufrene, Eric", "Dunn, Allison", "Dusek, Jiri", "Eamus, Derek", "Eichelmann, Uwe", "ElKhidir, Hatim Abdalla M.", "Eugster, Werner", "Ewenz, Cacilia M.", "Ewers, Brent", "Famulari, Daniela", "Fares, Silvano", "Feigenwinter, Iris", "Feitz, Andrew", "Fensholt, Rasmus", "Filippa, Gianluca", "Fischer, Marc", "Frank, John", "Galvagno, Marta", "Gharun, Mana", "Gianelle, Damiano", "Gielen, Bert", "Gioli, Beniamino", "Gitelson, Anatoly", "Goded, Ignacio", "Goeckede, Mathias", "Goldstein, Allen H.", "Gough, Christopher M.", "Goulden, Michael L.", "Graf, Alexander", "Griebel, Anne", "Gruening, Carsten", "Gruenwald, Thomas", "Hammerle, Albin", "Han, Shijie", "Han, Xingguo", "Hansen, Birger Ulf", "Hanson, Chad", "Hatakka, Juha", "He, Yongtao", "Hehn, Markus", "Heinesch, Bernard", "Hinko-Najera, Nina", "Hoertnagl, Lukas", "Hutley, Lindsay", "Ibrom, Andreas", "Ikawa, Hiroki", "Jackowicz-Korczynski, Marcin", "Janous, Dalibor", "Jans, Wilma", "Jassal, Rachhpal", "Jiang, Shicheng", "Kato, Tomomichi", "Khomik, Myroslava", "Klatt, Janina", "Knohl, Alexander", "Knox, Sara", "Kobayashi, Hideki", "Koerber, Georgia", "Kolle, Olaf", "Kosugi, Yoshiko", "Kotani, Ayumi", "Kowalski, Andrew", "Kruijt, Bart", "Kurbatova, Julia", "Kutsch, Werner L.", "Kwon, Hyojung", "Launiainen, Samuli", "Laurila, Tuomas", "Law, Bev", "Leuning, Ray", "Li, Yingnian", "Liddell, Michael", "Limousin, Jean-Marc", "Lion, Marryanna", "Liska, Adam J.", "Lohila, Annalea", "Lopez-Ballesteros, Ana", "Lopez-Blanco, Efren", "Loubet, Benjamin", "Loustau, Denis", "Lucas-Moffat, Antje", "Lueers, Johannes", "Ma, Siyan", "Macfarlane, Craig", "Magliulo, Vincenzo", "Maier, Regine", "Mammarella, Ivan", "Manca, Giovanni", "Marcolla, Barbara", "Margolis, Hank A.", "Marras, Serena", "Massman, William", "Mastepanov, Mikhail", "Matamala, Roser", "Matthes, Jaclyn Hatala", "Mazzenga, Francesco", "McCaughey, Harry", "McHugh, Ian", "McMillan, Andrew M. S.", "Merbold, Lutz", "Meyer, Wayne", "Meyers, Tilden", "Miller, Scott D.", "Minerbi, Stefano", "Moderow, Uta", "Monson, Russell K.", "Montagnani, Leonardo", "Moore, Caitlin E.", "Moors, Eddy", "Moreaux, Virginie", "Moureaux, Christine", "Munger, J. William", "Nakai, Taro", "Neirynck, Johan", "Nesic, Zoran", "Nicolini, Giacomo", "Noormets, Asko", "Northwood, Matthew", "Nosetto, Marcelo", "Nouvellon, Yann", "Novick, Kimberly", "Oechel, Walter", "Olesen, Jorgen Eivind", "Ourcival, Jean-Marc", "Papuga, Shirley A.", "Parmentier, Frans-Jan", "Paul-Limoges, Eugenie", "Pavelka, Marian", "Peichl, Matthias", "Pendall, Elise", "Phillips, Richard P.", "Pilegaard, Kim", "Pirk, Norbert", "Posse, Gabriela", "Powell, Thomas", "Prasse, Heiko", "Prober, Suzanne M.", "Rambal, Serge", "Rannik, Ullar", "Raz-Yaseef, Naama", "Reed, David", "de Dios, Victor Resco", "Restrepo-Coupe, Natalia", "Reverter, Borja R.", "Roland, Marilyn", "Sabbatini, Simone", "Sachs, Torsten", "Saleska, Scott R.", "Sanchez-Canete, Enrique P.", "Sanchez-Mejia, Zulia M.", "Schmid, Hans Peter", "Schmidt, Marius", "Schneider, Karl", "Schrader, Frederik", "Schroder, Ivan", "Scott, Russell L.", "Sedlak, Pavel", "Serrano-Ortiz, Penelope", "Shao, Changliang", "Shi, Peili", "Shironya, Ivan", "Siebicke, Lukas", "Sigut, Ladislav", "Silberstein, Richard", "Sirca, Costantino", "Spano, Donatella", "Steinbrecher, Rainer", "Stevens, Robert M.", "Sturtevant, Cove", "Suyker, Andy", "Tagesson, Torbern", "Takanashi, Satoru", "Tang, Yanhong", "Tapper, Nigel", "Thom, Jonathan", "Tiedemann, Frank", "Tomassucci, Michele", "Tuovinen, Juha-Pekka", "Urbanski, Shawn", "Valentini, Riccardo", "van der Molen, Michiel", "van Gorsel, Eva", "van Huissteden, Ko", "Varlagin, Andrej", "Verfaillie, Joseph", "Vesala, Timo", "Vincke, Caroline", "Vitale, Domenico", "Vygodskaya, Natalia", "Walker, Jeffrey P.", "Walter-Shea, Elizabeth", "Wang, Huimin", "Weber, Robin", "Westermann, Sebastian", "Wille, Christian", "Wofsy, Steven", "Wohlfahrt, Georg", "Wolf, Sebastian", "Woodgate, William", "Li, Yuelin", "Zampedri, Roberto", "Zhang, Junhui", "Zhou, Guoyi", "Zona, Donatella", "Agarwal, Deb", "Biraud, Sebastien", "Torn, Margaret", "Papale, Dario" ], "keywords": [ "" ], "year": "2020", "source": "SCIENTIFIC DATA", "publication_type": "J", "point2d": [ -47.12770462036133, 53.86591339111328 ], "cluster": 17.0 }, { "idx": 871, "title": "The Response of Spectral Vegetation Indices and Solar-Induced Fluorescence to Changes in Illumination Intensity and Geometry in the Days Surrounding the 2017 North American Solar Eclipse", "abstract": "Remote sensing is a key method for advancing our understanding of global photosynthesis and is thus critical to understanding terrestrial carbon uptake and climate change. Increasingly sophisticated spectral indices including solar-induced florescence (SIF) and the photochemical reflectance index (PRI) are considered good proxies of canopy structure, biochemistry, and physiology. However, the relative influences of illumination intensity and angle on these measures are difficult to unravel, particularly at the scale of whole forest canopies. We exploit the solar dimming during the 2017 North American solar eclipse as well as a clear day before and cloudy day after the day of the eclipse. This novel approach allows us to assess changes in spectral vegetation indices due to illumination intensity independent of changes in illumination angle. Physiologically relevant spectral indices were most affected by dimming, with illumination level explaining 97% of variability in SIF and 99% of variability in PRI during the eclipse. The spectral change in reflectance through the eclipse period revealed changes in PRI were driven by reflectance differences at the 570 nm reference band rather than at the 531 nm signal band associated with xanthophyll pigment interconversions. This study refines our interpretation of vegetation properties from space with implications for our interpretation of signals related to terrestrial photosynthesis derived from sensors spanning a range of illumination conditions and angles.", "authors": [ "Rogers, Cheryl A.", "Chen, Jing M.", "Zheng, Ting", "Croft, Holly", "Gonsamo, Alemu", "Luo, Xiangzhong", "Staebler, Ralf M." ], "keywords": [ "solar eclipse", "canopy reflectance", "solar‐", "induced fluorescence", "vegetation indices", "photochemical reflectance index", "remote sensing" ], "year": "2020", "source": "JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES", "publication_type": "J", "point2d": [ -66.40702819824219, 60.521968841552734 ], "cluster": 17.0 }, { "idx": 872, "title": "Daily leaf area index from photosynthetically active radiation for long term records of canopy structure and leaf phenology", "abstract": "Leaf area index (LAI) is a critical biophysical indicator that describes foliage abundance in ecosystems. An accurate and continuous estimation of LAI is therefore desirable to quantify ecosystem status and function (e.g. carbon and water exchange between the land surface and the atmosphere). However, deriving accurate LAI measurements at regular temporal intervals remains challenging, requiring either destructive sampling or manual collection of canopy gap fraction measurements at discrete time intervals. In this study, we present four methods to obtain continuous LAI data, simply derived from above and below canopy measurements of photosynthetically active radiation (PAR) at the Borden Forest Research Station from 1999 to 2018. We compared LAI derived using the four PAR-based methods to independent measurements of LAI from optical methods and the MODIS satellite LAI product. LAI derived from all four PAR-based methods captured the seasonal changes in observed and remotely sensed LAI and showed a close linear correspondence with one another (R-2 of 0.55 to 0.76 compared to MODIS LAI, and R-2 of 0.78 to 0.84 compared to LAI-2000 measurements). A PAR-based method using Miller's Integral theorem showed the strongest linear relationship with LAI-2000 measurements (R-2 =0.84, p<0.001, SE=0.40). In many years MODIS LAI indicated an earlier start of season and earlier end of season than the daily PAR-based LAI datasets showing systematic biases in the MODIS assessment of growing season. The four PAR-based LAI methods outlined in this study provide an LAI dataset of unprecedented temporal resolution. These methods will allow precise determination of phenological events, improve leaf to canopy scaling in process-based models, and provide valuable insight into dynamic vegetation responses to global climate change.", "authors": [ "Rogers, Cheryl", "Chen, Jing M.", "Croft, Holly", "Gonsamo, Alemu", "Luo, Xiangzhong", "Bartlett, Paul", "Staebler, Ralf M." ], "keywords": [ "Leaf area index", "Canopy structure", "Photosynthetically active radiation", "Phenology", "Remote sensing", "Carbon cycle" ], "year": "2021", "source": "AGRICULTURAL AND FOREST METEOROLOGY", "publication_type": "J", "point2d": [ -64.10821533203125, 63.96913528442383 ], "cluster": 17.0 }, { "idx": 873, "title": "Response of Soil CO2 Efflux to Shelterwood Harvesting in a Mature Temperate Pine Forest", "abstract": "In forest ecosystems, soil CO2 efflux is an important component of ecosystem respiration (R-E), which is generally driven by variability in soil temperature and soil moisture. Tree harvesting in forests can alter the soil variables and, consequently, impact soil CO2 efflux. This study investigated the response of total soil CO2 efflux, and its components, to a shelterwood harvesting event of a mature temperate white pine (Pinus strobus L.) forest located in Southern Ontario, Canada. The objective was to explore the response of soil CO2 effluxes to changes in the forest microclimate, such as soil temperature and soil moisture, after shelterwood harvesting removed approximately one-third of the overstory canopy. No significant differences were found in both soil temperature and soil moisture between the pre-harvesting (2008-2011) and post-harvesting (2012-2014) periods. Despite similar soil microclimates, total soil CO2 effluxes were significantly reduced by up to 37%. Soil CO2 effluxes from heterotrophic sources were significantly reduced post-harvesting by approximately 27%, while no significant difference in the mineral-soil horizon sources were measured. An analysis of R-E, measured with an eddy covariance tower over the study area, showed an increase post-harvesting. However, the overall net ecosystem carbon exchange showed no significant difference between pre- and post-harvesting. This was due to an increase in the gross ecosystem productivity post-harvesting, compensating for the increased losses (i.e., increased R-E). This study highlights the complexities of soil CO2 efflux after a disturbance, such as a harvest. The knowledge gained from this study adds to our understanding of how shelterwood harvesting may influence ecosystem carbon exchange and will be useful for forest managers focused on carbon sequestration and forest conservation.", "authors": [ "Thorne, Robin", "Khomik, Myroslava", "Hayman, Emily", "Arain, Altaf" ], "keywords": [ "soil respiration", "forest thinning", "shelterwood harvest", "soil temperature", "soil moisture", "Pinus strobus L", "temperate conifer forest" ], "year": "2020", "source": "FORESTS", "publication_type": "J", "point2d": [ -51.32939529418945, 65.46827697753906 ], "cluster": 17.0 }, { "idx": 874, "title": "Tracking the phenology of photosynthesis using carotenoid-sensitive and near-infrared reflectance vegetation indices in a temperate evergreen and mixed deciduous forest", "abstract": "Photosynthetic phenology is an important indicator of annual gross primary productivity (GPP). Assessing photosynthetic phenology remotely is difficult for evergreen conifers as they remain green year-round. Carotenoid-based vegetation indices such as the photochemical reflectance index (PRI) and chlorophyll/carotenoid index (CCI) are promising tools to remotely track the invisible phenology of photosynthesis by assessing carotenoid pigment dynamics. PRI, CCI and the near-infrared reflectance of vegetation (NIRV) index may act as proxies of photosynthetic efficiency (e), an important parameter in light-use efficiency models, or direct proxies of photosynthesis. To understand the physiological mechanisms reflected by PRI and CCI and the ability of vegetation indices to act as proxies of photosynthetic activity for estimating GPP, we measured leaf pigment composition, PRI, CCI, NIRV and photosynthetic activity at the leaf and canopy scales over 2 years in an evergreen and mixed deciduous forest. PRI and CCI captured the large seasonal carotenoid/chlorophyll ratio changes and good relationships were observed between PRI-e and CCI-photosynthesis and NIRV-photosynthesis. PRI-, CCI- and NIRV-based models effectively tracked observed seasonal GPP. We propose that carotenoid-based and near-infrared reflectance vegetation indices may provide useful proxies of photosynthetic activity and can improve remote sensing-based models of GPP in evergreen and deciduous forests.", "authors": [ "Wong, Christopher Y. S.", "D'Odorico, Petra", "Arain, M. Altaf", "Ensminger, Ingo" ], "keywords": [ "chlorophyll", "carotenoid index (CCI)", "deciduous forest", "evergreen forest", "gross primary productivity", "light-use efficiency", "near-infrared reflectance of vegetation (NIRV)", "photochemical reflectance index (PRI)", "photosynthetic pigments" ], "year": "2020", "source": "NEW PHYTOLOGIST", "publication_type": "J", "point2d": [ -69.30494689941406, 63.48194122314453 ], "cluster": 17.0 }, { "idx": 875, "title": "Stomatal response to decreased relative humidity constrains the acceleration of terrestrial evapotranspiration", "abstract": "Terrestrial evapotranspiration (ET) is thermodynamically expected to increase with increasing atmospheric temperature; however, the actual constraints on the intensification of ET remain uncertain due to a lack of direct observations. Based on the FLUXNET2015 Dataset, we found that relative humidity (RH) is a more important driver of ET than temperature. While actual ET decrease at reduced RH, potential ET increases, consistently with the complementary relationship (CR) framework stating that the fraction of energy not used for actual ET is dissipated as increased sensible heat flux that in turn increases potential ET. In this study, we proposed an improved CR formulation requiring no parameter calibration and assessed its reliability in estimating ET both at site-level with the FLUXNET2015 Dataset and at basin-level. Using the ERA-Interim meteorological dataset for 1979-2017 to calculate ET, we found that the global terrestrial ET showed an increasing trend until 1998, while the trend started to decline afterwards. Such decline was largely associated with a reduced RH, inducing water stress conditions that triggered stomatal closure to conserve water. For the first time, this study quantified the global-scale implications of changes in RH on terrestrial ET, indicating that the temperature-driven acceleration of the terrestrial water cycle will be likely constrained by terrestrial vegetation feedbacks.", "authors": [ "Xiao, Mingzhong", "Yu, Zhongbo", "Kong, Dongdong", "Gu, Xihui", "Mammarella, Ivan", "Montagnani, Leonardo", "Arain, M. Altaf", "Merbold, Lutz", "Magliulo, Vincenzo", "Lohila, Annalea", "Buchmann, Nina", "Wolf, Sebastian", "Gharun, Mana", "Hoertnagl, Lukas", "Beringer, Jason", "Gioli, Beniamino" ], "keywords": [ "terrestrial evapotranspiration", "relative humidity", "global warming", "stomata regulation" ], "year": "2020", "source": "ENVIRONMENTAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -59.75654220581055, 48.30156707763672 ], "cluster": 3.0 }, { "idx": 876, "title": "Seasonal variability of forest sensitivity to heat and drought stresses: A synthesis based on carbon fluxes from North American forest ecosystems", "abstract": "Climate extremes such as heat waves and droughts are projected to occur more frequently with increasing temperature and an intensified hydrological cycle. It is important to understand and quantify how forest carbon fluxes respond to heat and drought stress. In this study, we developed a series of daily indices of sensitivity to heat and drought stress as indicated by air temperature (T-a) and evaporative fraction (EF). Using normalized daily carbon fluxes from the FLUXNET Network for 34 forest sites in North America, the seasonal pattern of sensitivities of net ecosystem productivity (NEP), gross ecosystem productivity (GEP) and ecosystem respiration (RE) in response to T-a and EF anomalies were compared for different forest types. The results showed that warm temperatures in spring had a positive effect on NEP in conifer forests but a negative impact in deciduous forests. GEP in conifer forests increased with higher temperature anomalies in spring but decreased in summer. The drought-induced decrease in NEP, which mostly occurred in the deciduous forests, was mostly driven by the reduction in GEP. In conifer forests, drought had a similar dampening effect on both GEP and RE, therefore leading to a neutral NEP response. The NEP sensitivity to T-a anomalies increased with increasing mean annual temperature. Drier sites were less sensitive to drought stress in summer. Natural forests with older stand age tended to be more resilient to the climate stresses compared to managed younger forests. The results of the Classification and Regression Tree analysis showed that seasons and ecosystem productivity were the most powerful variables in explaining the variation of forest sensitivity to heat and drought stress. Our results implied that the magnitude and direction of carbon flux changes in response to climate extremes are highly dependent on the seasonal dynamics of forests and the timing of the climate extremes.", "authors": [ "Xu, Bing", "Arain, M. Altaf", "Black, T. Andrew", "Law, Beverly E.", "Pastorello, Gilberto Z.", "Chu, Housen" ], "keywords": [ "climatic stresses", "drought", "eddy covariance technique", "FLUXNET2015", "forest carbon cycle", "heat wave", "net ecosystem productivity" ], "year": "2020", "source": "GLOBAL CHANGE BIOLOGY", "publication_type": "J", "point2d": [ -55.29519271850586, 64.8692855834961 ], "cluster": 17.0 }, { "idx": 877, "title": "Attribute parameter characterized the seasonal variation of gross primary productivity (alpha(GPP)): Spatiotemporal variation and influencing factors", "abstract": "The seasonal dynamic of gross primary productivity (GPP) has influences on the annual GPP (AGPP) of the terrestrial ecosystem. However, the spatiotemporal variation of the seasonal dynamic of GPP and its effects on spatial and temporal variations of AGPP are still poorly addressed. In this study, we developed a parameter, alpha(GPP), defined as the ratio of mean daily GPP (GPP(mean)) to the maximum daily GPP (GPP(max)) during the growing season, to analyze the seasonal dynamic of GPP based on Weibull function. The alpha(GPP) was a comprehensive parameter characterizing the shape, scale, and location of the seasonal dynamic curve of GPP. We calculated aGPP based on the data of GPP for 942 site-years from 115 flux sites in the Northern Hemisphere, and analyzed the spatiotemporal variation and influencing factors of the aGPP. We found that the aGPP of terrestrial ecosystems in the Northern Hemisphere ranged from 0.47 to 0.85, with an average of 0.62 +/- 0.06. The aGPP varied significantly both among different climatic zones and different ecosystem types. The alpha(GPP) was stable on the interannual scale, while decreased as latitude increased, which was consistent across different ecosystem types. The spatial pattern of the seasonal dynamic of astronomical radiation was the dominating factor of the spatial pattern of alpha(GPP), that was, the spatial pattern of the seasonal dynamic of astronomical radiation determined that of the seasonal dynamic of GPP by controlling that of seasonal dynamics of total radiation and temperature. In addition, we assessed the spatial variation of AGPP preliminarily based on alpha(GPP) and other seasonal dynamic parameters of GPP, indicating that the understanding of the spatiotemporal variation of alpha(GPP) could provide a new approach for studying the spatial and temporal variations of AGPP and estimating AGPP based on the seasonal dynamic of GPP.", "authors": [ "Zhang, Weikang", "Yu, Guirui", "Chen, Zhi", "Zhang, Leiming", "Wang, Qiufeng", "Zhang, Yangjian", "He, Honglin", "Han, Lang", "Chen, Shiping", "Han, Shijie", "Li, Yingnian", "Sha, Liqing", "Shi, Peili", "Wang, Huimin", "Wang, Yanfen", "Xiang, Wenhua", "Yan, Junhua", "Zhang, Yiping", "Zona, Donatella", "Arain, M. Altaf", "Maximov, Trofim", "Oechel, Walter", "Kosugi, Yoshiko" ], "keywords": [ "Annual gross primary productivity", "Attribute parameter of seasonal dynamic", "Maximum daily gross primary productivity", "Mean daily gross primary productivity", "Spatiotemporal variation" ], "year": "2020", "source": "AGRICULTURAL AND FOREST METEOROLOGY", "publication_type": "J", "point2d": [ -60.50294494628906, 60.2592887878418 ], "cluster": 17.0 }, { "idx": 878, "title": "Modeling the impacts of diffuse light fraction on photosynthesis in ORCHIDEE (v5453) land surface model", "abstract": "Aerosol- and cloud-induced changes in diffuse light have important impacts on the global land carbon cycle, as they alter light distribution and photosynthesis in vegetation canopies. However, this effect remains poorly represented or evaluated in current land surface models. Here, we add a light partitioning module and a new canopy light transmission module to the ORCHIDEE (Organising Carbon and Hydrology In Dynamic Ecosystems) land surface model (trunk version, v5453) and use the revised model, ORCHIDEE_DF, to estimate the fraction of diffuse light and its effect on gross primary production (GPP) in a multilayer canopy. We evaluate the new parameterizations using flux observations from 159 eddy covariance sites over the globe. Our results show that, compared with the original model, ORCHIDEE_DF improves the GPP simulation under sunny conditions and captures the observed higher photosynthesis under cloudier conditions in most plant functional types (PFTs). Our results also indicate that the larger GPP under cloudy conditions compared with sunny conditions is mainly driven by increased diffuse light in the morning and in the afternoon as well as by a decreased vapor pressure deficit (VPD) and decreased air temperature at midday. The observations show that the strongest positive effects of diffuse light on photosynthesis are found in the range from 5 to 20 degrees C and at a VPD < 1 kPa. This effect is found to decrease when the VPD becomes too large or the temperature falls outside of the abovementioned range, which is likely due to the increasing stomatal resistance to leaf CO2 uptake. ORCHIDEE_DF underestimates the diffuse light effect at low temperature in all PFTs and overestimates this effect at high temperature and at a high VPD in grasslands and croplands. The new model has the potential to better investigate the impact of large-scale aerosol changes and long-term changes in cloudiness on the terrestrial carbon budget, both in the historical period and in the context of future air quality policies and/or climate engineering.", "authors": [ "Zhang, Yuan", "Bastos, Ana", "Maignan, Fabienne", "Goll, Daniel", "Boucher, Olivier", "Li, Laurent", "Cescatti, Alessandro", "Vuichard, Nicolas", "Chen, Xiuzhi", "Ammann, Christof", "Arain, M. Altaf", "Black, T. Andrew", "Chojnicki, Bogdan", "Kato, Tomomichi", "Mammarella, Ivan", "Montagnani, Leonardo", "Roupsard, Olivier", "Sanz, Maria J.", "Siebicke, Lukas", "Urbaniak, Marek", "Vaccari, Francesco Primo", "Wohlfahrt, Georg", "Woodgate, Will", "Ciais, Philippe" ], "keywords": [ "" ], "year": "2020", "source": "GEOSCIENTIFIC MODEL DEVELOPMENT", "publication_type": "J", "point2d": [ -64.97905731201172, 57.20326232910156 ], "cluster": 17.0 }, { "idx": 879, "title": "Application of GNSS Interferometric Reflectometry for the Estimation of Lake Ice Thickness", "abstract": "Lake ice thickness is a sensitive indicator of climate change largely through its dependency on near-surface air temperature and on-ice snow mass (depth and density). Monitoring of the seasonal variations and trends in ice thickness is also important for the operation of winter ice roads that northern communities rely on for the movement of goods as well as for cultural and leisure activities (e.g., snowmobiling). Therefore, consistent measurements of ice thickness over lakes is important; however, field measurements tend to be sparse in both space and time in many northern countries. Here, we present an application of L-band frequency Global Navigation Satellite System (GNSS) Interferometric Reflectometry (GNSS-IR) for the estimation of lake ice thickness. The proof of concept is demonstrated through the analysis of Signal-to-Noise Ratio (SNR) time series extracted from Global Positioning System (GPS) constellation L1 band raw data acquired between 8 and 22 March (2017 and 2019) at 14 lake ice sites located in the Northwest Territories, Canada. Dominant frequencies are extracted using Least Squares Harmonic Estimation (LS-HE) for the retrieval of ice thickness. Estimates compare favorably with in-situ measurements (mean absolute error = 0.05 m, mean bias error = -0.01 m, and root mean square error = 0.07 m). These results point to the potential of GPS/GNSS-IR as a complementary tool to traditional field measurements for obtaining consistent ice thickness estimates at many lake locations, given the relatively low cost of GNSS antennas/receivers.", "authors": [ "Ghiasi, Yusof", "Duguay, Claude R.", "Murfitt, Justin", "van der Sanden, Joost J.", "Thompson, Aaron", "Drouin, Hugo", "Prevost, Christian" ], "keywords": [ "GNSS", "GPS", "interferometry", "reflectometry", "lake ice thickness" ], "year": "2020", "source": "REMOTE SENSING", "publication_type": "J", "point2d": [ -76.96224212646484, 5.021014213562012 ], "cluster": 2.0 }, { "idx": 880, "title": "Improving sub-canopy snow depth mapping with unmanned aerial vehicles: lidar versus structure-from-motion techniques", "abstract": "Vegetation has a tremendous influence on snow processes and snowpack dynamics, yet remote sensing techniques to resolve the spatial variability of sub-canopy snow depth are not always available and are difficult from space-based platforms. Unmanned aerial vehicles (UAVs) have had recent widespread application to capture high-resolution information on snow processes and are herein applied to the sub-canopy snow depth challenge. Previous demonstrations of snow depth mapping with UAV structure from motion (SfM) and airborne lidar have focussed on non-vegetated surfaces or reported large errors in the presence of vegetation. In contrast, UAV-lidar systems have high-density point clouds and measure returns from a wide range of scan angles, increasing the likelihood of successfully sensing the subcanopy snow depth. The effectiveness of UAV lidar and UAV SfM in mapping snow depth in both open and forested terrain was tested in a 2019 field campaign at the Canadian Rockies Hydrological Observatory, Alberta, and at Canadian prairie sites near Saskatoon, Saskatchewan, Canada. Only UAV lidar could successfully measure the sub-canopy snow surface with reliable sub-canopy point coverage and consistent error metrics (root mean square error (RMSE) <0.17 m and bias -0.03 to -0.13 m). Relative to UAV lidar, UAV SfM did not consistently sense the sub-canopy snow surface, the interpolation needed to account for point cloud gaps introduced interpolation artefacts, and error metrics demonstrated relatively large variability (RMSE<0.33 m and bias 0.08 to -0.14 m). With the demonstration of sub-canopy snow depth mapping capabilities, a number of early applications are presented to showcase the ability of UAV lidar to effectively quantify the many multiscale snow processes defining snow-pack dynamics in mountain and prairie environments.", "authors": [ "Harder, Phillip", "Pomeroy, John W.", "Helgason, Warren D." ], "keywords": [ "" ], "year": "2020", "source": "CRYOSPHERE", "publication_type": "J", "point2d": [ -59.390357971191406, 2.414945125579834 ], "cluster": 8.0 }, { "idx": 881, "title": "Improving sub-canopy snow depth mapping with unmanned aerial vehicles: lidar versus structure-from-motion techniques", "abstract": "Vegetation has a tremendous influence on snow processes and snowpack dynamics, yet remote sensing techniques to resolve the spatial variability of sub-canopy snow depth are not always available and are difficult from space-based platforms. Unmanned aerial vehicles (UAVs) have had recent widespread application to capture high-resolution information on snow processes and are herein applied to the sub-canopy snow depth challenge. Previous demonstrations of snow depth mapping with UAV structure from motion (SfM) and airborne lidar have focussed on non-vegetated surfaces or reported large errors in the presence of vegetation. In contrast, UAV-lidar systems have high-density point clouds and measure returns from a wide range of scan angles, increasing the likelihood of successfully sensing the subcanopy snow depth. The effectiveness of UAV lidar and UAV SfM in mapping snow depth in both open and forested terrain was tested in a 2019 field campaign at the Canadian Rockies Hydrological Observatory, Alberta, and at Canadian prairie sites near Saskatoon, Saskatchewan, Canada. Only UAV lidar could successfully measure the sub-canopy snow surface with reliable sub-canopy point coverage and consistent error metrics (root mean square error (RMSE) <0.17 m and bias -0.03 to -0.13 m). Relative to UAV lidar, UAV SfM did not consistently sense the sub-canopy snow surface, the interpolation needed to account for point cloud gaps introduced interpolation artefacts, and error metrics demonstrated relatively large variability (RMSE<0.33 m and bias 0.08 to -0.14 m). With the demonstration of sub-canopy snow depth mapping capabilities, a number of early applications are presented to showcase the ability of UAV lidar to effectively quantify the many multiscale snow processes defining snow-pack dynamics in mountain and prairie environments.", "authors": [ "Harder, Phillip", "Pomeroy, John W.", "Helgason, Warren D." ], "keywords": [ "" ], "year": "2020", "source": "CRYOSPHERE", "publication_type": "J", "point2d": [ -59.175506591796875, 2.8757176399230957 ], "cluster": 8.0 }, { "idx": 882, "title": "Coupled model for water, vapour, heat, stress and strain fields in variably saturated freezing soils", "abstract": "Although many frost heave and freezing soil models have been developed in the past decades, saturated conditions are commonly assumed and/or the behavior of pore ice rather than ice lenses are conventionally predicted. This study presents a fully coupled thermal-hydraulic-mechanical (THM) model for variably saturated freezing soil, which examines a number of processes. These include heat conduction and convection, phase change, water (moisture) movement through cryosuction, and the development of independent ice lenses. Instead of directly solving for the pore pressure distributions, the void ratio is considered as a dependent variable related to the degree of water saturation. Both the stress-deformation and ice lens segregation are inextricably linked to the evolution of the void ratio as well. The coupled mechanism and performance of the model is first verified by comparison with laboratory freezing experiment observations obtained from literature and then is further evaluated by a series of parametric analyses. The results show that the calculated profiles of temperature, water content and frost heave are in good agreement with literature experimental data, demonstrating that the proposed THM coupling model appropriately represents the mechanisms of heat-moisture-deformation in variably saturated freezing soil. In addition, the sensitivity analysis illustrates that in the test cases considered, thermally-induced cryosuction due to phase change is the main driving force for water migrating towards the freezing front. Also, ahead of the freezing front, a significant increase in effective stress developed due to the elevated negative pore pressure and expansion of ice lenses causing substantial consolidation and reduction in porosity in the unfrozen zone. As the freezing front penetrated with time, the temperature, moisture, vapour and stress-strain fields interact with each other. The distribution of water vapour was mainly controlled by the temperature gradient and location of the freezing front. Both the initial degree of saturation and hydraulic conductivity affected the distribution of pore pressure and displacements. Higher compression moduli and lower overburden load led to greater frost heave but exerted little influence on the temperature field. Finally, the two-sided freezing scenario for soils underlain by permafrost made the middle ice-poor zone highly compacted with ice lenses accumulating near both freezing boundaries.", "authors": [ "Huang, Xiang", "Rudolph, David L." ], "keywords": [ "Unsaturated freezing soils", "Ice lens", "Frost heave", "Thermal-hydraulic-mechanic (THM)", "Void ratio" ], "year": "2021", "source": "ADVANCES IN WATER RESOURCES", "publication_type": "J", "point2d": [ -38.74347686767578, 22.900188446044922 ], "cluster": 2.0 }, { "idx": 883, "title": "Signal processing for in situ detection of effective heat pulse probe spacing radius as the basis of a self-calibrating heat pulse probe", "abstract": "A sensor comprised of an electronic circuit and a hybrid single and dual heat pulse probe was constructed and tested along with a novel signal processing procedure to determine changes in the effective dual-probe spacing radius over the time of measurement. The circuit utilized a proportional-integral-derivative (PID) controller to control heat inputs into the soil medium in lieu of a variable resistor. The system was designed for onboard signal processing and implemented USB, RS-232, and SDI-12 interfaces for machine-to-machine (M2M) exchange of data, thereby enabling heat inputs to be adjusted to soil conditions and data availability shortly after the time of experiment. Signal processing was introduced to provide a simplified single-probe model to determine thermal conductivity instead of reliance on late-time logarithmic curve fitting. Homomorphic and derivative filters were used with a dual-probe model to detect changes in the effective probe spacing radius over the time of experiment to compensate for physical changes in radius as well as model and experimental error. Theoretical constraints were developed for an efficient inverse of the exponential integral on an embedded system. Application of the signal processing to experiments on sand and peat improved the estimates of soil water content and bulk density compared to methods of curve fitting nominally used for heat pulse probe experiments. Applications of the technology may be especially useful for soil and environmental conditions under which effective changes in probe spacing radius need to be detected and compensated for over the time of experiment.", "authors": [ "Kinar, Nicholas J.", "Pomeroy, John W.", "Si, Bing" ], "keywords": [ "" ], "year": "2020", "source": "GEOSCIENTIFIC INSTRUMENTATION METHODS AND DATA SYSTEMS", "publication_type": "J", "point2d": [ -76.38494110107422, 28.258060455322266 ], "cluster": 2.0 }, { "idx": 884, "title": "Soil dielectric characterization during freeze-thaw transitions using L-band coaxial and soil moisture probes", "abstract": "Soil microwave permittivity is a crucial parameter in passive microwave retrieval algorithms but remains a challenging variable to measure. To validate and improve satellite microwave data products, precise and reliable estimations of the relative permittivity (epsilon(r) = epsilon/epsilon(0) = epsilon' - j epsilon ''; unitless) of soils are required, particularly for frozen soils. In this study, permittivity measurements were acquired using two different instruments: the newly designed openended coaxial probe (OECP) and the conventional Stevens HydraProbe. Both instruments were used to characterize the permittivity of soil samples undergoing several freeze- thaw cycles in a laboratory environment. The measurements were compared to soil permittivity models. The OECP measured frozen (epsilon(frozen)' = [3.5; 6.0], epsilon(frozen)'' = [0.46; 1.2]) and thawed (epsilon(thawed)' = [6.5; 22.8], epsilon(thawed '') = [1.43; 5.7]) soil microwave permittivity. We also demonstrate that cheaper and widespread soil permittivity probes operating at lower frequencies (i.e., Stevens HydraProbe) can be used to estimate microwave permittivity given proper calibration relative to an L-band (1-2 GHz) probe. This study also highlighted the need to improve dielectric soil models, particularly during freeze-thaw transitions. There are still important discrepancies between in situ and modeled estimates and no current model accounts for the hysteresis effect shown between freezing and thawing processes, which could have a significant impact on freeze-thaw detection from satellites.", "authors": [ "Mavrovic, Alex", "Lara, Renato Pardo", "Berg, Aaron", "Demontoux, Francois", "Royer, Alain", "Roy, Alexandre" ], "keywords": [ "" ], "year": "2021", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -73.8010025024414, 26.301170349121094 ], "cluster": 2.0 }, { "idx": 885, "title": "The catastrophic thermokarst lake drainage events of 2018 in northwestern Alaska: fast-forward into the future", "abstract": "Northwestern Alaska has been highly affected by changing climatic patterns with new temperature and precipitation maxima over the recent years. In particular, the Baldwin and northern Seward peninsulas are characterized by an abundance of thermokarst lakes that are highly dynamic and prone to lake drainage like many other regions at the southern margins of continuous permafrost. We used Sentinel-1 synthetic aperture radar (SAR) and Planet Cube-Sat optical remote sensing data to analyze recently observed widespread lake drainage. We then used synoptic weather data, climate model outputs and lake ice growth simulations to analyze potential drivers and future pathways of lake drainage in this region. Following the warmest and wettest winter on record in 2017/2018, 192 lakes were identified as having completely or partially drained by early summer 2018, which exceeded the average drainage rate by a factor of similar to 10 and doubled the rates of the previous extreme lake drainage years of 2005 and 2006. The combination of abundant rain- and snowfall and extremely warm mean annual air temperatures (MAATs), close to 0 degrees C, may have led to the destabilization of permafrost around the lake margins. Rapid snow melt and high amounts of excess meltwater further promoted rapid lateral breaching at lake shores and consequently sudden drainage of some of the largest lakes of the study region that have likely persisted for millennia. We hypothesize that permafrost destabilization and lake drainage will accelerate and become the dominant drivers of landscape change in this region. Recent MAATs are already within the range of the predictions by the University of Alaska Fairbanks' Scenarios Network for Alaska and Arctic Planning (UAF SNAP) ensemble climate predictions in scenario RCP6.0 for 2100. With MAAT in 2019 just below 0 degrees C at the nearby Kotzebue, Alaska, climate station, permafrost aggradation in drained lake basins will become less likely after drainage, strongly decreasing the potential for freeze-locking carbon sequestered in lake sediments, signifying a prominent regime shift in ice-rich permafrost lowland regions.", "authors": [ "Nitze, Ingmar", "Cooley, Sarah W.", "Duguay, Claude R.", "Jones, Benjamin M.", "Grosse, Guido" ], "keywords": [ "" ], "year": "2020", "source": "CRYOSPHERE", "publication_type": "J", "point2d": [ -41.47068405151367, 9.590612411499023 ], "cluster": 13.0 }, { "idx": 886, "title": "Assessment of machine learning classifiers for global lake ice cover mapping from MODIS TOA reflectance data", "abstract": "The topic of satellite remote sensing of lake ice has gained considerable attention in recent years. Optical satellite data from the Moderate Resolution Imaging Spectroradiometer (MODIS) allow for the monitoring of lake ice cover (an Essential Climate Variable or ECV), and dates associated with ice phenology (freeze-up, break-up, and ice cover duration) over large areas in an era where ground-based observational networks have nearly vanished in many northern countries. Ice phenology dates as well as dates of maximum and minimum ice cover extent (for lakes that do not form a complete ice cover in winter or do not totally lose their ice cover in summer) are useful for assessing long-term trends and variability in climate, particularly due to their sensitivity to changes in near-surface air temperature. Existing knowledge-driven (threshold-based) retrieval algorithms for lake ice cover mapping that use top-of-atmosphere (TOA) reflectance products do not perform well under lower solar illumination conditions (i.e. large solar zenith angles), resulting in low TOA reflectance. This research assessed the capability of four machine learning classifiers (i.e. multinomial logistic regression, MLR; support vector machine, SVM; random forest, RF; gradient boosting trees, GBT) for mapping lake ice cover, water and cloud cover during both break-up and freeze-up periods using the MODIS/Terra L1B TOA (MOD02) product. The classifiers were trained and validated using samples collected from 17 large lakes across the Northern Hemisphere (Europe and North America); lakes that represent different characteristics with regards to area, latitude, freezing frequency, and ice duration. Following an accuracy assessment using random k-fold cross-validation (k = 100), all machine learning classifiers using a 7-band combination (visible, near-infrared and shortwave-infrared) were found to be able to produce overall classification accuracies above 94%. Both RF and GBT provided overall and class-specific accuracies above 98% and a more visually accurate depiction of lake ice, water and cloud cover. The two tree-based classifiers offered the most robust spatial transferability over the 17 lakes and performed consistently well across ice seasons. However, only RF was relatively insensitive to the choice of the hyperparameters compared to the other three classifiers. The results demonstrate the potential of RF for mapping lake ice cover globally from MODIS TOA reflectance data.", "authors": [ "Wu, Yuhao", "Duguay, Claude R.", "Xu, Linlin" ], "keywords": [ "Lake ice", "MODIS", "Classification", "Machine learning" ], "year": "2021", "source": "REMOTE SENSING OF ENVIRONMENT", "publication_type": "J", "point2d": [ -82.23153686523438, 4.3881001472473145 ], "cluster": 2.0 }, { "idx": 887, "title": "Global Dam-Driven Changes to Riverine N:P:Si Ratios Delivered to the Coastal Ocean", "abstract": "River damming alters nutrient fluxes along the land-ocean aquatic continuum as a result of biogeochemical processes in reservoirs. Both the changes in riverine nutrient fluxes and nutrient ratios impact ecosystem functioning of receiving water bodies. We utilize spatially distributed mechanistic models of nitrogen (N), phosphorus (P), and silicon (Si) cycling in reservoirs to quantify changes in nutrient stoichiometry of river discharge to coastal waters. The results demonstrate that the growing number of dams decouples the riverine fluxes of N, P, and Si. Worldwide, preferential removal of P over N in reservoirs increases N:P ratios delivered to the ocean, raising the potential for P limitation of coastal productivity. By midcentury, more than half of the rivers discharging to the coastal zone will experience a higher removal of reactive Si relative to reactive P and total N, in response to the rapid pace at which new hydroelectric dams are being built. Plain Language Summary The damming of rivers is one of the most impactful modifications of the flows of water and associated materials from land to sea. Included in these materials are nutrient elements like nitrogen and phosphorus, which are elements required by all life on Earth, and silicon, which is required by diatoms, the algae that account for the largest fraction of biological productivity of the oceans. Past studies have shown that if you alter the ratios in which these nutrient elements enter the coastal oceans, plankton communities can change, even causing harmful algal blooms or red tides to occur. Here, we use models of nitrogen, phosphorus, and silicon cycling in dam reservoirs to determine how dams change the ratios delivered to coastal zones worldwide. We predict that by midcentury, more than half of the rivers flowing to the sea will experience greater removal of silicon over nitrogen and phosphorus, in response to ongoing construction of many new hydroelectric dams. This will impact the role of diatoms in nearshore marine production, as they are increasingly outcompeted by other, potentially harmful, algae that do not need silicon to grow.", "authors": [ "Maavara, Taylor", "Akbarzadeh, Zahra", "Van Cappellen, Philippe" ], "keywords": [ "dams", "phosphorus", "nitrogen", "silicon", "nutrient limitation", "coastal zone" ], "year": "2020", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ 35.779296875, -3.2855703830718994 ], "cluster": 19.0 }, { "idx": 889, "title": "Pore-scale controls on hydrological and geochemical processes in peat: Implications on interacting processes", "abstract": "Peatlands are wetlands that provide important ecosystem services including carbon sequestration and water storage that respond to hydrological, biological, and biogeochemical processes. These processes are strongly influenced by the complex pore structure of peat soils. We explore the literature on peat pore structure and the implications for hydrological, biogeochemical, and microbial processes in peat, highlighting the gaps in our current knowledge and a path to move forward. Peat is an elastic and multi-porous structured organic soil. Surficial (near-surface) pears are typically dominated by large interconnected macropores that rapidly transmit water and solutes when saturated, but these large pores drain rapidly with a reduction in pore-water pressure, and disproportionally decrease the bulk effective hydraulic conductivity, thus water fluxes that drive ecohydrological functions. The more advanced state of decomposition of older (deeper) peat, with a greater abundance of small pores, restricts the loss of moisture at similar soil water pressures and is associated with higher unsaturated hydraulic conductivities. As evaporation and precipitation occur, peat soils shrink and swell, respectively, changing the hydrological connectivity that maintain physiological processes at the peat surface. Due to the disproportionate change in pore structure and associated hydraulic properties with state of decomposition, transport processes are limited at depth, creating a zone of enhanced transport in the less decomposed peat near the surface. At the micro-scale, rapid equilibration of solutes and water occurs between the mobile and immobile pores due to diffusion, resulting in pore regions with similar chemical concentrations that are not affected by advective fluxes. These immobile regions may be the primary sites for microbial biogeochemical processes in peat. Mass transfer limitations may therefore largely regulate belowground microbial turnover and, hence, biogeochemical cycling. For peat, the development of a comprehensive theory that links the hydrological, biological, and biogeochemical processes will require a concerted interdisciplinary effort. To that end, we have highlighted four primary areas to focus our collective research: 1) understanding the combined and interrelated effects of parent material, decomposition, and nutrient status on peat pore connectivity, macropore development and collapse, and solute transport, 2) determining the influence of changing pore structure due to freeze-thaw or dewatering on the hydrology and biogeochemistry, 3) better elucidating the non-equilibrium transport processes in peat, and 4) exploring the implications of peat's pore structure on microbiological and biogeochemical processes.", "authors": [ "McCarter, C. P. R.", "Rezanezhad, F.", "Quinton, W. L.", "Gharedaghloo, B.", "Lennartz, B.", "Price, J.", "Connon, R.", "Van Cappellen, P." ], "keywords": [ "Biogeochemistry", "Ecohydrology", "Freeze-thaw", "Microbial", "Decomposition", "Pore network" ], "year": "2020", "source": "EARTH-SCIENCE REVIEWS", "publication_type": "J", "point2d": [ -6.353305816650391, 65.46408081054688 ], "cluster": 9.0 }, { "idx": 890, "title": "The Cold Region Critical Zone in Transition: Responses to Climate Warming and Land Use Change", "abstract": "Global climate warming disproportionately affects high-latitude and mountainous terrestrial ecosystems. Warming is accompanied by permafrost thaw, shorter winters, earlier snowmelt, more intense soil freeze-thaw cycles, drier summers, and longer fire seasons. These environmental changes in turn impact surface water and groundwater flow regimes, water quality, greenhouse gas emissions, soil stability, vegetation cover, and soil (micro)biological communities. Warming also facilitates agricultural expansion, urban growth, and natural resource development, adding growing anthropogenic pressures to cold regions' landscapes, soil health, and biodiversity. Further advances in the predictive understanding of how cold regions' critical zone processes, functions, and ecosystem services will continue to respond to climate warming and land use changes require multiscale monitoring technologies coupled with integrated observational and modeling tools. We highlight some of the major challenges, knowledge gaps, and opportunities in cold region critical zone research, with an emphasis on subsurface processes and responses in both natural and agricultural ecosystems.", "authors": [ "Pi, Kunfu", "Bieroza, Magdalena", "Brouchkov, Anatoli", "Chen, Weitao", "Dufour, Louis J. P.", "Gongalsky, Konstantin B.", "Herrmann, Anke M.", "Krab, Eveline J.", "Landesman, Catherine", "Laverman, Anniet M.", "Mazei, Natalia", "Mazei, Yuri", "Oquist, Mats G.", "Peichl, Matthias", "Pozdniakov, Sergey", "Rezanezhad, Fereidoun", "Roose-Amsaleg, Celine", "Shatilovich, Anastasia", "Shi, Andong", "Smeaton, Christina M.", "Tong, Lei", "Tsyganov, Andrey N.", "Van Cappellen, Philippe" ], "keywords": [ "cold regions", "environmental change", "critical zone", "hydrogeology", "biogeochemistry", "agroecosystems" ], "year": "2021", "source": "ANNUAL REVIEW OF ENVIRONMENT AND RESOURCES, VOL 46, 2021", "publication_type": "S", "point2d": [ 13.243881225585938, 18.507295608520508 ], "cluster": 13.0 }, { "idx": 891, "title": "Non-growing season carbon emissions in a northern peatland are projected to increase under global warming", "abstract": "Peatlands are important ecosystems that store approximately one third of terrestrial organic carbon. Non-growing season carbon fluxes significantly contribute to annual carbon budgets in peatlands, yet their response to climate change is poorly understood. Here, we investigate the governing environmental variables of non-growing season carbon emissions in a northern peatland. We develop a support-vector regression model using a continuous 13-year dataset of eddy covariance flux measurements from the Mer Blue Bog, Canada. We determine that only seven variables were needed to reproduce carbon fluxes, which were most sensitive to net radiation above the canopy, soil temperature, wind speed and soil moisture. We find that changes in soil temperature and photosynthesis drove changes in net carbon flux. Assessing net ecosystem carbon exchange under three representative concentration pathways, we project a 103% increase in peatland carbon loss by 2100 under a high emissions scenario. We suggest that peatland carbon losses constitute a strong positive climate feedback loop. Future changes in non-growing season conditions, particularly irradiance and temperature, will enhance carbon emissions from a northern peatland, according to projections with a data-driven machine learning model.", "authors": [ "Rafat, Arash", "Rezanezhad, Fereidoun", "Quinton, William L.", "Humphreys, Elyn R.", "Webster, Kara", "Van Cappellen, Philippe" ], "keywords": [ "" ], "year": "2021", "source": "COMMUNICATIONS EARTH & ENVIRONMENT", "publication_type": "J", "point2d": [ -22.57204818725586, 60.386051177978516 ], "cluster": 17.0 }, { "idx": 893, "title": "Differential impact of thermal and physical permafrost disturbances on High Arctic dissolved and particulate fluvial fluxes", "abstract": "Climate warming and changing precipitation patterns have thermally (active layer deepening) and physically (permafrost-thaw related mass movements) disturbed permafrost-underlain watersheds across much of the Arctic, increasing the transfer of dissolved and particulate material from terrestrial to aquatic ecosystems. We examined the multiyear (2006-2017) impact of thermal and physical permafrost disturbances on all of the major components of fluvial flux. Thermal disturbances increased the flux of dissolved organic carbon (DOC), but localized physical disturbances decreased multiyear DOC flux. Physical disturbances increased major ion and suspended sediment flux, which remained elevated a decade after disturbance, and changed carbon export from a DOC to a particulate organic carbon (POC) dominated system. As the magnitude and frequency of physical permafrost disturbance intensifies in response to Arctic climate change, disturbances will become an increasingly important mechanism to deliver POC from terrestrial to aquatic ecosystems. Although nival runoff remained the primary hydrological driver, the importance of pluvial runoff as driver of fluvial flux increased following both thermal and physical permafrost disturbance. We conclude the transition from a nival-dominated fluvial regime to a regime where rainfall runoff is proportionately more important will be a likely tipping point to accelerated High Arctic change.", "authors": [ "Beel, C. R.", "Lamoureux, S. F.", "Orwin, J. F.", "Pope, M. A.", "Lafreniere, M. J.", "Scott, N. A." ], "keywords": [ "" ], "year": "2020", "source": "SCIENTIFIC REPORTS", "publication_type": "J", "point2d": [ 15.590391159057617, 19.353229522705078 ], "cluster": 13.0 }, { "idx": 894, "title": "Concentrations of Metals in Fishes from the Athabasca and Slave Rivers of Northern Canada", "abstract": "There is growing concern about possible effects of exploitation of the Alberta Oil Sands on the ambient environment, including possible effects on populations of fishes in the Athabasca River and farther downstream in Lake Athabasca and the Slave River. In the present study, concentrations of metals in dorsal muscle tissue of 5 fish species-goldeye, northern pike, walleye, whitefish, and burbot-from the Slave, Peace, and Athabasca Rivers were quantified. A suite of 25 metals including As, Hg, Se, Tl, and V was analyzed. Most metals exhibited no significant variations in concentration among locations. Concentrations of 5 metals, As, Hg, Se, Tl, and V, revealed significant variations among locations and were of sufficient magnitude to be of interest. Concentrations of Hg did not vary significantly among locations; however, because it was detected at concentrations of concern and the use of the selected fishes was a local source of food for humans and pets, it was of interest. Concentrations of As, Se, Tl, and V in dorsal muscle of certain fishes in the farthest downstream sites on the Slave River were greater than those in the same tissues and species in the farther upstream sites on the Peace and Athabasca Rivers. This phenomenon was most prevalent with Tl and to a lesser extent with As and Se. Nevertheless, concentrations were not of concern for the health of human consumers. Although metals did not appear to be increased in fish in the Alberta Oil Sands region in the present study, further research is needed to understand the potential impacts.Environ Toxicol Chem2020;00:1-16. (c) 2020 SETAC", "authors": [ "Tendler, Brett", "Ohiozebau, Ehimai", "Codling, Garry", "Giesy, John P.", "Jones, Paul D." ], "keywords": [ "Metals", "Bioavailability", "Mercury", "Thallium", "Slave River", "Athabasca River" ], "year": "2020", "source": "ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY", "publication_type": "J", "point2d": [ 74.74986267089844, -11.893179893493652 ], "cluster": 0.0 }, { "idx": 895, "title": "The Use of Serially Complete Station Data to Improve the Temporal Continuity of Gridded Precipitation and Temperature Estimates", "abstract": "Stations are an important source of meteorological data, but often suffer from missing values and short observation periods. Gap filling is widely used to generate serially complete datasets (SCDs), which are subsequently used to produce gridded meteorological estimates. However, the value of SCDs in spatial interpolation is scarcely studied. Based on our recent efforts to develop a SCD over North America (SCDNA), we explore the extent to which gap filling improves gridded precipitation and temperature estimates. We address two specific questions: 1) Can SCDNA improve the statistical accuracy of gridded estimates in North America? 2) Can SCDNA improve estimates of trends on gridded data? In addressing these questions, we also evaluate the extent to which results depend on the spatial density of the station network and the spatial interpolation methods used. Results show that the improvement in statistical interpolation due to gap filling is more obvious for precipitation, followed by minimum temperature and maximum temperature. The improvement is larger when the station network is sparse and when simpler interpolation methods are used. SCDs can also notably reduce the uncertainties in spatial interpolation. Our evaluation across North America from 1979 to 2018 demonstrates that SCDs improve the accuracy of interpolated estimates for most stations and days. SCDNA-based interpolation also obtains better trend estimation than observation-based interpolation. This occurs because stations used for interpolation could change during a specific period, causing changepoints in interpolated temperature estimates and affect the long-term trends of observation-based interpolation, which can be avoided using SCDNA. Overall, SCDs improve the performance of gridded precipitation and temperature estimates.", "authors": [ "Tang, Guoqiang", "Clark, Martyn P.", "Papalexiou, Simon Michael" ], "keywords": [ "Precipitation", "Temperature", "Interpolation schemes", "Trends", "Machine learning", "North America" ], "year": "2021", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -45.1378288269043, -54.91013717651367 ], "cluster": 14.0 }, { "idx": 896, "title": "The Use of Serially Complete Station Data to Improve the Temporal Continuity of Gridded Precipitation and Temperature Estimates", "abstract": "Stations are an important source of meteorological data, but often suffer from missing values and short observation periods. Gap filling is widely used to generate serially complete datasets (SCDs), which are subsequently used to produce gridded meteorological estimates. However, the value of SCDs in spatial interpolation is scarcely studied. Based on our recent efforts to develop a SCD over North America (SCDNA), we explore the extent to which gap filling improves gridded precipitation and temperature estimates. We address two specific questions: 1) Can SCDNA improve the statistical accuracy of gridded estimates in North America? 2) Can SCDNA improve estimates of trends on gridded data? In addressing these questions, we also evaluate the extent to which results depend on the spatial density of the station network and the spatial interpolation methods used. Results show that the improvement in statistical interpolation due to gap filling is more obvious for precipitation, followed by minimum temperature and maximum temperature. The improvement is larger when the station network is sparse and when simpler interpolation methods are used. SCDs can also notably reduce the uncertainties in spatial interpolation. Our evaluation across North America from 1979 to 2018 demonstrates that SCDs improve the accuracy of interpolated estimates for most stations and days. SCDNA-based interpolation also obtains better trend estimation than observation-based interpolation. This occurs because stations used for interpolation could change during a specific period, causing changepoints in interpolated temperature estimates and affect the long-term trends of observation-based interpolation, which can be avoided using SCDNA. Overall, SCDs improve the performance of gridded precipitation and temperature estimates.", "authors": [ "Tang, Guoqiang", "Clark, Martyn P.", "Papalexiou, Simon Michael" ], "keywords": [ "Precipitation", "Temperature", "Interpolation schemes", "Trends", "Machine learning", "North America" ], "year": "2021", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -44.918678283691406, -55.47501754760742 ], "cluster": 14.0 }, { "idx": 897, "title": "Managing nitrogen legacies to accelerate water quality improvement", "abstract": "Increasing incidences of eutrophication and groundwater quality impairment from agricultural nitrogen pollution are threatening humans and ecosystem health. Minimal improvements in water quality have been achieved despite billions of dollars invested in conservation measures worldwide. Such apparent failures can be attributed in part to legacy nitrogen that has accumulated over decades of agricultural intensification and that can lead to time lags in water quality improvement. Here, we identify the key knowledge gaps related to landscape nitrogen legacies and propose approaches to manage and improve water quality, given the presence of these legacies. Agricultural nitrogen legacies are delaying improvements to water quality. Comprehensive management strategies that address legacy issues are needed to ensure better environmental outcomes.", "authors": [ "Basu, Nandita B.", "Van Meter, Kimberly J.", "Byrnes, Danyka K.", "Van Cappellen, Philippe", "Brouwer, Roy", "Jacobsen, Brian H.", "Jarsjo, Jerker", "Rudolph, David L.", "Cunha, Maria C.", "Nelson, Natalie", "Bhattacharya, Ruchi", "Destouni, Georgia", "Olsen, Soren Boye" ], "keywords": [ "" ], "year": "2022", "source": "NATURE GEOSCIENCE", "publication_type": "J", "point2d": [ 33.08708572387695, 3.2356114387512207 ], "cluster": 10.0 }, { "idx": 898, "title": "Assessment of Different Water Use Efficiency Calculations for Dominant Forage Crops in the Great Lakes Basin", "abstract": "Water use efficiency (WUE) can be calculated using a range of methods differing in carbon uptake and water use variable selection. Consequently, inconsistencies arise between WUE calculations due to complex physical and physiological interactions. The purpose of this study was to quantify and compare WUE estimates (harvest or flux-based) for alfalfa (C-3 plant) and maize (C-4 plant) and determine effects of input variables, plant physiology and farming practices on estimates. Four WUE calculations were investigated: two harvest-based methods, using above ground carbon content and either precipitation or evapotranspiration (ET), and two flux-based methods, using gross primary productivity (GPP) and either ET or transpiration. WUE estimates differed based on method used at both half-hourly and seasonal scales. Input variables used in calculations affected WUE estimates, and plant physiology led to different responses in carbon assimilation and water use variables. WUE estimates were also impacted by different plant physiological responses and processing methods, even when the same carbon assimilation and water use variables were considered. This study highlights a need to develop a metric of measuring cropland carbon-water coupling that accounts for all water use components, plant carbon responses, and biomass production.", "authors": [ "De Haan, Kevin", "Khomik, Myroslava", "Green, Adam", "Helgason, Warren", "Macrae, Merrin L.", "Kompanizare, Mazda", "Petrone, Richard M." ], "keywords": [ "ecosystem water use efficiency", "harvest water use efficiency", "alfalfa (Medicago sativa)", "maize (Zea mays)", "fluxpart (flux variance similarity partitioning)", "eddy covariance" ], "year": "2021", "source": "AGRICULTURE-BASEL", "publication_type": "J", "point2d": [ -66.96665954589844, 48.46121597290039 ], "cluster": 3.0 }, { "idx": 899, "title": "Vegetation-related influences on carbon and water dynamics of two temperate forage crops", "abstract": "Improving understanding of how water use efficiency (WUE), evapotranspiration (ET), and gross primary productivity (GPP) (CO2 exchange) vary across agricultural systems can help farmers better prepare for an uncertain future due to climate change by assessing water requirements for a crop as a function of current environmental conditions. This study: (a) quantified field-scale plant-water-carbon dynamics for silage maize (Zea mays L.) and alfalfa (Medicago sativa L.) crops - two dominant forage crops in southern Ontario, Canada; and (b) identified differences in plant carbon-water dynamics between these two crops, relating these differences to vegetation-driven ecosystem controls. Climate and soil properties were similar between the two study sites, and water availability was not limiting, suggesting that the overall temporal differences in carbon-water relations were driven by vegetation differences, mainly crop choice and management practices. Alfalfa had greater seasonal GPP, ET, and WUE than maize, due to a longer growing season. Differences in daily WUE between maize and alfalfa were driven by differences in GPP rather than ET. Multiple harvests reduced leaf-aging effects and promoted periods of rapid growth in alfalfa. In contrast, late seedling emergence and self-shading reduced GPP in maize. Under a warmer future climate, crop selection (i.e., perennial vs. annual), harvest regimes, and changes in growing season length should be considered when trying to manage for increased WUE. However, longer duration studies to validate these results are required to better address the impacts of climatic variability-especially antecedent conditions-to better inform future crop choices within a climate change context.", "authors": [ "De Haan, Kevin", "Khomik, Myroslava", "Kessel, Eric", "Green, Adam", "Kompanizare, Mazda", "Helgason, Warren", "Macrae, Merrin L.", "Petrone, Richard M." ], "keywords": [ "" ], "year": "2022", "source": "AGRONOMY JOURNAL", "publication_type": "J", "point2d": [ -67.01941680908203, 48.99277114868164 ], "cluster": 3.0 }, { "idx": 900, "title": "Assessment of effective LAI and water use efficiency using Eddy Covariance data", "abstract": "Globally, maize (Zea mays, a C4-plant) and alfalfa (Medicago sativa, a C3-plant) are common and economically important crops. Predicting the response of their water use efficiency, WUE, to changing hydrologic and climatic conditions is vital in helping farmers adapt to a changing climate. In this study, we assessed the effective leaf area index (eLAI - the leaf area most involved in CO2 and H2O exchange) and stomatal conductance in canopy scale in maize and alfalfa fields. In the process we used a theoretically-based photosynthesis C3-C4 model (C3C4PM) and carbon and water vapour fluxes measured by Eddy Covariance towers at our study sites. We found that in our study sites the eLAI was in the range of 25-32% of the observed total LAI in these crops. WUEs were in range of 8-9 mmol/mol. C3C4PM can be used in predictions of stomatal conductance and eLAI responses in C3 and C4 agricultural crops to elevated CO2 concentration and changes in precipitation and temperature under future climate scenarios. (C) 2021 Elsevier B.V. All rights reserved.", "authors": [ "Kompanizare, Mazda", "Petrone, Richard M.", "Macrae, Merrin L.", "De Haan, Kevin", "Khomik, Myroslava" ], "keywords": [ "Carbon assimilation", "Maize-alfalfa", "Effective LAIC3-C4-photosynthesis", "Eddy Covariance", "Canopy stomatal conductance" ], "year": "2022", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ -64.49371337890625, 49.41556167602539 ], "cluster": 3.0 }, { "idx": 901, "title": "Screening and scoping-level assessment of beneficial management practices in a Canadian prairie watershed", "abstract": "In the Canadian prairies, eutrophication is a widespread issue, with agriculture representing a major anthropogenic nutrient source in many watersheds. However, efforts to mitigate agricultural nutrient export are challenged by the lack of coordinated monitoring programs and the unique hydrological characteristics of the prairies, notably, the dominance of snowmelt in both water flows and nutrient loads, variable runoff, variable contributing area and the issues of understanding how scale affects nutrient concentrations and prevalence of dissolved nutrient transport (over total nutrients). Efforts are being made to integrate these characteristics in process-based water quality models, but the models are often complex and are not yet ready for use by watershed managers for prioritizing implementation of beneficial management practices (BMPs). In this study, a screening and scoping approach based on nutrient export coefficient modeling was used to prioritize BMPs for the 55,700 km(2) Qu'Appelle Watershed, Saskatchewan. By integrating land use information, in-stream monitoring data, stakeholder input and nutrient export coefficient modeling, the study assessed potential efficiencies of six BMPs involving fertilizer, manure, grazing, crop and wetland management in nutrient load reductions for nine tributaries of the watershed. Uncertainty around the effectiveness of the BMPs was assessed. Field-level export coefficients were adjusted with nutrient delivery ratios for estimating watershed-level exports. Of the BMPs examined, in general, wetland restoration had the greatest potential to reduce both nitrogen and phosphorus loads in most tributaries, followed by fertilizer management. The importance of wetland restoration was supported by positive, significant, linear correlations between nutrient delivery ratios and drainage intensity in the tributaries (nitrogen: R-2 = 0.67; phosphorus: R-2 = 0.82). Notably, the relative ranking of BMP efficiencies varied with tributaries, as a result of differing landscape characteristics, land uses and nutrient inputs. In conclusion, the approach developed here acknowledges uncertainty, but provides a means to guide management decisions within the context of an adaptive management approach, where BMP implementation is partnered with monitoring and assessment to revise ongoing plans and ensures selected practices are meeting goals for nutrient abatement.", "authors": [ "Liu, Jian", "Roste, Jennifer", "Baulch, Helen M.", "Elliott, Jane A.", "Davies, John-Mark", "Shupena-Soulodre, Etienne" ], "keywords": [ "Beneficial management practice", "Canadian prairies", "cold climate", "nutrient delivery ratio", "nutrient export coefficient", "water quality", "watershed management" ], "year": "2022", "source": "CANADIAN WATER RESOURCES JOURNAL", "publication_type": "J", "point2d": [ 49.07904052734375, -36.757198333740234 ], "cluster": 10.0 }, { "idx": 902, "title": "Phosphorus runoff from Canadian agricultural land: A dataset for 30 experimental fields", "abstract": "Phosphorus (P) runofffrom agricultural land plays a critical role in downstream water quality. This article summarizes P and sediment runoffdata for both snowmelt and rainfall runofffrom 30 arable fields in the Canadian provinces of Saskatchewan, Manitoba and Ontario. The data were collected from 216 site-years of field experiments, with climates ranging from semi-arid to humid and a wide range of field management practices. In the article, mean annual and seasonal (in terms of snowmelt and rain) precipitation inputs, runoffdepths, and P and sediment concentrations and loads are presented, along with ranges of yearly values. In addition, information of field management and soil characteristics (e.g. soil type and soil Olsen P) is also presented for each field. The data have potential to be reused for national and international cross-region comparisons of P and sediment losses, constructing and validating decision-support models and tools for assessing and managing P losses in both snowmelt and rainfall runoff, and informing beneficial management practices to improve agricultural water quality. Interpretation of the data is found in Phosphorus runoff from Canadian agricultural land: A cross-region synthesis of edge-of-field results[1]. (C) 2021 Published by Elsevier Inc.", "authors": [ "Liu, Jian", "Elliott, Jane A.", "Wilson, Henry F.", "Macrae, Merrin L.", "Baulch, Helen M.", "Lobb, David A." ], "keywords": [ "Beneficial management practices", "Canadian prairies", "Drainage, Edge-of-field", "Eutrophication", "Great Lakes", "Nutrient transport", "Watershed monitoring" ], "year": "2021", "source": "DATA IN BRIEF", "publication_type": "J", "point2d": [ 36.9063720703125, 15.009225845336914 ], "cluster": 10.0 }, { "idx": 903, "title": "Phosphorus runoff from Canadian agricultural land: A cross-region synthesis of edge-of-field results", "abstract": "Algal blooms fueled by phosphorus (P) enrichment are threatening surface water quality around the world. Although P loss from arable land is a critical contributor to P loads in many agricultural watersheds, there has been a lack of understanding of P loss patterns and drivers across regions. Here, we synthesized edge-of-field P and sediment runoff data for 30 arable fields in the Canadian provinces of Saskatchewan, Manitoba and Ontario (a total of 216 site-years) to elucidate spatial and temporal differences in runoff and P mobilization in snowmelt and rainfall runoff, and discuss climatic, soil and management drivers for these patterns. Across all regions, precipitation inputs were positively correlated with runoff amounts and consequently P loads. Runoff and P losses were dominated by snowmelt across all sites, however, regional differences in runoff amounts, and P concentrations, loads and speciation were apparent. Proportions of total P in the dissolved form were greater in the prairie region (55-94% in Manitoba) than in the Great Lakes region (26-35% in Ontario). In Manitoba, dissolved P concentrations in both snowmelt and rainfall runoff were strongly positively correlated to soil Olsen P concentrations in the 0-5 cm soil depth; however, this relationship was not found for Ontario fields, where tile drainage dominated hydrologic losses. Although precipitation amounts and runoff volumes were greater in Ontario than Manitoba, some of the greatest P loads were observed from Manitoba fields, driven by management practices. This synthesis highlights the differences across the Canadian agricultural regions in P runoff patterns and drivers, and suggests the need of co-ordinated and standardized monitoring programs to better understand regional differences and inform management.", "authors": [ "Liu, Jian", "Elliott, Jane A.", "Wilson, Henry F.", "Macrae, Merrin L.", "Baulch, Helen M.", "Lobb, David A." ], "keywords": [ "Agricultural management practice", "Climate variability", "Eutrophication", "Nutrient transport", "Water quality", "Watershed management" ], "year": "2021", "source": "AGRICULTURAL WATER MANAGEMENT", "publication_type": "J", "point2d": [ 36.81389617919922, 15.853337287902832 ], "cluster": 10.0 }, { "idx": 904, "title": "Contribution of bunker silo effluent discharged via a riparian zone to watershed phosphorus loads", "abstract": "Nutrient losses from agricultural operations are a major contributor to the eutrophication of freshwaters. Although many studies have quantified diffuse nutrient losses, less is known about agricultural pointsource contributions, such as bunker silos, to watershed phosphorus (P) loads. This study examined the contributions of a dairy farm bunker silo effluent to watershed soluble reactive P (SRP) and total P (TP) losses. The bunker silo effluent discharged to an adjacent stream via a riparian soakaway for ca. 15 years. Prior to the annual refilling of the bunker silo, flow weighted mean concentrations of SRP (TP) were similar between stream locations up and downstream of the farm. After the bunker silo was refilled, flow-weighted SRP (TP) concentrations in the stream increased by factors of 1.5(2.2) during events and 3.1(2.3) during baseflow. Higher P concentrations occurred in the riparian soils receiving bunker silo effluent (525-3125 mg/kg TP, and 0.1-9.9 mg/kg water extractable P (WEP), compared with 525- 939 mg/kg TP, and 0.11-1.43 mg/kg WEP on the opposite side of the stream with no bunker silo effluent. Riparian soils impacted by the bunker silo were near P-saturation, and the riparian zone did little to reduce P transfer in shallow groundwater. The net contributions of bunker silo effluent to annual watershed P losses were 32% (SRP) and 22% (TP). This study highlights the importance of agricultural point sources, and the need to quantify their contributions to watershed P budgets to target P remediation effectively. (c) 2021 Published by Elsevier B.V. on behalf of International Association for Great Lakes Research.", "authors": [ "Price, Dylan W.", "Plach, Janina M.", "Jarvie, Helen P.", "Macrae, Merrin L." ], "keywords": [ "Phosphorus", "Livestock farm", "Bunker silo", "Water quality", "Point source", "Effluent" ], "year": "2021", "source": "JOURNAL OF GREAT LAKES RESEARCH", "publication_type": "J", "point2d": [ 41.737117767333984, 5.455410003662109 ], "cluster": 10.0 }, { "idx": 905, "title": "Modelled changes in selected agroclimatic indices over the croplands of western Canada under the RCP8.5 scenario", "abstract": "To assess the potential change in agroclimatic indices in western Canada, this study used a convection-permitting Weather Research Forecasting (WRF) model to conduct simulations for the current climate (CTL, 2000-2015) and future climate under the RCP8.5 scenario based on a pseudo-global-warming (PGW) approach. Both CTL and PGW simulations were bias-corrected to the GEM-CaPA dataset using a multivariate quantile mapping method. An evaluation of the CTL simulation of daily maximum and minimum temperatures and precipitation during the growing season against the gridded observations has been performed, indicating good agreements in the spatial patterns of air temperature and precipitation in western Canada. The PGW - CTL differences in several selected agroclimatic indices were then examined. Due to rising temperatures, substantial increases in growing degree-days (GDD) by 800-1,200 degrees days and reductions in frost days by 10 to 20 days, favouring regional crop production, are found in southern Alberta and Saskatchewan. However, global warming also poses great risks to Canadian agriculture by modifying heat accumulations and water availability during the growing season. Plant heat stress will substantially increase by similar to 50 degrees days in southern Alberta and Saskatchewan, offsetting the positive effects caused by the reduction in frost days and increase in GDD. The southern Canadian Prairies will experience statistically significant increases in the number of dry days and precipitation deficit, suggesting an exacerbation of water stress on the Canadian Prairies by global warming.", "authors": [ "Agyeman, Richard Y. K.", "Huo, Fei", "Li, Zhenhua", "Li, Yanping" ], "keywords": [ "agroclimatic indices", "convection-permitting simulation", "crop production", "precipitation deficit", "western Canada" ], "year": "2021", "source": "QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY", "publication_type": "J", "point2d": [ -33.62796401977539, -33.87139892578125 ], "cluster": 1.0 }, { "idx": 906, "title": "Incentivizing the future adoption of best management practices on agricultural land to protect water resources: The role of past participation and experiences", "abstract": "Best Management Practices (BMPs) incentive programs have been introduced to protect agricultural land and reduce nutrient runoff in watersheds. However, their voluntary nature has not led to the expected high partic-ipation rates. We examine influencing factors and underlying drivers that are associated with BMP adoption and farmer preferences for specific BMPs. Data are collected through an online survey in Ontario, Canada in 2019. A binary logit model is estimated to explain current participation in BMP schemes and a multinomial logit model to predict preferences for future BMP uptake. Results show that a mix of farmer and farm characteristics and environmental attitudes explain both current participation in BMP schemes and the likelihood of adopting a future BMP. Farmers tend to endorse a BMP if they currently implement that BMP. The findings furthermore suggest that increasing farmers' environmental awareness and sharing positive BMP experiences with other farmers may help expand future BMP adoption in Ontario.", "authors": [ "Liu, Haiyan", "Brouwer, Roy" ], "keywords": [ "Best management practices", "Participation model", "Driving forces", "Farmer preferences", "Ontario, Canada" ], "year": "2022", "source": "ECOLOGICAL ECONOMICS", "publication_type": "J", "point2d": [ 45.7755012512207, -38.420921325683594 ], "cluster": 4.0 }, { "idx": 907, "title": "Peat surface compression reduces smouldering fire potential as a novel fuel treatment for boreal peatlands", "abstract": "The wildfire regime in Canada's boreal region is changing; extended fire seasons are characterized by more frequent large fires (>= 200 ha) burning greater areas of land, whilst climate-mediated drying is increasing the vulnerability of peatlands to deep burning. Proactive management strategies, such as fuel modification treatments, are necessary to reduce fire danger at the wildland-human interface (WHI). Novel approaches to fuel management are especially needed in peatlands where deep smouldering combustion is a challenge to suppression efforts and releases harmful emissions. Here, we integrate surface compression within conventional stand treatments to examine the potential for reducing smouldering of near-surface moss and peat. A linear model (adj. R-2 = 0.62, p = 2.2e(-16)) revealed that ground cover (F-[2,F-101] = 60.97, p < 0.001) and compression (F-[1,F-101] = 56.46, p < 0.001) had the greatest effects on smouldering potential, while stand treatment did not have a significant effect (F-[3,F-101] = 0.44, p = 0.727). On average, compressed Sphagnum and feather moss plots showed 57.1% and 58.7% lower smouldering potential, respectively, when compared to uncompressed analogs. While practical evaluation is warranted to better understand the evolving effectiveness of this strategy, these findings demonstrate that a compression treatment can be successfully incorporated within both managed and unmanaged peatlands to reduce fire danger at the WHI.", "authors": [ "Deane, P. J.", "Wilkinson, S. L.", "Verkaik, G. J.", "Moore, P. A.", "Schroeder, D.", "Waddington, J. M." ], "keywords": [ "compression", "fuel treatments", "peatland", "smouldering", "wildfire" ], "year": "2022", "source": "CANADIAN JOURNAL OF FOREST RESEARCH", "publication_type": "J", "point2d": [ -11.890533447265625, 71.69852447509766 ], "cluster": 9.0 }, { "idx": 908, "title": "Mapping organic layer thickness and fuel load of the boreal forest in Alberta, Canada", "abstract": "Forest organic layers are important soil carbon pools that can, in the absence of disturbance, accumulate to great depths, especially in lowland areas. Across the Canadian boreal forest, fire is the primary disturbance agent, often limiting organic layer accumulation through the direct consumption of these fuels. Organic layer thickness (OLT) and fuel load (OLFL) are common physical attributes used to characterize these layers, especially for wildland fire science. Understanding the drivers and spatial distribution of these attributes is important to improve predictions of fire behaviour, emissions and effects models. We developed maps of OLT and OLFL using machine learning approaches (weighted K-nearest neighbour and random forests) for the forested region of the province of Alberta, Canada (538, 058 km(2)). The random forests approach was found to be the best approach to model the spatial distribution of these forest floor attributes. A databased of 3, 237 OLT and 594 OLFL plots were used to train the models. The error in our final model, particularly for OLT (5 cm), was relatively close to the variability we would expect to find naturally (3 cm). The dominant tree species was the most important covariate in the models. Age, solar radiation, spatial location, climate variables and surficial geology were also important drivers, although their level of importance varied between tree species and depended on the modelling method that was used.", "authors": [ "Hanes, Chelene C.", "Wotton, Mike", "Woolford, Douglas G.", "Martell, David L.", "Flannigan, Mike" ], "keywords": [ "Fuel load", "Random forests", "Machine learning", "Wildland fire", "Spatial visualization", "Forest fuels" ], "year": "2022", "source": "GEODERMA", "publication_type": "J", "point2d": [ -26.874847412109375, 76.29222869873047 ], "cluster": 15.0 }, { "idx": 909, "title": "Ecohydrological trade-offs from multiple peatland disturbances: The interactive effects of drainage, harvesting, restoration and wildfire in a southern Ontario bog", "abstract": "Peatland disturbances can disrupt the ecohydrological functions that sustain net carbon sequestration in peatlands. Anthropogenic disturbances, such as peatland drainage and harvesting, are often followed by peatland restoration that aims to return the carbon sink function. This is typically achieved by raising the water table and re-establishing keystone Sphagnum moss species. However, with an increasingly uncertain climate and intensifying land-use changes, the potential for multiple disturbances (such as co-occurring wildfires, drainage, and harvesting) to disrupt the ecohydrological feedbacks that support peatland function is increasing. Yet, few studies investigate the ecohydrological trade-offs induced by multiple disturbances in peatlands. To elucidate the complexities of multiple disturbances and restoration on Sphagnum re-establishment and wildfire potential, we studied a Deep and Shallow harvested area in a drained and restored peatland in southern Ontario, Canada that experienced a wildfire in 2012. Harvesting depth did not significantly increase the bulk density of the upper 32 cm of exposed peat, but the shallower harvest depth did significantly increase the depth of burn (DOB) due to the more varied remnant topography. The difference in topography of the shallower harvested area increased peat carbon losses (16.5 kg C m(-2)) from the wildfire relative to the deeper harvest area (15.1 kg C m(-2)). The difference in post-fire peat hydrophysical properties of the Deep and Shallow harvest area drove divergent soil water conditions. In the post-burn peat, the establishment of suitable conditions for the regeneration of Sphagnum mosses was more prevalent at the Shallow harvest areas but the higher soil water retention capabilities of the Deep harvest peat lowered the risk of subsequent peat ignition. This study highlights the complex interactions multiple disturbances have on peatland ecohydrology and that we urgently need to understand these interactions to better manage our shared peatland resources in an increasingly uncertain future.", "authors": [ "McCarter, C. P. R.", "Wilkinson, S. L.", "Moore, P. A.", "Waddington, J. M." ], "keywords": [ "Fire", "Peat", "Management", "Numerical modelling", "Hydrology", "Carolinian temperate peatland" ], "year": "2021", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -10.182869911193848, 70.86189270019531 ], "cluster": 9.0 }, { "idx": 910, "title": "Be like the running water: Assessing gendered and age-based water insecurity experiences with Six Nations First Nation", "abstract": "Indigenous households are 90 times more likely to be without running water than non-Indigenous households in Canada. Current primary indicators of water quality and security for Indigenous Peoples are based on federal boil water advisories, which do not disaggregate at household levels to identify who is most at risk within or between communities. A mixed methods approach was used to assess the level of water insecurity and perceptions of water access by gender and age for a sample of households in Six Nations of the Grand River First Nations in Ontario, Canada. A household survey captured water security using the Household Water InSecurity Experiences (HWISE) scale and Likert-type responses to perceptions of water access, contextualized using semi-structured individual and group interviews. From 2019 to 2020, 66 households participated in the survey, 18 individuals participated in semi-structured individual interviews, and 7 individuals participated in 3 semi-structured group interviews. The survey sample demonstrated high levels of household water insecurity (57.5%, n = 38). Interviews revealed that women were more dissatisfied with their drinking water situations due to quality, source, and cost, though they shared water sharing as a coping strategy. Women faced more physical and mental barriers accessing water for their households, due to their roles as caretakers of their family and knowledge protectors for their communities. Generational divides were found in interviews about what qualified as good water, with older participants understanding it as relating to traditional water sourcing, and younger participants wanting clean, accessible tap water. Taken together, the participants demonstrated a frustration with the sub-standard drinking water on reserve.", "authors": [ "Duignan, Sarah", "Moffat, Tina", "Martin-Hill, Dawn" ], "keywords": [ "Gendered water security", "Environmental dispossession", "Water access and perceptions", "Indigenous water crisis", "Maternal indigenous health" ], "year": "2022", "source": "SOCIAL SCIENCE & MEDICINE", "publication_type": "J", "point2d": [ 64.5521469116211, -24.097360610961914 ], "cluster": 4.0 }, { "idx": 913, "title": "ContourDiff: Revealing Differential Trends in Spatiotemporal Data", "abstract": "Changes in spatiotemporal data may often go unnoticed due to their inherent noise and low variability (e.g., geological processes over years). Commonly used approaches such as side-by-side contour plots and spaghetti plots do not provide a clear idea about the temporal changes in such data. We propose ContourDiff, a vector-based visualization over contour plots to visualize the trends of change across spatial regions and temporal domain. Our approach first aggregates for each location, its value differences from the neighboring points over the temporal domain, and then creates a vector field representing the prominent changes. Finally, it overlays the vectors along the contour paths, revealing differential trends that the contour lines experienced over time. We evaluated our visualization using real-life datasets, consisting of millions of data points, where the visualizations were generated in less than a minute in a single-threaded execution. Our experimental results reveal that ContourDiff can reliably visualize the differential trends, and provide a new way to explore the change pattern in spatiotemporal data.", "authors": [ "Ahmed, Zonayed", "Beyene, Michael", "Mondal, Debajyoti", "Roy, Chanchal K.", "Dutchyn, Christopher", "Schneider, Kevin A." ], "keywords": [ "Spatiotemporal Data", "Change Detection", "Contour Plot", "Vector Overlay" ], "year": "2021", "source": "2021 25TH INTERNATIONAL CONFERENCE INFORMATION VISUALISATION (IV): AI & VISUAL ANALYTICS & DATA SCIENCE", "publication_type": "C", "point2d": [ -40.41619873046875, -44.95306396484375 ], "cluster": 14.0 }, { "idx": 914, "title": "Ten best practices to strengthen stewardship and sharing of water science data in Canada", "abstract": "Water science data are a valuable asset that both underpins the original research project and bolsters new research questions, particularly in view of the increasingly complex water issues facing Canada and the world. Whilst there is general support for making data more broadly accessible, and a number of water science journals and funding agencies have adopted policies that require researchers to share data in accordance with the findable, accessible, interoperable, reusable (FAIR) principles, there are still questions about effective management of data to protect their usefulness over time. Incorporating data management practices and standards at the outset of a water science research project will enable researchers to efficiently locate, analyse and use data throughout the project lifecycle, and will ensure the data maintain their value after the project has ended. Here, some common misconceptions about data management are highlighted, along with insights and practical advice to assist established and early career water science researchers as they integrate data management best practices and tools into their research. Freely available tools and training opportunities made available in Canada through Global Water Futures, The Gordon Foundation DataStream, the Digital Research Alliance of Canada Portage Network, Compute Canada, and university libraries, among others are compiled. These include webinars, training videos, and individual support for the water science community that together enable researchers to protect their data assets and meet the expectations of journals and funders. The perspectives shared here have been developed as part of the Global Water Futures programme's efforts to improve data management and promote the use of common data practices and standards in the context of water science in Canada. Ten best practices are proposed that may be broadly applicable to other disciplines in the natural sciences and can be adopted and adapted globally.", "authors": [ "Persaud, Bhaleka D.", "Dukacz, Krysha A.", "Saha, Gopal C.", "Peterson, Amber", "Moradi, Laleh", "O'Hearn, Stephen", "Clary, Erin", "Mai, Juliane", "Steeleworthy, Michael", "Venkiteswaran, Jason J.", "Pour, Homa Kheyrollah", "Wolfe, Brent B.", "Carey, Sean K.", "Pomeroy, John W.", "DeBeer, Chris M.", "Waddington, James M.", "Van Cappellen, Philippe", "Lin, Jimmy" ], "keywords": [ "best practices", "Canada", "data management plan", "data repositories", "FAIR principles", "metadata", "research data management", "water science" ], "year": "2021", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 49.73647689819336, -28.56910514831543 ], "cluster": 4.0 }, { "idx": 915, "title": "Supporting program comprehension by generating abstract code summary tree", "abstract": "Reading through code, finding relevant methods, classes and files takes a significant portion of software development time. Having good tool support for this code browsing activity can reduce human effort and increase overall developer productivity. To help with program comprehension activities, building an abstract code summary of a software system from its call graph is an active research area. A call graph is a visual representation of the caller-callee relationships between different methods of a software system. Call graphs can be difficult to comprehend for a large code-base. Previous work by Gharibi et al. on abstract code summarizing suggested using the Agglomerative Hierarchical Clustering (AHC) tree for understanding the codebase. Each node in the tree is associated with the top five method names. When we replicated the previous approach, we observed that the number of nodes in the AI IC tree is burdensome for developers to explore. We also noticed only five method names for each node is not sufficient to comprehend an abstract node. We propose a technique to transform the AHC tree using cluster flattening for natural grouping and reduced nodes. We also generate a natural text summary for each abstract node derived from method comments. In order to evaluate our proposed approach, we collected developers' opinions about the abstract code summary tree based on their codebase. The evaluation results confirm that our approach can not only help developers get an overview of their codebases but also could assist them in doing specific software maintenance tasks.", "authors": [ "Bhattacharjee, Avijit", "Roy, Banani", "Schneider, Kevin A." ], "keywords": [ "Program comprehension", "Static call graph", "Information retrieval", "Abstract Code Summary Tree", "Hierarchical Abstraction Tree" ], "year": "2022", "source": "2022 ACM/IEEE 44TH INTERNATIONAL CONFERENCE ON SOFTWARE ENGINEERING: NEW IDEAS AND EMERGING RESULTS (ICSE-NIER 2022)", "publication_type": "C", "point2d": [ 33.660160064697266, -97.34565734863281 ], "cluster": 5.0 }, { "idx": 922, "title": "A Testing Approach While Re-engineering Legacy Systems: An Industrial Case Study", "abstract": "Many organizations use legacy systems as these systems contain their valuable business rules. However, these legacy systems answer the past requirements but are difficult to maintain and evolve due to old technology use. In this situation, stockholders decide to renovate the system with a minimum amount of cost and risk. Although the renovation process is a more affordable choice over redevelopment, it comes with its risks such as performance loss and failure to obtain quality goals. A proper test process can minimize risks incorporated with the renovation process. This work introduces a testing model tailored for the migration and re-engineering process and employs test automation, which results in early bug detection. Moreover, the automated tests ensure functional sameness between the old and the new system. This process enhances reliability, accuracy, and speed of testing.", "authors": [ "Khodabandehloo, Hamid", "Roy, Banani", "Mondal, Manishankar", "Roy, Chanchal", "Schneider, Kevin" ], "keywords": [ "Re-engineering", "Legacy System", "Bug", "Unit test", "User acceptance test", "Test Automation" ], "year": "2021", "source": "2021 IEEE INTERNATIONAL CONFERENCE ON SOFTWARE ANALYSIS, EVOLUTION AND REENGINEERING (SANER 2021)", "publication_type": "C", "point2d": [ 30.11504554748535, -98.21854400634766 ], "cluster": 5.0 }, { "idx": 923, "title": "Rainfall-runoff prediction at multiple timescales with a single Long Short-Term Memory network", "abstract": "Long Short-Term Memory (LSTM) networks have been applied to daily discharge prediction with remarkable success. Many practical applications, however, require predictions at more granular timescales. For instance, accurate prediction of short but extreme flood peaks can make a life-saving difference, yet such peaks may escape the coarse temporal resolution of daily predictions. Naively training an LSTM on hourly data, however, entails very long input sequences that make learning difficult and computationally expensive. In this study, we propose two multi-timescale LSTM (MTS-LSTM) architectures that jointly predict multiple timescales within one model, as they process long-past inputs at a different temporal resolution than more recent inputs. In a benchmark on 516 basins across the continental United States, these models achieved significantly higher Nash-Sutcliffe efficiency (NSE) values than the US National Water Model. Compared to naive prediction with distinct LSTMs per timescale, the multi-timescale architectures are computationally more efficient with no loss in accuracy. Beyond prediction quality, the multi-timescale LSTM can process different input variables at different timescales, which is especially relevant to operational applications where the lead time of meteorological forcings depends on their temporal resolution.", "authors": [ "Gauch, Martin", "Kratzert, Frederik", "Klotz, Daniel", "Nearing, Grey", "Lin, Jimmy", "Hochreiter, Sepp" ], "keywords": [ "" ], "year": "2021", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -20.069835662841797, -62.49428176879883 ], "cluster": 16.0 }, { "idx": 926, "title": "FLeCCS: A Technique for Suggesting Fragment-Level Similar Co-change Candidates", "abstract": "When a programmer changes a particular code fragment, the other similar code fragments in the code-base may also need to be changed together (i.e., co-changed) consistently to ensure that the software system remains consistent. Existing studies and tools apply clone detectors to identify these similar co-change candidates for a target code fragment. However, clone detectors suffer from a confounding configuration choice problem and it affects their accuracy in retrieving co-change candidates. In our research, we propose and empirically evaluate a lightweight co-change suggestion technique that can automatically suggest fragment level similar co-change candidates for a target code fragment using WA-DiSC (Weighted Average Dice-Sorensen Co-efficient) through a context-sensitive mining of the entire code-base. We apply our technique, FLeCCS (Fragment Level Co-change Candidate Suggester), on six subject systems written in three different programming languages (Java, C, and C#) and compare its performance with the existing state-of-the-art techniques. According to our experiment, our technique outperforms not only the existing code clone based techniques but also the association rule mining based techniques in detecting co-change candidates with a significantly higher accuracy (precision and recall). We also find that File Proximity Ranking performs significantly better than Similarity Extent Ranking when ranking the co-change candidates suggested by our proposed technique.", "authors": [ "Mondal, Manishankar", "Roy, Chanchal K.", "Roy, Banani", "Schneider, Kevin A." ], "keywords": [ "Code Clones", "Clone-Types", "Micro-Clones", "Cochange Candidates" ], "year": "2021", "source": "2021 IEEE/ACM 29TH INTERNATIONAL CONFERENCE ON PROGRAM COMPREHENSION (ICPC 2021)", "publication_type": "C", "point2d": [ 30.629148483276367, -96.11447143554688 ], "cluster": 5.0 }, { "idx": 929, "title": "Mining Software Information Sites to Recommend Cross-Language Analogical Libraries", "abstract": "Software development is largely dependent on libraries to reuse existing functionalities instead of reinventing the wheel. Software developers often need to find analogical libraries (libraries similar to ones they are already familiar with) as an analogical library may offer improved or additional features. Developers also need to search for analogical libraries across programming languages when developing applications in different languages or for different platforms. However, manually searching for analogical libraries is a time-consuming and difficult task. This paper presents a technique, called XLibRec, that recommends analogical libraries across different programming languages. XLibRec collects Stack Overflow question titles containing library names, library usage information from Stack Overflow posts, and library descriptions from a third party website, Libraries.io. We generate word-vectors for each information and calculate a weight-based cosine similarity score from them to recommend analogical libraries. We performed an extensive evaluation using a large number of analogical libraries across four different programming languages. Results from our evaluation show that the proposed technique can recommend cross-language analogical libraries with great accuracy. The precision for the Top-3 recommendations ranges from 62-81% and has achieved 8-45% higher precision than the state-of-the-art technique.", "authors": [ "Nafi, Kawser Wazed", "Asaduzzaman, Muhammad", "Roy, Banani", "Roy, Chanchal K.", "Schneider, Kevin A." ], "keywords": [ "Cross-Language", "Analogical Libraries", "Stack Overflow", "Library Usage Information", "Word2Vec" ], "year": "2022", "source": "2022 IEEE INTERNATIONAL CONFERENCE ON SOFTWARE ANALYSIS, EVOLUTION AND REENGINEERING (SANER 2022)", "publication_type": "C", "point2d": [ 34.43145751953125, -95.23072052001953 ], "cluster": 5.0 }, { "idx": 930, "title": "Exploring Relevant Artifacts of Release Notes: The Practitioners' Perspective", "abstract": "A software release note is one of the essential documents in the software development life cycle. The software release contains a set of information, e.g., bug fixes and security fixes. Release notes are used in different phases, e.g., requirement engineering, software testing and release management. Different types of practitioners (e.g., project managers and clients) get benefited from the release notes to understand the overview of the latest release. As a result, several studies have been done about release notes production and usage in practice. However, two significant problems (e.g., duplication and inconsistency in release notes contents) exist in producing well-written & well-structured release notes and organizing appropriate information regarding different targeted users' needs. For that reason, practitioners face difficulties in writing and reading the release notes using existing tools. To mitigate these problems, we execute two different studies in our paper. First, we execute an exploratory study by analyzing 3,347 release notes of 21 GitHub repositories to understand the documented contents of the release notes. As a result, we find relevant key artifacts, e.g., issues (29%), pull-requests (32%), commits (19%), and common vulnerabilities and exposures (CVE) issues (6%) in the release note contents. Second, we conduct a survey study with 32 professionals to understand the key information that is included in release notes regarding users' roles. For example, project managers are more interested in learning about new features than less critical bug fixes. Our study can guide future research directions to help practitioners produce the release notes with relevant content and improve the documentation quality.", "authors": [ "Nath, Sristy Sumana", "Roy, Banani" ], "keywords": [ "Release notes", "Exploratory study", "Survey study", "GitHub" ], "year": "2022", "source": "2022 IEEE INTERNATIONAL CONFERENCE ON SOFTWARE ANALYSIS, EVOLUTION AND REENGINEERING (SANER 2022)", "publication_type": "C", "point2d": [ 31.537750244140625, -98.01301574707031 ], "cluster": 5.0 }, { "idx": 937, "title": "Qualitative property preservation of high-order operator splitting for the SIR model", "abstract": "The susceptible-infected-recovered (SIR) model is perhaps the most basic epidemiological model for the evolution of disease spread within a population. Because of its direct representation of fundamental physical quantities, a true solution to an SIR model possesses a number of qualitative properties, such as conservation of the total population or positivity or monotonicity of its constituent populations, that may only be guaranteed to hold numerically under step-size restrictions on the solver. Operator-splitting methods with order greater than two require backward sub-steps in each operator, and the effects of these backward sub-steps on the step-size restrictions for guarantees of qualitative correctness of numerical solutions are not well studied. In this study, we analyze the impact of backward steps on step-size restrictions for guaranteed qualitative properties by applying third-and fourth-order operator-splitting methods to the SIR epidemic model. We find that it is possible to provide step-size restrictions that guarantee qualitative property preservation of the numerical solution despite the negative sub-steps, but care must be taken in the choice of the method. Results such as this open the door for the design and application of high-order operator-splitting methods to other mathematical models in general for which qualitative property preservation is important. (C) 2021 IMACS. Published by Elsevier B.V. All rights reserved.", "authors": [ "Wei, Siqi", "Spiteri, Raymond J." ], "keywords": [ "Operator splitting", "SIR model", "High order" ], "year": "2022", "source": "APPLIED NUMERICAL MATHEMATICS", "publication_type": "J", "point2d": [ -5.85228157043457, -79.62660217285156 ], "cluster": 16.0 }, { "idx": 938, "title": "Structural analysis of integro-differential-algebraic equations", "abstract": "We describe a method for analyzing the structure of a system of nonlinear integro-differential-algebraic equations (IDAEs) that generalizes the Sigma-method for the structural analysis of differential-algebraic equations. The method is based on the sparsity pattern of the IDAE and the nu-smoothing property of a Volterra integral operator. It determines which equations and how many times they need to be differentiated to determine the index, and it reveals the hidden constraints and compatibility conditions in order to prove the existence of a solution. The success of the Sigma-method is indicated by the non-singularity of a certain Jacobian matrix. Although it is likely the Sigma-method can be directly applied with success to many problems of practical interest, it can fail on some solvable IDAEs. Accordingly, we also present two techniques for addressing these failures. (C) 2021 Elsevier B.V. All rights reserved.", "authors": [ "Zolfaghari, Reza", "Taylor, Jacob", "Spiteri, Raymond J." ], "keywords": [ "Integro-differential-algebraic equations", "Integral-algebraic equations", "Structural index", "nu-smoothing Volterra operator", "Sigma-method" ], "year": "2021", "source": "JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS", "publication_type": "J", "point2d": [ -5.37605619430542, -79.70062255859375 ], "cluster": 16.0 }, { "idx": 939, "title": "No evidence of isotopic fractionation in olive trees (Olea europaea): a stable isotope tracing experiment", "abstract": "Plant transpiration is the dominant water flux in the global terrestrial water balance and a key process in the hydrological sciences. Stable isotopes have contributed greatly to this understanding but one difficult assumption for plant water source quantification using hydrogen and oxygen isotopes is that no isotopic fractionation occurs during water uptake and transport within the plant. Here we present a simple glasshouse experiment with two potted olive trees to test isotopic fractionation. We irrigated the trees with labelled water and cryogenically extracted water from twigs, cores and roots. We found no significant differences in the isotopic composition of water extracted from wood cores and twigs in distinct parts of the trees as they reflected the signature of labelled water. However, significant differences were obtained between plant water and deep soil water. Our results suggest no isotopic fractionation in olive trees, under the specific experimental conditions, validating the traditional isotope-tracing approach.", "authors": [ "Amin, Anam", "Zuecco, Giulia", "Marchina, Chiara", "Engel, Michael", "Penna, Daniele", "McDonnell, Jeffrey J.", "Borga, Marco" ], "keywords": [ "plant water", "olive tree", "stable isotopes", "cryogenic vacuum distillation", "isotopic fractionation", "labelled water", "water extraction method", "deuterium excess" ], "year": "2021", "source": "HYDROLOGICAL SCIENCES JOURNAL-JOURNAL DES SCIENCES HYDROLOGIQUES", "publication_type": "J", "point2d": [ -11.27892017364502, 28.042844772338867 ], "cluster": 3.0 }, { "idx": 940, "title": "On the use of leaf water to determine plant water source: A proof of concept", "abstract": "Source water apportionment studies using the dual isotopes of oxygen and hydrogen have revolutionized our understanding of ecohydrology. But despite these developments-mostly over the past decade-many technical problems still exist in terms of linking xylem water to its soil water and groundwater sources. This is mainly due to sampling issues and possible fractionation of xylem water. Here we explore whether or not leaf water alone can be used to quantify the blend of rainfall event inputs from which the leaf water originates. Leaf water has historically been avoided in plant water uptake studies due to the extreme fractionation processes at the leaf surface. In our proof of concept work we embrace those processes and use the well-known Craig and Gordon model to map leaf water back to its individual precipitation event water sources. We also employ a Bayesian uncertainty estimation approach to quantify source apportionment uncertainties. We show this using a controlled, vegetated lysimeter experiment where we were able to use leaf water to correctly identify the mean seasonal rainfall that was taken up by the plant, with an uncertainty typically within +/- 1 parts per thousand for delta O-18. While not appropriate for all source water studies, this work shows that leaf water isotope composition may provide a new, relatively un-intrusive method for addressing questions about the plant water source.", "authors": [ "Benettin, Paolo", "Nehemy, Magali F.", "Cernusak, Lucas A.", "Kahmen, Ansgar", "McDonnell, Jeffrey J." ], "keywords": [ "fractionation", "isotopes", "leaf", "source water" ], "year": "2021", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -13.605746269226074, 26.933095932006836 ], "cluster": 3.0 }, { "idx": 941, "title": "Tracing and Closing the Water Balance in a Vegetated Lysimeter", "abstract": "Closure of the soil water balance is fundamental to ecohydrology. But closing the soil water balance with hydrometric information offers no insight into the age distribution of water transiting the soil column via deep drainage or the combination of soil evaporation and transpiration. This is a major challenge in our discipline currently; tracing the water balance is the needed next step. Here we report results from a controlled tracer experiment aimed at both closing the soil water balance and tracing its individual components. This was carried out on a 2.5 m(3) lysimeter planted with a willow tree. We applied 25 mm of isotopically enriched water on top of the lysimeter and tracked it for 43 days through the soil water, the bottom drainage, and the plant xylem. We then destructively sampled the system to quantify the remaining isotope mass. More than 900 water samples were collected for stable isotope analysis to trace the labeled irrigation. We then used these data to quantify when and where the labeled irrigation became the source of plant uptake or deep percolation. Evapotranspiration dominated the water balance outflow (88%). Tracing the transpiration flux showed further that transpiration was soil water that had fallen as precipitation 1-2 months prior. The tracer breakthrough in transpiration was complex and different from the breakthrough curves observed within the soil or in the bottom drainage. Given the lack of direct experimental data on travel time to transpiration, these results provide a first balance closure where all the relevant outflows are traced.", "authors": [ "Benettin, Paolo", "Nehemy, Magali F.", "Asadollahi, Mitra", "Pratt, Dyan", "Bensimon, Michael", "McDonnell, Jeffrey J.", "Rinaldo, Andrea" ], "keywords": [ "Soil column", "Tracer", "transpiration", "water age", "willow" ], "year": "2021", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -14.728110313415527, 27.539976119995117 ], "cluster": 3.0 }, { "idx": 942, "title": "Organic contamination detection for isotopic analysis of water by laser spectroscopy", "abstract": "Rationale Hydrogen and oxygen stable isotope ratios (delta H-2, delta O-17, and delta O-18 values) are commonly used tracers of water. These ratios can be measured by isotope ratio infrared spectroscopy (IRIS). However, IRIS approaches are prone to errors induced by organic compounds present in plant, soil, and natural water samples. A novel approach using O-17-excess values has shown promise for flagging spectrally contaminated plant samples during IRIS analysis. A systematic assessment of this flagging system is needed to prove it useful. Methods Errors induced by methanol and ethanol water mixtures on measured IRIS and isotope ratio mass spectrometry (IRMS) results were evaluated. For IRIS analyses both liquid- and vapour-mode (via direct vapour equilibration) methods are used. The delta H-2, delta O-17, and delta O-18 values were measured and compared with known reference values to determine the errors induced by methanol and ethanol contamination. In addition, the O-17-excess contamination detection approach was tested. This is a post-processing detection tool for both liquid and vapour IRIS triple-isotope analyses, utilizing calculated O-17-excess values to flag contaminated samples. Results Organic contamination induced significant errors in IRIS results, not seen in IRMS results. Methanol caused larger errors than ethanol. Results from vapour-IRIS analyses had larger errors than those from liquid-IRIS analyses. The O-17-excess approach identified methanol driven error in liquid- and vapour-mode IRIS samples at levels where isotope results became unacceptably erroneous. For ethanol contaminated samples, a mix of erroneous and correct flagging occurred with the O-17-excess method. Our results indicate that methanol is the more problematic contaminant for data corruption. The O-17-excess method was therefore useful for data quality control. Conclusions Organic contamination caused significant errors in IRIS stable isotope results. These errors were larger during vapour analyses than during liquid IRIS analyses, and larger for methanol than ethanol contamination. The O-17-excess method is highly sensitive for detecting narrowband (methanol) contamination error in vapour and liquid analysis modes in IRIS.", "authors": [ "Millar, Cody", "Janzen, Kim", "Nehemy, Magali F.", "Koehler, Geoff", "Herve-Fernandez, Pedro", "McDonnell, Jeffrey J." ], "keywords": [ "" ], "year": "2021", "source": "RAPID COMMUNICATIONS IN MASS SPECTROMETRY", "publication_type": "J", "point2d": [ -2.660053014755249, 20.94701385498047 ], "cluster": 0.0 }, { "idx": 943, "title": "Tree water deficit and dynamic source water partitioning", "abstract": "The stable isotopes of hydrogen and oxygen (delta H-2 and delta O-18, respectively) have been widely used to investigate tree water source partitioning. These tracers have shed new light on patterns of tree water use in time and space. However, there are several limiting factors to this methodology (e.g., the difficult assessment of isotope fractionation in trees, and the labor-intensity associated with the collection of significant sample sizes) and the use of isotopes alone has not been enough to provide a mechanistic understanding of source water partitioning. Here, we combine isotope data in xylem and soil water with measurements of tree's physiological information including tree water deficit (TWD), fine root distribution, and soil matric potential, to investigate the mechanism driving tree water source partitioning. We used a 2 m(3) lysimeter with willow trees (Salix viminalis) planted within, to conduct a high spatial-temporal resolution experiment. TWD provided an integrated response of plant water status to water supply and demand. The combined isotopic and TWD measurement showed that short-term variation (within days) in source water partitioning is determined mainly by plant hydraulic response to changes in soil matric potential. We observed changes in the relationship between soil matric potential and TWD that are matched by shifts in source water partitioning. Our results show that tree water use is a dynamic process on the time scale of days. These findings demonstrate tree's plasticity to water supply over days can be identified with high-resolution measurements of plant water status. Our results further support that root distribution alone is not an indicator of water uptake dynamics. Overall, we show that combining physiological measurements with traditional isotope tracing can reveal mechanistic insights into plant responses to changing environmental conditions.", "authors": [ "Nehemy, Magali F.", "Benettin, Paolo", "Asadollahi, Mitra", "Pratt, Dyan", "Rinaldo, Andrea", "McDonnell, Jeffrey J." ], "keywords": [ "ecohydrology", "soil water", "stable isotopes", "transpiration", "tree water deficit", "tree water source" ], "year": "2021", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -13.449676513671875, 25.84929656982422 ], "cluster": 3.0 }, { "idx": 944, "title": "Tracers reveal limited influence of plantation forests on surface runoff in a UK natural flood management catchment", "abstract": "Study region: United Kingdom (UK). Study focus: Natural flood management (NFM) schemes are increasingly prominent in the UK. Studies of NFM have not yet used natural tracers at catchment scale to investigate how interventions influence partitioning during storms between surface rainfall runoff and water already stored in catchments. Here we investigate how catchment properties, particularly plantation forestry, influence surface storm rainfall runoff. We used hydrograph separation based on hydrogen and oxygen isotopes (H-2,O-18) and acid neutralising capacity from high flow events to compare three headwater catchments (2.4-3.1 km(2)) with differences in plantation forest cover (Picea sitchensis: 94%, 41%, 1%) within a major UK NFM pilot, typical of the UK uplands. New hydrological insights: Plantation forest cover reduced the total storm rainfall runoff fraction during all events (by up to 11%) when comparing two paired catchments with similar soils, geology and topography but -50% difference in forest cover. However, comparison with the third catchment, with negligible forest cover but different characteristics, suggests that soils and geology were dominant controls on storm rainfall runoff fraction. Furthermore, differences between events were greater than differences between catchments. These findings suggest that while plantation forest cover may influence storm rainfall runoff fractions, it is not a dominant control in temperate upland UK catchments, especially for larger events. Soils and geology may exert greater influence, with implications for planning NFM.", "authors": [ "Peskett, Leo M.", "Heal, Kate, V", "MacDonald, Alan M.", "Black, Andrew R.", "McDonnell, Jeffrey J." ], "keywords": [ "Flooding", "Upland catchments", "Stable isotopes", "Runoff attenuation", "Afforestation", "Hydrograph separation" ], "year": "2021", "source": "JOURNAL OF HYDROLOGY-REGIONAL STUDIES", "publication_type": "J", "point2d": [ 12.48305606842041, -27.263683319091797 ], "cluster": 10.0 }, { "idx": 945, "title": "Tropical forest water source patterns revealed by stable isotopes: A preliminary analysis of 46 neighboring species", "abstract": "Stable isotope tracing of plant water use can illuminate plant water sources. But to date, the number of species tested at any given site has been minimal. Here, we sample 46 tropical hardwood tree species in a 0.32 ha plot with uniform soils. Soil water was characterized at 6 depths at 0.2 m intervals down to 1 m and showed simple and predictable depth patterns of 82H and 818O, and simple and spatially uniform isotope composition at each depth. Nevertheless, tree xylem water 82H and 818O showed remarkable variation covering the full range of soil composition, suggesting strong sorting and niche segregation across the small plot. Wood density, tree size and mean basal area increment together explained approximately 55% of the variance of xylem water isotope composition through principal component analysis. A Bayesian mixing model was applied to the data and showed that sampled trees were either sourcing their water from very shallow or deep soil layers, with very little contribution from the middle portion of the soil profile. The majority of the observed species relied on 0.0-0.2 m depth soil water. This layer contributed approximately 75% of the xylem water which was significantly higher than the contributions from all other depths. The contribution from shallow soil was highest for trees with high wood density, slow-growing trees and small-sized trees. Our work suggests that stable isotope tracers may aid a better understanding of tropical forest water uptake depths and their relation to tree functional traits and potential hydrological niche segregation among co-occurring tropical species.", "authors": [ "Sohel, Md. Shawkat I.", "Grau, Adriana Vega", "McDonnell, Jeffrey J.", "Herbohn, John" ], "keywords": [ "Ecohydrological separation", "Niche segregation", "Bayesian mixing model", "Dual isotope", "Tree water uptake depth", "Soil water partitioning", "Rainforest tree species" ], "year": "2021", "source": "FOREST ECOLOGY AND MANAGEMENT", "publication_type": "J", "point2d": [ -9.850296020507812, 25.889543533325195 ], "cluster": 3.0 }, { "idx": 946, "title": "Using stable isotopes to track hydrological processes at an oil sands mine, Alberta, Canada", "abstract": "Study region: This study was conducted at an oil sands operation in the Athabasca Oil Sands Region (AOSR), northeastern Alberta, Canada. The mine comprises open pit excavation of bituminous sands at two sites (Mildred Lake, ML, and Aurora North, AN), with a single hot-water extraction circuit connecting extraction plants at each mine.Study focus: Water samples were collected and analyzed regularly over an eight-year period to establish inventories of site-wide water isotope signatures including seasonal and interannual changes in the recycle water circuit, and to permit future application of an isotope balance model to constrain poorly quantified processes such as evaporation losses, dewatering of tailings, and tailings pond connectivity of the recycle water circuit.New hydrological insights for the region: Sampling of precipitation inputs over an 8-year period was used to constrain a local meteoric water line for the area. Differences in evaporative isotopic enrichment of tailings ponds at ML and AN are attributed to use of Athabasca River makeup water at the former site versus basal dewatering sources at the latter, with similar atmospheric controls at both. A conceptual model is developed summarizing temporal variations in water balance and isotopic signatures within the recycle water circuit, including accurate simulation of the unique isotopic enrichment of cooling tower blowdown. This study provides foundational evidence for application of stable isotope mass balance to monitor and improve industrial water use efficiency and management.", "authors": [ "Chad, Spencer J.", "Barbour, S. Lee", "McDonnell, Jeffrey J.", "Gibson, John J." ], "keywords": [ "Isotope hydrology", "Deuterium", "Oxygen-18", "Isotope mass balance", "Oil sands", "Mine water management", "Tailings management" ], "year": "2022", "source": "JOURNAL OF HYDROLOGY-REGIONAL STUDIES", "publication_type": "J", "point2d": [ 0.22722214460372925, 17.485261917114258 ], "cluster": 18.0 }, { "idx": 947, "title": "Isotopic fractionation from deep roots to tall shoots: A forensic analysis of xylem water isotope composition in mature tropical savanna trees", "abstract": "Studies of plant water sources generally assume that xylem water integrates the isotopic composition (delta H-2 and delta O-18) of water sources and does not fractionate during uptake or transport along the transpiration pathway. However, woody xerophytes, halophytes, and trees in mesic environments can show isotopic fractionation from source waters. Isotopic fractionation and variation in isotope composition can affect the interpretation of tree water sources, but most studies to date have been greenhouse experiments. Here we present a field-based forensic analysis of xylem water isotope composition for 12 Eucalyptus tetrodonta and Corymbia nesophila trees. We used a 25-tonne excavator to access materials from the trees' maximum rooting depth of 3 m to their highest canopies at 38 m. Substantial within-tree variation occurred in delta H-2 (-91.1%o to -35.7 parts per thousand. tetrodonta; -88.8 parts per thousand to -24.5 parts per thousand C. nesophila) and delta O-18 (-12.3 parts per thousand to -5.0 parts per thousand E. tetrodonta; -10.9 parts per thousand to -0.3 parts per thousand C. nesophila), with different root-to-branch isotope patterns in each species. Soil water delta H-2 and delta O-18 dual isotope slopes (7.26 E. tetrodonta, 6.66 C. nesophila) were closest to the Local Meteoric Water Line (8.4). The dual isotope slopes of the trees decreased progressively from roots (6.45 E. tetrodonta, 6.07 C. nesophila), to stems (4.61 E. tetrodonta, 5.97 C. nesophila) and branches (4.68 E. tetrodonta, 5.67 C. nesophila), indicative of fractionation along the xylem stream. Roots of both species were more enriched in H-2 and O-18 than soil water at all sampled depths. Bayesian mixing model analysis showed that estimated proportions of water sourced from different depths reflected the contrasting root systems of these species. Our study adds evidence of isotopic fractionation from water uptake and along the transpiration stream in mature trees in monsoonal environments, affecting the interpretation of water sources. We discuss the findings with view of interpreting aboveground xylem water isotopic composition, incorporating knowledge of root systems. (C) 2021 Elsevier B.V. All rights reserved.", "authors": [ "Vega-Grau, Adriana M.", "McDonnell, Jeffrey", "Schmidt, Susanne", "Annandale, Mark", "Herbohn, John" ], "keywords": [ "Ecohydrology", "Eucalyptus", "Corymbia plant water sources", "Plant water uptake", "Xylem water offsets" ], "year": "2021", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ -10.413236618041992, 26.45047950744629 ], "cluster": 3.0 }, { "idx": 948, "title": "Measuring the economic value of urban river restoration", "abstract": "Rivers are under enormous threat worldwide and large amounts of money are invested in river restoration. Contrary to the costs, the benefits of river restoration are much harder to quantify. In this study, the benefits of restoring different sections of the Yongding River in Beijing, China, are estimated through a discrete choice experiment (DCE). Place attachment is measured by sampling residents upstream and downstream and using the river sections as labelled alternatives in the DCE. As expected, the improvement of water quality is valued highly by all river basin residents, and place attachment and spatial preference heterogeneity play a significant role in public willingness to pay (WTP) for river restoration. Although respondents are willing to give up only a small share of their disposable income, public WTP for improved river water quality is a factor 2 to 4 higher than the current household water bill. These findings provide important guidance for the recovery of the investment costs associated with river restoration projects.", "authors": [ "Dai, Dan", "Brouwer, Roy", "Lei, Kun" ], "keywords": [ "Discrete choice experiment", "Urban river restoration", "Place attachment", "Spatial preference heterogeneity", "China" ], "year": "2021", "source": "ECOLOGICAL ECONOMICS", "publication_type": "J", "point2d": [ 58.92844772338867, -48.07320022583008 ], "cluster": 11.0 }, { "idx": 949, "title": "The economic benefits of recreation in Canada", "abstract": "Canadians spend approximately 2.2% of the country's gross domestic product on outdoor recreation, but we do not yet know the economic benefits people receive from participating in these activities. I provide the first ever comprehensive assessment of the economic benefits of outdoor recreation in Canada. I use a nationally representative survey of recreational behaviour on over 24,000 Canadians to estimate a Kuhn-Tucker demand model that accounts for substitution between activities and satiation in demand. The results demonstrate that participation in outdoor recreation provides Canadians with $98 billion in annual economic benefits, which is well over twice as large as reported expenditures. I also reveal substantial heterogeneity in recreation benefits across activities and regions in Canada.", "authors": [ "Lloyd-Smith, Patrick" ], "keywords": [ "" ], "year": "2021", "source": "CANADIAN JOURNAL OF ECONOMICS-REVUE CANADIENNE D ECONOMIQUE", "publication_type": "J", "point2d": [ 52.92811584472656, -45.340999603271484 ], "cluster": 11.0 }, { "idx": 950, "title": "Six decades of environmental resource valuation in Canada: A synthesis of the literature", "abstract": "This paper synthesizes Canada's environmental valuation literature over the last six decades. Focusing on primary valuation benefit estimates, we link multiple research outputs from the same data collection effort to obtain an accurate measure of unique studies. We identify a total of 269 unique valuation studies conducted in Canada between 1964 and 2019. The number of valuation studies conducted per year has not increased since 1975 and the median data collection year is 1996. Stated preference (SP) methods are the most popular valuation approaches being used in more than 50% of studies and this share has increased to over 80% within the last decade. We discuss numerous gaps in our knowledge for certain environmental resources and regions, in particular Canada's three Northern territories. The paper provides information on the state of environmental valuation research in Canada and identifies future research needs.", "authors": [ "Macaskill, James", "Lloyd-Smith, Patrick" ], "keywords": [ "ecosystem services", "nonmarket valuation", "revealed preference", "stated preference" ], "year": "2022", "source": "CANADIAN JOURNAL OF AGRICULTURAL ECONOMICS-REVUE CANADIENNE D AGROECONOMIE", "publication_type": "J", "point2d": [ 53.850990295410156, -43.13002395629883 ], "cluster": 11.0 }, { "idx": 951, "title": "Understanding the determinants of biodiversity non-use values in the context of climate change: Stated preferences for the Hawaiian coral reefs", "abstract": "Global climate change is leading to rapid deteriorations of the health and productivity of coral reefs. There is limited research on the associated human welfare implications, particularly in terms of the non-use values that people hold for coral reefs. We examine climate related changes in non-use values of coral health, coral cover, water clarity, fish numbers, fish species diversity and presence of turtles. Using a discrete choice experiment conducted among 1,369 Hawaiian and US mainland residents, we find that climate change induced declines in coral cover and fish numbers result in large welfare losses; whereas, declines in coral health and fish species diversity lead to moderate welfare losses. Deterioration in water clarity results in large welfare losses for US mainland residents but relatively smaller losses for Hawaiian residents. On aggregate, differences in welfare estimates for the US mainland and Hawaii sample are minor. However, we find significant differences in the underlying determinants of willingness-to-pay for partial climate change mitigation including income and beliefs in the need to mitigate climate change. The paper concludes with some recommendations for policy on the basis of these findings.", "authors": [ "Robinson, Peter John", "van Beukering, Pieter", "Brander, Luke", "Brouwer, Roy", "Haider, W.", "Taylor, Michael", "Mau, Paulus" ], "keywords": [ "Climate change", "Coral reefs", "Discrete choice experiment", "Hawaii", "Non-use value" ], "year": "2022", "source": "ECOSYSTEM SERVICES", "publication_type": "J", "point2d": [ 56.80162811279297, -43.680728912353516 ], "cluster": 11.0 }, { "idx": 952, "title": "How much are Canadians willing to pay for clean surface and ground water? A meta-analysis of the Canadian non-market valuation literature", "abstract": "Three decades of non-market water quality valuation (NMWQV) studies in Canada are analyzed to generate a generic benefits transfer function. Contrary to the large valuation literature focusing on water and wilderness-based recreation in Canada, the number of studies related to water quality is limited. NMWQV studies lack a common design, including consistent adherence to a Canada-specific water quality ladder (WQL). Despite the high degree of data heterogeneity, values extracted from the literature show an increasing step function when relating them to the Resources for the Future WQL. Meta-regression models (MRMs) explain a large share of the variation in value estimates based on the type of water resources, population and methodological characteristics. Baseline water quality and the size of the water quality change are significant determinants of the estimated non-market values. With a relative mean prediction error of no more than 20 percent, the predictive power of the estimated MRMs is high. As such, they are an important step forward in the development of a policy-relevant water quality valuation model. However, there is a clear need for the development of more coherent non-market valuation guidelines in the Canadian water context.", "authors": [ "Brouwer, Roy", "Pinto, Rute" ], "keywords": [ "Water quality", "non-market valuation", "meta-analysis", "water quality ladder", "Canada" ], "year": "2021", "source": "CANADIAN WATER RESOURCES JOURNAL", "publication_type": "J", "point2d": [ 54.30204772949219, -43.84416961669922 ], "cluster": 11.0 }, { "idx": 953, "title": "RNA metabarcoding helps reveal zooplankton community response to environmental stressors", "abstract": "DNA metabarcoding can provide a high-throughput and rapid method for characterizing responses of communities to environmental stressors. However, within bulk samples, DNA metabarcoding hardly distinguishes live from the dead organisms. Here, both DNA and RNA metabarcoding were applied and compared in experimental freshwater mesocosms conducted for assessment of ecotoxicological responses of zooplankton communities to remediation treatment until 38 days post oil-spill. Furthermore, a novel indicator of normalized vitality (NV), sequence counts of RNA metabarcoding normalized by that of DNA metabarcoding, was developed for assessment of ecological responses. DNA and RNA metabarcoding detected similar taxa richness and rank of relative abundances. Both DNA and RNA metabarcoding demonstrated slight shifts in measured alpha-diversities in response to treatments. NV presented relatively greater magnitudes of differential responses of community compositions to treatments compared to DNA or RNA metabarcoding. NV declined from the start of the experiment (3 days pre-spill) to the end (38 days post-spill). NV also differed between Rotifer and Arthropoda, possibly due to differential life histories and sizes of organisms. NV could be a useful indicator for characterizing ecological responses to anthropogenic influence; however, the biology of target organisms and subsequent RNA production need to be considered.", "authors": [ "Ankley, Phillip J.", "Xie, Yuwei", "Havens, Sonya", "Peters, Lisa", "Timlick, Lauren", "Rodriguez-Gil, Jose Luis", "Giesy, John P.", "Palace, Vince P." ], "keywords": [ "Community RNA", "COI", "Ecogenomics", "Freshwater ecosystem", "Boreal lake", "Ecological indicator" ], "year": "2022", "source": "ENVIRONMENTAL POLLUTION", "publication_type": "J", "point2d": [ 75.67623901367188, 9.599617958068848 ], "cluster": 0.0 }, { "idx": 955, "title": "Life Cycle Exposure to Environmentally Relevant Concentrations of Diphenyl Phosphate (DPhP) Inhibits Growth and Energy Metabolism of Zebrafish in a Sex-Specific Manner", "abstract": "Due to commercial uses and environmental degradation of aryl phosphate esters, diphenyl phosphate (DPhP) is frequently detected in environmental matrices and is thus of growing concern worldwide. However, information on potential adverse effects of chronic exposure to DPhP at environmentally realistic concentrations was lacking. Here, we investigated the effects of life cycle exposure to DPhP on zebrafish at environmentally relevant concentrations of 0.8, 3.9, or 35.6 mu g/L and employed a dual-omics approach (metabolomics and transcriptomics) to characterize potential modes of action. Exposure to DPhP at 35.6 mu g/L for 120 days resulted in significant reductions in body mass and length of male zebrafish, but did not cause those same effects to females. Predominant toxicological mechanisms, including inhibition of oxidative phosphorylation, down-regulation of fatty acid oxidation, and up-regulation of phosphatidylcholine degradation, were revealed by integrated dual-omics analysis and successfully linked to adverse outcomes. Activity of succinate dehydrogenase and protein content of carnitine O-palmitoyltransferase 1 were significantly decreased in livers of male fish exposed to DPhP, which further confirmed the proposed toxicological mechanisms. This study is the first to demonstrate that chronic, low-level exposure to DPhP can retard growth via inhibiting energy output in male zebrafish.", "authors": [ "Chen, Qiliang", "Lian, Xiaolong", "An, Jingjing", "Geng, Ningbo", "Zhang, Haijun", "Challis, Jonathan K.", "Luo, Yun", "Liu, Yaxin", "Su, Guanyong", "Xie, Yuwei", "Li, Yingwen", "Liu, Zhihao", "Shen, Yanjun", "Giesy, John P.", "Gong, Yufeng" ], "keywords": [ "diphenyl phosphate", "metabolomics", "transcriptomics", "gene set enrichment analysis (GSEA)", "oxidative phosphorylation", "fatty acid oxidation" ], "year": "2021", "source": "ENVIRONMENTAL SCIENCE & TECHNOLOGY", "publication_type": "J", "point2d": [ 82.74381256103516, 0.8562747240066528 ], "cluster": 0.0 }, { "idx": 959, "title": "Effects of Agricultural Stressors on Growth and an Immune Status Indicator in Wood Frog (Lithobates sylvaticus) Tadpoles and Metamorphs", "abstract": "Like many amphibians, wood frog (Lithobates sylvaticus) populations have likely declined or experienced local extirpations as a result of habitat alterations. Despite this, wood frogs are still present and breeding in altered landscapes, like the agricultural Prairie Pothole Region of central Canada, and are exposed to a variety of anthropogenic impacts. As tadpoles, water contamination can have negative effects on growth, development, and immune systems. To investigate the potential effects of agricultural land use on tadpole growth and immune system stress, we used boosted regression trees to model body mass, body condition, and neutrophil to lymphocyte ratios, a measure of immune stress, against 32 variables including water quality, wetland habitat, and landscape-level measures. Developmental stage strongly influenced all 3 endpoints, and body mass was negatively influenced by higher levels of total dissolved solids (>600-700 mg/L) and at the first sign of pesticide detection (>0.01 proportion pesticides detected of those screened). While correlative, these data suggest that tadpoles developing in agricultural environments may experience survival and reproductive disadvantages if they metamorphose at smaller body sizes. Given the potential impacts this can have on adult frogs and frog populations, these results provide an impetus for further field-based investigation into the effects that pesticides, and especially total dissolved solids, may have on tadpoles. Environ Toxicol Chem 2021;00:1-13. (c) 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.", "authors": [ "Ruso, Gabrielle E.", "Hogan, Natacha S.", "Sheedy, Claudia", "Gallant, Melanie J.", "Jardine, Timothy D." ], "keywords": [ "Agriculture", "Amphibians", "Immune system", "Pesticides", "Prairie Pothole Region", "Wetlands" ], "year": "2021", "source": "ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY", "publication_type": "J", "point2d": [ 61.850120544433594, -8.103754043579102 ], "cluster": 0.0 }, { "idx": 960, "title": "Absorption and elimination of per and poly-fluoroalkyl substances substitutes in salmonid species after pre-fertilization exposure", "abstract": "Due to their relatively large production and few restrictions on uses, novel substitutes for historically used per and poly-fluoroalkyl substances (PFAS) are being used and accumulating in the environment. However, due to a lack of information on their toxicological properties their hazards and risks are hard to estimate. Before fertilization, oocytes of two salmonid species, Arctic Char (Salvelinus alpinus) and Rainbow Trout (Oncorhynchus mykiss), were exposed to three PFAS substances used as substitutes for traditional PFAS, PFBA, PFBS or GenX or two archetypical, historically used, longer-chain PFAS, PFOA and PFOS. Exposed oocytes were subsequently fertilized, incubated and were sampled during several developmental stages, until swim-up. All five PFAS were accumulated into egg yolks with similar absorption rates, and their concentrations in egg yolks were less than respective concentrations in/on egg chorions. Rapid elimination of the five PFAS was observed during the first 3 days after fertilization. Thereafter, amounts of PFOS and PFOA were stable until swim-up, while PFBA, PFBS and GenX were further eliminated during development from one month after the fertilization to swim-up. In these two salmonid species, PFBA, PFBS and GenX were eliminated faster than were PFOS or PFOA.", "authors": [ "Su, Shu", "Jones, Paul D.", "Raine, Jason C.", "Yang, Zilin", "Gong, Yufeng", "Xie, Yuwei", "Tang, Jie", "Wang, Chao", "Zhao, Xiaoli", "Giesy, John P." ], "keywords": [ "Short-chain PFAS", "Char", "Trout", "Bioaccumulation", "Fluoro-chemical" ], "year": "2022", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 86.076904296875, 0.3681185841560364 ], "cluster": 0.0 }, { "idx": 961, "title": "Environmental DNA of preservative ethanol performed better than water samples in detecting macroinvertebrate diversity using metabarcoding", "abstract": "Aim High-throughput pipelines supported by eDNA metabarcoding have been applied in various freshwater ecosystems. Both eDNA in ethanol (EtOH) samples (ES-eDNA) and in water samples (WS-eDNA) can provide comprehensive classification lists with good taxonomic resolution and coverage for determining freshwater biodiversity and biomonitoring. But, the advantages of ES-eDNA metabarcoding over WS-eDNA metabarcoding remain unclear for routine assessments of diversity of benthic macroinvertebrates in streams. Location Qiantang River Basin, China. Methods Here, we compared ES-eDNA and WS-eDNA metabarcoding to evaluate the performance of two eDNA workflows in determining biodiversity and recovery of damaged macroinvertebrate communities. All eDNA samples from the environment and bulk specimen of macroinvertebrates were processed into available molecular operational taxonomic units (MOTUs) and identified to the level of genus. Results WS-eDNA detected more exact sequence variants (ESVs) (formerly referred to as operational taxonomic units; OTUs), than did ES-eDNA (2,866 vs. 2,406), but fewer macroinvertebrate ESVs (381 vs. 481). Among sampling sites, the two eDNA workflows exhibited relatively large dissimilarity on inferred community composition (p < .001). Furthermore, ES-eDNA metabarcoding exhibited more consistent with morphological identification approaches than did WS-eDNA metabarcoding (24.24% vs. 17.63%, p = .002), especially for species identified by traditional morphology (morphotaxa). Main conclusions Based on the attributes of ES-eDNA and WS-eDNA, it is suggested that ES-eDNA metabarcoding performs better than does WS-eDNA metabarcoding in detecting local biodiversity and was consistent with morphological results, while WS-eDNA was more suitable for exploring biodiversity patterns on a broad scale, as it is the easiest and most convenient way to collect samples. Results of this study suggest ES-eDNA metabarcoding could be an option in building molecular measurement biomonitoring programme based on EtOH sample used for preserving biological samples.", "authors": [ "Wang, Yu", "Chen, Kai", "Gao, Jin", "Wang, Meng", "Dong, Jie", "Xie, Yuwei", "Giesy, John P.", "Jin, Xiaowei", "Wang, Beixin" ], "keywords": [ "benthic invertebrates", "COI", "eDNA metabarcoding", "freshwater biomonitoring", "preservative ethanol", "stream" ], "year": "2021", "source": "DIVERSITY AND DISTRIBUTIONS", "publication_type": "J", "point2d": [ 74.29304504394531, 10.326077461242676 ], "cluster": 0.0 }, { "idx": 962, "title": "Effects of aqueous fluoxetine exposure on gut microbiome of adult Pimephales promelas", "abstract": "The microbiome of the gut is vital for homeostasis of hosts with its ability to detoxify and activate toxicants, as well as signal to the immune and nervous systems. However, in the field of environmental toxicology, the gut microbiome has only recently been identified as a measurable indicator for exposure to environmental pollutants. Antidepressants found in effluents of wastewater treatment plants and surface waters have been shown to exhibit antibacterial-like properties in vitro, where some bacteria are known to express homologous proteins that bind antidepressants in verte-brates. Therefore, it has been hypothesized that exposure to antidepressant drugs might affect gut microbiota of aquatic organisms. In this study, the common antidepressant, fluoxetine, was investigated to determine whether it can modulate the gut microbiome of adult fathead minnows. A 28-day, sub-chronic, static renewal exposure was per -formed with nominal fluoxetine concentrations of 0.01, 10 or 100 mu g/L. Using 16S rRNA amplicon sequencing, shifts among the gut-associated microbiota were observed in individuals exposed to the greatest concentration, with greater effects observed in females. These changes were associated with a decrease in relative proportions of commensal bac-teria, which can be important for health of fish including bacteria essential for fatty acid oxidation, and an increase in relative proportions of pathogenic bacteria associated with inflammation. Results demonstrate, for the first time, how antidepressants found in some aquatic environments can influence gut microbiota of fishes.", "authors": [ "Weber, Alana", "Xie, Yuwei", "Challis, Jonathan K.", "DeBofsky, Abigail", "Ankley, Phillip J.", "Hecker, Markus", "Jones, Paul", "Giesy, John P." ], "keywords": [ "Freshwater fish", "Gut microbiota", "Pharmaceuticals", "Prozac", "Aquatic toxicology" ], "year": "2022", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 77.35997772216797, 2.5271553993225098 ], "cluster": 0.0 }, { "idx": 963, "title": "RNA in Municipal Wastewater Reveals Magnitudes of COVID-19 Outbreaks across Four Waves Driven by SARS-CoV-2 Variants of Concern", "abstract": "ABSTRACT: There are no standardized protocols for quantifying severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in wastewater to date, especially for population normalization. Here, a pipeline was developed, applied, and assessed to quantify SARS-CoV2 and key variants of concern (VOCs) RNA in wastewater at Saskatoon, Canada. Normalization approaches using recovery ratio and extraction efficiency, wastewater parameters, or population indicators were assessed by comparing to daily numbers of new cases. Viral load was positively correlated with daily new cases reported in the sewershed. Wastewater surveillance (WS) had a lead time of approximately 7 days, which indicated surges in the number of new cases. WS revealed the variant alpha and delta driving the third and fourth wave, respectively. The adjustment with the recovery ratio and extraction efficiency improved the correlation between viral load and daily new cases. Normalization of viral concentration to concentrations of the artificial sweetener acesulfame K improved the trend of viral load during the Christmas and New Year holidays when populations were dynamic and variable. Acesulfame K performed better than pepper mild mottle virus, creatinine, and ammonia for population normalization. Hence, quality controls to characterize recovery ratios and extraction efficiencies and population normalization with acesulfame are promising for precise WS programs supporting decision-making in public health.", "authors": [ "Xie, Yuwei", "Challis, Jonathan K.", "Oloye, Femi F.", "Asadi, Mohsen", "Cantin, Jenna", "Brinkmann, Markus", "McPhedran, Kerry N.", "Hogan, Natacha", "Sadowski, Mike", "Jones, Paul D.", "Landgraff, Chrystal", "Mangat, Chand", "Servos, Mark R.", "Giesy, John P." ], "keywords": [ "Population health", "Infectious disease", "Environmental monitoring", "Wastewater-based epidemiology", "Population biomarker" ], "year": "2022", "source": "ACS ES&T WATER", "publication_type": "J", "point2d": [ 75.0435791015625, 24.739938735961914 ], "cluster": 19.0 }, { "idx": 964, "title": "Occurrence of BMAA Isomers in Bloom-Impacted Lakes and Reservoirs of Brazil, Canada, France, Mexico, and the United Kingdom", "abstract": "The neurotoxic alkaloid beta-N-methyl-amino-1-alanine (BMAA) and related isomers, including N-(2-aminoethyl glycine) (AEG), beta-amino-N-methyl alanine (BAMA), and 2,4-diaminobutyric acid (DAB), have been reported previously in cyanobacterial samples. However, there are conflicting reports regarding their occurrence in surface waters. In this study, we evaluated the impact of amending lake water samples with trichloroacetic acid (0.1 M TCA) on the detection of BMAA isomers, compared with pre-existing protocols. A sensitive instrumental method was enlisted for the survey, with limits of detection in the range of 5-10 ng L-1. Higher detection rates and significantly greater levels (paired Wilcoxon's signed-rank tests, p < 0.001) of BMAA isomers were observed in TCA-amended samples (method B) compared to samples without TCA (method A). The overall range of B/A ratios was 0.67-8.25 for AEG (up to +725%) and 0.69-15.5 for DAB (up to +1450%), with absolute concentration increases in TCA-amended samples of up to +15,000 ng L-1 for AEG and +650 ng L-1 for DAB. We also documented the trends in the occurrence of BMAA isomers for a large breadth of field-collected lakes from Brazil, Canada, France, Mexico, and the United Kingdom. Data gathered during this overarching campaign (overall, n = 390 within 45 lake sampling sites) indicated frequent detections of AEG and DAB isomers, with detection rates of 30% and 43% and maximum levels of 19,000 ng L-1 and 1100 ng L-1, respectively. In contrast, BAMA was found in less than 8% of the water samples, and BMAA was not found in any sample. These results support the analyses of free-living cyanobacteria, wherein BMAA was often reported at concentrations of 2-4 orders of magnitude lower than AEG and DAB. Seasonal measurements conducted at two bloom-impacted lakes indicated limited correlations of BMAA isomers with total microcystins or chlorophyll-a, which deserves further investigation.", "authors": [ "Abbes, Safa", "Sung Vo Duy", "Munoz, Gabriel", "Quoc Tuc Dinh", "Simon, Dana F.", "Husk, Barry", "Baulch, Helen M.", "Vincon-Leite, Brigitte", "Fortin, Nathalie", "Greer, Charles W.", "Larsen, Megan L.", "Venkiteswaran, Jason J.", "Martinez Jeronimo, Felipe Fernando", "Giani, Alessandra", "Lowe, Chris D.", "Tromas, Nicolas", "Sauve, Sebastien" ], "keywords": [ "lake water", "beta-N-methyl-amino-1-alanine (BMAA)", "2,4-diaminobutyric acid (DAB)", "N-(2-aminoethyl) glycine (AEG)", "trichloroacetic acid (TCA)", "temporal trends" ], "year": "2022", "source": "TOXINS", "publication_type": "J", "point2d": [ 61.29161834716797, 14.907971382141113 ], "cluster": 19.0 }, { "idx": 966, "title": "Improvement of field fluorometry estimates of chlorophyll a concentration in a cyanobacteria-rich eutrophic lake", "abstract": "Instrumented buoys are used to monitor water quality, yet there remains a need to evaluate whether in vivo fluorometric measures of chlorophyll a (Chl a) produce accurate estimates of phytoplankton abundance. Here, 6 years (2014-2019) of in vitro measurements of Chl a by spectrophotometry were compared with coeval estimates from buoy-based fluorescence measurements in eutrophic Buffalo Pound Lake, Saskatchewan, Canada. Analysis revealed that fluorometric and in vitro estimates of Chl a differed both in terms of absolute concentration and patterns of relative change through time. Three models were developed to improve agreement between metrics of Chl a concentration, including two based on Chl a and phycocyanin (PC) fluorescence and one based on multiple linear regressions with measured environmental conditions. All models were examined in terms of two performance metrics; accuracy (lowest error) and reliability (% fit within confidence intervals). The model based on PC fluorescence was most accurate (error = 35%), whereas that using environmental factors was most reliable (89% within 3 sigma of mean). Models were also evaluated on their ability to produce spatial maps of Chl a using remotely sensed imagery. Here, newly developed models significantly improved system performance with a 30% decrease in Chl a errors and a twofold increase in the range of reconstructed Chl a values. Superiority of the PC model likely reflected high cyanobacterial abundance, as well as the excitation-emission wavelength configuration of fluorometers. Our findings suggest that a PC fluorometer, used alone or in combination with environmental measurements, performs better than a single-excitation-band Chl a fluorometer in estimating Chl a content in highly eutrophic waters.", "authors": [ "Chegoonian, Amir M.", "Zolfaghari, Kiana", "Leavitt, Peter R.", "Baulch, Helen M.", "Duguay, Claude R." ], "keywords": [ "" ], "year": "2022", "source": "LIMNOLOGY AND OCEANOGRAPHY-METHODS", "publication_type": "J", "point2d": [ 59.91309356689453, 22.345840454101562 ], "cluster": 19.0 }, { "idx": 967, "title": "Marked blue discoloration of late winter ice and water due to autumn blooms of cyanobacteria", "abstract": "Haig HA, Chegoonian AM, Davies J-M, Bateson D, Leavitt PR. 2021. Marked blue discoloration of late winter ice and water due to autumn blooms of cyanobacteria. Lake Reserv Manage. XX:XXX-XXX. Continued eutrophication of inland waters by nutrient pollution can combine with unprecedented atmospheric and lake warming to create emergent environmental surprises. Here we report the first known occurrence of marked blue discoloration of ice and water in highly eutrophic prairie lakes during late winter 2021. Intense blue staining was reported first to governmental agencies by ice fishers in early March 2021, then communicated widely through social media, resulting in First Nations and public concern over potential septic field release, toxic spills, urban pollution, and agricultural mismanagement. Analysis of water from stained and reference sites using ultraviolet (UV)-visible spectrophotometry and high-performance liquid chromatography demonstrated that the blue color arose from high concentrations (similar to 14 mg/L) of the cyanobacterial pigment C-phycocyanin that was released after an unexpected bloom of Aphanizomenon flos-aquae in late October 2020 was frozen into littoral ice. Remote sensing using the Sentinel 3 A/B OLCI and Sentinel 2 A/B MSI satellite platforms suggested that blue staining encompassed 0.68 +/- 0.24 km(2) (4.25 +/- 1.5% of lake surface area), persisted over 4 weeks, and was located within 50 m of the lakeshore in regions where fall blooms of cyanobacteria had been particularly dense. Although toxin levels were low (similar to 0.2 mu g microcystin/L), high concentrations of C-phycocyanin raised public concern over eutrophication, pollution, and climate change, and resulted in rapid governmental and academic response. Given that climate change and nutrient pollution are increasing the magnitude and duration of cyanobacterial blooms, blue staining of lake ice may become widespread in eutrophic lakes subject to ice cover.", "authors": [ "Haig, Heather A.", "Chegoonian, Amir M.", "Davies, John-Mark", "Bateson, Deirdre", "Leavitt, Peter R." ], "keywords": [ "Aphanizomenon", "C-phycocyanin", "cyanobacteria", "fall bloom", "HPLC", "remote sensing", "Sentinel 2 MSI", "Sentinel 3 OLCI" ], "year": "2022", "source": "LAKE AND RESERVOIR MANAGEMENT", "publication_type": "J", "point2d": [ 57.06819152832031, 0.8171086311340332 ], "cluster": 19.0 }, { "idx": 968, "title": "Large Fractionation in Iron Isotopes Implicates Metabolic Pathways for Iron Cycling in Boreal Shield Lakes", "abstract": "Stable Fe isotopes have only recently been measured in freshwater systems, mainly in meromictic lakes. Here we report the (556Fe of dissolved, particulate, and sediment Fe in two small dimictic boreal shield headwater lakes: manipulated eutrophic Lake 227, with annual cyanobacterial blooms, and unmanipulated oligotrophic Lake 442. Within the lakes, the range in (556Fe is large (ca. -0.9 to +1.8%o), spanning more than half the entire range of natural Earth surface samples. Two layers in the water column with distinctive (556Fe of dissolved (dis) and particulate (spm) Fe were observed, despite differences in trophic states. In the epilimnia of both lakes, a large Delta 56Fedis-spm fractionation of 0.4-1%o between dissolved and particulate Fe was only observed during cyanobacterial blooms in Lake 227, possibly regulated by selective biological uptake of isotopically light Fe by cyanobacteria. In the anoxic layers in both lakes, upward flux from sediments dominates the dissolved Fe pool with an apparent Delta 56Fedis-spm fractionation of -2.2 to -0.6%o. Large Delta 56Fedis-spm and previously published metagenome sequence data suggest active Fe cycling processes in anoxic layers, such as microaerophilic Fe(II) oxidation or photoferrotrophy, could regulate biogeochemical cycling. Large fractionation of stable Fe isotopes in these lakes provides a potential tool to probe Fe cycling and the acquisition of Fe by cyanobacteria, with relevance for understanding biogeochemical cycling of Earth's early ferruginous oceans.", "authors": [ "Liu, Kai", "Schiff, Sherry L.", "Wu, Lingling", "Molot, Lewis A.", "Venkiteswaran, Jason J.", "Paterson, Michael J.", "Elgood, Richard J.", "Tsuji, Jackson M.", "Neufeld, Josh D." ], "keywords": [ "iron isotopes", "cyanobacteria", "photoferrotrophy", "microaerophilic iron oxidation", "iron uptake" ], "year": "2022", "source": "ENVIRONMENTAL SCIENCE & TECHNOLOGY", "publication_type": "J", "point2d": [ 65.90496063232422, 12.210785865783691 ], "cluster": 19.0 }, { "idx": 969, "title": "Phosphorus-only fertilization rapidly initiates large nitrogen-fixing cyanobacteria blooms in two oligotrophic lakes", "abstract": "Two small, oligotrophic lakes at the IISD-Experimental Lakes Area in northwestern Ontario, Canada were fertilized weekly with only phosphorus (P) in the summer and early fall of 2019. The P fertilization rates were high enough (13.3 mu g l(-1) added weekly) to produce dense, month-long blooms of N-2-fixing Dolichospermum species in both lakes within 9-12 weeks after fertilization began, turning them visibly green without the addition of nitrogen. P-only fertilization increased average seasonal chlorophyll a concentrations and cyanobacteria biomass well above the pre-fertilization levels of 2017 and 2018. Nitrogen (N) content in the epilimnion of thermally stratified Lake 304 and the water column of shallow Lake 303 doubled and P storage in the water column temporarily increased during the blooms. These whole-lake fertilization experiments demonstrate that large cyanobacteria blooms can develop rapidly under high P loading without anthropogenic N inputs, suggesting that aggressive N control programs are unlikely to prevent bloom formation and that P controls should remain the cornerstone for cyanobacteria management.", "authors": [ "Molot, Lewis A.", "Higgins, Scott N.", "Schiff, Sherry L.", "Venkiteswaran, Jason J.", "Paterson, Michael J.", "Baulch, Helen M." ], "keywords": [ "eutrophication", "phosphorus", "nitrogen", "whole-lake fertilization", "cyanobacteria blooms" ], "year": "2021", "source": "ENVIRONMENTAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ 57.859466552734375, 12.470842361450195 ], "cluster": 19.0 }, { "idx": 971, "title": "Warming combined with experimental eutrophication intensifies lake phytoplankton blooms", "abstract": "Phytoplankton blooms are a global water quality issue, and successful management depends on understanding their responses to multiple and interacting drivers, including nutrient loading and climate change. Here, we examine a long-term dataset from Lake 227, a site subject to a fertilization experiment (1969-present) with changing nitrogen:phosphorus (N:P) ratios. We applied a process-oriented model, MyLake, and updated the model structure with nutrient uptake kinetics that incorporated shifting N:P and competition among phytoplankton functional groups. We also tested different temperature and P-loading scenarios to examine the interacting effects of climate change and nutrient loading on phytoplankton blooms. The model successfully reproduced lake physics over 48 yr and the timing, overall magnitude, and shifting community structure (diazotrophs vs. non-diazotrophs) of phytoplankton blooms. Intra- and interannual variability was captured more accurately for the P-only fertilization period than for the high N:P and low N:P fertilization periods, highlighting the difficulty of modeling complex blooms even in well-studied systems. A model scenario was also run which removed climate-driven temperature trends, allowing us to disentangle concurrent drivers of blooms. Results showed that increases in water temperature in the spring led to earlier and larger phytoplankton blooms under climate change than under the effects of nutrient fertilization alone. These findings suggest that successful lake management efforts should incorporate the effects of climate change in addition to nutrient reductions, including intensifying and/or expanding monitoring periods and incorporating climate change into uncertainty estimates around future conditions.", "authors": [ "Salk, Kateri R.", "Venkiteswaran, Jason J.", "Couture, Raoul-Marie", "Higgins, Scott N.", "Paterson, Michael J.", "Schiff, Sherry L." ], "keywords": [ "" ], "year": "2022", "source": "LIMNOLOGY AND OCEANOGRAPHY", "publication_type": "J", "point2d": [ 56.661476135253906, 13.169129371643066 ], "cluster": 19.0 }, { "idx": 972, "title": "Anoxygenic photosynthesis and iron-sulfur metabolic potential ofChlorobiapopulations from seasonally anoxic Boreal Shield lakes", "abstract": "Aquatic environments with high levels of dissolved ferrous iron and low levels of sulfate serve as an important systems for exploring biogeochemical processes relevant to the early Earth. Boreal Shield lakes, which number in the tens of millions globally, commonly develop seasonally anoxic waters that become iron rich and sulfate poor, yet the iron-sulfur microbiology of these systems has been poorly examined. Here we use genome-resolved metagenomics and enrichment cultivation to explore the metabolic diversity and ecology of anoxygenic photosynthesis and iron/sulfur cycling in the anoxic water columns of three Boreal Shield lakes. We recovered four high-completeness and low-contamination draft genome bins assigned to the classChlorobia(formerly phylumChlorobi) from environmental metagenome data and enriched two novel sulfide-oxidizing species, also from theChlorobia. The sequenced genomes of both enriched species, including the novel CandidatusChlorobium canadense, encoded thecyc2gene that is associated with photoferrotrophy among culturedChlorobiamembers, along with genes for phototrophic sulfide oxidation. One environmental genome bin also encodedcyc2. Despite the presence ofcyc2in the corresponding draft genome, we were unable to induce photoferrotrophy in Ca. Chlorobium canadense. Genomic potential for phototrophic sulfide oxidation was more commonly detected thancyc2among environmental genome bins ofChlorobia, and metagenome and cultivation data suggested the potential for cryptic sulfur cycling to fuel sulfide-based growth. Overall, our results provide an important basis for further probing the functional role ofcyc2and indicate that anoxygenic photoautotrophs in Boreal Shield lakes could have underexplored photophysiology pertinent to understanding Earth's early microbial communities.", "authors": [ "Tsuji, J. M.", "Tran, N.", "Schiff, S. L.", "Venkiteswaran, J. J.", "Molot, L. A.", "Tank, M.", "Hanada, S.", "Neufeld, J. D." ], "keywords": [ "" ], "year": "2020", "source": "ISME JOURNAL", "publication_type": "J", "point2d": [ 66.6660385131836, 12.379480361938477 ], "cluster": 19.0 }, { "idx": 973, "title": "Controls of lithium isotope spatial variability across the Yukon River: Implications for weathering processes in a warming subarctic basin", "abstract": "With ongoing global warming and permafrost thawing, weathering processes will change on the Yukon River, with risks for water quality and ecosystem sustainability. Here, we explore the relationship between weathering processes and permafrost cover using elemental concentration and strontium and lithium isotopic data in the dissolved load of 102 samples collected during the summer across most major tributaries of the Yukon River. The Yukon River basin is dominated by silicate weathering with a high contribution from young volcanic rock units. In glaciated mountainous zones, we observe higher carbonate weathering contribution, low Li/Na ratios and low delta Li-7 values (< 15 parts per thousand & nbsp;). In these areas, the high denudation rate and high supply of fresh minerals associated with alpine glaciers favor congruent silicate weathering, and sulfide oxidation accelerates carbonate weathering. In floodplains covered by continuous permafrost, we observe a high carbonate weathering contribution, relatively high Li/Na ratios, and low delta Li-7 values (~& nbsp;18 parts per thousand). We argue that the minimal water-rock interactions in this setting inhibit silicate weathering and favor congruent weathering of easily weatherable minerals (i.e., carbonates). Conversely, in areas with discontinuous or sporadic permafrost, we observe a dominance of silicate weathering, with higher and more variable Li/Na ratios and high delta Li-7 values (11-33 parts per thousand). In this setting, longer water-rock interactions combined with the high supply of fresh minerals from mountain zones favor more incongruent weathering. The unique history of Pleistocene glaciations on the Yukon River basin also influences weathering processes. Many areas of the basin were never glaciated during the Pleistocene, and rivers draining those regions have higher delta Li-7 values suggesting more incongruent weathering associated with deeper flow paths and longer water residence time in the regolith. Our work underlines that water-rock interactions, including active layer weathering and groundwater inputs, are highly dependent on climate conditions and glacial processes across the Yukon River basin, with key implications for future water quality in this warming basin. Crown Copyright (C) 2022 Published by Elsevier Ltd. All rights reserved.& nbsp;", "authors": [ "Kang, Myunghak", "Skierszkan, Elliott", "Brennan, Sean", "Fernandez, Diego P.", "Yang, Zhaoping", "Girard, Isabelle", "Gammon, Paul", "de Laplante, Ghislain", "Bataille, Clement P." ], "keywords": [ "Lithium isotopes", "Weathering", "Permafrost", "Glaciers", "Yukon River" ], "year": "2022", "source": "GEOCHIMICA ET COSMOCHIMICA ACTA", "publication_type": "J", "point2d": [ 4.629245758056641, 15.950037002563477 ], "cluster": 18.0 }, { "idx": 974, "title": "Persistence of Uranium in Old and Cold Subpermafrost Groundwater Indicated by Linking U-234-U-235-U-238, Groundwater Ages, and Hydrogeochemistry", "abstract": "Uranium (U) contamination in groundwater from geogenic sources affects water quality globally. Here, we use a multifaceted isotopic and geochemical approach to elucidate U sources and controls on geogenic U release to groundwater and surface water at a prospective subarctic gold deposit in Yukon, Canada, that is characterized by permafrost, fractured bedrock, and cold (<2 degrees C) groundwater. X-ray absorption spectroscopy, sequential extractions, and micro X-ray fluorescence mapping show extensive subsurface oxidation and solid-phase U present in its hexavalent and mobile form. Limited U-238/U-2(35) isotope fractionation and predominance of U(VI) in rocks suggest U(VI) sorption-desorption is the main driver of U mobilization. Groundwater U concentrations are appreciable (median 38 mu g/L, range 1.2-535 mu g/L) and are explained by high-alkalinity, Ca-rich groundwater produced from oxidative weathering of sulfide and carbonate-mineralized structures around the deposit. Minor U-238/U-2(35) isotope fractionation in groundwater indicates that limited U(VI) reduction occurs beneath permafrost despite groundwater redox conditions below Fe(III) and S(VI) reduction, and groundwater ages inferred from H-3 and C-14 to be on the order of thousands of years. The complexation of U as uranyl-calcium-carbonate complexes and the resilience of these complexes to U(VI) reduction contributes to high U(VI) mobility under cold groundwater conditions. This study provides insight into processes and time scales of U transport in subarctic groundwater at a pivotal time when hydrogeochemical changes may be anticipated in cold regions worldwide due to permafrost degradation.", "authors": [ "Skierszkan, Elliott K.", "Dockrey, John W.", "Helsen, Jordi", "Findlater, Laura-Lee", "Bataille, Clement P.", "de Laplante, Ghislain", "McBeth, Joyce M.", "Mayer, K. Ulrich", "Beckie, Roger D." ], "keywords": [ "uranium", "geogenic contamination", "permafrost degradation", "permafrost hydrogeology", "uranium isotopes", "radiocarbon" ], "year": "2021", "source": "ACS EARTH AND SPACE CHEMISTRY", "publication_type": "J", "point2d": [ 11.624177932739258, 20.986309051513672 ], "cluster": 18.0 }, { "idx": 976, "title": "Grassroots and Global Governance: Can Global-Local Linkages Foster Food System Resilience for Small Northern Canadian Communities?", "abstract": "Communities in Canada's Northwest Territories (NWT) are at the forefront of the global climate emergency. Yet, they are not passive victims; local-level programs are being implemented across the region to maintain livelihoods and promote adaptation. At the same time, there is a recent call within global governance literature to pay attention to how global policy is implemented and affecting people on the ground. Thinking about these two processes, we ask the question: (how) can global governance assist northern Indigenous communities in Canada in reaching their goals of adapting their food systems to climate change? To answer this question, we argue for a community needs approach when engaging in global governance literature and practice, which puts community priorities and decision-making first. As part of a collaborative research partnership, we highlight the experiences of Ka'a'gee Tu First Nation, located in Kakisa, NWT, Canada. We include their successes of engaging in global network building and the systemic roadblock of lack of formal land tenure. Moreover, we analyze potential opportunities for this community to engage with global governance instruments and continue connecting to global networks that further their goals related to climate change adaptation and food sovereignty.", "authors": [ "Johnston, Carla", "Spring, Andrew" ], "keywords": [ "global governance", "food systems", "climate change", "adaptation", "knowledge sharing", "community-needs approach", "Indigenous", "northern Canada" ], "year": "2021", "source": "SUSTAINABILITY", "publication_type": "J", "point2d": [ 68.9813003540039, -28.590484619140625 ], "cluster": 4.0 }, { "idx": 977, "title": "Northern Food Systems in Transition: The Role of the Emerging Agri-Food Industry in the Northwest Territories (Canada) Food System", "abstract": "This paper reports the findings of an ethnographic study that involved working with local organizations, food advocates, and communities to develop strategies for expanding the nascent Northwest Territories (NWT), Canada agri-food industry. The NWT represents a unique case study in that the fledging agri-food industry has been recognized for its promise in contributing to the core goals of the transitioning NWT food system. The study is guided by two research questions: (1) How is the promise of the emerging NWT agri-food industry framed within the context of the broader food system? (2) Given this framing of the NWT agri-food industry, how can it contribute to the sustainability of the NWT food system and to the goals of food security, poverty reduction, nutrition, and economic development? Grounded in a food systems approach, we used a correlative, evolutionary SWOT analysis to profile the nascent NWT agri-food industry within the context of the existing NWT food system. Through further thematic analysis, we identify and describe two dominant narratives (agri-food industry business case narrative and agri-food industry implications narrative) and key themes within the narratives based on an adapted food systems framework. The agri-food business case narrative highlights discourse articulating the business or commercial viability for a local agri-food value chain to function, evolve, and expand. The agri-food industry implications narrative envisions the ways in which the emerging NWT agri-food industry may interact within the existing NWT food system, highlighting potential environmental, social, cultural, and political implications of an expanding commercial-based agri-food value chain. Within the two narratives, certain subcomponents of the NWT agri-food system appear to be more prevalent, including climate, soil, and ecosystems, policy/regulations/governance, socio-cultural norms, knowledge, inputs, finance, production, and consumption. We make policy and practice recommendations for co-designing an agri-food industry that serves the multiple goals of the NWT food system. As an exploratory, descriptive-structural analysis the study provides a critical empirical basis for future in-depth, fully integrated synthesis of the complex social, cultural, economic, political, and ecological dynamics shaping Northern food systems in transition.", "authors": [ "Lemay, Margaret A.", "Radcliffe, Josalyn", "Bysouth, David", "Spring, Andrew" ], "keywords": [ "agri-food industry", "transitions", "food security", "economic development", "poverty reduction", "northern food systems", "Northwest Territories (Canada)" ], "year": "2021", "source": "FRONTIERS IN SUSTAINABLE FOOD SYSTEMS", "publication_type": "J", "point2d": [ 70.45960235595703, -29.669811248779297 ], "cluster": 4.0 }, { "idx": 979, "title": "Biases Beyond the Mean in CMIP6 Extreme Precipitation: A Global Investigation", "abstract": "Climate models are crucial for assessing climate variability and change. A reliable model for future climate should reasonably simulate the historical climate. Here, we assess the performance of CMIP6 models in reproducing statistical properties of observed annual maxima of daily precipitation. We go beyond the commonly used methods and assess CMIP6 simulations on three scales by performing: (a) univariate comparison based on L-moments and relative difference measures; (b) bivariate comparison using Kernel densities of mean and L-variation, and of L-skewness and L-kurtosis, and (c) comparison of the entire distribution function using the Generalized Extreme Value (GEV) distribution coupled with a novel application of the Anderson-Darling Goodness-of-fit test. The results reveal that the statistical shape properties (related to the frequency and magnitude of extremes) of CMIP6 simulations match well with the observational datasets. The simulated mean and variation differ among the models with 70% of simulations having a difference within +/- 10% from the observations. Biases are observed in the bivariate investigation of mean and variation. Several models perform well with the HadGEM3-GC31-MM model performing well in all three scales when compared to the ground-based Global Precipitation Climatology Centre data. Finally, the study highlights biases of CMIP6 models in simulating extreme precipitation in the Arctic, Tropics, arid and semi-arid regions.", "authors": [ "Abdelmoaty, Hebatallah Mohamed", "Papalexiou, Simon Michael", "Rajulapati, Chandra Rupa", "AghaKouchak, Amir" ], "keywords": [ "precipitation extremes", "CMIP6", "climate change" ], "year": "2021", "source": "EARTHS FUTURE", "publication_type": "J", "point2d": [ -39.35956573486328, -71.19123840332031 ], "cluster": 14.0 }, { "idx": 980, "title": "Biases Beyond the Mean in CMIP6 Extreme Precipitation: A Global Investigation", "abstract": "Climate models are crucial for assessing climate variability and change. A reliable model for future climate should reasonably simulate the historical climate. Here, we assess the performance of CMIP6 models in reproducing statistical properties of observed annual maxima of daily precipitation. We go beyond the commonly used methods and assess CMIP6 simulations on three scales by performing: (a) univariate comparison based on L-moments and relative difference measures; (b) bivariate comparison using Kernel densities of mean and L-variation, and of L-skewness and L-kurtosis, and (c) comparison of the entire distribution function using the Generalized Extreme Value (GEV) distribution coupled with a novel application of the Anderson-Darling Goodness-of-fit test. The results reveal that the statistical shape properties (related to the frequency and magnitude of extremes) of CMIP6 simulations match well with the observational datasets. The simulated mean and variation differ among the models with 70% of simulations having a difference within +/- 10% from the observations. Biases are observed in the bivariate investigation of mean and variation. Several models perform well with the HadGEM3-GC31-MM model performing well in all three scales when compared to the ground-based Global Precipitation Climatology Centre data. Finally, the study highlights biases of CMIP6 models in simulating extreme precipitation in the Arctic, Tropics, arid and semi-arid regions.", "authors": [ "Abdelmoaty, Hebatallah Mohamed", "Papalexiou, Simon Michael", "Rajulapati, Chandra Rupa", "AghaKouchak, Amir" ], "keywords": [ "precipitation extremes", "CMIP6", "climate change" ], "year": "2021", "source": "EARTHS FUTURE", "publication_type": "J", "point2d": [ -39.55186080932617, -71.59090423583984 ], "cluster": 14.0 }, { "idx": 981, "title": "Evidence-based identification of integrated water quality systems", "abstract": "Identification of integrated models is still hindered by submodels' uncertainty propagation. In this article, a novel identifiability and identification framework is applied to screen and establish reasonable hypotheses of an integrated instream (WASP) and catchment water quality (VENSIM) model. Using the framework, the models were linked, and critical parameters and processes identified. First, an ensemble of catchment nutrient loads was simulated with randomized parameter settings of the catchment processes (e.g. nutrient decay rates). A second Monte Carlo analysis was then staged with randomized loadings and parameter values mimicking insteam processes (e.g. algae growth). The most significant parameters and their processes were identified. This coupling of models for a two-step global sensitivity analysis is a novel approach to integrated catchment-scale water quality model identification. Catchment processes were, overall, more significant to the river's water quality than the instream processes of this Prairie river system investigated (Qu'Appelle River).", "authors": [ "Akomeah, Eric", "Lindenschmidt, Karl-Erich", "Morales-Marin, Luis", "Hassanzadeh, Elmira" ], "keywords": [ "integrated water quality modeling", "identification", "identifiability", "uncertainty", "cold region" ], "year": "2023", "source": "JOURNAL OF ENVIRONMENTAL PLANNING AND MANAGEMENT", "publication_type": "J", "point2d": [ 2.652649164199829, -76.8974609375 ], "cluster": 16.0 }, { "idx": 982, "title": "Impacts of future climate on the hydrology of a transboundary river basin in northeastern North America", "abstract": "Climate change introduces substantial uncertainty in water resources planning and management. This is particularly the case for the river systems in the high latitudes of the Northern Hemisphere that are more vulnerable to global change. The situation becomes more challenging when there is a limited hydrological understanding of the basin. In this study, we assessed the impacts of future climate on the hydrology of the Saint John River Basin (SJRB), which is an important transboundary coastal river basin in northeastern North America. We also additionally performed model benchmarking for the SJRB using four different meteorological forcing datasets. Using the best performing forcing data and model parameters, we studied the water balance of the basin. Our results show that meteorological forcing data play a pivotal role in model performance and therefore can introduce a large degree of uncertainty in hydrological modelling. The analysis of the water balance highlights that runoff and evapotranspiration account for about 99% of the total basin precipitation, with each constituting approximately 50%. The simulation of future flows projects higher winter discharges, but summer flows are estimated to decrease in the 2041-2070 and 2071-2100 periods compared to the baseline period (1991-2020). However, the evaluation of model errors indicates higher confidence in the result that future winter flows will increase, but lower confidence in the results that future summer flows will decrease.", "authors": [ "Budhathoki, Sujata", "Rokaya, Prabin", "Lindenschmidt, Karl-Erich" ], "keywords": [ "Climate change", "Hydrological modelling", "Model benchmarking", "Water balance", "Saint John River basin" ], "year": "2022", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -11.448102951049805, -30.077747344970703 ], "cluster": 16.0 }, { "idx": 983, "title": "Open Science: Open Data, Open Models, ...and Open Publications?", "abstract": "This commentary explores the challenges and opportunities associated with a possible transition of Water Resources Research to a publication model where all articles are freely available upon publication (Gold open access). It provides a review of the status of open access publishing models, a summary of community input, and a path forward for AGU leadership. The decision to convert to open access is framed by a mix of finances and values. On the one hand, the challenge is to define who pays, and how, and what we can do to improve the affordability of publishing. On the other hand, the challenge is to increase the extent to which science is open and accessible. The next steps for the community include an incisive analysis of the financial feasibility of different cost models, and weighing the financial burden for open access against the desire to further advance open science.", "authors": [ "Clark, Martyn P.", "Luce, Charles H.", "AghaKouchak, Amir", "Berghuijs, Wouter", "David, Cedric H.", "Duan, Qingyun", "Ge, Shemin", "van Meerveld, Ilja", "Zheng, Chunmiao", "Parlange, Marc B.", "Tyler, Scott W." ], "keywords": [ "Open access", "open science", "the future of scholarly publications" ], "year": "2021", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 48.462215423583984, -28.628828048706055 ], "cluster": 4.0 }, { "idx": 984, "title": "The Abuse of Popular Performance Metrics in Hydrologic Modeling", "abstract": "The goal of this commentary is to critically evaluate the use of popular performance metrics in hydrologic modeling. We focus on the Nash-Sutcliffe Efficiency (NSE) and the Kling-Gupta Efficiency (KGE) metrics, which are both widely used in hydrologic research and practice around the world. Our specific objectives are: (a) to provide tools that quantify the sampling uncertainty in popular performance metrics; (b) to quantify sampling uncertainty in popular performance metrics across a large sample of catchments; and (c) to prescribe the further research that is, needed to improve the estimation, interpretation, and use of popular performance metrics in hydrologic modeling. Our large-sample analysis demonstrates that there is substantial sampling uncertainty in the NSE and KGE estimators. This occurs because the probability distribution of squared errors between model simulations and observations has heavy tails, meaning that performance metrics can be heavily influenced by just a few data points. Our results highlight obvious (yet ignored) abuses of performance metrics that contaminate the conclusions of many hydrologic modeling studies: It is essential to quantify the sampling uncertainty in performance metrics when justifying the use of a model for a specific purpose and when comparing the performance of competing models.", "authors": [ "Clark, Martyn P.", "Vogel, Richard M.", "Lamontagne, Jonathan R.", "Mizukami, Naoki", "Knoben, Wouter J. M.", "Tang, Guoqiang", "Gharari, Shervan", "Freer, Jim E.", "Whitfield, Paul H.", "Shook, Kevin R.", "Papalexiou, Simon Michael" ], "keywords": [ "" ], "year": "2021", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 4.730092525482178, -60.72471618652344 ], "cluster": 16.0 }, { "idx": 985, "title": "Exploring the Potential of Zoning Regulation for Reducing Ice-Jam Flood Risk Using a Stochastic Modelling Framework", "abstract": "Ice-jam floods pose a serious threat to many riverside communities in cold regions. Ice-jam-related flooding can cause loss of human life, millions of dollars in property damage, and adverse impacts on ecology. An effective flood management strategy is necessary to reduce the overall risk in flood-prone areas. Most of these strategies require a detailed risk-based management study to assess their effectiveness in reducing flood risk. Zoning regulation is a sustainable measure to reduce overall flood risk for a flood-prone area. Zoning regulation is a specified area in a floodplain where certain restrictions apply to different land uses (e.g., development or business). A stochastic framework was introduced to evaluate the effectiveness of a potential zoning regulation. A stochastic framework encompasses the impacts of all the possible expected floods instead of a more traditional approach where a single design flood is incorporated. The downtown area of Fort McMurray along the Athabasca River was selected to explore the impact of zoning regulation on reducing expected annual damages (EAD) from ice-jam flooding. The results show that a hypothetical zoning regulation for a certain area in the town of Fort McMurray (TFM) can be effective in substantially reducing the level of EAD. A global sensitivity analysis was also applied to understand the impacts of model inputs on ice-jam flood risk using a regional sensitivity method. The results show that model boundary conditions such as river discharge, the inflowing volume of ice and ice-jam toe locations are highly sensitive to ice-jam flood risk.", "authors": [ "Das, Apurba", "Lindenschmidt, Karl-Erich" ], "keywords": [ "ice jam", "flood hazard", "risk analysis", "expected annual damages", "sensitivity analysis" ], "year": "2021", "source": "WATER", "publication_type": "J", "point2d": [ 1.0061535835266113, -36.33513641357422 ], "cluster": 16.0 }, { "idx": 986, "title": "Modelling climatic impacts on ice-jam floods: a review of current models, modelling capabilities, challenges, and future prospects", "abstract": "River ice is an important hydraulic and hydrological component of many rivers in the high northern latitudes of the world. It controls the hydraulic characteristics of streamflow, affects the geomorphology of channels, and can cause flooding due to ice-jam formation during ice-cover freeze-up and breakup periods. In recent decades, climate change has considerably altered ice regimes, affecting the severity of ice-jam flooding. Although many approaches have been developed to model river ice regimes and the severity of ice-jam flooding, appropriate methods that account for the impacts of future climate on ice-jam flooding have not been well established. Therefore, the main goals of this study are to review current knowledge regarding climate change impacts on river ice processes and to assess current modelling capabilities to determine the severity of ice jams under future climatic conditions. Finally, a conceptual river ice-jam modelling approach is presented for incorporating climate change impacts on ice jams.", "authors": [ "Das, Apurba", "Lindenschmidt, Karl-Erich" ], "keywords": [ "ice jam", "climate change", "northern river", "modelling" ], "year": "2021", "source": "ENVIRONMENTAL REVIEWS", "publication_type": "J", "point2d": [ -6.580435752868652, -40.304664611816406 ], "cluster": 16.0 }, { "idx": 987, "title": "Towards more realistic runoff projections by removing limits on simulated soil moisture deficit", "abstract": "Rainfall-runoff models based on conceptual buckets are frequently used in climate change impact studies to provide runoff projections. When these buckets approach empty, the simulated evapotranspiration approaches zero, which places an implicit limit on the soil moisture deficit that can accrue within the model. Such models may cease to properly track the moisture deficit accumulating in reality as dry conditions continue, leading to overestimation of subsequent runoff and possible long-term bias under drying climate. Here, we suggest that model realism may be improved through alternatives which remove the upper limit on simulated soil moisture deficit, such as bottomless buckets or deficit-based soil moisture accounting. While some existing models incorporate such measures, no study until now has systematically assessed their impact on model realism under drying climate. Here, we alter a common bucket model by changing the soil moisture storage to a deficit accounting system in such a way as to remove the upper limit on simulated soil moisture deficit. Tested on 38 Australian catchments, the altered model is better able to track the decline in soil moisture at the end of seasonal dry periods, which leads to superior performance over varied historic climate, including the 13-year Millennium drought. However, groundwater and GRACE data reveal long-term trends that are not matched in simulations, indicating that further changes may be required. Nonetheless, the results suggest that a broader adoption of bottomless buckets and/or deficit accounting within conceptual rainfall runoff models may improve the realism of runoff projections under drying climate.", "authors": [ "Fowler, Keirnan J. A.", "Coxon, Gemma", "Freer, Jim E.", "Knoben, Wouter J. M.", "Peel, Murray C.", "Wagener, Thorsten", "Western, Andrew W.", "Woods, Ross A.", "Zhang, Lu" ], "keywords": [ "Rainfall-runoff modelling", "Runoff projections", "Model improvement", "Model realism", "Drought", "Climate change" ], "year": "2021", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ 20.507402420043945, -54.924217224121094 ], "cluster": 16.0 }, { "idx": 989, "title": "Mimicry of a Conceptual Hydrological Model (HBV): What's in a Name?", "abstract": "Models that mimic an original model might have a different model structure than the original model, that affects model output. This study assesses model structure differences and their impact on output by comparing 7 model implementations that carry the name HBV. We explain and quantify output differences with individual model structure components at both the numerical (e.g., explicit/implicit scheme) and mathematical level (e.g., lineair/power outflow). It was found that none of the numerical and mathematical formulations of the mimicking models were (originally) the same as the benchmark, HBV-light. This led to small but distinct output differences in simulated streamflow for different numerical implementations (KGE difference up to 0.15), and major output differences due to mathematical differences (KGE median loss of 0.27). These differences decreased after calibrating the individual models to the simulated streamflow of the benchmark model. We argue that the lack of systematic model naming has led to a diverging concept of the HBV-model, diminishing the concept of model mimicry. Development of a systematic model naming framework, open accessible model code and more elaborate model descriptions are suggested to enhance model mimicry and model development.", "authors": [ "Jansen, Koen F.", "Teuling, Adriaan J.", "Craig, James R.", "Dal Molin, Marco", "Knoben, Wouter J. M.", "Parajka, Juraj", "Vis, Marc", "Melsen, Lieke A." ], "keywords": [ "HBV model", "model intercomparison", "model mimicry", "modular modeling framework" ], "year": "2021", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 7.710773944854736, -58.04547119140625 ], "cluster": 16.0 }, { "idx": 991, "title": "Radiative Feedbacks on Land Surface Change and Associated Tropical Precipitation Shifts", "abstract": "Changes in land surface albedo and land surface evaporation modulate the atmospheric energy budget by changing temperatures, water vapor, clouds, snow and ice cover, and the partitioning of surface energy fluxes. Here idealized perturbations to land surface properties are imposed in a global model to understand how such forcings drive shifts in zonal mean atmospheric energy transport and zonal mean tropical precipitation. For a uniform decrease in global land albedo, the albedo forcing and a positive water vapor feedback contribute roughly equally to increased energy absorption at the top of the atmosphere (TOA), while radiative changes due to the temperature and cloud cover response provide a negative feedback and energy loss at TOA. Decreasing land albedo causes a northward shift in the zonal mean intertropical convergence zone (ITCZ). The combined effects on ITCZ location of all atmospheric feedbacks roughly cancel for the albedo forcing; the total ITCZ shift is comparable to that predicted for the albedo forcing alone. For an imposed increase in evaporative resistance that reduces land evaporation, low cloud cover decreases in the northern midlatitudes and more energy is absorbed at TOA there; longwave loss due to warming provides a negative feedback on the TOA energy balance and ITCZ shift. Imposed changes in land albedo and evaporative resistance modulate fundamentally different aspects of the surface energy budget. However, the patterns of TOA radiation changes due to the water vapor and air temperature responses are highly correlated for these two forcings because both forcings lead to near-surface warming.", "authors": [ "Lague, Marysa M.", "Swann, Abigail L. S.", "Boos, William R." ], "keywords": [ "Atmosphere-land interaction", "Cloud forcing", "Feedback", "Climate models" ], "year": "2021", "source": "JOURNAL OF CLIMATE", "publication_type": "J", "point2d": [ -60.16225814819336, -58.50351333618164 ], "cluster": 14.0 }, { "idx": 992, "title": "Terrestrial Evaporation and Global Climate: Lessons from Northland, a Planet with a Hemispheric Continent", "abstract": "Motivated by the hemispheric asymmetry of land distribution on Earth, we explore the climate of Northland, a highly idealized planet with a Northern Hemisphere continent and a Southern Hemisphere ocean. The climate of Northland can be separated into four distinct regions: the Southern Hemisphere ocean, the seasonally wet tropics, the midlatitude desert, and the Great Northern Swamp. We evaluate how modifying land surface properties on Northland drives changes in temperatures, precipitation patterns, the global energy budget, and atmospheric dynamics. We observe a surprising response to changes in land surface evaporation, where suppressing terrestrial evaporation in Northland cools both land and ocean. In previous studies, suppressing terrestrial evaporation has been found to lead to local warming by reducing latent cooling of the land surface. However, reduced evaporation can also decrease atmospheric water vapor, reducing the strength of the greenhouse effect and leading to large-scale cooling. We use a set of idealized climate model simulations to show that suppressing terrestrial evaporation over Northern Hemisphere continents of varying size can lead to either warming or cooling of the land surface, depending on which of these competing effects dominates. We find that a combination of total land area and contiguous continent size controls the balance between local warming from reduced latent heat flux and large-scale cooling from reduced atmospheric water vapor. Finally, we demonstrate how terrestrial heat capacity, albedo, and evaporation all modulate the location of the ITCZ both over the continent and over the ocean.", "authors": [ "Lague, Marysa M.", "Pietschnig, Marianne", "Ragen, Sarah", "Smith, Timothy A.", "Battisti, David S." ], "keywords": [ "Energy transport", "Atmosphere-land interaction", "Climatology", "Evaporation", "Water vapor", "Climate models", "General circulation models" ], "year": "2021", "source": "JOURNAL OF CLIMATE", "publication_type": "J", "point2d": [ -59.80287170410156, -58.948577880859375 ], "cluster": 14.0 }, { "idx": 993, "title": "Modelling transverse mixing of sediment and vanadium in a river impacted by oil sands mining operations", "abstract": "Study region: The lower Athabasca River was used as a test case using total suspended sediment, chloride and vanadium as the model variables. Upstream model boundary conditions included water from the tributary Clearwater River (right stream tube) and the upper Athabasca River extending upstream of the tributary mouth (left stream tube). This model will be extended to include the Peace-Athabasca Delta (PAD), to determine the implications of mining outfall dis-charges on a large region of the Athabasca - PAD region. Study focus: A novel, quasi-two-dimensional surface water-quality modelling approach is pre-sented in which the model domain can be discretised in two dimensions, but a one-dimension solver can still be applied to capture water flow between the discretisation units (segments). The approach requires a river reach to be divided into two stream tubes, along the left and right river sides, with flows exchanging through the segments longitudinally and also laterally between adjacent segments along the two streams. New hydrological insights for the region: The new method allows the transverse mixing of tributary and outfall water of different constituent concentrations to be simulated along the course of the river. Additional diffuse loading of dissolved vanadium could be determined from the model's substance balance. A scenario was then simulated in which the transport and fate of vanadium in a floodplain lake and a secondary channel was determined.", "authors": [ "Lindenschmidt, Karl-Erich", "Sabokruhie, Pouya", "Rosner, Tammy" ], "keywords": [ "Oil sands", "Quasi-two-dimensional model", "Sediment", "Vanadium", "WASP" ], "year": "2022", "source": "JOURNAL OF HYDROLOGY-REGIONAL STUDIES", "publication_type": "J", "point2d": [ 45.277015686035156, -6.389031887054443 ], "cluster": 18.0 }, { "idx": 994, "title": "Leveraging ensemble meteorological forcing data to improve parameter estimation of hydrologic models", "abstract": "As continental to global scale high-resolution meteorological datasets continue to be developed, there are sufficient meteorological datasets available now for modellers to construct a historical forcing ensemble. The forcing ensemble can be a collection of multiple deterministic meteorological datasets or come from an ensemble meteorological dataset. In hydrological model calibration, the forcing ensemble can be used to represent forcing data uncertainty. This study examines the potential of using the forcing ensemble to identify more robust parameters through model calibration. Specifically, we compare an ensemble forcing-based calibration with two deterministic forcing-based calibrations and investigate their flow simulation and parameter estimation properties and the ability to resist poor-quality forcings. The comparison experiment is conducted with a six-parameter hydrological model for 30 synthetic studies and 20 real data studies to provide a better assessment of the average performance of the deterministic and ensemble forcing-based calibrations. Results show that the ensemble forcing-based calibration generates parameter estimates that are less biased and have higher frequency of covering the true parameter values than the deterministic forcing-based calibration does. Using a forcing ensemble in model calibration reduces the risk of inaccurate flow simulation caused by poor-quality meteorological inputs, and improves the reliability and overall simulation skill of ensemble simulation results. The poor-quality meteorological inputs can be effectively filtered out via our ensemble forcing-based calibration methodology and thus discarded in any post-calibration model applications. The proposed ensemble forcing-based calibration method can be considered as a more generalized framework to include parameter and forcing uncertainties in model calibration.", "authors": [ "Liu, Hongli", "Tolson, Bryan A.", "Newman, Andrew J.", "Wood, Andrew W." ], "keywords": [ "ensemble forcing", "forcing uncertainty", "meteorological dataset", "model calibration", "parameter estimation", "parameter uncertainty" ], "year": "2021", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -40.52838897705078, -51.9389762878418 ], "cluster": 16.0 }, { "idx": 995, "title": "Dryline characteristics in North America's historical and future climates", "abstract": "Drylines are atmospheric boundaries separating dry from moist air that can initiate convection. Potential changes in the location, frequency, and characteristics of drylines in future climates are unknown. This study applies a multi-parametric algorithm to objectively identify and characterize the dryline in North America using convection-permitting regional climate model simulations with 4-km horizontal grid spacing for 13-years under a historical and a pseudo-global warming climate projection by the end of the century. The dryline identification is successfully achieved with a set of standardized algorithm parameters across the lee side of the Rocky Mountains from the Canadian Rockies to the Sierra Madres in Mexico. The dryline is present 27% of the days at 00 UTC between April and September in the current climate, with a mean humidity gradient magnitude of 0.16 g(-1) kg(-1) km(-1). The seasonal cycle of drylines peak around April and May in the southern Plains, and in June and July in the northern Plains. In the future climate, the magnitude and frequency of drylines increase 5% and 13%, correspondingly, with a stronger intensification southward. Future drylines strengthen during their peak intensity in the afternoon in the Southern U.S. and Northeast Mexico. Drylines also show increasing intensities in the morning with future magnitudes that are comparable to peak intensities found in the afternoon in the historical climate. Furthermore, an extension of the seasonality of intense drylines could produce end-of-summer drylines that are as strong as mid-summer drylines in the current climate. This might affect the seasonality and the diurnal cycle of convective activity in future climates, challenging weather forecasting and agricultural planning.", "authors": [ "Scaff, Lucia", "Prein, Andreas F.", "Li, Yanping", "Clark, Adam J.", "Krogh, Sebastian A.", "Taylor, Neil", "Liu, Changhai", "Rasmussen, Roy M.", "Ikeda, Kyoko", "Li, Zhenhua" ], "keywords": [ "Dryline", "Convection-permitting modeling", "Pseudo global warming", "Rocky mountains" ], "year": "2021", "source": "CLIMATE DYNAMICS", "publication_type": "J", "point2d": [ -52.868675231933594, -64.08871459960938 ], "cluster": 14.0 }, { "idx": 996, "title": "Dryline characteristics in North America's historical and future climates", "abstract": "Drylines are atmospheric boundaries separating dry from moist air that can initiate convection. Potential changes in the location, frequency, and characteristics of drylines in future climates are unknown. This study applies a multi-parametric algorithm to objectively identify and characterize the dryline in North America using convection-permitting regional climate model simulations with 4-km horizontal grid spacing for 13-years under a historical and a pseudo-global warming climate projection by the end of the century. The dryline identification is successfully achieved with a set of standardized algorithm parameters across the lee side of the Rocky Mountains from the Canadian Rockies to the Sierra Madres in Mexico. The dryline is present 27% of the days at 00 UTC between April and September in the current climate, with a mean humidity gradient magnitude of 0.16 g(-1) kg(-1) km(-1). The seasonal cycle of drylines peak around April and May in the southern Plains, and in June and July in the northern Plains. In the future climate, the magnitude and frequency of drylines increase 5% and 13%, correspondingly, with a stronger intensification southward. Future drylines strengthen during their peak intensity in the afternoon in the Southern U.S. and Northeast Mexico. Drylines also show increasing intensities in the morning with future magnitudes that are comparable to peak intensities found in the afternoon in the historical climate. Furthermore, an extension of the seasonality of intense drylines could produce end-of-summer drylines that are as strong as mid-summer drylines in the current climate. This might affect the seasonality and the diurnal cycle of convective activity in future climates, challenging weather forecasting and agricultural planning.", "authors": [ "Scaff, Lucia", "Prein, Andreas F.", "Li, Yanping", "Clark, Adam J.", "Krogh, Sebastian A.", "Taylor, Neil", "Liu, Changhai", "Rasmussen, Roy M.", "Ikeda, Kyoko", "Li, Zhenhua" ], "keywords": [ "Dryline", "Convection-permitting modeling", "Pseudo global warming", "Rocky mountains" ], "year": "2021", "source": "CLIMATE DYNAMICS", "publication_type": "J", "point2d": [ -52.868675231933594, -64.08871459960938 ], "cluster": 14.0 }, { "idx": 997, "title": "A Vector-Based River Routing Model for Earth System Models: Parallelization and Global Applications", "abstract": "A vector-river network explicitly uses realistic geometries of river reaches and catchments for spatial discretization in a river model. This enables improving the accuracy of the physical properties of the modeled river system, compared to a gridded river network that has been used in Earth System Models. With a finer-scale river network, resolving smaller-scale river reaches, there is a need for efficient methods to route streamflow and its constituents throughout the river network. The purpose of this study is twofold: (1) develop a new method to decompose river networks into hydrologically independent tributary domains, where routing computations can be performed in parallel; and (2) perform global river routing simulations with two global river networks, with different scales, to examine the computational efficiency and the differences in discharge simulations at various temporal scales. The new parallelization method uses a hierarchical decomposition strategy, where each decomposed tributary is further decomposed into many sub-tributary domains, enabling hybrid parallel computing. This parallelization scheme has excellent computational scaling for the global domain where it is straightforward to distribute computations across many independent river basins. However, parallel computing for a single large basin remains challenging. The global routing experiments show that the scale of the vector-river network has less impact on the discharge simulations than the runoff input that is generated by the combination of land surface model and meteorological forcing. The scale of vector-river networks needs to consider the scale of local hydrologic features such as lakes that are to be resolved in the network.", "authors": [ "Mizukami, Naoki", "Clark, Martyn P.", "Gharari, Shervan", "Kluzek, Erik", "Pan, Ming", "Lin, Peirong", "Beck, Hylke E.", "Yamazaki, Dai" ], "keywords": [ "Earth System modeling", "parallel computing", "river" ], "year": "2021", "source": "JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS", "publication_type": "J", "point2d": [ 1.2377872467041016, -17.087142944335938 ], "cluster": 16.0 }, { "idx": 998, "title": "Identifying sensitivities in flood frequency analyses using a stochastic hydrologic modeling system", "abstract": "This study employs a stochastic hydrologic modeling framework to evaluate the sensitivity of flood frequency analyses to different components of the hydrologic modeling chain. The major components of the stochastic hydrologic modeling chain, including model structure, model parameter estimation, initial conditions, and precipitation inputs were examined across return periods from 2 to 100 000 years at two watersheds representing different hydroclimates across the western USA. A total of 10 hydrologic model structures were configured, calibrated, and run within the Framework for Understanding Structural Errors (FUSE) modular modeling framework for each of the two watersheds. Model parameters and initial conditions were derived from long-term calibrated simulations using a 100 member historical meteorology ensemble. A stochastic event-based hydrologic modeling workflow was developed using the calibrated models in which millions of flood event simulations were performed for each basin. The analysis of variance method was then used to quantify the relative contributions of model structure, model parameters, initial conditions, and precipitation inputs to flood magnitudes for different return periods. Results demonstrate that different components of the modeling chain have different sensitivities for different return periods. Precipitation inputs contribute most to the variance of rare floods, while initial conditions are most influential for more frequent events. However, the hydrological model structure and structure-parameter interactions together play an equally important role in specific cases, depending on the basin characteristics and type of flood metric of interest. This study highlights the importance of critically assessing model underpinnings, understanding flood generation processes, and selecting appropriate hydrological models that are consistent with our understanding of flood generation processes.", "authors": [ "Newman, Andrew J.", "Stone, Amanda G.", "Saharia, Manabendra", "Holman, Kathleen D.", "Addor, Nans", "Clark, Martyn P." ], "keywords": [ "" ], "year": "2021", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -7.534735202789307, -63.55317306518555 ], "cluster": 16.0 }, { "idx": 999, "title": "Wild fish responses to wastewater treatment plant upgrades in the Grand River, Ontario", "abstract": "Municipal wastewater treatment plant (WWTP) effluent is one of several point sources of contaminants (nutrients, pharmaceuticals, estrogens, etc.) which can lead to adverse responses in aquatic life. Studies of WWTP effluent impacts on rainbow darter (Etheostoma caeruleum) collected downstream of WWTPs in the Grand River, Ontario have reported disruption at multiple levels of biological organization, including altered vitellogenin gene expression, lower levels of in vitro steroid production, and high frequency of intersex. However, major upgrades have occurred at treatment plants in the central Grand River over the last decade. Treatment upgrades to the Waterloo WWTP were initiated in 2009 but due to construction delays, the upgrades came fully on-line in 2017/ 2018. Responses in rainbow darter have been followed at sites associated with the outfall consistently over this entire time period. The treatment plant upgrade resulted in nitrification of effluent, and once complete there was a major reduction in effluent ammonia, selected pharmaceuticals, and estrogenicity. This study compared several key responses in rainbow darter associated with the Waterloo WWTP outfall prior to and post upgrades. Stable isotopes signatures in fish were used to track exposure to effluent and changed dramatically over time, corresponding to the effluent quality. Disruptions in in vitro steroid production and intersex in the darters that had been identified prior to the upgrades were no longer statistically different from the upstream reference sites after the upgrades. Although annual variations in water temperature and flow can potentially mask or exacerbate the effects of the WWTP effluent, major capital investments in wastewater treatment targeted at improving effluent quality have corresponded with the reduction of adverse responses in fish in the receiving environment.", "authors": [ "Nikel, Kirsten E.", "Tetreault, Gerald R.", "Marjan, Patricija", "Hicks, Keegan A.", "Fuzzen, Meghan L. M.", "Srikanthan, Nivetha", "McCann, Emily K.", "Dhiyebi, Hadi", "Bragg, Leslie M.", "Law, Pam", "Celmer-Repin, Dominika", "Kleywegt, Sonya", "Cunningham, Jessie", "Clark, Thomas", "McMaster, Mark E.", "Servos, Mark R." ], "keywords": [ "Ecotoxicity", "Endocrine disrupter", "Environmental toxicology", "Histopathology", "Reproductive system" ], "year": "2023", "source": "AQUATIC TOXICOLOGY", "publication_type": "J", "point2d": [ 73.08039855957031, -2.7611942291259766 ], "cluster": 0.0 }, { "idx": 1000, "title": "Probabilistic Evaluation of Drought in CMIP6 Simulations", "abstract": "As droughts have widespread social and ecological impacts, it is critical to develop long-term adaptation and mitigation strategies to reduce drought vulnerability. Climate models are important in quantifying drought changes. Here, we assess the ability of 285 CMIP6 historical simulations, from 17 models, to reproduce drought duration and severity in three observational data sets using the Standardized Precipitation Index (SPI). We used summary statistics beyond the mean and standard deviation, and devised a novel probabilistic framework, based on the Hellinger distance, to quantify the difference between observed and simulated drought characteristics. Results show that many simulations have less than +/- 10% error in reproducing the observed drought summary statistics. The hypothesis that simulations and observations are described by the same distribution cannot be rejected for more than 80% of the grids based on our H distance framework. No single model stood out as demonstrating consistently better performance over large regions of the globe. The variance in drought statistics among the simulations is higher in the tropics compared to other latitudinal zones. Though the models capture the characteristics of dry spells well, there is considerable bias in low precipitation values. Good model performance in terms of SPI does not imply good performance in simulating low precipitation. Our study emphasizes the need to probabilistically evaluate climate model simulations in order to both pinpoint model weaknesses and identify a subset of best-performing models that are useful for impact assessments.", "authors": [ "Papalexiou, Simon Michael", "Rajulapati, Chandra Rupa", "Andreadis, Konstantinos M.", "Foufoula-Georgiou, Efi", "Clark, Martyn P.", "Trenberth, Kevin E." ], "keywords": [ "CMIP6", "droughts", "reliability of climate models", "climate change", "Hellinger distance", "precipitation" ], "year": "2021", "source": "EARTHS FUTURE", "publication_type": "J", "point2d": [ -38.1306037902832, -72.66068267822266 ], "cluster": 14.0 }, { "idx": 1001, "title": "Exacerbated heat in large Canadian cities", "abstract": "Extreme temperature is a major threat to urban populations; thus, it is crucial to understand future changes to plan adaptation and mitigation strategies. We assess historical and CMIP6 projected trends of minimum and maximum temperatures for the 18 most populated Canadian cities. Temperatures increase (on average 0.3 degrees C/decade) in all cities during the historical period (1979-2014), with Prairie cities exhibiting lower rates (0.06 degrees C/decade). Toronto (0.5 degrees C/decade) and Montreal (0.7 degrees C/decade) show high increasing trends in the observation period. Higher-elevation cities, among those with the same population, show slower increasing temperature rates compared to the coastal ones. Projections for cities in the Prairies show 12% more summer days compared to the other regions. The number of heat waves (HWs) increases for all cities, in both the historical and future periods; yet alarming increases are projected for Vancouver, Vic-toria, and Halifax from no HWs in the historical period to approximately 4 HWs/year on average, towards the end of 2100 for the SSP5-8.5. The cold waves reduce considerably for all cities in the historical period at a rate of 2 CWs/decade on average and are projected to further reduce by 50% compared to the observed period.", "authors": [ "Rajulapati, Chandra Rupa", "Gaddam, Rohan Kumar", "Nerantzaki, Sofia D.", "Papalexiou, Simon Michael", "Cannon, Alex J.", "Clark, Martyn P." ], "keywords": [ "Urban temperature", "Extreme events", "Heat waves", "Cold waves", "Climate change" ], "year": "2022", "source": "URBAN CLIMATE", "publication_type": "J", "point2d": [ -39.47991180419922, -31.821504592895508 ], "cluster": 1.0 }, { "idx": 1002, "title": "Modelling of ice jam floods under past and future climates: A review", "abstract": "Ice-jam floods (IJFs) are a key concern in cold-region environments, where seasonal effects of river ice formation and break-up can have substantial impacts on flooding processes. Different statistical, machine learning, and process-based models have been developed to simulate IJF events in order to improve our understanding of river ice processes, to quantify potential flood magnitudes and backwater levels, and to undertake risk analysis under a changing climate. Assessment of IJF risks under future climate is limited due to constraints related to model input data. However, given the broad economic and environmental significance of IJFs and their sensitivity to a changing climate, robust modelling frameworks that can incorporate future climatic changes, and produce reliable scenarios of future IJF risks are needed. In this review paper, we discuss the probable impacts of future climate on IJFs and provide suggestions on modelling IJFs under both past and future climates. We also make recommendations around existing approaches and highlight some data and research opportunities, that could lead to further improvements in IJF modelling and prediction.", "authors": [ "Rokaya, Prabin", "Lindenschmidt, Karl-Erich", "Pietroniro, Alain", "Clark, Martyn" ], "keywords": [ "Ice-jam flood", "Future climate", "Cold regions", "Modelling", "Risk assessment" ], "year": "2022", "source": "JOURNAL OF HYDROLOGY X", "publication_type": "J", "point2d": [ -6.653720378875732, -41.0963249206543 ], "cluster": 16.0 }, { "idx": 1003, "title": "Changing River Network Synchrony Modulates Projected Increases in High Flows", "abstract": "Projections of change in high-flow extremes with global warming vary widely among, and within, large midlatitude river basins. The spatial variability of these changes is attributable to multiple causes. One possible and little-studied cause of changes in high-flow extremes is a change in the synchrony of mainstem and tributary streamflow during high-flow extremes at the mainstem-tributary confluence. We examined reconstructed and simulated naturalized daily streamflow at confluences on the Columbia River in western North America, quantifying changes in synchrony in future streamflow projections and estimating the impact of these changes on high-flow extremes. In the Columbia River basin, projected flow regimes across colder tributaries initially diverge with warming as they respond to climate change at different rates, leading to a general decrease in synchrony, and lower high-flow extremes, relative to a scenario with no changes in synchrony. Where future warming is sufficiently large to cause most subbasins upstream from a confluence to transition toward a rain-dominated, warm regime, the decreasing trend in synchrony reverses itself. At one confluence with a major tributary (the Willamette River), where the mainstem and tributary flow regimes are initially very different, warming increases synchrony and, therefore, high-flow magnitudes. These results may be generalizable to the class of large rivers with large contributions to flood risk from the snow (i.e., cold) regime, but that also receive considerable discharge from tributaries that drain warmer basins.", "authors": [ "Rupp, David E.", "Chegwidden, Oriana S.", "Nijssen, Bart", "Clark, Martyn P." ], "keywords": [ "climate change", "Columbia River", "extremes", "flood", "large rivers", "streamflow" ], "year": "2021", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -12.670215606689453, -32.332889556884766 ], "cluster": 16.0 }, { "idx": 1004, "title": "Incorporating Aleatoric Uncertainties in Lake Ice Mapping Using RADARSAT-2 SAR Images and CNNs", "abstract": "With the increasing availability of SAR imagery in recent years, more research is being conducted using deep learning (DL) for the classification of ice and open water; however, ice and open water classification using conventional DL methods such as convolutional neural networks (CNNs) is not yet accurate enough to replace manual analysis for operational ice chart mapping. Understanding the uncertainties associated with CNN model predictions can help to quantify errors and, therefore, guide efforts on potential enhancements using more-advanced DL models and/or synergistic approaches. This paper evaluates an approach for estimating the aleatoric uncertainty [a measure used to identify the noise inherent in data] of CNN probabilities to map ice and open water with a custom loss function applied to RADARSAT-2 HH and HV observations. The images were acquired during the 2014 ice season of Lake Erie and Lake Ontario, two of the five Laurentian Great Lakes of North America. Operational image analysis charts from the Canadian Ice Service (CIS), which are based on visual interpretation of SAR imagery, are used to provide training and testing labels for the CNN model and to evaluate the accuracy of the model predictions. Bathymetry, as a variable that has an impact on the ice regime of lakes, was also incorporated during model training in supplementary experiments. Adding aleatoric loss and bathymetry information improved the accuracy of mapping water and ice. Results are evaluated quantitatively (accuracy metrics) and qualitatively (visual comparisons). Ice and open water scores were improved in some sections of the lakes by using aleatoric loss and including bathymetry. In Lake Erie, the ice score was improved by similar to 2 on average in the shallow near-shore zone as a result of better mapping of dark ice (low backscatter) in the western basin. As for Lake Ontario, the open water score was improved by similar to 6 on average in the deepest profundal off-shore zone.", "authors": [ "Saberi, Nastaran", "Scott, Katharine Andrea", "Duguay, Claude" ], "keywords": [ "SAR", "RADARSAT-2", "deep learning", "convolutional neural network", "aleatoric uncertainty" ], "year": "2022", "source": "REMOTE SENSING", "publication_type": "J", "point2d": [ -79.6180191040039, 2.052029609680176 ], "cluster": 2.0 }, { "idx": 1005, "title": "Incorporating Aleatoric Uncertainties in Lake Ice Mapping Using RADARSAT-2 SAR Images and CNNs", "abstract": "With the increasing availability of SAR imagery in recent years, more research is being conducted using deep learning (DL) for the classification of ice and open water; however, ice and open water classification using conventional DL methods such as convolutional neural networks (CNNs) is not yet accurate enough to replace manual analysis for operational ice chart mapping. Understanding the uncertainties associated with CNN model predictions can help to quantify errors and, therefore, guide efforts on potential enhancements using more-advanced DL models and/or synergistic approaches. This paper evaluates an approach for estimating the aleatoric uncertainty [a measure used to identify the noise inherent in data] of CNN probabilities to map ice and open water with a custom loss function applied to RADARSAT-2 HH and HV observations. The images were acquired during the 2014 ice season of Lake Erie and Lake Ontario, two of the five Laurentian Great Lakes of North America. Operational image analysis charts from the Canadian Ice Service (CIS), which are based on visual interpretation of SAR imagery, are used to provide training and testing labels for the CNN model and to evaluate the accuracy of the model predictions. Bathymetry, as a variable that has an impact on the ice regime of lakes, was also incorporated during model training in supplementary experiments. Adding aleatoric loss and bathymetry information improved the accuracy of mapping water and ice. Results are evaluated quantitatively (accuracy metrics) and qualitatively (visual comparisons). Ice and open water scores were improved in some sections of the lakes by using aleatoric loss and including bathymetry. In Lake Erie, the ice score was improved by similar to 2 on average in the shallow near-shore zone as a result of better mapping of dark ice (low backscatter) in the western basin. As for Lake Ontario, the open water score was improved by similar to 6 on average in the deepest profundal off-shore zone.", "authors": [ "Saberi, Nastaran", "Scott, Katharine Andrea", "Duguay, Claude" ], "keywords": [ "SAR", "RADARSAT-2", "deep learning", "convolutional neural network", "aleatoric uncertainty" ], "year": "2022", "source": "REMOTE SENSING", "publication_type": "J", "point2d": [ -79.6180191040039, 2.052029609680176 ], "cluster": 2.0 }, { "idx": 1006, "title": "Effects of quality controlled measured and re-analysed meteorological data on the performance of water temperature simulations", "abstract": "One of the most prominent sources of error and uncertainty in water quality modelling results is the input data. In this study, data from three meteorological databases were used to test the performance of a water temperature model of Lake Diefenbaker: the data from Environment and Climate Change Canada (ECCC) had long-term quality control history (>20 years); the data from the AccuWeather had short-term quality control history (<10 years), and the data from the MeteoBlue database were modelled values. The CE-QUAL-W2 hydrodynamic and water quality model was used for this study. The model was calibrated by adjusting model coefficients controlling the amounts of measured solar radiation and wind that reach the surface of the water. The sensitivity results showed very similar performances, with slightly better performances (root mean square root difference of +/- 0.1) with the ECCC data followed by the MeteoBlue data and thereafter by the AccuWeather data.", "authors": [ "Sadeghian, Amir", "Hudson, Jeff", "Lindenschmidt, Karl-Erich" ], "keywords": [ "Lake Diefenbaker", "hydrodynamic modelling", "meteorological data", "model calibration" ], "year": "2022", "source": "HYDROLOGICAL SCIENCES JOURNAL", "publication_type": "J", "point2d": [ -32.13785171508789, -21.90186882019043 ], "cluster": 16.0 }, { "idx": 1007, "title": "VISCOUS: A Variance-Based Sensitivity Analysis Using Copulas for Efficient Identification of Dominant Hydrological Processes", "abstract": "Global sensitivity analysis (GSA) has long been recognized as an indispensable tool for model analysis. GSA has been extensively used for model simplification, identifiability analysis, and diagnostic tests. Nevertheless, computationally efficient methodologies are needed for GSA, not only to reduce the computational overhead, but also to improve the quality and robustness of the results. This is especially the case for process-based hydrologic models, as their simulation time typically exceeds the computational resources available for a comprehensive GSA. To overcome this computational barrier, we propose a data-driven method called VISCOUS, variance-based sensitivity analysis using copulas. VISCOUS uses Gaussian mixture copulas to approximate the joint probability density function of a given set of input-output pairs for estimating the variance-based sensitivity indices. Our method identifies dominant hydrologic factors by recycling existing input-output data, and thus can deal with arbitrary sample sets drawn from the input-output space. We used two hydrologic models of increasing complexity (HBV and VIC) to assess the performance of VISCOUS. Our results confirm that VISCOUS and the conventional variance-based method can detect similar important and unimportant factors. Furthermore, the VISCOUS method can substantially reduce the computational cost required for sensitivity analysis. Our proposed method is particularly useful for process-based models with many uncertain parameters, large domain size, and high spatial and temporal resolution.", "authors": [ "Sheikholeslami, Razi", "Gharari, Shervan", "Papalexiou, Simon Michael", "Clark, Martyn P." ], "keywords": [ "global sensitivity analysis", "uncertainty analysis", "copula model", "variance-based sensitivity analysis", "process-based hydrologic models", "computationally expensive models" ], "year": "2021", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 3.352332830429077, -73.74889373779297 ], "cluster": 16.0 }, { "idx": 1008, "title": "How Do Climate and Catchment Attributes Influence Flood Generating Processes? A Large-Sample Study for 671 Catchments Across the Contiguous USA", "abstract": "Hydrometeorological flood generating processes (excess rain, short rain, long rain, snowmelt, and rain-on-snow) underpin our understanding of flood behavior. Knowledge about flood generating processes improves hydrological models, flood frequency analysis, estimation of climate change impact on floods, etc. Yet, not much is known about how climate and catchment attributes influence the spatial distribution of flood generating processes. This study aims to offer a comprehensive and structured approach to close this knowledge gap. We employ a large sample approach (671 catchments across the contiguous United States) and evaluate how catchment attributes and climate attributes influence the distribution of flood processes. We use two complementary approaches: A statistics-based approach which compares attribute frequency distributions of different flood processes; and a random forest model in combination with an interpretable machine learning approach (accumulated local effects [ALE]). The ALE method has not been used often in hydrology, and it overcomes a significant obstacle in many statistical methods, the confounding effect of correlated catchment attributes. As expected, we find climate attributes (fraction of snow, aridity, precipitation seasonality, and mean precipitation) to be most influential on flood process distribution. However, the influence of catchment attributes varies both with flood generating process and climate type. We also find flood processes can be predicted for ungauged catchments with relatively high accuracy (R-2 between 0.45 and 0.9). The implication of these findings is flood processes should be considered for future climate change impact studies, as the effect of changes in climate on flood characteristics varies between flood processes.", "authors": [ "Stein, L.", "Clark, M. P.", "Knoben, W. J. M.", "Pianosi, F.", "Woods, R. A." ], "keywords": [ "accumulated local effects", "catchment attributes", "climate", "flood generating process", "interpretable machine learning", "large sample" ], "year": "2021", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -9.32278823852539, -61.93935012817383 ], "cluster": 16.0 }, { "idx": 1009, "title": "SC-Earth: A Station-Based Serially Complete Earth Dataset from 1950 to 2019", "abstract": "Meteorological data from ground stations suffer from temporal discontinuities caused by missing values and short measurement periods. Gap-filling and reconstruction techniques have proven to be effective in producing serially complete station datasets (SCDs) that are used for a myriad of meteorological applications (e.g., developing gridded meteorological datasets and validating models). To our knowledge, all SCDs are developed at regional scales. In this study, we developed the serially complete Earth (SC-Earth) dataset, which provides daily precipitation, mean temperature, temperature range, dewpoint temperature, and wind speed data from 1950 to 2019. SC-Earth utilizes raw station data from the Global Historical Climatology Network-Daily (GHCN-D) and the Global Surface Summary of the Day (GSOD). A unified station repository is generated based on GHCN-D and GSOD after station merging and strict quality control. ERAS is optimally matched with station data considering the time shift issue and then used to assist the global gap filling. SC-Earth is generated by merging estimates from 15 strategies based on quantile mapping, spatial interpolation, machine learning, and multistrategy merging. The final estimates are bias corrected using a combination of quantile mapping and quantile delta mapping. Comprehensive validation demonstrates that SC-Earth has high accuracy around the globe, with degraded quality in the tropics and oceanic islands due to sparse station networks, strong spatial precipitation gradients, and degraded ERAS estimates. Meanwhile, SC-Earth inherits potential limitations such as inhomogeneity and precipitation undercatch from raw station data, which may affect its application in some cases. Overall, the high-quality and high-density SC-Earth dataset will benefit research in fields of hydrology, ecology, meteorology, and climate. The dataset is available at https://zenodo.org/record/4762586.", "authors": [ "Tang, Guoqiang", "Clark, Martyn P.", "Papalexiou, Simon Michael" ], "keywords": [ "Precipitation", "Temperature", "Wind", "Databases", "Machine learning", "In situ atmospheric observations" ], "year": "2021", "source": "JOURNAL OF CLIMATE", "publication_type": "J", "point2d": [ -44.06272506713867, -53.50959777832031 ], "cluster": 14.0 }, { "idx": 1010, "title": "EM-Earth The Ensemble Meteorological Dataset for Planet Earth", "abstract": "Gridded meteorological estimates are essential for many applications. Most existing meteorological datasets are deterministic and have limitations in representing the inherent uncertainties from both the data and methodology used to create gridded products. We develop the Ensemble Meteorological Dataset for Planet Earth (EM-Earth) for precipitation, mean daily temperature, daily temperature range, and dewpoint temperature at 0.1 degrees spatial resolution over global land areas from 1950 to 2019. EM-Earth provides hourly/daily deterministic estimates, and daily probabilistic estimates (25 ensemble members), to meet the diverse requirements of hydrometeorological applications. To produce EM-Earth, we first developed a station-based Serially Complete Earth (SC-Earth) dataset, which removes the temporal discontinuities in raw station observations. Then, we optimally merged SC-Earth station data and ERA5 estimates to generate EM-Earth deterministic estimates and their uncertainties. The EM-Earth ensemble members are produced by sampling from parametric probability distributions using spatiotemporally correlated random fields. The EM- Earth dataset is evaluated by leave-one-out validation, using independent evaluation stations, and comparing it with many widely used datasets. The results show that EM-Earth is better in Europe, North America, and Oceania than in Africa, Asia, and South America, mainly due to differences in the available stations and differences in climate conditions. Probabilistic spatial meteorological datasets are particularly valuable in regions with large meteorological uncertainties, where almost all existing deterministic datasets face great challenges in obtaining accurate estimates.", "authors": [ "Tang, Guoqiang", "Clark, Martyn P.", "Papalexiou, Simon Michael" ], "keywords": [ "Atmosphere", "Precipitation", "Temperature", "Data processing/distribution", "Databases" ], "year": "2022", "source": "BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY", "publication_type": "J", "point2d": [ -43.46916198730469, -52.098201751708984 ], "cluster": 14.0 }, { "idx": 1011, "title": "EMDNA: an Ensemble Meteorological Dataset for North America", "abstract": "Probabilistic methods are useful to estimate the uncertainty in spatial meteorological fields (e.g., the uncertainty in spatial patterns of precipitation and temperature across large domains). In ensemble probabilistic methods, equally plausible ensemble members are used to approximate the probability distribution, hence the uncertainty, of a spatially distributed meteorological variable conditioned to the available information. The ensemble members can be used to evaluate the impact of uncertainties in spatial meteorological fields for a myriad of applications. This study develops the Ensemble Meteorological Dataset for North America (EMDNA). EMDNA has 100 ensemble members with daily precipitation amount, mean daily temperature, and daily temperature range at 0.1 degrees spatial resolution (approx. 10 km grids) from 1979 to 2018, derived from a fusion of station observations and reanalysis model outputs. The station data used in EMDNA are from a serially complete dataset for North America (SCDNA) that fills gaps in precipitation and temperature measurements using multiple strategies. Outputs from three reanalysis products are regridded, corrected, and merged using Bayesian model averaging. Optimal interpolation (OI) is used to merge station- and reanalysis-based estimates. EMDNA estimates are generated using spatiotemporally correlated random fields to sample from the OI estimates. Evaluation results show that (1) the merged reanalysis estimates outperform raw reanalysis estimates, particularly in high latitudes and mountainous regions; (2) the OI estimates are more accurate than the reanalysis and station-based regression estimates, with the most notable improvements for precipitation evident in sparsely gauged regions; and (3) EMDNA estimates exhibit good performance according to the diagrams and metrics used for probabilistic evaluation. We discuss the limitations of the current framework and highlight that further research is needed to improve ensemble meteorological datasets. Overall, EMDNA is expected to be useful for hydrological and meteorological applications in North America. The entire dataset and a teaser dataset (a small subset of EMDNA for easy download and preview) are available at https://doi.org/10.20383/101.0275 (Tang et al., 2020a).", "authors": [ "Tang, Guoqiang", "Clark, Martyn P.", "Papalexiou, Simon Michael", "Newman, Andrew J.", "Wood, Andrew W.", "Brunet, Dominique", "Whitfield, Paul H." ], "keywords": [ "" ], "year": "2021", "source": "EARTH SYSTEM SCIENCE DATA", "publication_type": "J", "point2d": [ -42.51901626586914, -52.68696975708008 ], "cluster": 14.0 }, { "idx": 1012, "title": "Buffalo Pound Lake-Modelling Water Resource Management Scenarios of a Large Multi-Purpose Prairie Reservoir", "abstract": "Water quality models are an emerging tool in water management to understand and inform decisions related to eutrophication. This study tested flow scenario effects on the water quality of Buffalo Pound Lake-a eutrophic reservoir supplying water for approximately 25% of Saskatchewan's population. The model CE-QUAL-W2 was applied to assess the impact of inter-basin water diversion after the impounded lake received high inflows from local runoff. Three water diversion scenarios were tested: continuous flow, immediate release after nutrient loading increased, and a timed release initiated when water levels returned to normal operating range. Each scenario was tested at three different transfer flow rates. The transfers had a dilution effect but did not affect the timing of the nutrient peaks in the upstream portion of the lake. In the lake's downstream section, nutrients peaked at similar concentrations as the base model, but peaks arrived earlier in the season and attenuated rapidly. Results showed greater variation among scenarios in wet years compared to dry years. Dependent on the timing and quantity of water transferred, some but not all water quality parameters are predicted to improve along with the water diversion flows over the period tested. The results suggest that it is optimal to transfer water while local watershed runoff is minimal.", "authors": [ "Terry, Julie", "Davies, John-Mark", "Lindenschmidt, Karl-Erich" ], "keywords": [ "CE-QUAL-W2", "water quality model", "reservoir management", "water transfers" ], "year": "2022", "source": "WATER", "publication_type": "J", "point2d": [ 33.963741302490234, -10.359856605529785 ], "cluster": 10.0 }, { "idx": 1013, "title": "Hydrologic Model Sensitivity to Temporal Aggregation of Meteorological Forcing Data: A Case Study for the Contiguous United States", "abstract": "Surface meteorological analyses are an essential input (termed forcing) for hydrologic modeling. This study investigated the sensitivity of different hydrologic model configurations to temporal variations of seven forcing variables (precipitation rate, air temperature, longwave radiation, specific humidity, shortwave radiation, wind speed, and air pressure). Specifically, the effects of temporally aggregating hourly forcings to hourly daily average forcings were examined. The analysis was based on 14 hydrological outputs from the Structure for Unifying Multiple Modeling Alternatives (SUMMA) model for the 671 Catchment Attributes and Meteorology for Large-Sample Studies (CAMELS) basins across the contiguous United States (CONUS). Results demonstrated that the hydrologic model sensitivity to temporally aggregating the forcing inputs varies across model output variables and model locations. We used Latin hypercube sampling to sample model parameters from eight combinations of three influential model physics choices (three model decisions with two options for each decision, i.e., eight model configurations). Results showed that the choice of model physics can change the relative influence of forcing on model outputs and the forcing importance may not be dependent on the parameter space. This allows for model output sensitivity to forcing aggregation to be tested prior to parameter calibration. More generally, this work provides a comprehensive analysis of the dependence of modeled outcomes on input forcing behavior, providing insight into the regional variability of forcing variable dominance on modeled outputs across CONUS.", "authors": [ "Van Beusekom, Ashley E.", "Hay, Lauren E.", "Bennett, Andrew R.", "Choi, Young-Don", "Clark, Martyn P.", "Goodall, Jon L.", "Li, Zhiyu", "Maghami, Iman", "Nijssen, Bart", "Wood, Andrew W." ], "keywords": [ "Forcing", "Hydrology", "Hydrologic models" ], "year": "2022", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -6.861558437347412, -65.24291229248047 ], "cluster": 16.0 }, { "idx": 1014, "title": "Simulating the Impact of Global Reservoir Expansion on the Present-Day Climate", "abstract": "Reservoir expansion over the last century has largely affected downstream flow characteristics. Yet very little is known about the impacts of reservoir expansion on the climate. Here, we implement reservoir construction in the Community Land Model by enabling dynamical lake area changes, while conserving mass and energy. Transient global lake and reservoir extent are prescribed from the HydroLAKES and Global Reservoir and Dam databases. Land-only simulations covering the 20th century with reservoir expansion enabled, highlight increases in terrestrial water storage and decreases in albedo matching the increase in open water area. The comparison of coupled simulations including and excluding reservoirs shows only limited influence of reservoirs on global temperatures and the surface energy balance, but demonstrates substantial responses locally, in particular where reservoirs make up a large fraction of the grid cell. In those locations, reservoirs dampen the diurnal temperature range by up to -1.5 K (for reservoirs covering >15% of the grid cell), reduce temperature extremes, and moderate the seasonal temperature cycle. This study provides a first step towards a coupled representation of reservoirs in Earth System Models.", "authors": [ "Vanderkelen, I", "Lipzig, N. P. M.", "Sacks, W. J.", "Lawrence, D. M.", "Clark, M. P.", "Mizukami, N.", "Pokhrel, Y.", "Thiery, W." ], "keywords": [ "" ], "year": "2021", "source": "JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES", "publication_type": "J", "point2d": [ 23.683881759643555, -57.01109313964844 ], "cluster": 16.0 }, { "idx": 1015, "title": "Canadian historical Snow Water Equivalent dataset (CanSWE, 1928-2020)", "abstract": "In situ measurements of water equivalent of snow cover (SWE) - the vertical depth of water that would be obtained if all the snow cover melted completely - are used in many applications including water management, flood forecasting, climate monitoring, and evaluation of hydrological and land surface models. The Canadian historical SWE dataset (CanSWE) combines manual and automated pan-Canadian SWE observations collected by national, provincial and territorial agencies as well as hydropower companies. Snow depth (SD) and bulk snow density (defined as the ratio of SWE to SD) are also included when available. This new dataset supersedes the previous Canadian Historical Snow Survey (CHSSD) dataset published by Brown et al. (2019), and this paper describes the efforts made to correct metadata, remove duplicate observations and quality control records. The CanSWE dataset was compiled from 15 different sources and includes SWE information for all provinces and territories that measure SWE. Data were updated to July 2020, and new historical data from the Government of Northwest Territories, Government of Newfoundland and Labrador, Saskatchewan Water Security Agency, and Hydro-Quebec were included. CanSWE includes over 1 million SWE measurements from 2607 different locations across Canada over the period 1928-2020. It is publicly available at https://doi.org/10.5281/zenodo.4734371 (Vionnet et al., 2021).", "authors": [ "Vionnet, Vincent", "Mortimer, Colleen", "Brady, Mike", "Arnal, Louise", "Brown, Ross" ], "keywords": [ "" ], "year": "2021", "source": "EARTH SYSTEM SCIENCE DATA", "publication_type": "J", "point2d": [ -36.45477294921875, -4.966974258422852 ], "cluster": 8.0 }, { "idx": 1016, "title": "Advances in modelling large river basins in cold regions with Modelisation Environmentale Communautaire-Surface and Hydrology (MESH), the Canadian hydrological land surface scheme", "abstract": "Cold regions provide water resources for half the global population yet face rapid change. Their hydrology is dominated by snow, ice and frozen soils, and climate warming is having profound effects. Hydrological models have a key role in predicting changing water resources but are challenged in cold regions. Ground-based data to quantify meteorological forcing and constrain model parameterization are limited, while hydrological processes are complex, often controlled by phase change energetics. River flows are impacted by poorly quantified human activities. This paper discusses the scientific and technical challenges of the large-scale modelling of cold region systems and reports recent modelling developments, focussing on MESH, the Canadian community hydrological land surface scheme. New cold region process representations include improved blowing snow transport and sublimation, lateral land-surface flow, prairie pothole pond storage dynamics, frozen ground infiltration and thermodynamics, and improved glacier modelling. New algorithms to represent water management include multistage reservoir operation. Parameterization has been supported by field observations and remotely sensed data; new methods for parameter identification have been used to evaluate model uncertainty and support regionalization. Additionally, MESH has been linked to broader decision-support frameworks, including river ice simulation and hydrological forecasting. The paper also reports various applications to the Saskatchewan and Mackenzie River basins in western Canada (0.4 and 1.8 million km(2)). These basins arise in glaciated mountain headwaters, are partly underlain by permafrost, and include remote and incompletely understood forested, wetland, agricultural and tundra ecoregions. These illustrate the current capabilities and limitations of cold region modelling, and the extraordinary challenges to prediction, including the need to overcoming biases in forcing data sets, which can have disproportionate effects on the simulated hydrology.", "authors": [ "Wheater, Howard S.", "Pomeroy, John W.", "Pietroniro, Alain", "Davison, Bruce", "Elshamy, Mohamed", "Yassin, Fuad", "Rokaya, Prabin", "Fayad, Abbas", "Tesemma, Zelalem", "Princz, Daniel", "Loukili, Youssef", "DeBeer, Chris M.", "Ireson, Andrew M.", "Razavi, Saman", "Lindenschmidt, Karl-Erich", "Elshorbagy, Amin", "MacDonald, Matthew", "Abdelhamed, Mohamed", "Haghnegahdar, Amin", "Bahrami, Ala" ], "keywords": [ "cold regions", "hydrological modelling", "large river basins" ], "year": "2022", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -22.728492736816406, -13.167842864990234 ], "cluster": 12.0 }, { "idx": 1017, "title": "Climate change impacts on ice jam behavior in an inland delta: a new ice jam projection framework", "abstract": "Ice jams are impacted by several climatic factors that are likely to change under a future warming climate. Due to the complexity of river ice phenology, projection of future ice jams is challenging. However, it is important to be able to project future ice jam behavior. Additionally, ice jam research is limited by the shortage of long-term monitoring data. In this paper, a novel framework for projecting future ice jam behavior is developed and implemented for ice jams in a data-sparse region, the Slave River Delta, NWT, Canada, situated in the Mackenzie River Basin (MRB). This framework employs both historical records and future hydro-meteorological data, acquired from climate and hydrological models, to drive the river ice models and quantify climate-induced influences on ice jams. Ice jam behavior analysis is based on three outputs of the framework: potential of river ice jamming, ice jam initiation date, and the stage frequency distribution of backwater elevation induced by ice jams. Trends of later ice jam initiation and decreased possibility of ice jam formation are projected, but ice jamming events in the Slave River Delta are likely to be more severe and cause higher backwater levels.", "authors": [ "Zhang, Fan", "Elshamy, Mohamed", "Lindenschmidt, Karl-Erich" ], "keywords": [ "Climate change projection", "Future ice jam behavior projection framework", "Modeling", "The Slave River Delta" ], "year": "2022", "source": "CLIMATIC CHANGE", "publication_type": "J", "point2d": [ -7.826854228973389, -39.21629333496094 ], "cluster": 1.0 }, { "idx": 1018, "title": "The Perils of Regridding: Examples Using a Global Precipitation Dataset", "abstract": "Significance StatementRegridding has a substantial impact on the statistical properties of precipitation. The impacts of regridding vary spatially as well as at different quantiles. Regridding should be used with great caution. Gridded precipitation datasets are used in many applications such as the analysis of climate variability/change and hydrological modeling. Regridding precipitation datasets is common for model coupling (e.g., coupling atmospheric and hydrological models) or comparing different models and datasets. However, regridding can considerably alter precipitation statistics. In this global analysis, the effects of regridding a precipitation dataset are emphasized using three regridding methods (first-order conservative, bilinear, and distance-weighted averaging). The differences between the original and regridded dataset are substantial and greatest at high quantiles. Differences of 46 and 0.13 mm are noted in high (0.95) and low (0.05) quantiles, respectively. The impacts of regridding vary spatially for land and oceanic regions; there are substantial differences at high quantiles in tropical land regions, and at low quantiles in polar regions. These impacts are approximately the same for different regridding methods. The differences increase with the size of the grid at higher quantiles and vice versa for low quantiles. As the grid resolution increases, the difference between original and regridded data declines, yet the shift size dominates for high quantiles for which the differences are higher. While regridding is often necessary to use gridded precipitation datasets, it should be used with great caution for fine resolutions (e.g., daily and subdaily), because it can severely alter the statistical properties of precipitation, specifically at high and low quantiles.", "authors": [ "Rajulapati, Chandra Rupa", "Papalexiou, Simon Michael", "Clark, Martyn P.", "Pomeroy, John W." ], "keywords": [ "Precipitation", "Data processing", "Interpolation schemes" ], "year": "2021", "source": "JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY", "publication_type": "J", "point2d": [ -46.820831298828125, -54.55061721801758 ], "cluster": 14.0 }, { "idx": 1019, "title": "Advances in the simulation of nutrient dynamics in cold climate agricultural basins: Developing new nitrogen and phosphorus modules for the Cold Regions Hydrological Modelling Platform", "abstract": "Excess nutrients in aquatic ecosystems is a major water quality problem globally. Worsening eutrophication issues are notable in cold temperate areas, with pervasive problems in many agriculturally dominated catchments. Predicting nutrient export to rivers and lakes is particularly difficult in cold agricultural environments because of challenges in modelling snow, soil, frozen ground, climate, and anthropogenic controls. Previous research has shown that the use of many popular small basin nutrient models can be problematic in cold regions due to poor representation of cold region hydrology. In this study, the Cold Regions Hydrological Modelling Platform (CRHM), a modular modelling system, which has been widely deployed across Canada and cold regions worldwide, was used to address this problem. CRHM was extended to simulate biogeochemical and transport processes for nitrogen and phosphorus through a complex of new process-based modules that represent physicochemical processes in snow, soil and freshwater. Agricultural practices such as tillage and fertilizer application, which strongly impact the availability and release of soil nutrients, can be explicitly represented in the model. A test case in an agricultural basin draining towards Lake Winnipeg shows that the model can capture the extreme hydrology and nutrient load variability of small agricultural basins at hourly time steps. It was demonstrated that fine temporal resolutions are an essential modelling requisite to capture strong concentration changes in agricultural tributaries in cold agricultural environments. Within these ephemeral and intermittent streams, on average, 30%, 31%, 20%, and 16% of the total annual load of nitrate (NO3), ammonium (NH4), soluble reactive phosphorus (SRP), and particulate phosphorous (partP)NO3, NH4, SRP and partP occurred during the episodic snowmelt freshet (similar to 9 days, accounting for 21% of the annual flow), but shows extreme temporal variation. The new nutrient modules are critical tools for predicting nutrient export from small agricultural drainage basins in cold climates via better representation of key hydrological processes, and a temporal resolution more suited to capture dynamics of ephemeral and intermittent streams.", "authors": [ "Costa, Diogo", "Pomeroy, John W.", "Brown, Tom", "Baulch, Helen", "Elliott, Jane", "Macrae, Merrin" ], "keywords": [ "Catchment nutrients", "Hydrology", "Cold regions", "Simulation", "Management" ], "year": "2021", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ 27.461599349975586, 12.819549560546875 ], "cluster": 10.0 }, { "idx": 1020, "title": "Agricultural phosphorus surplus trajectories for Ontario, Canada (1961-2016), and erosional export risk", "abstract": "Management strategies aimed at reducing nutrient enrichment of surface waters may be hampered by nutrient legacies that have accumulated in the landscape. Here, we apply the Net Anthropogenic Phosphorus Input (NAPI) model to reconstruct the historical phosphorus (P) input trajectories for the province of Ontario, which encompasses the Canadian portion of the drainage basin of the Laurentian Great Lakes (LGL). NAPI considers P inputs from detergent, human and livestock waste, fertilizer inputs, and P outputs by crop uptake. During the entire time period considered, from1961 to 2016, Ontario experienced positive annual NAPI values. Despite a generally downward NAPI trend since the late 1970s, the lower LGL, especially Lake Erie, continue to be plagued by algal blooms. When comparing NAPI results and river monitoring data for the period 2003 to 2013, P discharged by Canadian rivers into Lake Erie only accounts for 12.5% of the NAPI supplied to the watersheds' agricultural areas. Thus, over 85% of the agricultural NAPI is retained in the watersheds where it contributes to a growing P legacy, primarily as soil P. The slow release of legacy P therefore represents a long-term risk to the recovery of the lake. To help mitigate this risk, we present a methodology to spatially map out the source areas with the greatest potential of erosional export of legacy soil P to surface waters. These areas should be prioritized in soil conservation efforts. (c) 2021 Elsevier B.V. All rights reserved.", "authors": [ "Van Staden, Tamara L.", "Van Meter, Kim J.", "Basu, Nandita B.", "Parsons, Chris T.", "Akbarzadeh, Zahra", "Van Cappellen, Philippe" ], "keywords": [ "Nutrient legacies", "Phosphorus", "NAPI", "Ontario", "Lake Erie", "Erosional risk" ], "year": "2022", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 41.54362869262695, 11.491286277770996 ], "cluster": 10.0 }, { "idx": 1021, "title": "A stochastic modelling approach to forecast real-time ice jam flood severity along the transborder (New Brunswick/Maine) Saint John River of North America", "abstract": "In the higher latitudes of the northern hemisphere, ice jam related flooding can result in millions of dollars of property damages, loss of human life and adverse impacts on ecology. Since ice-jam formation mechanism is stochastic and depends on numerous unpredictable hydraulic and river ice factors, ice-jam associated flood forecasting is a very challenging task. A stochastic modelling framework was developed to forecast real-time ice jam flood severity along the transborder (New Brunswick/Maine) Saint John River of North America during the spring breakup 2021. Modelisation environnementale communautaire-surface hydrology (MESH), a semi-distributed physically-based land-surface hydrological modelling system was used to acquire a 10-day flow forecast. A Monte-Carlo analysis (MOCA) framework was applied to simulate hundreds of possible ice-jam scenarios for the model domain from Fort Kent to Grand Falls using a hydrodynamic river ice model, RIVICE. First, a 10-day outlook was simulated to provide insight on the severity of ice jam flooding during spring breakup. Then, 3-day forecasts were modelled to provide longitudinal profiles of exceedance probabilities of ice jam flood staging along the river during the ice-cover breakup. Overall, results show that the stochastic approach performed well to estimate maximum probable ice-jam backwater level elevations for the spring 2021 breakup season.", "authors": [ "Das, Apurba", "Budhathoki, Sujata", "Lindenschmidt, Karl-Erich" ], "keywords": [ "Ice jam", "Flood forecasting", "Stochastic approach", "Flood outlook" ], "year": "2022", "source": "STOCHASTIC ENVIRONMENTAL RESEARCH AND RISK ASSESSMENT", "publication_type": "J", "point2d": [ -4.40528678894043, -42.303367614746094 ], "cluster": 16.0 }, { "idx": 1022, "title": "Joint effects of climate, tree size, and year on annual tree growth derived from tree-ring records of ten globally distributed forests", "abstract": "Tree rings provide an invaluable long-term record for understanding how climate and other drivers shape tree growth and forest productivity. However, conventional tree-ring analysis methods were not designed to simultaneously test effects of climate, tree size, and other drivers on individual growth. This has limited the potential to test ecologically relevant hypotheses on tree growth sensitivity to environmental drivers and their interactions with tree size. Here, we develop and apply a new method to simultaneously model nonlinear effects of primary climate drivers, reconstructed tree diameter at breast height (DBH), and calendar year in generalized least squares models that account for the temporal autocorrelation inherent to each individual tree's growth. We analyze data from 3811 trees representing 40 species at 10 globally distributed sites, showing that precipitation, temperature, DBH, and calendar year have additively, and often interactively, influenced annual growth over the past 120 years. Growth responses were predominantly positive to precipitation (usually over >= 3-month seasonal windows) and negative to temperature (usually maximum temperature, over <= 3-month seasonal windows), with concave-down responses in 63% of relationships. Climate sensitivity commonly varied with DBH (45% of cases tested), with larger trees usually more sensitive. Trends in ring width at small DBH were linked to the light environment under which trees established, but basal area or biomass increments consistently reached maxima at intermediate DBH. Accounting for climate and DBH, growth rate declined over time for 92% of species in secondary or disturbed stands, whereas growth trends were mixed in older forests. These trends were largely attributable to stand dynamics as cohorts and stands age, which remain challenging to disentangle from global change drivers. By providing a parsimonious approach for characterizing multiple interacting drivers of tree growth, our method reveals a more complete picture of the factors influencing growth than has previously been possible.", "authors": [ "Anderson-Teixeira, Kristina J.", "Herrmann, Valentine", "Rollinson, Christine R.", "Gonzalez, Bianca", "Gonzalez-Akre, Erika B.", "Pederson, Neil", "Alexander, M. Ross", "Allen, Craig D.", "Alfaro-Sanchez, Raquel", "Awada, Tala", "Baltzer, Jennifer L.", "Baker, Patrick J.", "Birch, Joseph D.", "Bunyavejchewin, Sarayudh", "Cherubini, Paolo", "Davies, Stuart J.", "Dow, Cameron", "Helcoski, Ryan", "Kaspar, Jakub", "Lutz, James A.", "Margolis, Ellis Q.", "Maxwell, Justin T.", "McMahon, Sean M.", "Piponiot, Camille", "Russo, Sabrina E.", "Samonil, Pavel", "Sniderhan, Anastasia E.", "Tepley, Alan J.", "Vasickova, Ivana", "Vlam, Mart", "Zuidema, Pieter A." ], "keywords": [ "climate sensitivity", "environmental change", "Forest Global Earth Observatory (ForestGEO)", "generalized least squares (GLS)", "nonlinear", "tree diameter", "tree rings" ], "year": "2022", "source": "GLOBAL CHANGE BIOLOGY", "publication_type": "J", "point2d": [ -43.261295318603516, 69.28343963623047 ], "cluster": 17.0 }, { "idx": 1023, "title": "Joint effects of climate, tree size, and year on annual tree growth derived from tree-ring records of ten globally distributed forests", "abstract": "Tree rings provide an invaluable long-term record for understanding how climate and other drivers shape tree growth and forest productivity. However, conventional tree-ring analysis methods were not designed to simultaneously test effects of climate, tree size, and other drivers on individual growth. This has limited the potential to test ecologically relevant hypotheses on tree growth sensitivity to environmental drivers and their interactions with tree size. Here, we develop and apply a new method to simultaneously model nonlinear effects of primary climate drivers, reconstructed tree diameter at breast height (DBH), and calendar year in generalized least squares models that account for the temporal autocorrelation inherent to each individual tree's growth. We analyze data from 3811 trees representing 40 species at 10 globally distributed sites, showing that precipitation, temperature, DBH, and calendar year have additively, and often interactively, influenced annual growth over the past 120 years. Growth responses were predominantly positive to precipitation (usually over >= 3-month seasonal windows) and negative to temperature (usually maximum temperature, over <= 3-month seasonal windows), with concave-down responses in 63% of relationships. Climate sensitivity commonly varied with DBH (45% of cases tested), with larger trees usually more sensitive. Trends in ring width at small DBH were linked to the light environment under which trees established, but basal area or biomass increments consistently reached maxima at intermediate DBH. Accounting for climate and DBH, growth rate declined over time for 92% of species in secondary or disturbed stands, whereas growth trends were mixed in older forests. These trends were largely attributable to stand dynamics as cohorts and stands age, which remain challenging to disentangle from global change drivers. By providing a parsimonious approach for characterizing multiple interacting drivers of tree growth, our method reveals a more complete picture of the factors influencing growth than has previously been possible.", "authors": [ "Anderson-Teixeira, Kristina J.", "Herrmann, Valentine", "Rollinson, Christine R.", "Gonzalez, Bianca", "Gonzalez-Akre, Erika B.", "Pederson, Neil", "Alexander, M. Ross", "Allen, Craig D.", "Alfaro-Sanchez, Raquel", "Awada, Tala", "Baltzer, Jennifer L.", "Baker, Patrick J.", "Birch, Joseph D.", "Bunyavejchewin, Sarayudh", "Cherubini, Paolo", "Davies, Stuart J.", "Dow, Cameron", "Helcoski, Ryan", "Kaspar, Jakub", "Lutz, James A.", "Margolis, Ellis Q.", "Maxwell, Justin T.", "McMahon, Sean M.", "Piponiot, Camille", "Russo, Sabrina E.", "Samonil, Pavel", "Sniderhan, Anastasia E.", "Tepley, Alan J.", "Vasickova, Ivana", "Vlam, Mart", "Zuidema, Pieter A." ], "keywords": [ "climate sensitivity", "environmental change", "Forest Global Earth Observatory (ForestGEO)", "generalized least squares (GLS)", "nonlinear", "tree diameter", "tree rings" ], "year": "2022", "source": "GLOBAL CHANGE BIOLOGY", "publication_type": "J", "point2d": [ -43.60824966430664, 69.58641052246094 ], "cluster": 17.0 }, { "idx": 1024, "title": "Increasing fire and the decline of fire adapted black spruce in the boreal forest", "abstract": "Intensifying wildfire activity and climate change can drive rapid forest compositional shifts. In boreal North America, black spruce shapes forest flammability and depends on fire for regeneration. This relationship has helped black spruce maintain its dominance through much of the Holocene. However, with climate change and more frequent and severe fires, shifts away from black spruce dominance to broadleaf or pine species are emerging, with implications for ecosystem functions including carbon sequestration, water and energy fluxes, and wildlife habitat. Here, we predict that such reductions in black spruce after fire may already be widespread given current trends in climate and fire. To test this, we synthesize data from 1,538 field sites across boreal North America to evaluate compositional changes in tree species following 58 recent fires (1989 to 2014). While black spruce was resilient following most fires (62%), loss of resilience was common, and spruce regeneration failed completely in 18% of 1,140 black spruce sites. In contrast, postfire regeneration never failed in forests dominated by jack pine, which also possesses an aerial seed bank, or broad-leaved trees. More complete combustion of the soil organic layer, which often occurs in better-drained landscape positions and in dryer duff, promoted compositional changes throughout boreal North America. Forests in western North America, however, were more vulnerable to change due to greater long-term climate moisture deficits. While we find considerable remaining resilience in black spruce forests, predicted increases in climate moisture deficits and fire activity will erode this resilience, pushing the system toward a tipping point that has not been crossed in several thousand years.", "authors": [ "Baltzer, Jennifer L.", "Day, Nicola J.", "Walker, Xanthe J.", "Greene, David", "Mack, Michelle C.", "Alexander, Heather D.", "Arseneault, Dominique", "Barnes, Jennifer", "Bergeron, Yves", "Boucher, Yan", "Bourgeau-Chavez, Laura", "Brown, Carissa D.", "Carriere, Suzanne", "Howard, Brian K.", "Gauthier, Sylvie", "Parisien, Marc-Andre", "Reid, Kirsten A.", "Rogers, Brendan M.", "Roland, Carl", "Sirois, Luc", "Stehn, Sarah", "Thompson, Dan K.", "Turetsky, Merritt R.", "Veraverbeke, Sander", "Whitman, Ellen", "Yang, Jian", "Johnstone, Jill F." ], "keywords": [ "wildfire", "ecological state change", "resilience", "climate change", "tree regeneration" ], "year": "2021", "source": "PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA", "publication_type": "J", "point2d": [ -25.919702529907227, 72.30117797851562 ], "cluster": 15.0 }, { "idx": 1025, "title": "Application of L-band SAR for mapping tundra shrub biomass, leaf area index, and rainfall interception", "abstract": "Rapid shrub expansion has been observed across the Arctic, driving a need for regional-scale estimates of shrub biomass and shrub-mediated ecosystem processes such as rainfall interception. Synthetic-Aperture Radar (SAR) data have been shown sensitive to vegetation canopy characteristics across many ecosystems, thereby potentially providing an accurate and cost-effective tool to quantify shrub canopy cover. This study evaluated the sensitivity of L-band Advanced Land Observing Satellite 2 (ALOS-2) data to the aboveground biomass and Leaf Area Index (LAI) of dwarf birch and alder in the Trail Valley Creek watershed, Northwest Territories, Canada. The sigma degrees VH /sigma degrees VV ratio showed strong sensitivity to both LAI (R2 = 0.72 with respect to in-situ measurements) and wet aboveground biomass (R2 = 0.63) of dwarf birch. Our ALOS-2-derived maps revealed high variability of birch shrub LAI and biomass across spatial scales. The LAI map was fed into the sparse Gash model to estimate shrub rainfall interception, an important but under-studied component of the Arctic water balance. Results suggest that on average across the watershed, 17 +/- 3% of incoming rainfall was intercepted by dwarf birch (during summer 2018), highlighting the importance of shrub rainfall interception for the regional water balance. These findings demonstrate the unexploited potential of L-band SAR observations from satellites for quantifying the impact of shrub expansion on Arctic ecosystem processes.", "authors": [ "Chang, Qianyu", "Zwieback, Simon", "DeVries, Ben", "Berg, Aaron" ], "keywords": [ "Arctic tundra", "L-band SAR", "Arctic shrub biomass", "Rainfall interception" ], "year": "2022", "source": "REMOTE SENSING OF ENVIRONMENT", "publication_type": "J", "point2d": [ -65.13806915283203, 12.779017448425293 ], "cluster": 8.0 }, { "idx": 1026, "title": "The implications of permafrost thaw and land cover change on snow water equivalent accumulation, melt and runoff in discontinuous permafrost peatlands", "abstract": "In the discontinuous permafrost zone of the Northwest Territories (NWT), Canada, snow covers the ground surface for half the year. Snowmelt constitutes a primary source of moisture supply for the short growing season and strongly influences stream hydrographs. Permafrost thaw has changed the landscape by increasing the proportional coverage of permafrost-free wetlands at the expense of permafrost-cored peat plateau forests. The biophysical characteristics of each feature affect snow water equivalent (SWE) accumulation and melt rates. In headwater streams in the southern Dehcho region of the NWT, snowmelt runoff has significantly increased over the past 50 years, despite no significant change in annual SWE. At the Fort Simpson A climate station, we found that SWE measurements made by Environment and Climate Change Canada using a Nipher precipitation gauge were more accurate than the Adjusted and Homogenized Canadian Climate Dataset which was derived from snow depth measurements. Here, we: (a) provide 13 years of snow survey data to demonstrate differences in end-of-season SWE between wetlands and plateau forests; (b) provide ablation stake and radiation measurements to document differences in snow melt patterns among wetlands, plateau forests, and upland forests; and (c) evaluate the potential impact of permafrost-thaw induced wetland expansion on SWE accumulation, melt, and runoff. We found that plateaus retain significantly (p < 0.01) more SWE than wetlands. However, the differences are too small (123 mm and 111 mm, respectively) to cause any substantial change in basin SWE. During the snowmelt period in 2015, wetlands were the first feature to become snow-free in mid-April, followed by plateau forests (7 days after wetlands) and upland forests (18 days after wetlands). A transition to a higher percentage cover of wetlands may lead to more rapid snowmelt and provide a more hydrologically-connected landscape, a plausible mechanism driving the observed increase in spring freshet runoff.", "authors": [ "Connon, Ryan F.", "Chasmer, Laura", "Haughton, Emily", "Helbig, Manuel", "Hopkinson, Chris", "Sonnentag, Oliver", "Quinton, William L." ], "keywords": [ "land cover change", "permafrost thaw", "runoff", "snow", "snowmelt" ], "year": "2021", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -19.989931106567383, 3.99574875831604 ], "cluster": 13.0 }, { "idx": 1027, "title": "Arctic freshwater biodiversity: Establishing baselines, trends, and drivers of ecological change", "abstract": "Climate change is predicted to have dramatic effects on Arctic freshwater ecosystems through changes to the abiotic template that are expected to influence biodiversity. Changes are already ongoing in Arctic systems, but there is a lack of coordinated monitoring of Arctic freshwaters that hinders our ability to assess changes in biodiversity. To address the need for coordinated monitoring on a circumpolar scale, the Arctic Council working group, Conservation of Arctic Flora and Fauna, established the Circumpolar Biodiversity Monitoring Program, which is an adaptive monitoring program for the Arctic centred around four ecosystem themes (i.e., Freshwater, Terrestrial, Coastal, Marine). The freshwater theme developed a monitoring plan for Arctic freshwater biodiversity and recently completed the first assessment of status and trends in Arctic freshwater biodiversity. Circumpolar Biodiversity Monitoring Program-Freshwater has compiled and analysed a database of Arctic freshwater monitoring data to form the first report of the state of circumpolar Arctic freshwater biodiversity. This special issue presents the scientific analyses that underlie the Circumpolar Biodiversity Monitoring Program-Freshwater report and provides analyses of spatial and temporal diversity patterns and the multiple-stressor scenarios that act on the biological assemblages and biogeochemistry of Arctic lakes and rivers. This special issue includes regional patterns for selected groups of organisms in Arctic rivers and lakes of northern Europe, Russia, and North America. Circumpolar assessments for benthic diatoms, macrophytes, plankton, benthic macroinvertebrates, and fish demonstrate how climate change and associated environmental drivers affect freshwater biodiversity. Also included are papers on spatial and temporal trends in water chemistry across the circumpolar region, and a systematic review of documented Indigenous Knowledge that demonstrates its potential to support assessment and conservation of Arctic freshwaters. This special issue includes the first circumpolar assessment of trends in Arctic freshwater biodiversity and provides important baseline information for future assessments and studies. It represents the largest compilation and assessment of Arctic freshwater biodiversity data to date and strives to provide a holistic view of ongoing change in these ecosystems to support future monitoring efforts. By identifying gaps in monitoring data across the circumpolar region, as well as identifying best practices for monitoring and assessment, this special issue presents an important resource for researchers, policy makers, and Indigenous and local communities that can support future assessments of ecosystem change.", "authors": [ "Culp, Joseph M.", "Goedkoop, Willem", "Christensen, Tom", "Christoffersen, Kirsten S.", "Fefilova, Elena", "Liljaniemi, Petri", "Novichkova, Anna A.", "Olafsson, Jon S.", "Sandoy, Steinar", "Zimmerman, Christian E.", "Lento, Jennifer" ], "keywords": [ "Arctic", "biomonitoring", "climate change", "freshwater", "policy" ], "year": "2022", "source": "FRESHWATER BIOLOGY", "publication_type": "J", "point2d": [ 17.10172462463379, 18.094635009765625 ], "cluster": 19.0 }, { "idx": 1028, "title": "Range shifts in a foundation sedge potentially induce large Arctic ecosystem carbon losses and gains", "abstract": "Foundation species have disproportionately large impacts on ecosystem structure and function. As a result, future changes to their distribution may be important determinants of ecosystem carbon (C) cycling in a warmer world. We assessed the role of a foundation tussock sedge (Eriophorum vaginatum) as a climatically vulnerable C stock using field data, a machine learning ecological niche model, and an ensemble of terrestrial biosphere models (TBMs). Field data indicated that tussock density has decreased by similar to 0.97 tussocks per m(2) over the past similar to 38 years on Alaska's North Slope from similar to 1981 to 2019. This declining trend is concerning because tussocks are a large Arctic C stock, which enhances soil organic layer C stocks by 6.9% on average and represents 745 Tg C across our study area. By 2100, we project that changes in tussock density may decrease the tussock C stock by 41% in regions where tussocks are currently abundant (e.g. -0.8 tussocks per m(2) and -85 Tg C on the North Slope) and may increase the tussock C stock by 46% in regions where tussocks are currently scarce (e.g. +0.9 tussocks per m(2) and +81 Tg C on Victoria Island). These climate-induced changes to the tussock C stock were comparable to, but sometimes opposite in sign, to vegetation C stock changes predicted by an ensemble of TBMs. Our results illustrate the important role of tussocks as a foundation species in determining future Arctic C stocks and highlight the need for better representation of this species in TBMs.", "authors": [ "Curasi, Salvatore R.", "Fetcher, Ned", "Hewitt, Rebecca E.", "Lafleur, Peter M.", "Loranty, Michael M.", "Mack, Michelle C.", "May, Jeremy L.", "Myers-Smith, Isla H.", "Natali, Susan M.", "Oberbauer, Steven F.", "Parker, Thomas C.", "Sonnentag, Oliver", "Zesati, Sergio A. Vargas", "Wullschleger, Stan D.", "Rocha, Adrian, V" ], "keywords": [ "Arctic", "tundra", "carbon cycle", "climate change", "Eriophorum vaginatum", "carbon stocks" ], "year": "2022", "source": "ENVIRONMENTAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -31.047779083251953, 51.54599380493164 ], "cluster": 17.0 }, { "idx": 1029, "title": "FLUXNET-CH4: a global, multi-ecosystem dataset and analysis of methane seasonality from freshwater wetlands", "abstract": "Methane (CH4) emissions from natural landscapes constitute roughly half of global CH4 contributions to the atmosphere, yet large uncertainties remain in the absolute magnitude and the seasonality of emission quantities and drivers. Eddy covariance (EC) measurements of CH4 flux are ideal for constraining ecosystem-scale CH4 emissions due to quasi-continuous and high-temporal-resolution CH4 flux measurements, coincident carbon dioxide, water, and energy flux measurements, lack of ecosystem disturbance, and increased availability of datasets over the last decade. Here, we (1) describe the newly published dataset, FLUXNET-CH4 Version 1.0, the first open-source global dataset of CH4 EC measurements (available at https://fluxnet.org/data/fluxnet-ch4-community-product/, last access: 7 April 2021). FLUXNET-CH4 includes half-hourly and daily gap-filled and non-gap-filled aggregated CH4 fluxes and meteorological data from 79 sites globally: 42 freshwater wetlands, 6 brackish and saline wetlands, 7 formerly drained ecosystems, 7 rice paddy sites, 2 lakes, and 15 uplands. Then, we (2) evaluate FLUXNET-CH4 representativeness for freshwater wetland coverage globally because the majority of sites in FLUXNET-CH4 Version 1.0 are freshwater wetlands which are a substantial source of total atmospheric CH4 emissions; and (3) we provide the first global estimates of the seasonal variability and seasonality predictors of freshwater wetland CH4 fluxes. Our representativeness analysis suggests that the freshwater wetland sites in the dataset cover global wetland bioclimatic attributes (encompassing energy, moisture, and vegetation-related parameters) in arctic, boreal, and temperate regions but only sparsely cover humid tropical regions. Seasonality metrics of wetland CH4 emissions vary considerably across latitudinal bands. In freshwater wetlands (except those between 20 degrees S to 20 degrees N) the spring onset of elevated CH4 emissions starts 3 d earlier, and the CH4 emission season lasts 4 d longer, for each degree Celsius increase in mean annual air temperature. On average, the spring onset of increasing CH4 emissions lags behind soil warming by 1 month, with very few sites experiencing increased CH4 emissions prior to the onset of soil warming. In contrast, roughly half of these sites experience the spring onset of rising CH4 emissions prior to the spring increase in gross primary productivity (GPP). The timing of peak summer CH4 emissions does not correlate with the timing for either peak summer temperature or peak GPP. Our results provide seasonality parameters for CH4 modeling and highlight seasonality metrics that cannot be predicted by temperature or GPP (i.e., seasonality of CH4 peak). FLUXNET-CH4 is a powerful new resource for diagnosing and understanding the role of terrestrial ecosystems and climate drivers in the global CH4 cycle, and future additions of sites in tropical ecosystems and site years of data collection will provide added value to this database. All seasonality parameters are available at https://doi.org/10.5281/zenodo.4672601 (Delwiche et al., 2021). Additionally, raw FLUXNET-CH4 data used to extract seasonality parameters can be downloaded from https://fluxnet. org/data/fluxnet-ch4-community-product/ (last access: 7 April 2021), and a complete list of the 79 individual site data DOIs is provided in Table 2 of this paper.", "authors": [ "Delwiche, Kyle B.", "Knox, Sara Helen", "Malhotra, Avni", "Fluet-Chouinard, Etienne", "McNicol, Gavin", "Feron, Sarah", "Ouyang, Zutao", "Papale, Dario", "Trotta, Carlo", "Canfora, Eleonora", "Cheah, You-Wei", "Christianson, Danielle", "Alberto, Ma Carmelita R.", "Alekseychik, Pavel", "Aurela, Mika", "Baldocchi, Dennis", "Bansal, Sheel", "Billesbach, David P.", "Bohrer, Gil", "Bracho, Rosvel", "Buchmann, Nina", "Campbell, David I.", "Celis, Gerardo", "Chen, Jiquan", "Chen, Weinan", "Chu, Housen", "Dalmagro, Higo J.", "Dengel, Sigrid", "Desai, Ankur R.", "Detto, Matteo", "Dolman, Han", "Eichelmann, Elke", "Euskirchen, Eugenie", "Famulari, Daniela", "Fuchs, Kathrin", "Goeckede, Mathias", "Gogo, Sebastien", "Gondwe, Mangaliso J.", "Goodrich, Jordan P.", "Gottschalk, Pia", "Graham, Scott L.", "Heimann, Martin", "Helbig, Manuel", "Helfter, Carole", "Hemes, Kyle S.", "Hirano, Takashi", "Hollinger, David", "Hortnagl, Lukas", "Iwata, Hiroki", "Jacotot, Adrien", "Jurasinski, Gerald", "Kang, Minseok", "Kasak, Kuno", "King, John", "Klatt, Janina", "Koebsch, Franziska", "Krauss, Ken W.", "Lai, Derrick Y. F.", "Lohila, Annalea", "Mammarella, Ivan", "Marchesini, Luca Belelli", "Manca, Giovanni", "Matthes, Jaclyn Hatala", "Maximov, Trofim", "Merbold, Lutz", "Mitra, Bhaskar", "Morin, Timothy H.", "Nemitz, Eiko", "Nilsson, Mats B.", "Niu, Shuli", "Oechel, Walter C.", "Oikawa, Patricia Y.", "Ono, Keisuke", "Peichl, Matthias", "Peltola, Olli", "Reba, Michele L.", "Richardson, Andrew D.", "Riley, William", "Runkle, Benjamin R. K.", "Ryu, Youngryel", "Sachs, Torsten", "Sakabe, Ayaka", "Sanchez, Camilo Rey", "Schuur, Edward A.", "Schafer, Karina V. R.", "Sonnentag, Oliver", "Sparks, Jed P.", "Stuart-Haentjens, Ellen", "Sturtevant, Cove", "Sullivan, Ryan C.", "Szutu, Daphne J.", "Thom, Jonathan E.", "Torn, Margaret S.", "Tuittila, Eeva-Stiina", "Turner, Jessica", "Ueyama, Masahito", "Valach, Alex C.", "Vargas, Rodrigo", "Varlagin, Andrej", "Vazquez-Lule, Alma", "Verfaillie, Joseph G.", "Vesala, Timo", "Vourlitis, George L.", "Ward, Eric J.", "Wille, Christian", "Wohlfahrt, Georg", "Wong, Guan Xhuan", "Zhang, Zhen", "Zona, Donatella", "Windham-Myers, Lisamarie", "Poulter, Benjamin", "Jackson, Robert B." ], "keywords": [ "" ], "year": "2021", "source": "EARTH SYSTEM SCIENCE DATA", "publication_type": "J", "point2d": [ -32.199188232421875, 63.20893096923828 ], "cluster": 17.0 }, { "idx": 1030, "title": "Hydrology of peat estimated from near-surface water contents", "abstract": "Simple and robust hydrological modelling is critical for peat studies as water content (theta) and water table depth (d(WT)) are key controls on many biogeochemical processes. We show that near-surface theta can be a good predictor of theta at any depth and/or d(WT) in peat. This was achieved by further developing the formulae of an existing model and applying it for Mer Bleue bog (Ontario, Canada) and a permafrost peat plateau at Scotty Creek (Northwest Territories, Canada). Simulated theta dynamics at various depths in hummocks and hollows at both sites matched observations with R-2, Willmott's index of agreement (d), and normalized Nash-Sutcliffe efficiency coefficient (NNSE), reaching 0.97, 0.95, and 0.86, respectively. Simulated bog WT dynamics matched observations with R-2, d, and NNSE reaching 0.67, 0.87, and 0.72. Our approach circumvents the difficulties of measuring subsurface hydrology and reveals a perspective for large spatial scale estimation of theta and d(WT) in peat.", "authors": [ "Dimitrov, Dimitre D.", "Lafleur, Peter", "Sonnentag, Oliver", "Talbot, Julie", "Quinton, William L." ], "keywords": [ "peatlands", "permafrost peat plateaus", "near-surface", "soil water contents", "water table", "modelling" ], "year": "2022", "source": "HYDROLOGICAL SCIENCES JOURNAL", "publication_type": "J", "point2d": [ -8.23696231842041, 64.02964782714844 ], "cluster": 9.0 }, { "idx": 1032, "title": "Biomarkers of poly- and perfluoroalkyl substances (PFAS) in Sub-Arctic and Arctic communities in Canada", "abstract": "Polyfluoroalkyl substances and perfluoroalkyl substances (PFAS) are a family of anthropogenic chemicals that are used in food packaging, waterproof clothing, and firefighting foams for their water and oil resistant properties. Though levels of some PFAS appear to be decreasing in Canada's south, environmental levels have been increasing in the Arctic due to long-range transport. However, the implications of this on human exposures in sub-Arctic and Arctic populations in Canada have yet to be established. To address this data gap, human biomonitoring research was completed in Old Crow, Yukon, and the Dehcho region, Northwest Territories. Blood samples were collected from adults residing in seven northern First Nations and were analyzed by liquid chromatography mass spectrometry. A total of nine PFAS were quantified: perfluorooctanoic acid (PFOA), perfluorooctane sulphonic acid (PFOS), perfluorohexane sulphonic acid (PFHxS), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUdA), perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), and perfluorobutane sulphonic acid (PFBS). In the Dehcho (n = 124), five PFAS had a detection rate greater than 50% including PFOS, PFOA, PFHxS, PFNA, and PFDA. In addition to these PFAS, PFUdA was also detected in at least half of the samples collected in Old Crow (n = 54). Generally, male participants had higher concentrations of PFAS compared to female participants, and PFAS concentrations tended to increase with age. For most PFAS, Old Crow and Dehcho levels were similar or lower to those measured in the general Canadian population (as measured through the Canadian Health Measures Survey or CHMS) and other First Nations populations in Canada (as measured through the First Nations Biomonitoring Initiative or FNBI). The key exception to this was for PFNA which, relative to the CHMS (0.51 mu g/L), was approximately 1.8 times higher in Old Crow (0.94 mu g/L) and 2.8 times higher in Dehcho (1.42 mu g/L) than observed in the general Canadian population. This project provides baseline PFAS levels for participating communities, improving understanding of human exposures to PFAS in Canada. Future research should investigate site-specific PFNA exposure sources and monitor temporal trends in these regions.", "authors": [ "Garcia-Barrios, Joshua", "Drysdale, Mallory", "Ratelle, Mylene", "Gaudreau, Eric", "LeBlanc, Alain", "Gamberg, Mary", "Laird, Brian D." ], "keywords": [ "Poly-and Perfluoroalkylated substances", "Human biomonitoring", "Arctic", "Persistent organic pollutants", "Indigenous health" ], "year": "2021", "source": "INTERNATIONAL JOURNAL OF HYGIENE AND ENVIRONMENTAL HEALTH", "publication_type": "J", "point2d": [ 79.54292297363281, -15.581416130065918 ], "cluster": 7.0 }, { "idx": 1033, "title": "allodb: An R package for biomass estimation at globally distributed extratropical forest plots", "abstract": "Allometric equations for calculation of tree above-ground biomass (AGB) form the basis for estimates of forest carbon storage and exchange with the atmosphere. While standard models exist to calculate forest biomass across the tropics, we lack a standardized tool for computing AGB across boreal and temperate regions that comprise the global extratropics. Here we present an integrated R package, allodb, containing systematically selected published allometric equations and proposed functions to compute AGB. The data component of the package is based on 701 woody species identified at 24 large Forest Global Earth Observatory (ForestGEO) forest dynamics plots representing a wide diversity of extratropical forests. A total of 570 parsed allometric equations to estimate individual tree biomass were retrieved, checked and combined using a weighting function designed to ensure optimal equation selection over the full tree size range with smooth transitions across equations. The equation dataset can be customized with built-in functions that subset the original dataset and add new equations. Although equations were curated based on a limited set of forest communities and number of species, this resource is appropriate for large portions of the global extratropics and can easily be expanded to cover novel forest types.", "authors": [ "Gonzalez-Akre, Erika", "Piponiot, Camille", "Lepore, Mauro", "Herrmann, Valentine", "Lutz, James A.", "Baltzer, Jennifer L.", "Dick, Christopher W.", "Gilbert, Gregory S.", "He, Fangliang", "Heym, Michael", "Huerta, Alejandra, I", "Jansen, Patrick A.", "Johnson, Daniel J.", "Knapp, Nikolai", "Kral, Kamil", "Lin, Dunmei", "Malhi, Yadvinder", "McMahon, Sean M.", "Myers, Jonathan A.", "Orwig, David", "Rodriguez-Hernandez, Diego, I", "Russo, Sabrina E.", "Shue, Jessica", "Wang, Xugao", "Wolf, Amy", "Yang, Tonghui", "Davies, Stuart J.", "Anderson-Teixeira, Kristina J." ], "keywords": [ "above-ground biomass", "extratropics", "forest carbon storage", "Forest Global Earth Observatory (ForestGEO)", "R", "temperate forest", "tree allometry", "tree biomass" ], "year": "2022", "source": "METHODS IN ECOLOGY AND EVOLUTION", "publication_type": "J", "point2d": [ -45.18303298950195, 65.06623077392578 ], "cluster": 17.0 }, { "idx": 1034, "title": "Warming response of peatland CO2 sink is sensitive to seasonality in warming trends", "abstract": "Peatlands have acted as net CO2 sinks over millennia, exerting a global climate cooling effect. Rapid warming at northern latitudes, where peatlands are abundant, can disturb their CO2 sink function. Here we show that sensitivity of peatland net CO2 exchange to warming changes in sign and magnitude across seasons, resulting in complex net CO2 sink responses. We use multiannual net CO2 exchange observations from 20 northern peatlands to show that warmer early summers are linked to increased net CO2 uptake, while warmer late summers lead to decreased net CO2 uptake. Thus, net CO2 sinks of peatlands in regions experiencing early summer warming, such as central Siberia, are more likely to persist under warmer climate conditions than are those in other regions. Our results will be useful to improve the design of future warming experiments and to better interpret large-scale trends in peatland net CO2 uptake over the coming few decades. Peatlands have historically acted as a carbon sink, but it is unclear how climate warming will affect this. The response of peatland carbon uptake to warming depends on the timing of summer warming; early warming leads to increased CO2 uptake and later warming to decreased uptake.", "authors": [ "Helbig, M.", "Zivkovic, T.", "Alekseychik, P.", "Aurela, M.", "El-Madany, T. S.", "Euskirchen, E. S.", "Flanagan, L. B.", "Griffis, T. J.", "Hanson, P. J.", "Hattakka, J.", "Helfter, C.", "Hirano, T.", "Humphreys, E. R.", "Kiely, G.", "Kolka, R. K.", "Laurila, T.", "Leahy, P. G.", "Lohila, A.", "Mammarella, I.", "Nilsson, M. B.", "Panov, A.", "Parmentier, F. J. W.", "Peichl, M.", "Rinne, J.", "Roman, D. T.", "Sonnentag, O.", "Tuittila, E. -s", "Ueyama, M.", "Vesala, T.", "Vestin, P.", "Weldon, S.", "Weslien, P.", "Zaehle, S." ], "keywords": [ "" ], "year": "2022", "source": "NATURE CLIMATE CHANGE", "publication_type": "J", "point2d": [ -21.385417938232422, 61.39243698120117 ], "cluster": 17.0 }, { "idx": 1035, "title": "Tracking transient boreal wetland inundation with Sentinel-1 SAR: Peace-Athabasca Delta, Alberta and Yukon Flats, Alaska", "abstract": "Accurate and frequent mapping of transient wetland inundation in the boreal region is critical for monitoring the ecological and societal functions of wetlands. Satellite Synthetic Aperture Radar (SAR) has long been used to map wetlands due to its sensitivity to surface inundation and ability to penetrate clouds, darkness, and certain vegetation canopies. Here, we track boreal wetland inundation by developing a two-step modified decision-tree algorithm implemented in Google Earth Engine using Sentinel-1 C-band SAR and Sentinel-2 Multispectral Instrument (MSI) time-series data as inputs. This approach incorporates temporal as well as spatial characteristics of SAR backscatter and is evaluated for the Peace-Athabasca Delta, Alberta (PAD), and Yukon Flats, Alaska (YF) from May 2017 to October 2019. Within these two boreal study areas, we map spatiotemporal patterns in wetland inundation classes of Open Water (OW), Floating Plants (FP), Emergent Plants (EP), and Flooded Vegetation (FV). Temporal variability, frequency, and maximum extents of transient wetland inundation are quantified. Retrieved inundation estimates are compared with in-situ field mapping obtained during the NASA Arctic-Boreal Vulnerability Experiment (ABoVE), and a multi-temporal Landsat-derived surface water map. Over the 2017-2019 study period, we find that fractional inundation area ranged from 18.0% to 19.0% in the PAD, and from 10.7% to 12.1% in the YF. Transient wetland inundation covered similar to 595 km(2) of the PAD, comprising similar to 9.1% of its landscape, and similar to 102 km(2) of the YF, comprising similar to 3.6%. The implications of these findings for wetland function monitoring, and estimating landscape-scale methane emissions are discussed, together with limitations and uncertainties of our approach. We conclude that time series of Sentinel-1 C-band SAR backscatter, screened with Sentinel-2 MSI optical imagery and validated by field measurements, offer a valuable tool for tracking transient boreal wetland inundation. [GRAPHICS] .", "authors": [ "Huang, Chang", "Smith, Laurence C.", "Kyzivat, Ethan D.", "Fayne, Jessica, V", "Ming, Yisen", "Spence, Christopher" ], "keywords": [ "Ephemeral wetlands", "surface water", "inundation dynamics", "emergent plants", "flooded vegetation", "NASA ABoVE", "Synthetic Aperture Radar", "Google Earth Engine" ], "year": "2022", "source": "GISCIENCE & REMOTE SENSING", "publication_type": "J", "point2d": [ -63.240257263183594, 15.285555839538574 ], "cluster": 13.0 }, { "idx": 1036, "title": "Gap-filling eddy covariance methane fluxes: Comparison of machine learning model predictions and uncertainties at FLUXNET-CH4 wetlands", "abstract": "Time series of wetland methane fluxes measured by eddy covariance require gap-filling to estimate daily, seasonal, and annual emissions. Gap-filling methane fluxes is challenging because of high variability and complex responses to multiple drivers. To date, there is no widely established gap-filling standard for wetland methane fluxes, with regards both to the best model algorithms and predictors. This study synthesizes results of different gap-filling methods systematically applied at 17 wetland sites spanning boreal to tropical regions and including all major wetland classes and two rice paddies. Procedures are proposed for: 1) creating realistic artificial gap scenarios, 2) training and evaluating gap-filling models without overstating performance, and 3) predicting halfhourly methane fluxes and annual emissions with realistic uncertainty estimates. Performance is compared between a conventional method (marginal distribution sampling) and four machine learning algorithms. The conventional method achieved similar median performance as the machine learning models but was worse than the best machine learning models and relatively insensitive to predictor choices. Of the machine learning models, decision tree algorithms performed the best in cross-validation experiments, even with a baseline predictor set, and artificial neural networks showed comparable performance when using all predictors. Soil temperature was frequently the most important predictor whilst water table depth was important at sites with substantial water table fluctuations, highlighting the value of data on wetland soil conditions. Raw gap-filling uncertainties from the machine learning models were underestimated and we propose a method to calibrate uncertainties to observations. The python code for model development, evaluation, and uncertainty estimation is publicly available. This study outlines a modular and robust machine learning workflow and makes recommendations for, and evaluates an improved baseline of, methane gap-filling models that can be implemented in multi-site syntheses or standardized products from regional and global flux networks (e.g., FLUXNET).", "authors": [ "Irvin, Jeremy", "Zhou, Sharon", "McNicol, Gavin", "Lu, Fred", "Liu, Vincent", "Fluet-Chouinard, Etienne", "Ouyang, Zutao", "Knox, Sara Helen", "Lucas-Moffat, Antje", "Trotta, Carlo", "Papale, Dario", "Vitale, Domenico", "Mammarella, Ivan", "Alekseychik, Pavel", "Aurela, Mika", "Avati, Anand", "Baldocchi, Dennis", "Bansal, Sheel", "Bohrer, Gil", "Campbell, David, I", "Chen, Jiquan", "Chu, Housen", "Dalmagro, Higo J.", "Delwiche, Kyle B.", "Desai, Ankur R.", "Euskirchen, Eugenie", "Feron, Sarah", "Goeckede, Mathias", "Heimann, Martin", "Helbig, Manuel", "Helfter, Carole", "Hemes, Kyle S.", "Hirano, Takashi", "Iwata, Hiroki", "Jurasinski, Gerald", "Kalhori, Aram", "Kondrich, Andrew", "Lai, Derrick Y. F.", "Lohila, Annalea", "Malhotra, Avni", "Merbold, Lutz", "Mitra, Bhaskar", "Ng, Andrew", "Nilsson, Mats B.", "Noormets, Asko", "Peichl, Matthias", "Rey-Sanchez, A. Camilo", "Richardson, Andrew D.", "Runkle, Benjamin R. K.", "Schafer, Karina V. R.", "Sonnentag, Oliver", "Stuart-Haentjens, Ellen", "Sturtevant, Cove", "Ueyama, Masahito", "Valach, Alex C.", "Vargas, Rodrigo", "Vourlitis, George L.", "Ward, Eric J.", "Wong, Guan Xhuan", "Zona, Donatella", "Alberto, Ma Carmelita R.", "Billesbach, David P.", "Celis, Gerardo", "Dolman, Han", "Friborg, Thomas", "Fuchs, Kathrin", "Gogo, Sebastien", "Gondwe, Mangaliso J.", "Goodrich, Jordan P.", "Gottschalk, Pia", "Hortnagl, Lukas", "Jacotot, Adrien", "Koebsch, Franziska", "Kasak, Kuno", "Maier, Regine", "Morin, Timothy H.", "Nemitz, Eiko", "Oechel, Walter C.", "Oikawa, Patricia Y.", "Ono, Keisuke", "Sachs, Torsten", "Sakabe, Ayaka", "Schuur, Edward A.", "Shortt, Robert", "Sullivan, Ryan C.", "Szutu, Daphne J.", "Tuittila, Eeva-Stiina", "Varlagin, Andrej", "Verfaillie, Joeseph G.", "Wille, Christian", "Windham-Myers, Lisamarie", "Poulter, Benjamin", "Jackson, Robert B." ], "keywords": [ "Machine learning", "time series", "imputation", "gap-filling", "methane", "flux", "wetlands" ], "year": "2021", "source": "AGRICULTURAL AND FOREST METEOROLOGY", "publication_type": "J", "point2d": [ -34.319095611572266, 63.675228118896484 ], "cluster": 17.0 }, { "idx": 1037, "title": "Snow water equivalent measurement in the Arctic based on cosmic ray neutron attenuation", "abstract": "Grounded in situ, or invasive, cosmic ray neutron sensors (CRNSs) may allow for continuous, unattended measurements of snow water equivalent (SWE) over complete winter seasons and allow for measurements that are representative of spatially variable Arctic snow covers, but few studies have tested these types of sensors or considered their applicability at remote sites in the Arctic. During the winters of 2016/2017 and 2017/2018 we tested a grounded in situ CRNS system at two locations in Canada: a cold, low- to high-SWE environment in the Canadian Arctic and at a warm, low-SWE landscape in southern Ontario that allowed easier access for validation purposes. Five CRNS units were applied in a transect to obtain continuous data for a single significant snow feature; CRNS-moderated neutron counts were compared to manual snow survey SWE values obtained during both winter seasons. The data indicate that grounded in situ CRNS instruments appear able to continuously measure SWE with sufficient accuracy utilizing both a linear regression and nonlinear formulation. These sensors can provide important SWE data for testing snow and hydrological models, water resource management applications, and the validation of remote sensing applications.", "authors": [ "Jitnikovitch, Anton", "Marsh, Philip", "Walker, Branden", "Desilets, Darin" ], "keywords": [ "" ], "year": "2021", "source": "CRYOSPHERE", "publication_type": "J", "point2d": [ -37.0070915222168, -3.5892879962921143 ], "cluster": 8.0 }, { "idx": 1038, "title": "A Comparative Policy Analysis of Wild Food Policies Across Ontario, Northwest Territories, and Yukon Territory, Canada", "abstract": "Access to and availability of food harvested from the land (called traditional food, country food, or wild food) are critical to food security and food sovereignty of Indigenous People. These foods can be particularly difficult to access for those living in urban environments. We ask: what policies are involved in the regulation of traditional/country foods and how do these policies affect access to traditional/country food for Indigenous Peoples living in urban centers? Which policies act as barriers? This paper provides a comparative policy analysis of wild food policies across Ontario, the Northwest Territories (NWT), and the Yukon Territory, Canada, by examining and making comparisons between various pieces of legislation, such as fish and wildlife acts, hunting regulations, food premises legislation, and meat inspection regulations. We provide examples of how some programs serving Indigenous Peoples have managed to provide wild foods, using creative ways to operate within the existing system. While there is overwhelming evidence that traditional/country food plays a critical role for the health and well-being of Indigenous Peoples within Canada, Indigenous food systems are often undermined by provincial and territorial wild food policies. Provinces like Ontario with more restrictive policies may be able to learn from the policies in the Territories. We found that on a system level, there are significant constraints on the accessibility of wild foods in urban spaces because the regulatory food environment is designed to manage a colonial market-based system that devalues Indigenous values of sharing and reciprocity and Indigenous food systems, particularly for traditional/country foods. Dismantling the barriers to traditional/country food access in that system can be an important way forward.", "authors": [ "Judge, Connor", "Spring, Andrew", "Skinner, Kelly" ], "keywords": [ "wild food", "traditional", "country food", "policy", "regulations", "urban", "Indigenous", "Canada" ], "year": "2022", "source": "FRONTIERS IN COMMUNICATION", "publication_type": "J", "point2d": [ 70.248291015625, -28.424297332763672 ], "cluster": 7.0 }, { "idx": 1039, "title": "Identifying dominant environmental predictors of freshwater wetland methane fluxes across diurnal to seasonal time scales", "abstract": "While wetlands are the largest natural source of methane (CH4) to the atmosphere, they represent a large source of uncertainty in the global CH4 budget due to the complex biogeochemical controls on CH4 dynamics. Here we present, to our knowledge, the first multi-site synthesis of how predictors of CH4 fluxes (FCH4) in freshwater wetlands vary across wetland types at diel, multiday (synoptic), and seasonal time scales. We used several statistical approaches (correlation analysis, generalized additive modeling, mutual information, and random forests) in a wavelet-based multi-resolution framework to assess the importance of environmental predictors, nonlinearities and lags on FCH4 across 23 eddy covariance sites. Seasonally, soil and air temperature were dominant predictors of FCH4 at sites with smaller seasonal variation in water table depth (WTD). In contrast, WTD was the dominant predictor for wetlands with smaller variations in temperature (e.g., seasonal tropical/subtropical wetlands). Changes in seasonal FCH4 lagged fluctuations in WTD by similar to 17 +/- 11 days, and lagged air and soil temperature by median values of 8 +/- 16 and 5 +/- 15 days, respectively. Temperature and WTD were also dominant predictors at the multiday scale. Atmospheric pressure (PA) was another important multiday scale predictor for peat-dominated sites, with drops in PA coinciding with synchronous releases of CH4. At the diel scale, synchronous relationships with latent heat flux and vapor pressure deficit suggest that physical processes controlling evaporation and boundary layer mixing exert similar controls on CH4 volatilization, and suggest the influence of pressurized ventilation in aerenchymatous vegetation. In addition, 1- to 4-h lagged relationships with ecosystem photosynthesis indicate recent carbon substrates, such as root exudates, may also control FCH4. By addressing issues of scale, asynchrony, and nonlinearity, this work improves understanding of the predictors and timing of wetland FCH4 that can inform future studies and models, and help constrain wetland CH4 emissions.", "authors": [ "Knox, Sara H.", "Bansal, Sheel", "McNicol, Gavin", "Schafer, Karina", "Sturtevant, Cove", "Ueyama, Masahito", "Valach, Alex C.", "Baldocchi, Dennis", "Delwiche, Kyle", "Desai, Ankur R.", "Euskirchen, Eugenie", "Liu, Jinxun", "Lohila, Annalea", "Malhotra, Avni", "Melling, Lulie", "Riley, William", "Runkle, Benjamin R. K.", "Turner, Jessica", "Vargas, Rodrigo", "Zhu, Qing", "Alto, Tuula", "Fluet-Chouinard, Etienne", "Goeckede, Mathias", "Melton, Joe R.", "Sonnentag, Oliver", "Vesala, Timo", "Ward, Eric", "Zhang, Zhen", "Feron, Sarah", "Ouyang, Zutao", "Alekseychik, Pavel", "Aurela, Mika", "Bohrer, Gil", "Campbell, David, I", "Chen, Jiquan", "Chu, Housen", "Dalmagro, Higo J.", "Goodrich, Jordan P.", "Gottschalk, Pia", "Hirano, Takashi", "Iwata, Hiroki", "Jurasinski, Gerald", "Kang, Minseok", "Koebsch, Franziska", "Mammarella, Ivan", "Nilsson, Mats B.", "Ono, Keisuke", "Peichl, Matthias", "Peltola, Olli", "Ryu, Youngryel", "Sachs, Torsten", "Sakabe, Ayaka", "Sparks, Jed P.", "Tuittila, Eeva-Stiina", "Vourlitis, George L.", "Wong, Guan X.", "Windham-Myers, Lisamarie", "Poulter, Benjamin", "Jackson, Robert B." ], "keywords": [ "eddy covariance", "generalized additive modeling", "lags", "methane", "mutual information", "predictors", "random forest", "synthesis", "time scales", "wetlands" ], "year": "2021", "source": "GLOBAL CHANGE BIOLOGY", "publication_type": "J", "point2d": [ -31.49489402770996, 64.73210144042969 ], "cluster": 17.0 }, { "idx": 1040, "title": "Fill-and-Spill: A Process Description of Runoff Generation at the Scale of the Beholder", "abstract": "Descriptions of runoff generation processes continue to grow, helping to reveal complexities and hydrologic behavior across a wide range of environments and scales. But to date, there has been little grouping of these process facts. Here, we discuss how the fill-and-spill concept can provide a framework to group event-based runoff generation processes. The fill-and-spill concept describes where vertical and lateral additions of water to a landscape unit are placed into storage (the fill)-and only when this storage reaches a critical level (the spill), and other storages are filled and become connected, does a previously infeasible (but subsequently important) outflow pathway become activated. We show that fill-and-spill can be observed at a range of scales and propose that future fieldwork should first define the scale of interest and then evaluate what is filling-and-spilling at that scale. Such an approach may be helpful for those instrumenting and modeling new hillslopes or catchments because it provides a structured way to develop perceptual models for runoff generation and to group behaviors at different sites and scales.", "authors": [ "McDonnell, Jeffrey J.", "Spence, Christopher", "Karran, Daniel J.", "van Meerveld, H. J. (Ilja)", "Harman, Ciaran J." ], "keywords": [ "" ], "year": "2021", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 10.787248611450195, -18.90654182434082 ], "cluster": 10.0 }, { "idx": 1041, "title": "Invited perspective: What lies beneath a changing Arctic?", "abstract": "As permafrost thaws in the Arctic, new subsurface pathways open for the transport of groundwater, energy, and solutes. We identify different ways that these subsurface changes are driving observed surface consequences, including the potential for increased contaminant transport, modification to water resources, and enhanced rates of infrastructure (e.g. buildings and roads) damage. Further, as permafrost thaws it allows groundwater to transport carbon, nutrients, and other dissolved constituents from terrestrial to aquatic environments via progressively deeper subsurface flow paths. Cryohydrogeology, the study of groundwater in cold regions, should be included in northern research initiatives to account for this hidden catalyst of environmental and societal change. the underpinnings of many of these water-related changes lie beneath the depths of these investigations. Thawing of ancient permafrost is opening new subsurface pathways for groundwater flow (Walvoord and Kurylyk, 2016), thereby altering fluxes and distribution of water, energy, and solutes that can be observed at the Earth's surface. Scientific advances in predicting future climate change require integration of subsurface processes within a broader understanding of change in the Arctic, herein broadly defined to include Arctic and subarctic regions. We argue that groundwater is a catalyst of change in Arctic regions, and we call for a more prominent inclusion of cryohydrogeology, the study of groundwater in cold regions, in transdisciplinary research initiatives.", "authors": [ "McKenzie, Jeffrey M.", "Kurylyk, Barret L.", "Walvoord, Michelle A.", "Bense, Victor F.", "Fortier, Daniel", "Spence, Christopher", "Grenier, Christophe" ], "keywords": [ "" ], "year": "2021", "source": "CRYOSPHERE", "publication_type": "J", "point2d": [ 13.896700859069824, 19.5281925201416 ], "cluster": 18.0 }, { "idx": 1042, "title": "Characterizing tundra snow sub-pixel variability to improve brightness temperature estimation in satellite SWE retrievals", "abstract": "Topography and vegetation play a major role in sub-pixel variability of Arctic snowpack properties but are not considered in current passive microwave (PMW) satellite SWE retrievals. Simulation of sub-pixel variability of snow properties is also problematic when downscaling snow and climate models. In this study, we simplified observed variability of snowpack properties (depth, density, microstructure) in a two-layer model with mean values and distributions of two multi-year tundra dataset so they could be incorporated in SWE retrieval schemes. Spatial variation of snow depth was parameterized by a log-normal distribution with mean (mu(sd)) values and coefficients of variation (CVsd). Snow depth variability (CVsd) was found to increase as a function of the area measured by a remotely piloted aircraft system (RPAS). Distributions of snow specific surface area (SSA) and density were found for the wind slab (WS) and depth hoar (DH) layers. The mean depth hoar fraction (DHF) was found to be higher in Trail Valley Creek (TVC) than in Cambridge Bay (CB), where TVC is at a lower latitude with a subarctic shrub tundra compared to CB, which is a graminoid tundra. DHFs were fitted with a Gaussian process and predicted from snow depth. Simulations of brightness temperatures using the Snow Microwave Radiative Transfer (SMRT) model incorporating snow depth and DHF variation were evaluated with measurements from the Special Sensor Microwave/Imager and Sounder (SSMIS) sensor. Variation in snow depth (CVsd) is proposed as an effective parameter to account for sub-pixel variability in PMW emission, improving simulation by 8 K. SMRT simulations using a CVsd of 0.9 best matched CVsd observations from spatial datasets for areas > 3 km(2), which is comparable to the 3.125 km pixel size of the Equal-Area Scalable Earth (EASE)-Grid 2.0 enhanced resolution at 37 GHz.", "authors": [ "Meloche, Julien", "Langlois, Alexandre", "Rutter, Nick", "Royer, Alain", "King, Josh", "Walker, Branden", "Marsh, Philip", "Wilcox, Evan J." ], "keywords": [ "" ], "year": "2022", "source": "CRYOSPHERE", "publication_type": "J", "point2d": [ -65.97041320800781, 4.056542873382568 ], "cluster": 8.0 }, { "idx": 1043, "title": "Applying Machine Learning and Time-Series Analysis on Sentinel-1A SAR/InSAR for Characterizing Arctic Tundra Hydro-Ecological Conditions", "abstract": "Synthetic aperture radar (SAR) is a widely used tool for Earth observation activities. It is particularly effective during times of persistent cloud cover, low light conditions, or where in situ measurements are challenging. The intensity measured by a polarimetric SAR has proven effective for characterizing Arctic tundra landscapes due to the unique backscattering signatures associated with different cover types. However, recently, there has been increased interest in exploiting novel interferometric SAR (InSAR) techniques that rely on both the amplitude and absolute phase of a pair of acquisitions to produce coherence measurements, although the simultaneous use of both intensity and interferometric coherence in Arctic tundra image classification has not been widely tested. In this study, a time series of dual-polarimetric (VV, VH) Sentinel-1 SAR/InSAR data collected over one growing season, in addition to a digital elevation model (DEM), was used to characterize an Arctic tundra study site spanning a hydrologically dynamic coastal delta, open tundra, and high topographic relief from mountainous terrain. SAR intensity and coherence patterns based on repeat-pass interferometry were analyzed in terms of ecological structure (i.e., graminoid, or woody) and hydrology (i.e., wet, or dry) using machine learning methods. Six hydro-ecological cover types were delineated using time-series statistical descriptors (i.e., mean, standard deviation, etc.) as model inputs. Model evaluations indicated SAR intensity to have better predictive power than coherence, especially for wet landcover classes due to temporal decorrelation. However, accuracies improved when both intensity and coherence were used, highlighting the complementarity of these two measures. Combining time-series SAR/InSAR data with terrain derivatives resulted in the highest per-class F1 score values, ranging from 0.682 to 0.955. The developed methodology is independent of atmospheric conditions (i.e., cloud cover or sunlight) as it does not rely on optical information, and thus can be regularly updated over forthcoming seasons or annually to support ecosystem monitoring.", "authors": [ "Merchant, Michael Allan", "Obadia, Mayah", "Brisco, Brian", "DeVries, Ben", "Berg, Aaron" ], "keywords": [ "ArcticDEM", "Arctic tundra", "coherence", "InSAR", "SAR", "Sentinel-1", "machine learning" ], "year": "2022", "source": "REMOTE SENSING", "publication_type": "J", "point2d": [ -66.9880142211914, 12.36669921875 ], "cluster": 8.0 }, { "idx": 1044, "title": "Understanding among-lake variability of mercury concentrations in Northern Pike (Esox lucius): A whole-ecosystem study in subarctic lakes", "abstract": "Mercury concentrations ([Hg]) in fish reflect complex biogeochemical and ecological interactions that occur at a range of spatial and biological scales. Elucidating these interactions is crucial to understanding and predicting fish [Hg], particularly at northern latitudes, where environmental perturbations are having profound effects on land-water-animal interactions, and where fish are a critical subsistence food source. Using data from eleven subarctic lakes that span an area of similar to 60,000 km(2) in the Dehcho Region of Northwest Territories (Canada), we investigated how trophic ecology and growth rates of fish, lake water chemistry, and catchment characteristics interact to affect [Hg] in Northern Pike (Esox lucius), a predatory fish of widespread subsistence and commercial importance. Results from linear regression and piecewise structural equation models showed that 83% of among-lake variability in Northern Pike [Hg] was explained by fish growth rates (negative) and concentrations of methyl Hg ([MeHg]) in benthic invertebrates (positive). These variables were in turn influenced by concentrations of dissolved organic carbon, MeHg (water), and total Hg (sediment) in lakes, which were ultimately driven by catchment characteristics. Lakes in relatively larger catchments and with more temperate/subpolar needleleaf and mixed forests had higher [Hg] in Northern Pike. Our results provide a plausible mechanistic understanding of how interacting processes at scales ranging from whole catchments to individual organisms influence fish [Hg], and give insight into factors that could be considered for prioritizing lakes for monitoring in subarctic regions.", "authors": [ "Moslemi-Aqdam, Mehdi", "Baker, Leanne F.", "Baltzer, Jennifer L.", "Branfireun, Brian A.", "Evans, Marlene S.", "Laird, Brian D.", "Low, George", "Low, Mike", "Swanson, Heidi K." ], "keywords": [ "Subsistence fish", "Food security", "Mercury accumulation", "Lake", "Catchment", "Subarctic" ], "year": "2022", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 64.45320129394531, 2.1442339420318604 ], "cluster": 19.0 }, { "idx": 1045, "title": "Catchments affect growth rate of Northern Pike, Esox lucius, in subarctic lakes", "abstract": "A comprehensive understanding of how interactions between catchments and downstream lakes affect fish growth rate is lacking for many species and systems, yet is necessary for predicting impacts of environmental change on productivity of freshwater fish populations. We investigated among-lake variability in growth rate of Northern Pike (Esox lucius), a fish species of widespread subsistence and commercial importance. Northern Pike were captured from 11 subarctic lakes that span 60,000 km(2) and four ecoregions in the Dehcho Region of the Northwest Territories, Canada. Growth rates were related to stable isotope ratios and to lake and catchment physicochemistry. Growth, modelled using increment widths (n = 2953) measured on cleithra (n = 432), was significantly slower (p < 0.001, adj. r(2) = 0.78) in lakes subject to greater inferred catchment influence, which was quantified using a combination of lake and catchment characteristics. While Northern Pike growth rate was not related to delta N-15, it was positively related to delta C-13 (p < 0.001, adj. r(2) = 0.75). Further analyses revealed that benthic invertebrates in lakes subject to greater inferred catchment influence had more depleted delta C-13 ratios, and we posit that Northern Pike growth is slower in these lakes because terrestrially derived organic matter has relatively lower nutritional value and bioaccessibility, but further research is necessary. By linking current among-lake variability in Northern Pike growth to trophic ecology and to both lake and catchment physicochemical data, results inform predictions of how future changes to subarctic lakes and catchments may affect fish growth and productivity.", "authors": [ "Moslemi-Aqdam, Mehdi", "Low, George", "Low, Mike", "Branfireun, Brian A.", "Swanson, Heidi K." ], "keywords": [ "Catchment", "Fish growth", "Trophic ecology", "Stable isotopes", "Subarctic", "Northwest Territories" ], "year": "2021", "source": "AQUATIC SCIENCES", "publication_type": "J", "point2d": [ 64.92611694335938, 1.89922034740448 ], "cluster": 19.0 }, { "idx": 1046, "title": "Analyzing spatio-temporal patterns in atmospheric carbon dioxide concentration across Iran from 2003 to 2020", "abstract": "Adapting to climate change as a consequence of increasing greenhouse gas (GHG) emissions is of paramount importance in the near future. Therefore, recognition of spatial and temporal variations of atmospheric carbon dioxide (CO2) concentration both globally and regionally is critical. The goal of this study was to analyze spatiotemporal patterns of atmospheric CO2 concentration (XCO2) for Iran over the period from 2003 to 2020 to shed light on the role of various biotic and abiotic controls. First, by using atmospheric XCO2 data obtained from the SCIAMACHY and GOSAT satellite instruments, a series of spatio-temporal XCO2 distribution maps were developed. Second, to understand of the potential causes underlying the spatio-temporal distributions in XCO2, the correlations between monthly XCO2 and vegetation abundance, air temperature, precipitation, and fossil fuel CO2 emissions were examined. The spatio-temporal patterns in XCO2 indicated an increasing gradient of XCO2 from north to south and from west to east in Iran, with the highest XCO2 in the central, southern and southeastern parts of the country. The findings revealed that XCO2 was negatively correlated with vegetation abundance and precipitation, and positively correlated with air temperature in different months from 2003 to 2020. Among the different explanatory variables, vegetation abundance explained most of the spatial variation in XCO2. Furthermore, in spring (April and May), which has the highest amount of vegetation abundance and precipitation, biotic controls had a substantial impact on the diffusion and absorption of XCO2 in the northern and northwestern parts of Iran. Our results suggest that CO2 is moved from the center of Iran to the outer parts of the country in summer (July-September) and vice-versa in winter (January-March). Our findings provide policy and decision makers with crucial information regarding the spatio-temporal dynamics in XCO2 to reduce and, ultimately, halt its increase.", "authors": [ "Mousavi, Seyed Mohsen", "Dinan, Naghmeh Mobarghaee", "Ansarifard, Saeed", "Sonnentag, Oliver" ], "keywords": [ "CO2", "Spatio-temporal", "Geostatistics", "Iran", "ODIAC", "Satellite", "Remote sensing", "Surface fluxes" ], "year": "2022", "source": "ATMOSPHERIC ENVIRONMENT-X", "publication_type": "J", "point2d": [ -47.72972869873047, 46.67766189575195 ], "cluster": 17.0 }, { "idx": 1047, "title": "A new lake classification scheme for the Peace-Athabasca Delta (Canada) characterizes hydrological processes that cause lake-level variation", "abstract": "Study region: The Peace-Athabasca Delta, a Ramsar Wetland of International Importance in northeastern Alberta, is protected within Wood Buffalo National Park and contributes to its UNESCO World Heritage status yet is threatened by climate change and upstream energy projects. Study focus: Recent drawdown of the delta's abundant shallow lakes and rivers has deteriorated vital habitat for wildlife and impaired navigation routes. Here, we report continuous measurements at similar to 50 lakes during open-water seasons of 2018 and 2019 to improve understanding of hydrological processes causing lake-level variation. New hydrological insights for the region: Analyses reveal four patterns of lake-level variation attributable to influential hydrological processes, which provide the basis for a new lake classification scheme: 1) 'Drawdown' (>= 15 cm decline) by evaporation and/or outflow after ice-jam floods, 2) 'Stable' lake levels (<15 cm change) sustained by rainfall, 3) 'Gradual Rise' by inundation from the open-drainage network, and 4) 'Rapid Rise' by input of river floodwater. River flooding during the open-water season is an under-recognized recharge mechanism yet occurred extensively in the Athabasca sector and appears to be a common occurrence based on the Athabasca River hydrometric record. Lake-level loggers show strong ability to track shifts in hydrological processes, and can be integrated with other methods to decipher their causes and ecological consequences across water-rich landscapes.", "authors": [ "Neary, Laura K.", "Remmer, Casey R.", "Krist, Jadine", "Wolfe, Brent B.", "Hall, Roland, I" ], "keywords": [ "Floodplain lakes", "Shallow lakes", "Lake-level variation", "Lake monitoring", "Open-water season flooding", "Peace-Athabasca Delta" ], "year": "2021", "source": "JOURNAL OF HYDROLOGY-REGIONAL STUDIES", "publication_type": "J", "point2d": [ 4.562041282653809, 11.77206039428711 ], "cluster": 13.0 }, { "idx": 1048, "title": "Snowmelt Water Use at Transpiration Onset: Phenology, Isotope Tracing, and Tree Water Transit Time", "abstract": "Studies of tree water source partitioning have primarily focused on the growing season. However, little is yet known about the source of transpiration before, during, and after snowmelt when trees rehydrate and recommence transpiration in the spring. This study investigates tree water use during spring snowmelt following tree's winter stem shrinkage. We document the source of transpiration of three boreal forest tree species-Pinus banksiana, Picea mariana, and Larix laricina-by combining observations of weekly isotopic signatures (delta O-18 and delta H-2) of xylem, soil water, rainfall and snowmelt with measurements of soil moisture dynamics, snow depth and high-resolution temporal measurements of stem radius changes and sap flow. Our data shows that the onset of stem rehydration and transpiration overlaps with snowmelt for evergreens. During rehydration and transpiration onset, xylem water at the canopy reflected a constant pre-melt isotopic signature likely showing late fall conditions. As snowmelt infiltrates the soil and recharges the soil matrix, soil water shows a rapid isotopic shift to depleted-snowmelt water values. While there was an overlap between snowmelt and transpiration timing, xylem and soil water isotopic values did not overlap during transpiration onset. Our data showed 1-2-week delay in the shift in xylem water from pre-melt to clear snowmelt-depleted water signatures in evergreen species. This delay appears to be controlled by tree water transit time that was in the order of 9-18 days. Our study shows that snowmelt is a key source for stem rehydration and transpiration in the boreal forest during spring onset.", "authors": [ "Nehemy, Magali F.", "Maillet, Jason", "Perron, Nia", "Pappas, Christoforos", "Sonnentag, Oliver", "Baltzer, Jennifer L.", "Laroque, Colin P.", "McDonnell, Jeffrey J." ], "keywords": [ "ecohydrology", "snowmelt", "transpiration", "tree rehydration", "tree water source", "tree water transit time" ], "year": "2022", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -14.063034057617188, 24.44895362854004 ], "cluster": 3.0 }, { "idx": 1049, "title": "The Boreal-Arctic Wetland and Lake Dataset (BAWLD)", "abstract": "Methane emissions from boreal and arctic wetlands, lakes, and rivers are expected to increase in response to warming and associated permafrost thaw. However, the lack of appropriate land cover datasets for scaling field-measured methane emissions to circumpolar scales has contributed to a large uncertainty for our understanding of present-day and future methane emissions. Here we present the BorealArctic Wetland and Lake Dataset (BAWLD), a land cover dataset based on an expert assessment, extrapolated using random forest modelling from available spatial datasets of climate, topography, soils, permafrost conditions, vegetation, wetlands, and surface water extents and dynamics. In BAWLD, we estimate the fractional coverage of five wetland, seven lake, and three river classes within 0.5 x 0.5 degrees grid cells that cover the northern boreal and tundra biomes (17 % of the global land surface). Land cover classes were defined using criteria that ensured distinct methane emissions among classes, as indicated by a co-developed comprehensive dataset of methane flux observations. In BAWLD, wetlands occupied 3.2 x 10(6) km(2) (14 % of domain) with a 95 % confidence interval between 2.8 and 3.8 x 10(6) km(2). Bog, fen, and permafrost bog were the most abundant wetland classes, covering similar to 28 % each of the total wetland area, while the highest-methane-emitting marsh and tundra wetland classes occupied 5 % and 12 %, respectively. Lakes, defined to include all lentic open-water ecosystems regardless of size, covered 1.4 x 10(6) km(2) (6 % of domain). Low-methane-emitting large lakes (>10 km(2)) and glacial lakes jointly represented 78 % of the total lake area, while high-emitting peatland and yedoma lakes covered 18 % and 4 %, respectively. Small (<0.1 km(2)) glacial, peatland, and yedoma lakes combined covered 17 % of the total lake area but contributed disproportionally to the overall spatial uncertainty in lake area with a 95 % confidence interval between 0.15 and 0.38 x 10(6) km(2). Rivers and streams were estimated to cover 0.12 x 10(6) km(2) (0.5 % of domain), of which 8 % was associated with high-methane-emitting headwaters that drain organic-rich landscapes. Distinct combinations of spatially co-occurring wetland and lake classes were identified across the BAWLD domain, allowing for the mapping of wetscapes that have characteristic methane emission magnitudes and sensitivities to climate change at regional scales. With BAWLD, we provide a dataset which avoids double-accounting of wetland, lake, and river extents and which includes confidence intervals for each land cover class. As such, BAWLD will be suitable for many hydrological and biogeochemical modelling and upscaling efforts for the northern boreal and arctic region, in particular those aimed at improving assessments of current and future methane emissions.", "authors": [ "Olefeldt, David", "Hovemyr, Mikael", "Kuhn, McKenzie A.", "Bastviken, David", "Bohn, Theodore J.", "Connolly, John", "Crill, Patrick", "Euskirchen, Eugenie S.", "Finkelstein, Sarah A.", "Genet, Helene", "Grosse, Guido", "Harris, Lorna, I", "Heffernan, Liam", "Helbig, Manuel", "Hugelius, Gustaf", "Hutchins, Ryan", "Juutinen, Sari", "Lara, Mark J.", "Malhotra, Avni", "Manies, Kristen", "McGuire, A. David", "Natali, Susan M.", "O'Donnell, Jonathan A.", "Parmentier, Frans-Jan W.", "Raesaenen, Aleksi", "Schaedel, Christina", "Sonnentag, Oliver", "Strack, Maria", "Tank, Suzanne E.", "Treat, Claire", "Varner, Ruth K.", "Virtanen, Tarmo", "Warren, Rebecca K.", "Watts, Jennifer D." ], "keywords": [ "" ], "year": "2021", "source": "EARTH SYSTEM SCIENCE DATA", "publication_type": "J", "point2d": [ -32.38765335083008, 61.15358352661133 ], "cluster": 13.0 }, { "idx": 1050, "title": "Hair to blood mercury concentration ratios and a retrospective hair segmental mercury analysis in the Northwest Territories, Canada", "abstract": "Concentrations of total mercury were measured in blood and hair samples collected as part of a human biomonitoring project conducted in First Nations communities of the Mackenzie Valley, Northwest Territories, Canada. Hair (n = 443) and blood (n = 276) samples were obtained from six communities in the Dehcho region and three communities in the Sahtti region of the Mackenzie Valley. The aim of this paper was to calculate hair to blood mercury ratios (for matched samples) and determine if: 1) ratios differed significantly between the two regions; 2) ratios differed from the 250:1 ratio proposed by the WHO; and, 3) point estimates of hair to blood mercury ratios could be used to estimate blood mercury concentrations. In addition, this paper aims to determine if there were seasonal patterns in hair mercury concentrations in these regions and if so, if patterns were related to among-season variability in fish consumption. The majority of mercury levels in hair and blood were below relevant health-based guidance values. The geometric mean hair (most recent segment) to blood mercury ratio (stratified by region) was 619:1 for the Dehcho region and 1220:1 for the Sahtu region. Mean log-transformed hair to blood mercury ratios were statistically significantly different between the two regions. Hair to blood ratios calculated in this study were far higher (2-5 times higher) than those typically reported in the literature and there was a large amount of interindividual variation in calculated ratios (range: 114:1 to 4290:1). Using the 250:1 ratio derived by the World Health Organisation to estimate blood mercury concentrations from hair mercury concentrations would substantially over-estimate blood mercury concentrations in the studied regions. However, geometric mean sitespecific hair to blood mercury ratios can provide estimates of measures of central tendency for blood mercury concentrations from hair mercury concentrations at a population level. Mercury concentrations were determined in segments of long hair samples to examine exposure of participants to mercury over the past year. Hair segments were assigned to six time periods and the highest hair mercury concentrations were generally observed in hair segments that aligned with September/October and November/ December, whereas the lowest hair mercury concentrations were aligned with March/April and May/June. Mean log-transformed hair mercury concentrations were statistically significantly different between time periods. Between time periods (e.g., September/October vs. March/April), the geometric mean mercury concentration in hair differed by up to 0.22 mu g/g, and the upper margins of mercury exposure (e.g., 95th percentile of hair mercury) varied by up to 0.86 mu g/g. Results from self-reported fish consumption frequency questionnaires (subset of participants; n = 170) showed total fish intake peaked in late summer, decreased during the winter, and then increased during the spring. Visual assessment of results indicated that mean hair mercury concentrations followed this same seasonal pattern. Results from mixed effects models, however, indicated that variability in hair mercury concentrations among time periods was not best explained by total fish consumption frequency. Instead, seasonal trends in hair mercury concentrations may be more related to the consumption of specific fish species (rather than total wild-harvested fish in general). Future work should examine whether seasonal changes in the consumption of specific fish species are associated with seasonal changes in hair mercury concentrations.", "authors": [ "Packull-McCormick, Sara", "Ratelle, Mylene", "Lam, Christina", "Napenas, Jean", "Bouchard, Michele", "Swanson, Heidi", "Laird, Brian Douglas" ], "keywords": [ "Total mercury", "Hair to blood ratio", "Biomarkers", "Indigenous risk assessment", "Biomonitoring" ], "year": "2022", "source": "ENVIRONMENTAL RESEARCH", "publication_type": "J", "point2d": [ 75.29222106933594, -16.29948616027832 ], "cluster": 7.0 }, { "idx": 1051, "title": "Tower-Based Remote Sensing Reveals Mechanisms Behind a Two-phased Spring Transition in a Mixed-Species Boreal Forest", "abstract": "The boreal forest is a major contributor to the global climate system, therefore, reducing uncertainties in how the forest will respond to a changing climate is critical. One source of uncertainty is the timing and drivers of the spring transition. Remote sensing can provide important information on this transition, but persistent foliage greenness, seasonal snow cover, and a high prevalence of mixed forest stands (both deciduous and evergreen species) complicate interpretation of these signals. We collected tower-based remotely sensed data (reflectance-based vegetation indices and Solar-Induced Chlorophyll Fluorescence [SIF]), stem radius measurements, gross primary productivity, and environmental conditions in a boreal mixed forest stand. Evaluation of this data set shows a two-phased spring transition. The first phase is the reactivation of photosynthesis and transpiration in evergreens, marked by an increase in relative SIF, and is triggered by thawed stems, warm air temperatures, and increased available soil moisture. The second phase is a reduction in bulk photoprotective pigments in evergreens, marked by an increase in the Chlorophyll-Carotenoid Index. Deciduous leaf-out occurs during this phase, marked by an increase in all remotely sensed metrics. The second phase is controlled by soil thaw. Our results demonstrate that remote sensing metrics can be used to detect specific physiological changes in boreal tree species during the spring transition. The two-phased transition explains inconsistencies in remote sensing estimates of the timing and drivers of spring recovery. Our results imply that satellite-based observations will improve by using a combination of vegetation indices and SIF, along with species distribution information. Plain Language Summary The boreal forest is one of the most sensitive regions on the planet to climate change, yet its sensitivity remains poorly understood. In particular, the timing and drivers of the spring transition, as the forest changes from a winter adapted state to a summer adapted state, carry significant uncertainties. Remote sensing metrics can be used to characterize the spring transition, but their interpretation is complicated by persistent greenness, frequent snow cover, and a high prevalence of forests containing both deciduous and evergreen species. We collected tower-based remotely sensed metrics, stem radius, and carbon uptake measurements and show that the spring transition occurs in two distinct phases. The first phase is a reactivation of photosynthesis in evergreens and is triggered by thawed stems, warm air temperature, and moist soil. The second phase is a change in evergreen photoprotective pigment levels and the leaf-out of deciduous species. It is triggered by soil thaw. Both phases were detected with different remote sensing metrics that depended on species type. Our results illustrate how satellite measurements could be improved to capture the spring transition over diverse landscapes and what environmental factors control the spring transition.", "authors": [ "Pierrat, Zoe", "Nehemy, Magali F.", "Roy, Alexandre", "Magney, Troy", "Parazoo, Nicholas C.", "Laroque, Colin", "Pappas, Christoforos", "Sonnentag, Oliver", "Grossmann, Katja", "Bowling, David R.", "Seibt, Ulli", "Ramirez, Alexandra", "Johnson, Bruce", "Helgason, Warren", "Barr, Alan", "Stutz, Jochen" ], "keywords": [ "boreal forest", "mixed-species forest", "remote sensing", "solar-induced chlorophyll fluorescence", "spring transition", "stem radius" ], "year": "2021", "source": "JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES", "publication_type": "J", "point2d": [ -65.0728530883789, 62.216400146484375 ], "cluster": 17.0 }, { "idx": 1052, "title": "Dietary Intakes of Traditional Foods for Dene/Metis in the Dehcho and Sahtu Regions of the Northwest Territories", "abstract": "A dietary transition away from traditional foods and toward a diet of the predominantly unhealthy market is a public health and sociocultural concern throughout Indigenous communities in Canada, including those in the sub-Arctic and remote regions of Dehcho and Sahtu of the Northwest Territories, Canada. The main aim of the present study is to describe dietary intakes for macronutrients and micronutrients in traditional and market food from the Mackenzie Valley study. We also show the trends of contributions and differences of dietary intakes over time from 1994 data collected and reported by the Centre for Indigenous People's Nutrition and Environment (CINE) in 1996. Based on 24-h dietary recall data, the study uses descriptive statistics to describe the observed dietary intake of the Dene First Nations communities in the Dehcho and Sahtu regions of the NWT. Indigenous people in Canada, like the sub-Arctic regions of Dehcho and Sahtu of the NWT, continue to consume traditional foods, although as a small percentage of their total dietary intake. The observed dietary intake calls for action to ensure that traditional food remains a staple as it is critical for the wellbeing of Dene in the Dehcho and Sahtu regions and across the territory.", "authors": [ "Ramirez Prieto, Maria", "Ratelle, Mylene", "Laird, Brian Douglas", "Skinner, Kelly" ], "keywords": [ "dietary transition", "traditional food", "nutrition", "dietary intake", "sub-Arctic", "Dene", "Northwest Territories", "Canada" ], "year": "2022", "source": "NUTRIENTS", "publication_type": "J", "point2d": [ 77.75389862060547, -22.117084503173828 ], "cluster": 7.0 }, { "idx": 1053, "title": "Thermodynamic basis for the demarcation of Arctic and alpine treelines", "abstract": "At the edge of alpine and Arctic ecosystems all over the world, a transition zone exists beyond which it is either infeasible or unfavorable for trees to exist, colloquially identified as the treeline. We explore the possibility of a thermodynamic basis behind this demarcation in vegetation by considering ecosystems as open systems driven by thermodynamic advantage-defined by vegetation's ability to dissipate heat from the earth's surface to the air above the canopy. To deduce whether forests would be more thermodynamically advantageous than existing ecosystems beyond treelines, we construct and examine counterfactual scenarios in which trees exist beyond a treeline instead of the existing alpine meadow or Arctic tundra. Meteorological data from the Italian Alps, United States Rocky Mountains, and Western Canadian Taiga-Tundra are used as forcing for model computation of ecosystem work and temperature gradients at sites on both sides of each treeline with and without trees. Model results indicate that the alpine sites do not support trees beyond the treeline, as their presence would result in excessive CO2 loss and extended periods of snowpack due to temperature inversions (i.e., positive temperature gradient from the earth surface to the atmosphere). Further, both Arctic and alpine sites exhibit negative work resulting in positive feedback between vegetation heat dissipation and temperature gradient, thereby extending the duration of temperature inversions. These conditions demonstrate thermodynamic infeasibility associated with the counterfactual scenario of trees existing beyond a treeline. Thus, we conclude that, in addition to resource constraints, a treeline is an outcome of an ecosystem's ability to self-organize towards the most advantageous vegetation structure facilitated by thermodynamic feasibility.", "authors": [ "Martin, Meredith Richardson", "Kumar, Praveen", "Sonnentag, Oliver", "Marsh, Philip" ], "keywords": [ "" ], "year": "2022", "source": "SCIENTIFIC REPORTS", "publication_type": "J", "point2d": [ -32.832332611083984, 49.4285888671875 ], "cluster": 17.0 }, { "idx": 1054, "title": "Application of artificial substrate samplers to assess enrichment of metals of concern by river floodwaters to lakes across the Peace-Athabasca Delta", "abstract": "Study region: Peace-Athabasca Delta (PAD), northeastern Alberta. Study focus: Potential for downstream delivery of contaminants via Athabasca River floodwaters to lakes of the PAD has raised local to international concern. Here, we quantify enrichment of eight metals (Be, Cd, Cr, Cu, Ni, Pb, V, Zn) in aquatic biota, relative to sediment-based pre-industrial baselines, via analysis of biofilm-sediment mixtures accrued on artificial substrate samplers deployed during summers of 2017 and 2018 in > 40 lakes. Widespread flooding in the southern portion of the delta in spring 2018 allows for assessment of metal enrichment by Athabasca River floodwaters. New hydrological insights: River floodwaters are not implicated as a pathway of metal enrichment to biofilm-sediment mixtures in PAD lakes from upstream sources. MANOVA tests revealed no significant difference in residual concentrations of all eight metals in lakes that did not flood versus lakes that flooded during one or both study years. Also, no enrichment was detected for concentrations of biologically inert metals (Be, Cr, Pb) and those related to oil-sands development (Ni, V). Enrichment of Cd, Cu, and Zn at non-flooded lakes, however, suggests uptake of biologically active metals complicates comparisons of organic-rich biofilm-sediment mixtures to sediment-derived baselines for these metals. Results demonstrate that this novel approach could be adopted for lake monitoring within the federal Action Plan.", "authors": [ "Savage, Cory A. M.", "Owca, Tanner", "Kay, Mitchell L.", "Faber, Jelle", "Wolfe, Brent B.", "Hall, Roland, I" ], "keywords": [ "Contaminant monitoring", "Periphyton", "Floodplain", "Peace-Athabasca Delta", "Athabasca Oil Sands", "Wood Buffalo National Park Action Plan" ], "year": "2021", "source": "JOURNAL OF HYDROLOGY-REGIONAL STUDIES", "publication_type": "J", "point2d": [ 49.110328674316406, -2.178457260131836 ], "cluster": 19.0 }, { "idx": 1055, "title": "Permafrost condition determines plant community composition and community-level foliar functional traits in a boreal peatland", "abstract": "Boreal peatlands are critical ecosystems globally because they house 30%-40% of terrestrial carbon (C), much of which is stored in permafrost soil vulnerable to climate warming-induced thaw. Permafrost thaw leads to thickening of the active (seasonally thawed) layer and alters nutrient and light availability. These physical changes may influence community-level plant functional traits through intraspecific trait variation and/or species turnover. As permafrost thaw is expected to cause an efflux of carbon dioxide (CO2) and methane (CH4) from the soil to the atmosphere, it is important to understand thaw-induced changes in plant community productivity to evaluate whether these changes may offset some of the anticipated increases in C emissions. To this end, we collected vascular plant community composition and foliar functional trait data along gradients in aboveground tree biomass and active layer thickness (ALT) in a rapidly thawing boreal peatland, with the expectation that changes in above- and belowground conditions are indicative of altered resource availability. We aimed to determine whether community-level traits vary across these gradients, and whether these changes are dominated by intraspecific trait variation, species turnover, or both. Our results highlight that variability in community-level traits was largely attributable to species turnover and that both community composition and traits were predominantly driven by ALT. Specifically, thicker active layers associated with permafrost-free peatlands (i.e., bogs and fens) shifted community composition from slower-growing evergreen shrubs to faster-growing graminoids and forbs with a corresponding shift toward more productive trait values. The results from this rapidly thawing peatland suggest that continued warming-induced permafrost thaw and thermokarst development alter plant community composition and community-level traits and thus ecosystem productivity. Increased productivity may help to mitigate anticipated CO2 efflux from thawing permafrost, at least in the short term, though this response may be swamped by increase CH4 release.", "authors": [ "Standen, Katherine M.", "Baltzer, Jennifer L." ], "keywords": [ "carbon cycling", "climate change", "discontinuous permafrost", "ecosystem function", "environmental gradients", "leaf economic spectrum", "northwest territories", "plant functional traits" ], "year": "2021", "source": "ECOLOGY AND EVOLUTION", "publication_type": "J", "point2d": [ -26.725210189819336, 51.96820831298828 ], "cluster": 9.0 }, { "idx": 1056, "title": "Statistical upscaling of ecosystem CO2 fluxes across the terrestrial tundra and boreal domain: Regional patterns and uncertainties", "abstract": "The regional variability in tundra and boreal carbon dioxide (CO2) fluxes can be high, complicating efforts to quantify sink-source patterns across the entire region. Statistical models are increasingly used to predict (i.e., upscale) CO2 fluxes across large spatial domains, but the reliability of different modeling techniques, each with different specifications and assumptions, has not been assessed in detail. Here, we compile eddy covariance and chamber measurements of annual and growing season CO2 fluxes of gross primary productivity (GPP), ecosystem respiration (ER), and net ecosystem exchange (NEE) during 1990-2015 from 148 terrestrial high-latitude (i.e., tundra and boreal) sites to analyze the spatial patterns and drivers of CO2 fluxes and test the accuracy and uncertainty of different statistical models. CO2 fluxes were upscaled at relatively high spatial resolution (1 km(2)) across the high-latitude region using five commonly used statistical models and their ensemble, that is, the median of all five models, using climatic, vegetation, and soil predictors. We found the performance of machine learning and ensemble predictions to outperform traditional regression methods. We also found the predictive performance of NEE-focused models to be low, relative to models predicting GPP and ER. Our data compilation and ensemble predictions showed that CO2 sink strength was larger in the boreal biome (observed and predicted average annual NEE -46 and -29 g C m(-2) yr(-1), respectively) compared to tundra (average annual NEE +10 and -2 g C m(-2) yr(-1)). This pattern was associated with large spatial variability, reflecting local heterogeneity in soil organic carbon stocks, climate, and vegetation productivity. The terrestrial ecosystem CO2 budget, estimated using the annual NEE ensemble prediction, suggests the high-latitude region was on average an annual CO2 sink during 1990-2015, although uncertainty remains high.", "authors": [ "Virkkala, Anna-Maria", "Aalto, Juha", "Rogers, Brendan M.", "Tagesson, Torbern", "Treat, Claire C.", "Natali, Susan M.", "Watts, Jennifer D.", "Potter, Stefano", "Lehtonen, Aleksi", "Mauritz, Marguerite", "Schuur, Edward A. G.", "Kochendorfer, John", "Zona, Donatella", "Oechel, Walter", "Kobayashi, Hideki", "Humphreys, Elyn", "Goeckede, Mathias", "Iwata, Hiroki", "Lafleur, Peter M.", "Euskirchen, Eugenie S.", "Bokhorst, Stef", "Marushchak, Maija", "Martikainen, Pertti J.", "Elberling, Bo", "Voigt, Carolina", "Biasi, Christina", "Sonnentag, Oliver", "Parmentier, Frans-Jan W.", "Ueyama, Masahito", "Celis, Gerardo", "St.Louis, Vincent L.", "Emmerton, Craig A.", "Peichl, Matthias", "Chi, Jinshu", "Jarveoja, Jarvi", "Nilsson, Mats B.", "Oberbauer, Steven F.", "Torn, Margaret S.", "Park, Sang-Jong", "Dolman, Han", "Mammarella, Ivan", "Chae, Namyi", "Poyatos, Rafael", "Lopez-Blanco, Efren", "Christensen, Torben Rojle", "Kwon, Min Jung", "Sachs, Torsten", "Holl, David", "Luoto, Miska" ], "keywords": [ "Arctic", "CO2 balance", "empirical", "greenhouse gas", "land", "permafrost", "remote sensing" ], "year": "2021", "source": "GLOBAL CHANGE BIOLOGY", "publication_type": "J", "point2d": [ -43.65353775024414, 55.07248306274414 ], "cluster": 17.0 }, { "idx": 1057, "title": "The ABCflux database: Arctic-boreal CO2 flux observations and ancillary information aggregated to monthly time steps across terrestrial ecosystems", "abstract": "Past efforts to synthesize and quantify the magnitude and change in carbon dioxide (CO2) fluxes in terrestrial ecosystems across the rapidly warming Arctic-boreal zone (ABZ) have provided valuable information but were limited in their geographical and temporal coverage. Furthermore, these efforts have been based on data aggregated over varying time periods, often with only minimal site ancillary data, thus limiting their potential to be used in large-scale carbon budget assessments. To bridge these gaps, we developed a standardized monthly database of Arctic-boreal CO2 fluxes (ABCflux) that aggregates in situ measurements of terrestrial net ecosystem CO2 exchange and its derived partitioned component fluxes: gross primary productivity and ecosystem respiration. The data span from 1989 to 2020 with over 70 supporting variables that describe key site conditions (e.g., vegetation and disturbance type), micrometeorological and environmental measurements (e.g., air and soil temperatures), and flux measurement techniques. Here, we describe these variables, the spatial and temporal distribution of observations, the main strengths and limitations of the database, and the potential research opportunities it enables. In total, ABCflux includes 244 sites and 6309 monthly observations; 136 sites and 2217 monthly observations represent tundra, and 108 sites and 4092 observations represent the boreal biome. The database includes fluxes estimated with chamber (19 % of the monthly observations), snow diffusion (3 %) and eddy covariance (78 %) techniques. The largest number of observations were collected during the climatological summer (June-August; 32 %), and fewer observations were available for autumn (September-October; 25 %), winter (December-February; 18 %), and spring (March-May; 25 %). ABCflux can be used in a wide array of empirical, remote sensing and modeling studies to improve understanding of the regional and temporal variability in CO2 fluxes and to better estimate the terrestrial ABZ CO2 budget. ABCflux is openly and freely available online (Virkkala et al., 2021b, https://doi.org/10.3334/ORNLDAAC/1934).", "authors": [ "Virkkala, Anna-Maria", "Natali, Susan M.", "Rogers, Brendan M.", "Watts, Jennifer D.", "Savage, Kathleen", "Connon, Sara June", "Mauritz, Marguerite", "Schuur, Edward A. G.", "Peter, Darcy", "Minions, Christina", "Nojeim, Julia", "Commane, Roisin", "Emmerton, Craig A.", "Goeckede, Mathias", "Helbig, Manuel", "Holl, David", "Iwata, Hiroki", "Kobayashi, Hideki", "Kolari, Pasi", "Lopez-Blanco, Efren", "Marushchak, Maija E.", "Mastepanov, Mikhail", "Merbold, Lutz", "Parmentier, Frans-Jan W.", "Peichl, Matthias", "Sachs, Torsten", "Sonnentag, Oliver", "Ueyama, Masahito", "Voigt, Carolina", "Aurela, Mika", "Boike, Julia", "Celis, Gerardo", "Chae, Namyi", "Christensen, Torben R.", "Bret-Harte, M. Syndonia", "Dengel, Sigrid", "Dolman, Han", "Edgar, Colin W.", "Elberling, Bo", "Euskirchen, Eugenie", "Grelle, Achim", "Hatakka, Juha", "Humphreys, Elyn", "Jarveoja, Jarvi", "Kotani, Ayumi", "Kutzbach, Lars", "Laurila, Tuomas", "Lohila, Annalea", "Mammarella, Ivan", "Matsuura, Yojiro", "Meyer, Gesa", "Nilsson, Mats B.", "Oberbauer, Steven F.", "Park, Sang-Jong", "Petrov, Roman", "Prokushkin, Anatoly S.", "Schulze, Christopher", "St Louis, Vincent L.", "Tuittila, Eeva-Stiina", "Tuovinen, Juha-Pekka", "Quinton, William", "Varlagin, Andrej", "Zona, Donatella", "Zyryanov, Viacheslav I." ], "keywords": [ "" ], "year": "2022", "source": "EARTH SYSTEM SCIENCE DATA", "publication_type": "J", "point2d": [ -43.04280471801758, 53.80801773071289 ], "cluster": 17.0 }, { "idx": 1058, "title": "Soil respiration strongly offsets carbon uptake in Alaska and Northwest Canada", "abstract": "Soil respiration (i.e. from soils and roots) provides one of the largest global fluxes of carbon dioxide (CO2) to the atmosphere and is likely to increase with warming, yet the magnitude of soil respiration from rapidly thawing Arctic-boreal regions is not well understood. To address this knowledge gap, we first compiled a new CO2 flux database for permafrost-affected tundra and boreal ecosystems in Alaska and Northwest Canada. We then used the CO2 database, multi-sensor satellite imagery, and random forest models to assess the regional magnitude of soil respiration. The flux database includes a new Soil Respiration Station network of chamber-based fluxes, and fluxes from eddy covariance towers. Our site-level data, spanning September 2016 to August 2017, revealed that the largest soil respiration emissions occurred during the summer (June-August) and that summer fluxes were higher in boreal sites (1.87 +/- 0.67 g CO2-C m(-2) d(-1)) relative to tundra (0.94 +/- 0.4 g CO2-C m(-2) d(-1)). We also observed considerable emissions (boreal: 0.24 +/- 0.2 g CO2-C m(-2) d(-1); tundra: 0.18 +/- 0.16 g CO2-C m(-2) d(-1)) from soils during the winter (November-March) despite frozen surface conditions. Our model estimates indicated an annual region-wide loss from soil respiration of 591 +/- 120 Tg CO2-C during the 2016-2017 period. Summer months contributed to 58% of the regional soil respiration, winter months contributed to 15%, and the shoulder months contributed to 27%. In total, soil respiration offset 54% of annual gross primary productivity (GPP) across the study domain. We also found that in tundra environments, transitional tundra/boreal ecotones, and in landscapes recently affected by fire, soil respiration often exceeded GPP, resulting in a net annual source of CO2 to the atmosphere. As this region continues to warm, soil respiration may increasingly offset GPP, further amplifying global climate change.", "authors": [ "Watts, Jennifer D.", "Natali, Susan M.", "Minions, Christina", "Risk, Dave", "Arndt, Kyle", "Zona, Donatella", "Euskirchen, Eugenie S.", "Rocha, Adrian, V", "Sonnentag, Oliver", "Helbig, Manuel", "Kalhori, Aram", "Oechel, Walt", "Ikawa, Hiroki", "Ueyama, Masahito", "Suzuki, Rikie", "Kobayashi, Hideki", "Celis, Gerardo", "Schuur, Edward A. G.", "Humphreys, Elyn", "Kim, Yongwon", "Lee, Bang-Yong", "Goetz, Scott", "Madani, Nima", "Schiferl, Luke D.", "Commane, Roisin", "Kimball, John S.", "Liu, Zhihua", "Torn, Margaret S.", "Potter, Stefano", "Wang, Jonathan A.", "Jorgenson, M. Torre", "Xiao, Jingfeng", "Li, Xing", "Edgar, Colin" ], "keywords": [ "Arctic", "boreal", "soil respiration", "carbon", "CO2", "ecosystem vulnerability", "climate change" ], "year": "2021", "source": "ENVIRONMENTAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -40.26163101196289, 54.341365814208984 ], "cluster": 17.0 }, { "idx": 1059, "title": "Earlier snowmelt may lead to late season declines in plant productivity and carbon sequestration in Arctic tundra ecosystems", "abstract": "Arctic warming is affecting snow cover and soil hydrology, with consequences for carbon sequestration in tundra ecosystems. The scarcity of observations in the Arctic has limited our understanding of the impact of covarying environmental drivers on the carbon balance of tundra ecosystems. In this study, we address some of these uncertainties through a novel record of 119 site-years of summer data from eddy covariance towers representing dominant tundra vegetation types located on continuous permafrost in the Arctic. Here we found that earlier snowmelt was associated with more tundra net CO2 sequestration and higher gross primary productivity (GPP) only in June and July, but with lower net carbon sequestration and lower GPP in August. Although higher evapotranspiration (ET) can result in soil drying with the progression of the summer, we did not find significantly lower soil moisture with earlier snowmelt, nor evidence that water stress affected GPP in the late growing season. Our results suggest that the expected increased CO2 sequestration arising from Arctic warming and the associated increase in growing season length may not materialize if tundra ecosystems are not able to continue sequestering CO2 later in the season.", "authors": [ "Zona, Donatella", "Lafleur, Peter M.", "Hufkens, Koen", "Bailey, Barbara", "Gioli, Beniamino", "Burba, George", "Goodrich, Jordan P.", "Liljedahl, Anna K.", "Euskirchen, Eugenie S.", "Watts, Jennifer D.", "Farina, Mary", "Kimball, John S.", "Heimann, Martin", "Goeckede, Mathias", "Pallandt, Martijn", "Christensen, Torben R.", "Mastepanov, Mikhail", "Lopez-Blanco, Efren", "Jackowicz-Korczynski, Marcin", "Dolman, Albertus J.", "Marchesini, Luca Belelli", "Commane, Roisin", "Wofsy, Steven C.", "Miller, Charles E.", "Lipson, David A.", "Hashemi, Josh", "Arndt, Kyle A.", "Kutzbach, Lars", "Holl, David", "Boike, Julia", "Wille, Christian", "Sachs, Torsten", "Kalhori, Aram", "Song, Xia", "Xu, Xiaofeng", "Humphreys, Elyn R.", "Koven, Charles D.", "Sonnentag, Oliver", "Meyer, Gesa", "Gosselin, Gabriel H.", "Marsh, Philip", "Oechel, Walter C." ], "keywords": [ "" ], "year": "2022", "source": "SCIENTIFIC REPORTS", "publication_type": "J", "point2d": [ -34.689945220947266, 48.25838851928711 ], "cluster": 17.0 }, { "idx": 1060, "title": "Special Issue Levering Sustainable Food Systems to Address Climate Change (Pandemics and Other Shocks and Hazards): Possible Transformations", "abstract": "", "authors": [ "Spring, Andrew", "Nelson, Erin", "Knezevic, Irena", "Ballamingie, Patricia", "Blay-Palmer, Alison" ], "keywords": [ "" ], "year": "2021", "source": "SUSTAINABILITY", "publication_type": "J", "point2d": [ 70.34929656982422, -33.09339141845703 ], "cluster": 4.0 }, { "idx": 1062, "title": "Determining the role of diffusion and basement flux in controlling He-4 distribution in sedimentary basin fluids", "abstract": "The transport of helium from the crystalline continental basement and overlying Phanerozoic sedimentary formations to the near surface can be controlled by both diffusive and advective processes. The relative role of each is vital to helium resource prediction, and important in quantifying the residence times of fluids relevant to groundwater resources, hydrocarbon systems, geologic repositories for nuclear waste and carbon sequestration. The Williston Basin, North America, is a prominent sedimentary basin, providing an excellent natural laboratory to assess these processes. Here, we report noble gas isotopic and composition data for 28 gas samples from natural gas wells that sample different stratigraphic horizons down to the basement (Cretaceous to the Cambrian). Helium isotope ratios show a resolvable mantle He-3 component (up to 4.7%) in most samples. Neon isotopic compositions of the Cambrian samples are consistent with a crystalline basement gas contribution. Both helium and neon isotopic observations provide evidence for the contribution of conservative noble gases from the crystalline basement or deeper into the overlying sedimentary basin. He-4 groundwater concentrations in the sedimentary formations, calculated from He-4/Ne-20 values in gas samples, are in excess of in situ U+Th He-4 production in some shallow units and depleted in others, providing further evidence of cross formation gas contributions. The highest He-4 groundwater concentrations can be compared with the results obtained from a fullycoupled vertical scale transport model characterising diffusive-dominated transport through a static groundwater column. The model includes the He-4 flux into the basin from the Precambrian basement and quantifies the apparent basement He-4 flux to be between 0.8 - 1.6 x 10(-6) mol He-4/m(2)yr, comparable to the steady-state flux estimated for the average continental crust (1.47x10(-6) mol He-4/m(2)yr) (Torgersen, 2010). The lithologies in which He-4 concentrations are significantly lower than the reference model predictions are consistent with a history of water flooding and produced water disposal in those formations over decades of hydrocarbon production. While an advective component cannot be ruled out, this work demonstrates the importance of both diffusion and the basin architecture development in controlling He-4 flux into and out of different lithologies. The assumption of negligible He-4 loss from the top surface of a lithology is often made when determining the He-4 age of its groundwater. In the Williston Basin, this study shows that deeper lithologies may reach steady state at different stages of basin development, with shallower lithologies sometimes also showing significant He-4 loss from their top surface. In the Williston Basin, He-4 diffusive loss from the target lithology must be considered to accurately interpret He-4 groundwater residence times and accumulation potential. (c) 2021 Elsevier B.V. All rights reserved.", "authors": [ "Cheng, Anran", "Lollar, Barbara Sherwood", "Warr, Oliver", "Ferguson, Grant", "Idiz, Erdem", "Mundle, Scott O. C.", "Barry, Peter H.", "Byrne, David J.", "Mabry, Jennifer C.", "Ballentine, Chris J." ], "keywords": [ "noble gases", "helium residence ages", "diffusive transport", "basement flux" ], "year": "2021", "source": "EARTH AND PLANETARY SCIENCE LETTERS", "publication_type": "J", "point2d": [ 7.608006954193115, 21.794628143310547 ], "cluster": 18.0 }, { "idx": 1063, "title": "The hidden crisis beneath our feet", "abstract": "Disappearing groundwater requires action to prevent widespread water scarcity", "authors": [ "Famiglietti, James S.", "Ferguson, Grant" ], "keywords": [ "" ], "year": "2021", "source": "SCIENCE", "publication_type": "J", "point2d": [ 15.169431686401367, 27.060548782348633 ], "cluster": 4.0 }, { "idx": 1064, "title": "Crustal Groundwater Volumes Greater Than Previously Thought", "abstract": "Global groundwater volumes in the upper 2 km of the Earth's continental crust-critical for water security-are well estimated. Beyond these depths, a vast body of largely saline and non-potable groundwater exists down to at least 10 km-a volume that has not yet been quantified reliably at the global scale. Here, we estimate the amount of groundwater present in the upper 10 km of the Earth's continental crust by examining the distribution of sedimentary and crystalline rocks with depth and applying porosity-depth relationships. We demonstrate that groundwater in the 2-10 km zone (what we call deep groundwater) has a volume comparable to that of groundwater in the upper 2 km of the Earth's crust. These new estimates make groundwater the largest continental reservoir of water, ahead of ice sheets, provide a basis to quantify geochemical cycles, and constrain the potential for large-scale isolation of waste fluids.", "authors": [ "Ferguson, Grant", "McIntosh, Jennifer C.", "Warr, Oliver", "Lollar, Barbara Sherwood", "Ballentine, Christopher J.", "Famiglietti, James S.", "Kim, Ji-Hyun", "Michalski, Joseph R.", "Mustard, John F.", "Tarnas, Jesse", "McDonnell, Jeffrey J." ], "keywords": [ "deep groundwater", "porosity", "sedimentary basins", "cratons", "global hydrology" ], "year": "2021", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ 11.197525024414062, 25.155282974243164 ], "cluster": 18.0 }, { "idx": 1065, "title": "Global Groundwater Sustainability, Resources, and Systems in the Anthropocene", "abstract": "Groundwater is a crucial resource for current and future generations, but it is not being sustainably used in many parts of the world. The objective of this review is to provide a clear portrait of global-scale groundwater sustainability, systems, and resources in the Anthropocene to inspire a pivot toward more sustainable pathways of groundwater use. We examine groundwater from three different but related perspectives of sustainability science, natural resource governance and management, and Earth System science. An Earth System approach highlights the connections between groundwater and the other parts of the system and how these connections are impacting, or are impacted by, groundwater pumping. Groundwater is the largest store of unfrozen freshwater on Earth and is heterogeneously connected to many Earth System processes on different timescales. We propose a definition of groundwater sustainability that has a direct link with observable data, governance, andmanagement as well as the crucial functions and services of groundwater. Groundwater is depleted or contaminated in some regions; it is ubiquitously distributed, which, importantly, makes it broadly accessible but also slow and invisible and therefore challenging to govern and manage. Regional differences in priorities, hydrology, politics, culture, and economic contexts mean that different governance and management tools are important, but a global perspective can support higher level international policies in an increasingly globalized world that require broader analysis of interconnections and knowledge transfer between regions. A coherent, overarching framework of groundwater sustainability is more important for groundwater governance and management than the concepts of safe yield, renewability, depletion, or stress.", "authors": [ "Gleeson, Tom", "Cuthbert, Mark", "Ferguson, Grant", "Perrone, Debra" ], "keywords": [ "groundwater sustainability", "natural resources", "Earth System", "groundwater governance", "groundwater management", "water cycle" ], "year": "2020", "source": "ANNUAL REVIEW OF EARTH AND PLANETARY SCIENCES, VOL 48, 2020", "publication_type": "S", "point2d": [ 15.95939826965332, 27.05225372314453 ], "cluster": 4.0 }, { "idx": 1066, "title": "Changes in Deep Groundwater Flow Patterns Related to Oil and Gas Activities", "abstract": "Large volumes of saline formation water are both produced from and injected into sedimentary basins as a by-product of oil and gas production. Despite this, the location of production and injection wells has not been studied in detail at the regional scale and the effects on deep groundwater flow patterns (i.e., below the base of groundwater protection) possibly driving fluid flow toward shallow aquifers remain uncertain. Even where injection and production volumes are equal at the basin scale, local changes in hydraulic head can occur due to the distribution of production and injection wells. In the Canadian portion of the Williston Basin, over 4.6 x 10(9) m(3) of water has been co-produced with 5.4 x 10(8) m(3) of oil, and over 5.5 x 10(9) m(3) of water has been injected into the subsurface for salt water disposal or enhanced oil recovery. Despite approximately equal values of produced and injected fluids at the sedimentary basin scale over the history of development, cumulative fluid deficits and surpluses per unit area in excess of a few 100 mm are present at scales of a few 100 km(2). Fluid fluxes associated with oil and gas activities since 1950 likely exceed background groundwater fluxes in these areas. Modeled pressures capable of creating upward hydraulic gradients are predicted for the Midale Member and Mannville Group, two of the strata with the highest amounts of injection in the study area. This could lead to upward leakage of fluids if permeable pathways, such as leaky wells, are present.", "authors": [ "Jellicoe, Keegan", "McIntosh, Jennifer C.", "Ferguson, Grant" ], "keywords": [ "" ], "year": "2022", "source": "GROUNDWATER", "publication_type": "J", "point2d": [ 12.211488723754883, 36.421478271484375 ], "cluster": 18.0 }, { "idx": 1067, "title": "Changes in Deep Groundwater Flow Patterns Related to Oil and Gas Activities", "abstract": "Large volumes of saline formation water are both produced from and injected into sedimentary basins as a by-product of oil and gas production. Despite this, the location of production and injection wells has not been studied in detail at the regional scale and the effects on deep groundwater flow patterns (i.e., below the base of groundwater protection) possibly driving fluid flow toward shallow aquifers remain uncertain. Even where injection and production volumes are equal at the basin scale, local changes in hydraulic head can occur due to the distribution of production and injection wells. In the Canadian portion of the Williston Basin, over 4.6 x 10(9) m(3) of water has been co-produced with 5.4 x 10(8) m(3) of oil, and over 5.5 x 10(9) m(3) of water has been injected into the subsurface for salt water disposal or enhanced oil recovery. Despite approximately equal values of produced and injected fluids at the sedimentary basin scale over the history of development, cumulative fluid deficits and surpluses per unit area in excess of a few 100 mm are present at scales of a few 100 km(2). Fluid fluxes associated with oil and gas activities since 1950 likely exceed background groundwater fluxes in these areas. Modeled pressures capable of creating upward hydraulic gradients are predicted for the Midale Member and Mannville Group, two of the strata with the highest amounts of injection in the study area. This could lead to upward leakage of fluids if permeable pathways, such as leaky wells, are present.", "authors": [ "Jellicoe, Keegan", "McIntosh, Jennifer C.", "Ferguson, Grant" ], "keywords": [ "" ], "year": "2022", "source": "GROUNDWATER", "publication_type": "J", "point2d": [ 12.211488723754883, 36.421478271484375 ], "cluster": 18.0 }, { "idx": 1068, "title": "Evaluation of strontium isotope tracers of produced water sources from multiple stacked reservoirs in Appalachian, Williston and Permian basins", "abstract": "Both unconventional and conventional oil and gas production have led to instances of brine contamination of near-surface environments from spills of saline produced waters. Strontium isotope ratios (87Sr/86Sr) have been used as a sensitive tracer of sources of brine contamination in surface waters and shallow aquifers in areas where oil and gas production are limited to only a few reservoirs and produced water sources are well-defined. Recent expansion of conventional and unconventional oil and gas production to additional tight formations within sedimentary basins has resulted in production of formation waters from multiple oil and gas reservoirs that may have similar chemical and isotopic ratios, including 87Sr/86Sr. This study evaluates the utility of 87Sr/86Sr, the most widely available tracer dataset beyond major ion chemistry and water stable isotopes, as a tracer of brine contamination related to conventional and unconventional oil and gas production in the Williston, Appalachian and Permian basins. Multiple stacked oil and gas reservoirs within each basin have overlapping formation water 87Sr/86Sr, based on a non-parametric statistical test. For example, in the Appalachian Basin, produced waters from unconventional gas production in the Middle Devonian Marcellus and Upper Ordovician Utica shales have overlapping 87Sr/86Sr. In the Permian Basin, produced waters from the unconventional Pennsylvanian-Permian Wolfcamp Shale and conventional and unconventional Pennsylvanian Cisco/Canyon/Strawn formations have similar 87Sr/86Sr. In the Williston Basin produced waters from Late Devonian to Early Mississippian Bakken Formation unconventional oil production have overlapping 87Sr/86Sr with produced waters associated with minor production of conventional oil from the Middle Devonian Winnipegosis. Improved spatial characterization of 87Sr/86Sr and other isotopic signatures of produced waters from various oil/gas reservoirs are needed to constrain geographic and depth variability of produced waters in hydrocarbon producing regions. This is particularly important, as unconventional oil and gas production expands in areas of existing conventional oil and gas production, where delineating sources of saline produced waters in cases of accidental surface spills or subsurface leakage will become a greater challenge. Sr isotopes alone may not be able to distinguish produced waters in areas with overlapping production from reservoirs with similar isotopic signatures.", "authors": [ "Marza, Mohammad", "Mowat, Aidan", "Jellicoe, Keegan", "Ferguson, Grant", "McIntosh, Jennifer" ], "keywords": [ "Geochemical tracers", "Produced water", "Formation water", "Strontium isotopes" ], "year": "2022", "source": "JOURNAL OF GEOCHEMICAL EXPLORATION", "publication_type": "J", "point2d": [ 10.386181831359863, 31.344392776489258 ], "cluster": 18.0 }, { "idx": 1069, "title": "Variability in Timing and Transport of Pleistocene Meltwater Recharge to Regional Aquifers", "abstract": "The impacts of Pleistocene glaciation on groundwater flow systems in sedimentary basins are widely recognized, but the timing and distribution of subglacial recharge events remain poorly constrained. We investigate the spatial and temporal variability of recharge events from glaciations over the last 2 million years in the Williston Basin, Canada. Integration of fluid chemistry, stable isotope data, and transport modeling indicate that meltwater arrived at depths of similar to 600-1000 m in the northcentral region of the Williston Basin at two separate time periods, 75-150 and 300 ka, which we attribute to permeability differences between stacked aquifer systems. Our findings indicate that meltwater recharge extended along the northern margin of the Williston Basin as well as previously identified recharge areas to the east. Given the distance of measurements from recharge areas, evidence of recharge from the early to mid-Pleistocene appears to be preserved in the Williston Basin. Plain Language Summary Continental glaciations can reorganize large-scale groundwater flow systems, but the timing of recharge events is not well known. We investigated local and regional variations in groundwater flow and the timing of meltwater influx resulting from glaciations over the last 2 million years in a deep aquifer system in the Williston Basin, Canada. Isotopic signatures of groundwaters indicate the presence of subglacial meltwater and older marine-derived brines within these aquifers. These isotopic signatures were used to constrain groundwater transport models and estimate arrival times of Pleistocene meltwater recharge at study sites in the northcentral Williston Basin. We identified two arrival time periods (i.e., 75,000 to 150,000 and 300,000 years before present) and attribute these to local and regional variations in aquifer properties. Our results also indicate that recharge occurred at the northern margin of the Williston Basin, along with the eastern margin, to form a continuous recharge belt. Key Points Pleistocene glacial meltwater recharge migrated non-uniformly within and between stacked Paleozoic aquifers of the Williston Basin Deep, stacked, carbonate aquifers were impacted by Pleistocene recharge at two arrival intervals, attributed to permeability differences The arrival times of subglacial recharge are constrained to early to mid-Pleistocene and appear fully preserved in the Williston Basin", "authors": [ "Mowat, Aidan C.", "Francis, Daniel J.", "McIntosh, Jennifer C.", "Lindsay, Matthew B. J.", "Ferguson, Grant A. G." ], "keywords": [ "hydrogeology", "sedimentary basin", "groundwater", "Pleistocene" ], "year": "2021", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ 6.776589870452881, 19.80833625793457 ], "cluster": 18.0 }, { "idx": 1070, "title": "Commingled Fluids in Abandoned Boreholes: Proximity Analysis of a Hidden Liability", "abstract": "The interactions between old abandoned wellbores of suspect well integrity with hydraulic fracturing (HF), enhanced oil recovery (EOR), or salt water disposal (SWD) operations can result in upward leakage of deep aqueous liquids into overlying aquifers. This potential for upward fluid migration is largely unquantified as monitoring abandoned wells is rarely done, and leakage may go unnoticed especially when in deeper aquifers. This study performs a proximity analysis between old abandoned wells and HF, EOR, and SWD wells, and identifies commingled old abandoned wellbores, which are those wells where groundwater may flow from one aquifer to one or more other aquifers, to identify the locations with the greatest potential for upward aqueous fluid migration at three study sites in the Western Canadian Sedimentary Basin. Our analysis indicates that at all three study sites there are several locations where HF, EOR, or SWD operations are located in close proximity to a given old abandoned well. Much of this overlap occurs in formations above typically produced hydrocarbon reservoirs but below exploited potable aquifers, otherwise known as the intermediate zone, which is often connected between abandonment plugs in old abandoned wells. Information on the intermediate zone is often lacking, and this study suggests that unanticipated alterations to groundwater flow systems within the intermediate zone may be occurring. Results indicate the need for more field-based research on the intermediate zone.", "authors": [ "Perra, Christopher", "McIntosh, Jennifer C.", "Watson, Theresa", "Ferguson, Grant" ], "keywords": [ "" ], "year": "2022", "source": "GROUNDWATER", "publication_type": "J", "point2d": [ 15.153176307678223, 33.71817398071289 ], "cluster": 18.0 }, { "idx": 1071, "title": "Commingled Fluids in Abandoned Boreholes: Proximity Analysis of a Hidden Liability", "abstract": "The interactions between old abandoned wellbores of suspect well integrity with hydraulic fracturing (HF), enhanced oil recovery (EOR), or salt water disposal (SWD) operations can result in upward leakage of deep aqueous liquids into overlying aquifers. This potential for upward fluid migration is largely unquantified as monitoring abandoned wells is rarely done, and leakage may go unnoticed especially when in deeper aquifers. This study performs a proximity analysis between old abandoned wells and HF, EOR, and SWD wells, and identifies commingled old abandoned wellbores, which are those wells where groundwater may flow from one aquifer to one or more other aquifers, to identify the locations with the greatest potential for upward aqueous fluid migration at three study sites in the Western Canadian Sedimentary Basin. Our analysis indicates that at all three study sites there are several locations where HF, EOR, or SWD operations are located in close proximity to a given old abandoned well. Much of this overlap occurs in formations above typically produced hydrocarbon reservoirs but below exploited potable aquifers, otherwise known as the intermediate zone, which is often connected between abandonment plugs in old abandoned wells. Information on the intermediate zone is often lacking, and this study suggests that unanticipated alterations to groundwater flow systems within the intermediate zone may be occurring. Results indicate the need for more field-based research on the intermediate zone.", "authors": [ "Perra, Christopher", "McIntosh, Jennifer C.", "Watson, Theresa", "Ferguson, Grant" ], "keywords": [ "" ], "year": "2022", "source": "GROUNDWATER", "publication_type": "J", "point2d": [ 15.153176307678223, 33.71817398071289 ], "cluster": 18.0 }, { "idx": 1072, "title": "Continuous hydrologic modelling for small and ungauged basins: A comparison of eight rainfall models for sub-daily runoff simulations", "abstract": "Continuous hydrologic modelling is a natural evolution of the event-based design approach in modern hydrology. It improves the rainfall-runoff transformation and provides the practitioner with more effective hydrological output information for risk assessment. However, this approach is still not widely adopted, mainly because the choice of the most appropriate rainfall simulation model (which is the core of continuous frameworks) for the specific aim of risk analysis has not been sufficiently investigated. In this paper, we test eight rainfall models by evaluating the performances of the simulated rainfall time series when used as input for a simplified continuous rainfall-runoff model, the COSMO4SUB, which is particularly designed for small and ungauged basins. The comparison confirms the capability of all models to provide realistic flood events and allows identifying the models to be further improved and tailored for data-scarce hydrological risk applications. The suggested framework is transferable to any catchment while different hydrologic and rainfall models can be used.", "authors": [ "Grimaldi, Salvatore", "Volpi, Elena", "Langousis, Andreas", "Papalexiou, Simon Michael", "De Luca, Davide Luciano", "Piscopia, Rodolfo", "Nerantzaki, Sofia D.", "Papacharalampous, Georgia", "Petroselli, Andrea" ], "keywords": [ "Continuous hydrologic modelling", "Risk assessment", "Small and ungauged basins", "Rainfall models", "Rainfall simulations" ], "year": "2022", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -4.778456687927246, -61.46662902832031 ], "cluster": 16.0 }, { "idx": 1073, "title": "Extreme Precipitation in China: A Review on Statistical Methods and Applications", "abstract": "Recent years have witnessed global massive property losses and casualties caused by extreme precipitation and its subsequent natural disasters, including floods and landslides. China is one of the countries deeply affected by these casualties. If the statistical characteristics and laws of extreme precipitation could be clearly grasped, then the negative impacts triggered by it may be minimized. China is a vast country and diverse in climate and terrain, hence different regions may be suitable for different analyses and research methods. Therefore, it is necessary to clarify the research progress, methods and current status of extreme precipitation across the country. This paper attempts to provide a comprehensive review of techniques and methods used in extreme precipitation research and engineering practice and their applications. The literature is reviewed focusing on seven aspects: (1) annual maxima method (AM), (2) peaks over threshold method (POT), (3) probable maximum precipitation (PMP), (4) non-stationary analysis of precipitation extremes, (5) intensity-duration-frequency curves (IDF), (6) uncertainty in extreme precipitation frequency analysis, and (7) spatial variability of extreme precipitation. Research on extreme precipitation in China is generally based or centered on the above seven aspects. The current study aims to provide ideas for further research on extreme precipitation frequency analysis and its response to climate change and human activities.", "authors": [ "Gu, Xuezhi", "Ye, Lei", "Xin, Qian", "Zhang, Chi", "Zeng, Fanzhang", "Nerantzaki, Sofia D.", "Papalexiou, Simon Michael" ], "keywords": [ "Extreme precipitation", "China", "Annual maxima", "Peaks over threshold", "PMP", "Non-stationary", "IDF", "Uncertainty", "Spatial variability" ], "year": "2022", "source": "ADVANCES IN WATER RESOURCES", "publication_type": "J", "point2d": [ -34.883541107177734, -59.53569030761719 ], "cluster": 14.0 }, { "idx": 1074, "title": "A new very simply explicitly invertible approximation for the standard normal cumulative distribution function", "abstract": "This paper proposes a new very simply explicitly invertible function to approximate the standard normal cumulative distribution function (CDF). The new function was fit to the standard normal CDF using both MATLAB's Global Optimization Toolbox and the BARON software package. The results of three separate fits are presented in this paper. Each fit was performed across the range 0 <= z <= 7 and achieved a maximum absolute error (MAE) superior to the best MAE reported for previously published very simply explicitly invertible approximations of the standard normal CDF. The best MAE reported from this study is 2.73e-05, which is nearly a factor of five better than the best MAE reported for other published very simply explicitly invertible approximations.", "authors": [ "Lipoth, Jessica", "Tereda, Yoseph", "Papalexiou, Simon Michael", "Spiteri, Raymond J." ], "keywords": [ "normal distribution", "cumulative distribution function", "optimization" ], "year": "2022", "source": "AIMS MATHEMATICS", "publication_type": "J", "point2d": [ -28.379337310791016, -58.10749816894531 ], "cluster": 16.0 }, { "idx": 1075, "title": "Spatial variability of precipitation extremes over Italy using a fine-resolution gridded product", "abstract": "Study region: Italy. Study focus: Knowing magnitude and frequency of extreme precipitation is necessary to reduce their impact on vulnerable areas. Here we investigate the performance of the Generalized Extreme Value (GEV) distribution, using a fine-resolution satellite-based gridded product, to analyze 13,247 daily rainfall annual maxima samples. A non-extreme value distribution with a power-type behavior, that is, the Burr Type XII (BrXII), is also evaluated and used to test the reliability of the GEV in describing extreme rainfall. New hydrological insights for the region: (1) in 44.9 % of the analyzed samples the GEV predicts an upper rainfall limit; we deem this is an artifact due to sample variations; (2) we suggest the GEV(+) distribution, that is, the GEV with shape parameters restricted only to positive values as a more consistent model complying with the nature of extreme precipitation; (3) GEV, GEV (+) and BrXII performed equally well in describing the observed annual precipitation, yet all distributions underestimate the observed sample maximum; (4) the BrXII, for large return periods, predicts larger rainfall amounts compared to GEV indicating that GEV estimates could underestimate the risk of extremes; and (5) the correlation between the predicted rainfall and the elevation is investigated. Based on the results of this study, we suggest instead of using the classical GEV to use the GEV(+) and non-extreme value distributions such as the BrXII to describe precipitation extremes.", "authors": [ "Moccia, Benedetta", "Papalexiou, Simon Michael", "Russo, Fabio", "Napolitano, Francesco" ], "keywords": [ "Extreme rainfall analysis over Italy", "Generalized extreme value distribution", "Burr type XII distribution", "CHIRPS v2.0 dataset" ], "year": "2021", "source": "JOURNAL OF HYDROLOGY-REGIONAL STUDIES", "publication_type": "J", "point2d": [ -32.369117736816406, -58.55426788330078 ], "cluster": 14.0 }, { "idx": 1076, "title": "Assessing extremes in hydroclimatology: A review on probabilistic methods", "abstract": "Here we review methods used for probabilistic analysis of extreme events in Hydroclimatology. We focus on streamflow, precipitation, and temperature extremes at regional and global scales. The review has four thematic sections: (1) probability distributions used to describe hydroclimatic extremes, (2) comparative studies of parameter estimation methods, (3) non-stationarity approaches, and (4) model selection tools. Synthesis of the literature shows that: (1) recent studies, in general, agree that precipitation and streamflow extremes should be described by heavy-tailed distributions, (2) the Method of Moments (MOM) is typically the first choice in estimating distribution parameters but it is outperformed by methods such as L-Moments (LM), Maximum Likelihood (ML), Least Squares (LS), and Bayesian Markov Chain Monte Carlo (BMCMC), (3) there are less popular parameter estimation techniques such as the Maximum Product of Spacings (MPS), the Elemental Percentile (EP), and the Minimum Density Power Divergence Estimator (MDPDE) that have shown competitive performance in fitting extreme value distributions, and (4) non-stationary analyses of extreme events are gaining popularity; the ML is the typically used method, yet literature suggests that the Generalized Maximum Likelihood (GML) and the Weighted Least Squares (WLS) may be better alternatives. The review offers a synthesis of past and contemporary methods used in the analysis of hydroclimatic extremes, aiming to highlight their strengths and weaknesses. Finally, the comparative studies summary helps the reader identify the most suitable modeling framework for their analyses, based on the extreme hydroclimatic variables, sample sizes, locations, and evaluation metrics reviewed.", "authors": [ "Nerantzaki, Sofia D.", "Papalexiou, Simon Michael" ], "keywords": [ "Extremes", "Streamflow", "Precipitation", "Temperature", "Non-stationarity", "Probabilistic parameter estimation" ], "year": "2022", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -31.58564567565918, -59.69319152832031 ], "cluster": 14.0 }, { "idx": 1077, "title": "Advancing Space-Time Simulation of Random Fields: From Storms to Cyclones and Beyond", "abstract": "Realistic stochastic simulation of hydro-environmental fluxes in space and time, such as rainfall, is challenging yet of paramount importance to inform environmental risk analysis and decision making under uncertainty. Here, we advance random fields simulation by introducing the concepts of general velocity fields and general anisotropy transformations. This expands the capabilities of the so-called Complete Stochastic Modeling Solution (CoSMoS) framework enabling the simulation of random fields (RF's) preserving: (a) any non-Gaussian marginal distribution, (b) any spatiotemporal correlation structure (STCS), (c) general advection expressed by velocity fields with locally varying speed and direction, and (d) locally varying anisotropy. We also introduce new copula-based STCS's and provide conditions guaranteeing their positive definiteness. To illustrate the potential of CoSMoS, we simulate RF's with complex patterns and motion mimicking rainfall storms moving across an area, spiraling fields resembling weather cyclones, fields converging to (or diverging from) a point, and colliding air masses. The proposed methodology is implemented in the freely available CoSMoS R package.", "authors": [ "Papalexiou, Simon Michael", "Serinaldi, Francesco", "Porcu, Emilio" ], "keywords": [ "random fields", "advection", "anisotropy", "storms", "cyclones", "risk analysis" ], "year": "2021", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -32.28561019897461, -65.42942810058594 ], "cluster": 14.0 }, { "idx": 1078, "title": "Review of GPM IMERG performance: A global perspective", "abstract": "Accurate, reliable, and high spatio-temporal resolution precipitation data are vital for many applications, including the study of extreme events, hydrological modeling, water resource management, and hydroclimatic research in general. In this study, we performed a systematic review of the available literature to assess the performance of the Integrated Multi-Satellite Retrievals for GPM (IMERG) products across different geographical locations and climatic conditions around the globe. Asia, and in particular China, are the subject of the largest number of IMERG evaluation studies on the continental and country level. When compared to ground observational records, IMERG is found to vary with seasons, as well as precipitation type, structure, and intensity. It is shown to appropriately estimate and detect regional precipitation patterns, and their spatial mean, while its performance can be improved over mountainous regions characterized by orographic precipitation, complex terrains, and for winter precipitation. Furthermore, despite IMERG's better performance compared to other satellite products in reproducing spatio-temporal patterns and variability of extreme precipitation, some limitations were found regarding the precipitation intensity. At the temporal scales, IMERG performs better at monthly and annual time steps than the daily and sub-daily ones. Finally, in terms of hydrological application, the use of IMERG has resulted in significant discrepancies in streamflow simulation. However, and most importantly, we find that each new version that replaces the previous one, shows substantial improvement in almost every spatiotemporal scale and climatic condition. Thus, despite its limitations, IMERG evolution reveals a promising path for current and future applications.", "authors": [ "Pradhan, Rajani K.", "Markonis, Yannis", "Godoy, Mijael Rodrigo Vargas", "Villalba-Pradas, Anahi", "Andreadis, Konstantinos M.", "Nikolopoulos, Efthymios I.", "Papalexiou, Simon Michael", "Rahim, Akif", "Tapiador, Francisco J.", "Hanel, Martin" ], "keywords": [ "IMERG", "GPM validation", "Remote sensing of precipitation", "Precipitation extremes", "Hydrological modeling" ], "year": "2022", "source": "REMOTE SENSING OF ENVIRONMENT", "publication_type": "J", "point2d": [ -47.42726135253906, -42.886837005615234 ], "cluster": 14.0 }, { "idx": 1079, "title": "Changes in the risk of extreme temperatures in megacities worldwide", "abstract": "Globally, extreme temperatures have severe impacts on the economy, human health, food and water security, and ecosystems. Mortality rates have been increased due to heatwaves in several regions. Specifically, megacities have high impacts with the increasing temperature and everexpanding urban areas; it is important to understand extreme temperature changes in terms of duration, magnitude, and frequency for future risk management and disaster mitigation. Here we framed a novel Semi-Parametric quantile mapping method to bias-correct the CMIP6 minimum and maximum temperature projections for 199 megacities worldwide. The changes in maximum and minimum temperature are quantified in terms of climate indices (ETCCDI and HDWI) for the four Shared Socioeconomic Pathways (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5). Cities in northern Asia and northern North America (Kazan, Samara, Heihe, Montre ' al, Edmonton, and Moscow) are warming at a higher rate compared to the other regions. There is an increasing and decreasing trend for the warm and cold extremes respectively. Heatwaves increase exponentially in the future with the increase in warming, that is, from SSP1-2.6 to SSP5-8.5. Among the CMIP6 models, a huge variability is observed, and this further increases as the warming increases. All climate indices have steep slopes for the far future (2066-2100) compared to the near future (2031-2065). Yet the variability among CMIP6 models in near future is high compared to the far future for cold indices.", "authors": [ "Rajulapati, Chandra Rupa", "Abdelmoaty, Hebatallah Mohamed", "Nerantzaki, Sofia D.", "Papalexiou, Simon Michael" ], "keywords": [ "Temperature trends", "CMIP6 projections", "ETCCDI indices", "Heatwaves", "Extreme temperature", "Megacities" ], "year": "2022", "source": "CLIMATE RISK MANAGEMENT", "publication_type": "J", "point2d": [ -37.37431716918945, -65.29682159423828 ], "cluster": 14.0 }, { "idx": 1080, "title": "The Global Water Cycle Budget: A Chronological Review", "abstract": "Like civilization and technology, our understanding of the global water cycle has been continuously evolving, and we have adapted our quantification methods to better exploit new technological resources. The accurate quantification of global water fluxes and storages is crucial in studying the global water cycle. These fluxes and storages physically interact with each other, are related through the water budget, and are constrained by it. First attempts to quantify them date back to the early 1900s, and during the past few decades, they have received an increasing research interest, which is reflected in the vast amount of data sources available nowadays. However, these data have not been comprehensive enough due to the high spatiotemporal variability of the global water cycle. Herein, we provide a comprehensive review of the chronological evolution of global water cycle quantification, the distinct data sources and methods used, and a critical assessment of their contribution to improving the spatiotemporal monitoring of the global water cycle. The chronology of global water cycle components shows that the uncertainty of flux estimates over oceans remains higher than that over land. Comparing the standard deviation and the interquartile range of the estimates from the 2000s onward with those from all the estimates (1905-2019), we can affirm that statistical variability has diminished in recent years. Moreover, the variability of ocean precipitation and evaporation estimates from the 2000 onward was reduced by more than 70% compared with earlier studies. These findings advocate that the consistency of global water cycle quantification has been improved.", "authors": [ "Vargas Godoy, Mijael Rodrigo", "Markonis, Yannis", "Hanel, Martin", "Kysely, Jan", "Papalexiou, Simon Michael" ], "keywords": [ "Global water cycle", "Water budget", "Multi-source quantification" ], "year": "2021", "source": "SURVEYS IN GEOPHYSICS", "publication_type": "J", "point2d": [ 0.4130637049674988, 11.86709976196289 ], "cluster": 14.0 }, { "idx": 1081, "title": "Increasing trends in rainfall erosivity in the Yellow River basin from 1971 to 2020", "abstract": "Hourly precipitation data from 1971 to 2020, collected from 98 stations distributed across the Yellow River basin, were analyzed to detect changes in characteristics on rainfall and rainfall erosivity for all storms and storms with extreme erosivity (greater than 90th percentile). Results showed that over the past 50 years, rainfall erosivity at both event and seasonal scales over the whole basin increased significantly (p < 0.05) with rates of 5.46% and 6.86% decade-1, respectively, compared to the 1981-2010 average values. Approximate 80% of 98 stations showed increasing trends and 20% of stations had statistically significant trends (p < 0.1). The increase of rainfall erosivity resulted from the significant increasing trends of average storm precipitation (p < 0.1), duration (p < 0.1), rainfall energy (p < 0.05) and maximum 1-h intensity (p < 0.05). In addition, the total extreme erosivity showed significant upward trends at a relative rate of 6.05% decade(-1) (p < 0.05). Extreme erosivity storms occurred more frequently and with higher rainfall energy during the study period (p < 0.05). Trends for seasonal total and extreme erosivity were also estimated based on daily rainfall data, and the changing magnitudes were similar to those based on hourly rainfall data, which suggested daily rainfall can be applied to detect interannual and long-term variations of rainfall erosivity in the absence of rainfall data with higher resolution. It was suggested that soil and water conservation strategies and vegetation projects conducted within the Yellow River basin should be continued and enhanced in the future.", "authors": [ "Wang, W.", "Yin, S.", "Gao, G.", "Papalexiou, S. M.", "Wang, Z." ], "keywords": [ "Yellow River basin", "Rainfall erosivity", "Extreme precipitation", "Sediment reduction", "Climate change" ], "year": "2022", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -35.874935150146484, -58.35247039794922 ], "cluster": 14.0 }, { "idx": 1082, "title": "Informing Stochastic Streamflow Generation by Large-Scale Climate Indices at Single and Multiple Sites", "abstract": "Despite the existence of several stochastic streamflow generators, not much attention has been given to representing the impacts of large-scale climate indices on seasonal to interannual streamflow variability. By merging a formal predictor selection scheme with vine copulas, we propose a generic approach to explicitly incorporate large-scale climate indices in ensemble streamflow generation at single and multiple sites and in both short-term prediction and long-term projection modes. The proposed framework is applied at three headwater streams in the Oldman River Basin in southern Alberta, Canada. The results demonstrate higher skills than existing models both in terms of representing intra- and inter-annual variability, as well as accuracy and predictability of streamflow, particularly during high flow seasons. The proposed algorithm presents a globally relevant scheme for the stochastic streamflow generation, where the impacts of large-scale climate indices on streamflow variability across time and space are significant.", "authors": [ "Zaerpour, Masoud", "Papalexiou, Simon Michael", "Nazemi, Ali" ], "keywords": [ "Streamflow variability", "Large-scale climate indices", "Stochastic streamflow generation", "Predictor selection", "Vine copulas", "Algorithm development" ], "year": "2021", "source": "ADVANCES IN WATER RESOURCES", "publication_type": "J", "point2d": [ -29.081321716308594, -27.7764892578125 ], "cluster": 16.0 }, { "idx": 1083, "title": "A Low-Cost Multi-Parameter Water Quality Monitoring System", "abstract": "Multi-parameter water quality monitoring is crucial in resource-limited areas to provide persistent water safety. Conventional water monitoring techniques are time-consuming, require skilled personnel, are not user-friendly and are incompatible with operating on-site. Here, we develop a multi-parameter water quality monitoring system (MWQMS) that includes an array of low-cost, easy-to-use, high-sensitivity electrochemical sensors, as well as custom-designed sensor readout circuitry and smartphone application with wireless connectivity. The system overcomes the need of costly laboratory-based testing methods and the requirement of skilled workers. The proposed MWQMS system can simultaneously monitor pH, free chlorine, and temperature with sensitivities of 57.5 mV/pH, 186 nA/ppm and 16.9 mV/degrees C, respectively, as well as sensing of BPA with <10 nM limit of detection. The system also provides seamless interconnection between transduction of the sensors' signal, signal processing, wireless data transfer and smartphone app-based operation. This interconnection was accomplished by fabricating nanomaterial and carbon nanotube-based sensors on a common substrate, integrating these sensors to a readout circuit and transmitting the sensor data to an Android application. The MWQMS system provides a general platform technology where an array of other water monitoring sensors can also be easily integrated and programmed. Such a system can offer tremendous opportunity for a broad range of environmental monitoring applications.", "authors": [ "Alam, Arif Ul", "Clyne, Dennis", "Deen, M. Jamal" ], "keywords": [ "electrochemical sensors", "free chlorine", "heavy metal", "pH", "pharmaceutical contaminants", "potentiostat", "temperature sensor", "water quality monitoring", "water sensors" ], "year": "2021", "source": "SENSORS", "publication_type": "J", "point2d": [ 77.93988800048828, 42.30190658569336 ], "cluster": 6.0 }, { "idx": 1084, "title": "Quantifying the Impact of Electrically Conductive Membrane-Generated Hydrogen Peroxide and Extreme pH on the Viability of Escherichia coli Biofilms", "abstract": "Electrically conductive membranes (ECMs) self-induce antifouling mechanisms at their surface under certain applied electrical currents. Quantifying these mechanisms is critical to enhancing ECMs' self-cleaning performance. Local pH change and H2O2 production are among the most important self-cleaning mechanisms previously hypothesized for ECMs. However, the impacts of these mechanisms have not previously been isolated and comprehensively studied. In this study, we quantified the individual impact of electrochemically induced acidic conditions, alkaline conditions, and H2O2 concentration on model bacteria, Escherichia coli. To this end, we first quantified the electrochemical potential of carbon nanotube-based ECMs to generate stressors, such as protons, hydroxyl ions, and H2O2, under a range of applied electrical currents (+0-150 mA, 0-2.7 V). Next, these chemical stressors with similar magnitude to that generated at the ECM surfaces were imposed on E. coli cells and biofilms. In the flow-through ECM systems, biofilm viability using LIVE/DEAD staining indicated biofilm viabilities of 39 +/- 9.9%, 38 +/- 4.7%, 45 +/- 5.0%, 34 +/- 3.1%, and 75 +/- 4.9% after separate exposure to pH 3.5, anodic potential (2 V), pH 11, cathodic potential (2 V), and H2O2 concentration (188 mu M). Electrical current-induced pH change at the membrane surface was shown to be more effective in reducing bacterial viability than H2O2 generation and more efficient than bulk pH changes. This study identified antibiofouling mechanisms of ECMs and provides guidance for determining the current patterns that maximize their antifouling effects.", "authors": [ "Halali, Mohamad Amin", "de Lannoy, Charles-Francois" ], "keywords": [ "" ], "year": "2022", "source": "INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH", "publication_type": "J", "point2d": [ 71.39202880859375, 48.37094497680664 ], "cluster": 6.0 }, { "idx": 1085, "title": "Integrated Microfluidic-Based Platforms for On-Site Detection and Quantification of Infectious Pathogens: Towards On-Site Medical Translation of SARS-CoV-2 Diagnostic Platforms", "abstract": "The rapid detection and quantification of infectious pathogens is an essential component to the control of potentially lethal outbreaks among human populations worldwide. Several of these highly infectious pathogens, such as Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have been cemented in human history as causing epidemics or pandemics due to their lethality and contagiousness. SARS-CoV-2 is an example of these highly infectious pathogens that have recently become one of the leading causes of globally reported deaths, creating one of the worst economic downturns and health crises in the last century. As a result, the necessity for highly accurate and increasingly rapid on-site diagnostic platforms for highly infectious pathogens, such as SARS-CoV-2, has grown dramatically over the last two years. Current conventional non-microfluidic diagnostic techniques have limitations in their effectiveness as on-site devices due to their large turnaround times, operational costs and the need for laboratory equipment. In this review, we first present criteria, both novel and previously determined, as a foundation for the development of effective and viable on-site microfluidic diagnostic platforms for several notable pathogens, including SARS-CoV-2. This list of criteria includes standards that were set out by the WHO, as well as our own seven pillars for effective microfluidic integration. We then evaluate the use of microfluidic integration to improve upon currently, and previously, existing platforms for the detection of infectious pathogens. Finally, we discuss a stage-wise means to translate our findings into a fundamental framework towards the development of more effective on-site SARS-CoV-2 microfluidic-integrated platforms that may facilitate future pandemic diagnostic and research endeavors. Through microfluidic integration, many limitations in currently existing infectious pathogen diagnostic platforms can be eliminated or improved upon.", "authors": [ "Escobar, Andres", "Chiu, Phyllis", "Qu, Jianxi", "Zhang, Yushan", "Xu, Chang-qing" ], "keywords": [ "microfluidics", "diagnostics", "infectious pathogens", "SARS-CoV-2", "COVID-19", "on-site", "medical diagnosis" ], "year": "2021", "source": "MICROMACHINES", "publication_type": "J", "point2d": [ 73.57491302490234, 28.68874168395996 ], "cluster": 6.0 }, { "idx": 1086, "title": "Critical review of bio/nano sensors for arsenic detection", "abstract": "Detection of arsenic is a long-standing challenge in environmental analytical chemistry. In recent years, using biomolecules and nanomaterials for sensing arsenic has been growingly reported. In this article, this field is critically reviewed based on some recent fundamental understandings including interactions between arsenic and gold, thiol, and DNA aptamers. First, taking advantage of the adsorption of As(III) on noble metal surfaces such as silver and gold, sensors were developed based on surface enhanced Raman spectroscopy, electrochemistry and colorimetry. In addition, by functionalizing metal nanoparticles with thiol containing molecules, As(III) induced aggregation of the particles based on As(III)/thiol interactions. As(V) interacts with metal oxides strongly and competitive sensors were developed by displacing pre-adsorbed DNA oligonucleotides. A DNA aptamer was selected for As(III) and many sensors were reported based on this aptamer, although careful binding measurements indicated that the sequence has no affinity towards As(III). Overall, bio/nano systems are promising for the detection of arsenic. Future work on fundamental studies, searching for more specific arsenic binding materials and aptamers, incorporation of sensors into portable devices, and more systematic test of sensors in real samples could be interesting and useful research topics.", "authors": [ "Zong, Chenghua", "Jin, Xiaoting", "Liu, Juewen" ], "keywords": [ "Biosensors", "Gold nanoparticles", "Aptamers", "Arsenite", "Arsenate" ], "year": "2021", "source": "TRENDS IN ENVIRONMENTAL ANALYTICAL CHEMISTRY", "publication_type": "J", "point2d": [ 83.13811492919922, 40.767417907714844 ], "cluster": 6.0 }, { "idx": 1087, "title": "Tuning the Chemical and Mechanical Properties of Conductive MoS2 Thin Films by Surface Modification with Aryl Diazonium Salts", "abstract": "Molybdenum disulfide (MoS2) is a promising material for applications in sensors, energy storage, energy conversion devices, solar cells, and fuel cells. Because many of those applications require conductive materials, we recently developed a method for preparing a conductive form of MoS2 (c-MoS2) using dilute aqueous hydrogen peroxide in a simple and safe way. Here, we investigate modulating the chemical and mechanical surface properties of c-MoS2 thin films using diazonium chemistry. In addition to a direct passivation strategy of c-MoS2 with diazonium salts for electron-withdrawing groups, we also propose a novel in situ synthetic pathway for modification with electron-donating groups. The obtained results are examined by Raman spectroscopy and X-ray photoelectron spectroscopy. The degree of surface passivation of pristine and functionalized c-MoS2 films was tested by exposing them to aqueous solutions of different metal cations (Fe2+, Zn2+, Cu2+, and Co2+) and detecting the chemiresistive response. While pristine films were found to interact with several of the cations, modified films did not. We propose that a surface charge transfer mechanism is responsible for the chemiresistive response of the pristine films, while both modification routes succeeded at complete surface passivation. Functionalization was also found to lower the coefficient of friction for semiconducting 2H-MoS2, while all conductive materials (modified or not) also had lower coefficients of friction. This opens up a pathway to a palette of dry lubricant materials with improved chemical stability and tunable conductivity. Thus, both in situ and direct diazonium chemistries are powerful tools for tuning chemical and mechanical properties of conductive MoS2 for new devices and lubricants based on conductive MoS2.", "authors": [ "Saha, Dipankar", "Angizi, Shayan", "Darestani-Farahani, Maryam", "Dalmieda, Johnson", "Selvaganapathy, Ponnambalam Ravi", "Kruse, Peter" ], "keywords": [ "" ], "year": "2022", "source": "LANGMUIR", "publication_type": "J", "point2d": [ 84.48033905029297, 54.39219284057617 ], "cluster": 6.0 }, { "idx": 1088, "title": "Facile fabrication of conductive MoS2 thin films by sonication in hot water and evaluation of their electrocatalytic performance in the hydrogen evolution reaction", "abstract": "Molybdenum disulfide (MoS2) has long been used in catalysis and is a promising material for energy conversion devices. In order to utilize MoS2 in electrocatalytic applications, it needs to be sufficiently conductive. Even though a metallic 1T phase of MoS2 exists, its exfoliation process is expensive and difficult to scale because it involves hazardous materials and procedures, limiting its practical applications. We have previously reported an efficient and environmentally friendly procedure to exfoliate conductive MoS(2)via sonication in very dilute aqueous hydrogen peroxide. Here, we report a new way of exfoliating heavily doped conductive MoS2 by sonication in pure water at 60 degrees C without additives. Conductivity measurements, Raman spectroscopy and X-ray photoelectron spectroscopy demonstrate that controlling the sonication time and temperature lead to the generation of small quantities of hydrogen peroxide in the water that interact with MoS2 to form a small amount of sub-stoichiometric MoO3-y. This impurity acts as a dopant and is responsible for the increase in conductivity of the MoS2 films without compromising their structural integrity. We also evaluate the performance of the doped MoS2 films as electrocatalysts in the hydrogen evolution reaction. We elucidate the mechanistic origin of the catalytic properties of these materials which may be of future use to develop a family of electrocatalysts based on doped MoS2.", "authors": [ "Saha, Dipankar", "Patel, Vinay", "Selvaganapathy, Ponnambalam Ravi", "Kruse, Peter" ], "keywords": [ "" ], "year": "2021", "source": "NANOSCALE ADVANCES", "publication_type": "J", "point2d": [ 83.03856658935547, 54.36785888671875 ], "cluster": 6.0 }, { "idx": 1089, "title": "Methods for stability assessment of electrically conductive membranes", "abstract": "The surface properties of electrically conductive membranes (ECMs) govern their advanced abilities. During operation, these properties may differ considerably from their initially measured properties. Depending on their operating conditions, ECMs may undergo various degrees of passivation. ECM passivation can detrimentally impact their real time performance, causing large deviations from expected behaviour based on their initially measured properties. Quantifying these changes will enable consistent performance comparisons across the active and electrically conductive membrane research field. As such, consistent methods must be established to quantify ECM membrane properties. In this work, we proposed three standardized methods to assess the electrochemical, chemical, and physical stability of such membrane coatings: 1) electrochemical oxidation, 2) surface scratch testing, and 3) pressurized leaching. ECMs were synthesized by the most common approach coating support ultrafiltration (UF) and/or microfiltration (MF) polyethersulfone (PES) membranes with carbon nanotubes (CNT) cross-linked with polyvinyl alcohol (PVA) and two types of cross-linkers (either succinic acid (SA) or glutaraldehyde (GA)). We then evaluated these ECMs based on the three standardized methods: 1) We evaluated electrochemical stability as a function of electro-oxidation induced by applying anodic potentials. 2) We measured the scratch resistance to quantify the surface mechanical stability. 3) We measured physical stability by quantifying the leaching of PVA during separation of a model foulant (polyethylene oxide (PEO)). Our methods can be extended to all types of electrically conductive membranes including MF, UF, nanofiltration (NF), and reverse osmosis (RO) ECMs. We propose that these fundamental measurements are critical to assessing the viability of ECMs for industrial MF, UF, NF, and RO applications. Anodic-oxidation was used to check the electrochemical stability of ECMs Depth of penetration resulted from scratch test is an indicator of the electrically conductive membrane coating's mechanical stability The leaching of the main components forming the nanolayer was quantified to assess the membranes' physical stability (C) 2022 The Authors. Published by Elsevier B.V.", "authors": [ "Halali, Mohamad Amin", "de lannoy, Charles-Francois" ], "keywords": [ "Electrically conductive membranes", "Scratch resistance", "Mechanical stability", "Electrochemical oxidation", "Polyvinyl alcohol", "Carbon nanotubes", "Glutaraldehyde", "Succinic acid", "Anodic potential", "Electrified membranes" ], "year": "2022", "source": "METHODSX", "publication_type": "J", "point2d": [ 69.46354675292969, 50.25923538208008 ], "cluster": 6.0 }, { "idx": 1090, "title": "Simultaneous Dechlorination and Advanced Oxidation Using Electrically Conductive Carbon Nanotube Membranes", "abstract": "Electrically conductive membranes have shown significant promise in combining conventional separations with in situ contaminant oxidation, but little has been done to consider chlorine removal. This study demonstrates the simultaneous chlorine removal and oxidation of organic compounds during filtration using an electrochemically assisted electrically conductive carbon nanotube (CNT) membrane. As much as 80% of chlorine was removed in the feed by CNT membranes at the initial phase of continuous filtration. The efficacy of these CNT membranes toward chlorine removal was dependent on the mass of CNTs within the membranes and the applied pressure to the membranes, indicating the central role of available CNT active sites and sufficient reaction time. Furthermore, the removal mechanism of chlorine by CNTs was revealed by studying the degradation of benzoic acid and cyclic voltammetry on the membrane surface. Reactive oxidants were generated by the reductive decomposition of chlorine through the catalytic interaction with CNTs. Subsequently, electrical potentials were applied to the CNT membrane surfaces during the filtration of chlorinated feed waters. The simultaneous decomposition of chlorine and oxidation of benzoic acid were significantly enhanced by applying a cathodic current to CNT membranes enabling continuous dechlorination. The cathodic current applied to CNT membranes is believed to regenerate CNT membranes by providing electrons for the reductive decomposition of chlorine. In situ chemical-free dechlorination coupled with membrane filtration offers great opportunity to reducing the environmental impact of desalination, while maximizing the lifetime of reverse osmosis membranes and demonstrating greener approaches available to industrial water treatment.", "authors": [ "Lee, Hye-Jin", "Zhang, Nan", "Ganzoury, Mohamed A.", "Wu, Yichen", "de Lannoy, Charles-Francois" ], "keywords": [ "chlorine activation", "single-/double-walled carbon nanotubes", "advanced oxidation", "electrically conductive membranes", "reductive decomposition" ], "year": "2021", "source": "ACS APPLIED MATERIALS & INTERFACES", "publication_type": "J", "point2d": [ 74.22001647949219, 47.155521392822266 ], "cluster": 6.0 }, { "idx": 1091, "title": "Pencil graphite as electrode platform for free chlorine sensors and energy storage devices", "abstract": "Multifunctional and low-cost electrode materials are desirable for the next-generation sensors and energy storage applications. This paper reports the use of pencil graphite as an electrode for dual applications that include the detection of free residual chlorine using electro-oxidation process and as an electrochemical energy storage cathode. The pencil graphite is transferred to cellulose paper by drawing ten times and applied for the detection of free residual chlorine, which shows a sensitivity of 27 mu A mM(-1) cm(-2) with a limit of detection of 88.9 mu M and linearity up to 7 mM. The sample matrix effect study for the commonly interfering ions such as NO3-, SO42-, CO32-, Cl-, HCO3- shows minimal impact on free residual chlorine detection. Pencil graphite then used after cyclic voltammogram treatment as a cathode in the aqueous Zn/Al-ion battery, showing an average discharge potential plateau of similar to 1.1 V, with a specific cathode capacity of similar to 54.1 mAh g(-1) at a current of 55 mA g(-1). It maintains similar to 95.8% of its initial efficiency after 100 cycles. Results obtained from the density functional theory calculation is consistent with the electro-oxidation process involved in the detection of free residual chlorine, as well as intercalation and de-intercalation behavior of Al3+ into the graphite layers of Zn/Al-ion battery. Therefore, pencil graphite due to its excellent electro-oxidation and conducting properties, can be successfully implemented as low cost, disposable and green material for both sensor and energy-storage applications.", "authors": [ "Islam, Jahidul", "Shao, Han", "Badal, Md Mizanur Rahman", "Razeeb, Kafil M.", "Jamal, Mamun" ], "keywords": [ "" ], "year": "2021", "source": "PLOS ONE", "publication_type": "J", "point2d": [ 76.45610809326172, 46.56407928466797 ], "cluster": 6.0 }, { "idx": 1092, "title": "A Microflow Cytometry-Based Agglutination Immunoassay for Point-of-Care Quantitative Detection of SARS-CoV-2 IgM and IgG", "abstract": "A rapid, sensitive and simple microflow cytometry-based agglutination immunoassay (MCIA) was developed for point-of-care (POC) quantitative detection of SARS-CoV-2 IgM and IgG antibodies. The antibody concentration was determined by using the transit time of beads aggregates. A linear relationship was established between the average transit time and the concentration of SARS-CoV-2 IgM and IgG, respectively. The limit of detection (LOD) of SARS-CoV-2 IgM and IgG by the MCIA measurement are 0.06 mg/L and 0.10 mg/L, respectively. The 10 mu L sample consumption, 30 min assay time and the compact setup make this technique suitable for POC quantitative detection of SARS-CoV-2 antibodies.", "authors": [ "Qu, Jianxi", "Chenier, Mathieu", "Zhang, Yushan", "Xu, Chang-qing" ], "keywords": [ "SARS-CoV-2 IgM", "SARS-CoV-2 IgG", "microflow cytometry", "agglutination immunoassay", "point-of-care" ], "year": "2021", "source": "MICROMACHINES", "publication_type": "J", "point2d": [ 72.80919647216797, 29.061738967895508 ], "cluster": 6.0 }, { "idx": 1093, "title": "Selection of a self-cleaving ribozyme activated in a chemically and thermally denaturing environment", "abstract": "A new self-cleaving ribozyme was obtained from in vitro selection, displaying site-specific cleavage activity under denaturing conditions, such as high temperatures up to 95 degrees C, and denaturing solvents (20 M formamide). Adding salt such as Mg2+ also inhibited its activity. The conserved ribozyme sequence was found in the genome of several extremophiles, suggesting its potential biological relevance. This study provides an example of a ribozyme working under exotic conditions, which may expand the application of ribozymes in non-biological environments.", "authors": [ "Ma, Lingzi", "Huang, Zhicheng", "Liu, Juewen" ], "keywords": [ "" ], "year": "2021", "source": "CHEMICAL COMMUNICATIONS", "publication_type": "J", "point2d": [ 93.07969665527344, 34.416969299316406 ], "cluster": 6.0 }, { "idx": 1094, "title": "Colorimetric Detection of Heavy Metal Ions Using Superabsorptive Hydrogels and Evaporative Concentration for Water Quality Monitoring", "abstract": "Prevalence of high levels of metal ions in naturaland drinking water is a growing problem to both ecosystems andhuman health. Several methods are broadly used for heavy metalmonitoring in water resources, but most of them are laboratory-based. Here, we describe a method that simplifies the measurementprocess by enabling passive aliquoting and preconcentration ofheavy metals. We use superabsorbent polymer beads that can takeup hundreds of times their volume to aliquot the sample andpreconcentrate the ionic species present in them by 2 orders ofmagnitude. We then use commercially available colorimetric dyesthat are sensitive only at high concentrations to reveal a visiblerange change in the bead color that can be measured opticallyusing a camera. Using this approach, we have detected theconcentration of copper(II) ions in water as low as 5.4 ppb. We demonstrate that this method can also be used for drinking waterand tap water samples to assess concentrations of copper and iron. This solid-state method significantly simplifies the analyticalprocedure and provides extremely low detection levels of heavy metals, eliminating the need for expensive equipment and hencecould be useful in remote settings.", "authors": [ "Fathalla, Mohamed", "Selvaganapathy, Ponnambalam Ravi" ], "keywords": [ "superabsorbent polymers", "hydrogel", "heavy metals", "preconcentration", "colorimetric detection", "solid state" ], "year": "2022", "source": "ACS ES&T WATER", "publication_type": "J", "point2d": [ 79.85466766357422, 39.61546325683594 ], "cluster": 6.0 }, { "idx": 1095, "title": "Selection of Aptamers for Sensing Caffeine and Discrimination of Its Three Single Demethylated Analogues", "abstract": "With the growing consumption of caffeine-containing beverages, detection of caffeine has become an important biomedical, bioanalytical, and environmental topic. We herein isolated four high-quality aptamers for caffeine with dissociation constants ranging from 2.2 to 14.6 mu M as characterized using isothermal titration calorimetry. Different binding patterns were obtained for the three single demethylated analogues: theobromine, theophylline, and paraxanthine, highlighting the effect of the molecular symmetry of the arrangement of the three methyl groups in caffeine. A structure-switching fluorescent sensor was designed showing a detection limit of 1.2 mu M caffeine, which reflected the labeled caffeine concentration within 6.1% difference for eight commercial beverages. In 20% human serum, a detection limit of 4.0 mu M caffeine was achieved. With the four aptamer sensors forming an array, caffeine and the three analogues were well separated from nine other closely related molecules.", "authors": [ "Huang, Po-Jung Jimmy", "Liu, Juewen" ], "keywords": [ "" ], "year": "2022", "source": "ANALYTICAL CHEMISTRY", "publication_type": "J", "point2d": [ 86.41746520996094, 38.49949264526367 ], "cluster": 6.0 }, { "idx": 1096, "title": "Phosphorothioate nucleic acids for probing metal binding, biosensing and nanotechnology", "abstract": "Phosphorothioate (PS) modification replaces one of the non-bridging oxygen atoms by sulfur in the phosphate backbone of nucleic acids. While PS DNAs have been traditionally used as nuclease-resistant antisense agents and PS RNA as probe of metal binding in ribozymes, multiple new applications have emerged in recent years. In this review, we start by briefly introducing the structure and synthesis of PS nucleic acids followed by their fundamental chemical and biochemical properties. Further, their recently emerged surface science applications are discussed, such as attachment of DNA to various surfaces and nanomaterials containing thiophilic metals such as gold, silver and cadmium, and templating the growth of these materials. Their role in conferring structural effects in the presence of certain metal ions and in fishing out novel aptamers are also discussed. Covalent chemistry can be performed on the sulfur atom for further grafting functional groups to the backbone of DNA. For PS RNA, we discuss their role as probes for metal binding in ribozymes and DNAzymes, which leads to applications in detection of thiophilic metal ions. Since each PS modification site produces a chiral phosphorus center, the synthesis and purification of diastereomers and their applications are emphasized throughout this review. In the end, a few future research directions are discussed. (C) 2020 Elsevier B.V. All rights reserved.", "authors": [ "Saran, Runjhun", "Huang, Zhicheng", "Liu, Juewen" ], "keywords": [ "Aptamers", "DNAzymes", "Nanomaterials", "Metal ions", "Coordination chemistry" ], "year": "2021", "source": "COORDINATION CHEMISTRY REVIEWS", "publication_type": "J", "point2d": [ 89.60966491699219, 37.2198600769043 ], "cluster": 6.0 }, { "idx": 1097, "title": "Green Approach Using RuO2/GO Nanocomposite for Low Cost and Highly Sensitive pH Sensing", "abstract": "Rapid and inexpensive monitoring the real-time status of food products using pH sensors is critical for food quality and safety to determine if pathogens are present and growing. A promising material for pH sensors is ruthenium dioxide (RuO2) due to its chemical stability and excellent performance including: high sensitivity, low drift and hysteresis, and good selectivity. Furthermore, graphene oxide (GO) provides an electrode with large surface area, and good electrical properties. In this work, the in situ sol-gel deposition of RuO2 nanoparticles on the surface of GO as a facile, cost-effective, and environmentally friendly approach is used for the fabrication of a flexible pH sensor. The as-synthesized GO-RuO2 nanocomposites with a low volume were applied on the surface of screen printed carbon paste. The obtained GO-RuO2 nanocomposite pH sensor achieved high pH sensitivity (55.3 mV pH(-1)) in the pH range of 4-10, up to 4 times higher than the unmodified carbon electrode. The increased sensitivity of the modified electrode could be attributed to the uniform anchoring of small, crystallized RuO2 nanoparticles on the surface of GO sheets, resulting in synergistic effects between them. It also shows low drift (0.36 mV h(-1)) and low hysteretic width (0.8 mV). Considering the novel method of deposition and also sensing material with the cost-effective green synthesis approach, as well as excellent pH sensing properties, GO-RuO2 can be considered as a promising material for production of high-performance electrochemical pH sensors for food quality monitoring. (C) 2022 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited.", "authors": [ "Taheri, Mahtab", "Deen, M. Jamal" ], "keywords": [ "" ], "year": "2022", "source": "JOURNAL OF THE ELECTROCHEMICAL SOCIETY", "publication_type": "J", "point2d": [ 81.52836608886719, 43.69940185546875 ], "cluster": 6.0 }, { "idx": 1098, "title": "Reagent-Free Hydrogen Peroxide Sensing Using Carbon Nanotube Chemiresistors with Electropolymerized Crystal Violet", "abstract": "Hydrogen peroxide (H2O2) is an intermediate molecule generated in numerous peroxidase assays used to measure concentrations of biomolecules such as glucose, galactose, and lactate. Here, we develop a solid-state reagent-free chemiresistive H2O2 sensor, which can measure H2O2 over a wide measuring range of 0.5-1000 ppm (0.015-29.4 mM). The sensor was fabricated using a network of functionalized single-walled carbon nanotubes (SWCNTs) as a sensitive layer and a xurographically patterned gold leaf as a contact electrode. The SWCNTs were functionalized with crystal violet to impart selective detection of H2O2. The crystal violet was self-assembled on the SWCNT film and subsequently polymerized via cyclic voltammetry to improve its retention on the sensing layer. The functionalized sensor exhibited good selectivity against common interferents such as uric acid, urea, glucose, and galactose. In addition, the sensor was used to measure in situ H2O2 generated during peroxidase assays performed using enzymes like glucose oxidase. The sensor was tested in standard buffer solutions for both enzymes. The glucose oxidase assay was also demonstrated in spiked pooled human plasma samples. The glucose oxidase-coated sensor exhibited a glucose detection range of 2-20 mM in standard buffer and blood plasma solutions, with a good recovery rate (similar to 95-107%) for glucose measurements in blood plasma.", "authors": [ "Patel, Vinay", "Saha, Dipankar", "Kruse, Peter", "Selvaganapathy, Ponnambalam Ravi" ], "keywords": [ "hydrogen peroxide", "chemiresistive biosensor", "solid-state sensor", "crystal violet", "electropolymerized self-assembled monolayer" ], "year": "2022", "source": "ACS APPLIED NANO MATERIALS", "publication_type": "J", "point2d": [ 82.71745300292969, 50.1066780090332 ], "cluster": 6.0 }, { "idx": 1099, "title": "A xurography based rapid prototyping method to fabricate low-cost and high quality metal thin film micropatterns using metal leaves", "abstract": "Metal leaves are commercially available for decoration purposes and offers a low-cost alternative to sputtering thin metal films. Although thin metal leaves have been sparingly used in physical and chemical sensing and solar cells, their application has been limited primarily due to lack of a simple patterning methods and to form microscale features with them. Here, a low-cost, rapid and simple xurography based cutting method has been developed for direct pattering of metal leaves. The method was able to pattern features with line width of < 100 mu m and it was also able to cut patterns with a pitch of < 100 mu m. Conductive lines < 250 mu m were also achieved which is a sufficient resolution for application in sensors and most biomedical devices. The versatile capability of this method to cut various geometric shapes like circle, rectangle, triangles and hexagons was also demonstrated. The method is robust and can be applied to pattern leaves made of several materials or which gold, silver, palladium, aluminum and copper were demonstrated. This patterning method was used to fabricate contact electrodes for chemiresistive sensors with low and high surface roughness. These sensors were evaluated using the resistance and noise characteristics. The peak-to-peak noise for gold contact electrodes (11.5 nA) for chemiresistive sensors was significantly lower than the copper tape contact electrodes (18.2 nA). The process was also used to fabricate gold interdigitated electrodes for biamperometric glucose sensing at low potential (similar to 10 mV). Finally, the method was used to indirectly pattern gold leaf on a shrink film to fabricate high surface 3D electrodes costing around one-fifth (similar to 20%) of a sputtered gold electrode.", "authors": [ "Patel, Vinay", "Kruse, Peter", "Selvaganapathy, P. Ravi" ], "keywords": [ "Xurography", "Metal leaf thin film electrodes", "Rapid prototyping", "Chemiresistors", "High surface area electrodes" ], "year": "2022", "source": "MATERIALS TODAY COMMUNICATIONS", "publication_type": "J", "point2d": [ 70.6175308227539, 54.499778747558594 ], "cluster": 6.0 }, { "idx": 1100, "title": "Enhancing the sensitivity of cobalt based solid-state phosphate sensor using electrical pretreatment", "abstract": "Phosphate is an important analyte to monitor in various water bodies. Cobalt based sensors are attractive for this application as they are solid-state, have a quick response time, are easy to fabricate and can perform reagent-less measurements. However, these sensors have lower sensitivity, limited dynamic range and require a chemical conditioning in a standard solution before measurement. In this study, an in situ anodic current pretreatment method in sample solution itself is used to enhance the sensitivity of the sensor and alleviate the need of chemical conditioning before measurement. With electrical pretreatment, the sensor exhibited a linear range from 10(-6) M to 10(-3) M with a sensitivity of -91.4 mV/decade of change in dihydrogen phosphate concentration. No significant interference was detected with common interfering anions that are typically present in field water samples such as nitrate, sulfate and chloride. Finally, the sensor was also responsive when tested real water samples such as tap water, lake water and creek water spiked with phosphate.", "authors": [ "Patel, Vinay", "Selvaganapathy, P. Ravi" ], "keywords": [ "Cobalt based phosphate sensor", "Solid state sensor", "Electrochemical", "Electrical pretreatment", "Phosphate sensor", "Phosphorus" ], "year": "2021", "source": "SENSORS AND ACTUATORS B-CHEMICAL", "publication_type": "J", "point2d": [ 76.47941589355469, 43.438453674316406 ], "cluster": 6.0 }, { "idx": 1101, "title": "Selection of a metal ligand modified DNAzyme for detecting Ni2+", "abstract": "Nickel is a highly important metal, and the detection of Ni2+ using biosensors is a long-stand analytical challenge. DNA has been widely used for metal detection, although no DNA-based sensors were reported for Ni2+. DNAzymes are DNA-based catalysts, and they recruit metal ions for catalysis. In this work, in vitro selection of RNA-cleaving DNAzymes was carried out using a library containing a region of 50 random nucleotides in the presence of Ni2+. To increase Ni2+ binding, a glycyl-histidine-functionalized tertiary amine moiety was inserted at the cleavage junction. A representative DNAzyme named Ni03 showed a high cleavage yield with Ni2+ and it was further studied. After truncation, the optimal sequence of Ni03l could bind one Ni2+ or two Co2+ for catalysis, while other metal ions were inactive. Its cleavage rates for 100 mu M Ni2+ reached 0.63 h(-1) at pH 8.0. A catalytic beacon biosensor was designed by labeling a fluomphore and a quencher on the Ni03l DNAzyme. Fluorescence enhancement was observed in the presence of Ni2+ with a detection limit of 12.9 mu M. The sensor was also tested in spiked Lake Ontario water achieving a similar sensitivity. This is another example of using single-site modified DNAzyme for sensing transition metal ions.", "authors": [ "Ren, Wei", "Huang, Po-Jung Jimmy", "de Rochambeau, Donatien", "Moon, Woohyun J.", "Zhang, Jinyi", "Lyu, Mingsheng", "Wang, Shujun", "Sleiman, Hanadi", "Liu, Juewen" ], "keywords": [ "Biosensors", "DNAzymes", "Aptamers", "Fluorescence", "SELEX" ], "year": "2020", "source": "BIOSENSORS & BIOELECTRONICS", "publication_type": "J", "point2d": [ 89.71549224853516, 34.776527404785156 ], "cluster": 6.0 }, { "idx": 1102, "title": "Probing Metal-Dependent Phosphate Binding for the Catalysis of the 17E DNAzyme", "abstract": "The RNA-cleaving 17E DNAzyme exhibits different levels of cleavage activity in the presence of various divalent metal ions, with Pb2+ giving the fastest cleavage. In this study, the metal-phosphate interaction is probed to understand the trend of activity with different metal ions. For the first-row transition metals, the lowest activity shown by Ni2+ correlates with the inhibition by the inorganic phosphate and its water ligand exchange rate, suggesting inner-sphere metal coordination. Cleavage activity with the two stereoisomers of the phosphorothioate-modified substrates, R-p and S-p, indicated that Mg2+, Mn2+, Fe2+, and Co2+ had the highest S-p:R-p activity ratio of >900. Comparatively, the activity was much less affected using the thiophilic metals, including Pb2+, suggesting inner-sphere coordination. The pH-rate profiles showed that Pb2+ was different than the rest of the metal ions in having a smaller slope and a similar fitted apparent pK(a) and the pK(a) of metal-bound water. Combining previous reports and our current results, we propose that Pb2+ most likely plays the role of a general acid while the other metal ions are Lewis acid catalysts interacting with the scissile phosphate.", "authors": [ "Moon, Woohyun J.", "Huang, Po-Jung Jimmy", "Liu, Juewen" ], "keywords": [ "" ], "year": "2021", "source": "BIOCHEMISTRY", "publication_type": "J", "point2d": [ 92.03330993652344, 36.285335540771484 ], "cluster": 6.0 }, { "idx": 1103, "title": "Zn2+-Dependent DNAzymes: From Solution Chemistry to Analytical, Materials and Therapeutic Applications", "abstract": "Since 1994, deoxyribozymes or DNAzymes have been in vitro selected to catalyze various types of reactions. Metal ions play a critical role in DNAzyme catalysis, and Zn2+ is a very important one among them. Zn2+ has good biocompatibility and can be used for intracellular applications. Chemically, Zn2+ is a Lewis acid and it can bind to both the phosphate backbone and the nucleobases of DNA. Zn2+ undergoes hydrolysis even at neutral pH, and the partially hydrolyzed polynuclear complexes can affect the interactions with DNA. These features have made Zn2+ a unique cofactor for DNAzyme reactions. This review summarizes Zn2+-dependent DNAzymes with an emphasis on RNA-/DNA-cleaving reactions. A key feature is the sharp Zn2+ concentration and pH-dependent activity for many of the DNAzymes. The applications of these DNAzymes as biosensors for Zn2+, as therapeutic agents to cleave intracellular RNA, and as chemical biology tools to manipulate DNA are discussed. Future studies can focus on the selection of new DNAzymes with improved performance and detailed biochemical characterizations to understand the role of Zn2+, which can facilitate practical applications of Zn2+-dependent DNAzymes.", "authors": [ "Moon, Woohyun J.", "Yang, Yongjie", "Liu, Juewen" ], "keywords": [ "aptamers", "biosensors", "deoxyribozymes", "SELEX", "zinc" ], "year": "2021", "source": "CHEMBIOCHEM", "publication_type": "J", "point2d": [ 91.21915435791016, 35.15908432006836 ], "cluster": 6.0 }, { "idx": 1104, "title": "Critical evaluation of aptamer binding for biosensor designs", "abstract": "Over the last three decades, numerous aptamer-based biosensors have been reported. The basis of these sensors is the selective binding of target analytes by aptamers. In the last few years, a number of papers have been published questioning the binding ability of some popular aptamers such as those documented for As(III), ampicillin, chloramphenicol, isocarbophos, phorate and dopamine. In this article, these papers are reviewed, and the binding assays are described, which may provide possible reasons for obtaining false positive aptamers. Additionally, relevant aptamer selection methods and typical characterization steps are described. It is found that for small molecular targets, using an immobilized library might result in better aptamers. Furthermore, the importance of carefully designed controls to ensure the quality of binding assays is discussed, especially in the case of mutated nonbinding aptamers. Only then, with fully validated aptamers, can subsequent biosensor design bring about meaningful results. (C) 2021 Elsevier B.V. All rights reserved.", "authors": [ "Zhao, Yichen", "Yavari, Kayvan", "Liu, Juewen" ], "keywords": [ "Aptamers", "Dissociation constant", "Biosensors", "Isothermal titration calorimetry", "SELEX" ], "year": "2022", "source": "TRAC-TRENDS IN ANALYTICAL CHEMISTRY", "publication_type": "J", "point2d": [ 87.6578369140625, 37.8498420715332 ], "cluster": 6.0 }, { "idx": 1106, "title": "Integrating biofouling sensing with fouling mitigation in a two-electrode electrically conductive membrane filtration system", "abstract": "Biofouling detection enables the adoption of effective cleaning strategies for biofouling prevention. This work investigates the use of electrical impedance spectroscopy (EIS) to monitor the biofilm development and the use of electric fields to mitigate biofouling on the surface of gold-coated membranes. The multi-bacterial suspension was injected into a two-electrode crossflow filtration system where the permeate flux and impedance spectra were recorded to monitor the biofilm growth. Permeate flux declined over time while the impedance at low frequency regions (< 10 Hz) rapidly decreased with fouling at the early stages of fouling, and then gradually decreased as biofilm matured. The normalized diffusion-related impedance (R-d), an EIS-derived parameter, was extracted to determine the sensitivity of EIS detection. We observed that impedance-based detection was more sensitive to changes as compared to the decline of permeate flux during the early stage of biofouling. With early detection of fouling, fouling mitigation strategies could be applied more effectively. Further, under the same conditions as fouling detection, either applying an intermittent cathodic potential (-1.5 V) or cross-flow flushing delayed the biofilm growth on the electrically conductive membranes (ECMs). EIS sensitivity was repeatably recovered across four cycles of mechanical fouling removal. Hence ECMs were demonstrated to play a dual function: EIS-enabled detection of biofouling evolution and surface biofouling mitigation.", "authors": [ "Zhang, Nan", "Lee, Hye-Jin", "Wu, Yichen", "Ganzoury, Mohamed A.", "de Lannoy, Charles-Francois" ], "keywords": [ "Electrical impedance spectroscopy (EIS)", "Diffusion-related impedance", "Intermittent cleaning", "In-situ monitoring and fouling mitigation", "Electrified membranes" ], "year": "2022", "source": "SEPARATION AND PURIFICATION TECHNOLOGY", "publication_type": "J", "point2d": [ 70.4719467163086, 49.189762115478516 ], "cluster": 6.0 }, { "idx": 1108, "title": "Sensitivity of C-Band SAR Polarimetric Variables to the Directionality of Surface Roughness Parameters", "abstract": "Surface roughness is an important factor in many soil moisture retrieval models. Therefore, any mischaracterization of surface roughness parameters (root mean square height, RMSH, and correlation length, l) may result in unreliable predictions and soil moisture estimations. In many environments, but particularly in agricultural settings, surface roughness parameters may show different behaviours with respect to the orientation or azimuth. Consequently, the relationship between SAR polarimetric variables and surface roughness parameters may vary depending on measurement orientation. Generally, roughness obtained for many SAR-based studies is estimated using pin profilers that may, or may not, be collected with careful attention to orientation to the satellite look angle. In this study, we characterized surface roughness parameters in multi-azimuth mode using a terrestrial laser scanner (TLS). We characterized the surface roughness parameters in different orientations and then examined the sensitivity between polarimetric variables and surface roughness parameters; further, we compared these results to roughness profiles obtained using traditional pin profilers. The results showed that the polarimetric variables were more sensitive to the surface roughness parameters at higher incidence angles (theta). Moreover, when surface roughness measurements were conducted at the look angle of RADARSAT-2, more significant correlations were observed between polarimetric variables and surface roughness parameters. Our results also indicated that TLS can represent more reliable results than pin profiler in the measurement of the surface roughness parameters.", "authors": [ "Alijani, Zohreh", "Lindsay, John", "Chabot, Melanie", "Rowlandson, Tracy", "Berg, Aaron" ], "keywords": [ "surface roughness", "orientation", "sensitivity analysis", "radar parameters" ], "year": "2021", "source": "REMOTE SENSING", "publication_type": "J", "point2d": [ -71.2679443359375, 9.701946258544922 ], "cluster": 8.0 }, { "idx": 1109, "title": "The influence of tree transmissivity variations in winter on satellite snow parameter observations", "abstract": "The ability to correct for the influence of forest cover is crucial for retrieval of surface geophysical parameters such as snow cover and soil properties from microwave remote sensing. Existing correction approaches to brightness temperatures for northern boreal forest regions consider forest transmissivity constant during wintertime. However, due to biophysical protection mechanisms, below freezing air temperatures freeze the water content of northern tree species only gradually. As a consequence, the permittivity of many northern tree species decreases with the decrease of air temperature under sub-zero temperature conditions. This results in a monotonic increase of the tree vegetation transmissivity, as the permittivity contrast to the surrounding air decreases. The influence of this tree temperature-transmissivity relationship on the performance of the frequency difference passive microwave snow retrieval algorithms has not been considered. Using ground-based observations and an analytical model simulation based on Matzler's approach (1994), the influence of the temperature-transmissivity relationship on the snow retrieval algorithms, based on the spectral difference of two microwave channels, is characterized. A simple approximation approach is then developed to successfully characterize this influence (the RMSE between the analytical model simulation and the approximation approach estimation is below 0.3 K). The approximation is applied to spaceborne observations, and demonstrates the capacity to reduce the influence of the forest temperature-transmissivity relationship on passive microwave frequency difference brightness temperature.", "authors": [ "Li, Qinghuan", "Kelly, Richard", "Lemmetyinen, Juha", "De Roo, Roger D.", "Pan, Jinmei", "Qiu, Yubao" ], "keywords": [ "Passive microwave", "snow", "forest" ], "year": "2021", "source": "INTERNATIONAL JOURNAL OF DIGITAL EARTH", "publication_type": "J", "point2d": [ -69.30864715576172, 23.59686851501465 ], "cluster": 8.0 }, { "idx": 1110, "title": "Investigating the Effect of Lake Ice Properties on Multifrequency Backscatter Using the Snow Microwave Radiative Transfer Model", "abstract": "Recent investigations using polarimetric decomposition and numerical models have helped to improve the understanding of how radar signals interact with lake ice. However, further research is needed on how radar signals are impacted by varying lake ice properties. Radiative transfer (RT) models provide one method of improving this understanding. These are the first published experiments using the snow microwave RT (SMRT) model to investigate the response of different frequencies (L-, C-, and X-band) at horizontal-horizontal (HH) and vertical-vertical (VV) polarizations using various incidence angles (20 degrees, 30 degrees, and 40 degrees) to changes in ice thickness, porosity, bubble radius, and ice-water interface roughness. This is also the first use of SMRT in combination with a thermodynamic lake ice model. Experiments were for a lake with tubular bubbles and one without tubular bubbles under difference scenarios. An analysis of the backscatter response to different properties indicates that increasing ice thickness and layer porosity have little impact on backscatter from lake ice. X-band backscatter shows increased response to surface ice layer bubble radius; however, this was limited to other frequencies except at shallower incidence angles (40 degrees). All three frequencies display the largest response to increasing root mean square (rms) height at the ice-water interface, which supports surface scattering at the ice-water interface as being the dominant scattering mechanism. These results demonstrate that the SMRT is a valuable tool for understanding the response of backscatter to changes in freshwater lake ice properties and could be used in the development of inversion models.", "authors": [ "Murfitt, Justin", "Duguay, Claude R.", "Picard, Ghislain", "Gunn, Grant E." ], "keywords": [ "Ice", "Lakes", "Backscatter", "Microwave integrated circuits", "Microwave FET integrated circuits", "Mathematical models", "Synthetic aperture radar", "Lake ice", "radar", "radiative transfer (RT) model", "synthetic aperture radar (SAR)" ], "year": "2022", "source": "IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING", "publication_type": "J", "point2d": [ -82.39430236816406, 9.063493728637695 ], "cluster": 2.0 }, { "idx": 1111, "title": "Implications of measurement metrics on soil freezing curves: A simulation of freeze-thaw hysteresis", "abstract": "Soil freeze-thaw events have important implications for water resources, flood risk, land productivity, and climate change. A property of these phenomena is the relationship between unfrozen water content and sub-freezing temperature, known as the soil freezing characteristic curve (SFC). It is documented that this relationship exhibits hysteretic behaviour when frozen soil thaws, leading to the definition of the soil thawing characteristic curve (STC). Although explanations have been given for SFC/STC hysteresis, the effect that 'scale' - particularly 'measurement scale' - may have on these curves has received little attention. The most commonly used measurement scale metric is the 'support', which is the spatial (or temporal) unit within which the measured variable is integrated or soil volume sampled. We show (a) measurement support can influence the range and shape of the SFC and (b) hysteresis can be attributed, in part, to the support and location of the measurements comprising the SFC/STC. We simulated lab measured temperature, volumetric water content (VWC), and permittivity from soil samples undergoing freeze-thaw transitions using Hydrus-1D and a modified Dobson permittivity model. To assess the effect of measurement support and location on SFC/STC, we masked the simulated temperature and VWC/permittivity extent to match the instrument's support and location. By creating a detailed simulation of the intra- and inter-support variability associated with the penetration of a freezing front, we demonstrate how measurement support and location can influence the temperature range over which water freezing events are captured. We show it is possible to simulate hysteresis in homogenous media with purely geometric considerations, suggesting that SFC/STC hysteresis may be more of an apparent phenomenon than mechanistically real. Lastly, we develop an understanding of how the location and support of soil temperature and VWC/permittivity measurements influence the temperature range over which water freezing events are captured.", "authors": [ "Lara, Renato Pardo", "Berg, Aaron A.", "Warland, Jon", "Parkin, Gary" ], "keywords": [ "" ], "year": "2021", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -76.28526306152344, 24.94495964050293 ], "cluster": 2.0 }, { "idx": 1112, "title": "Estimating wind slab thickness in a Tundra snowpack using Ku-band scatterometer observations", "abstract": "Estimating snow water equivalent (SWE) in the northern high latitudesis important from climate, ecological and human perspectives since it enables us to track changes in spatiotemporal distribution of snow. The snow in much of this region is described as tundra, comprised of wind slab and depth hoar. Recent work in tundra environments has identified the potential of wind slab to limit radar sensitivity to SWE at 17.2 GHz, which has negative implications for SWE retrievals and demonstrates a need to constrain retrieval parameters. Radar measurements at 17.2 GHz were made in Trail Valley Creek using the University of Waterloo Scatterometer (UWScat), and combined with the Freeman-Durden polarimetric decomposition to address this need by introducing a novel relationship between wind slab thickness and double-bounce scattering, which can be used to constrain wind slab thickness. The relationship strengthens with path length through wind slab and was strong at incidence angles >= 46 degrees and wind slab with thickness >= 19 cm. Wind slab thickness and SWE were estimated with an RMSE of 6.0 cm and 5.5 mm, respectively. This relationship is valid for use in tundra snow with depth hoar. More testing is recommended to determine the maximum detectable wind slab thickness.", "authors": [ "Thompson, Aaron", "Kelly, Richard" ], "keywords": [ "" ], "year": "2021", "source": "REMOTE SENSING LETTERS", "publication_type": "J", "point2d": [ -66.93889617919922, 2.4811766147613525 ], "cluster": 8.0 }, { "idx": 1113, "title": "Considerations for Ku-Band Radar Retrieval of Snow Water Equivalent at Mid-Latitude Ontario Agricultural Sites", "abstract": "Mid-latitude snow is understudied compared to snow in the northern high latitudes despite its importance as a source of freshwater to this economically significant region. The mid-latitudes provide opportunity to understand the influence on SWE retrievals of ice and vegetation, conditions which may encroach the north with a warming climate. Successful retrieval of SWE and snow depth was demonstrated using the Microwave Emission Model of Layered Snowpacks, adapted for backscattering (MEMLS3&a) with multi-angle Ku-band UWScat snow observations (VV polarization), of agricultural fields in Maryhill and Englehart, Ontario. A single-layer parameterization provided best results for Maryhill (RMSE of 21.9 mm SWE) while a dual-layer parameterization provided best results for Englehart (RMSE of 24.6 mm). Accounting for soil effects using a soil-subtraction method improved RMSE by up to 6.3 mm SWE. Retrievals were repeated with in situ snow depths improving accuracy at both sites (RMSE = 12.0 and 10.9 mm SWE for Maryhill and Englehart, respectively). Observations containing ice lenses and partially buried vegetation yielded a retrieval accuracy of RMSE = 60.4 mm which improved with in situ snow depths (RMSE = 21.1 mm SWE). These results compared favorably with the often-cited accuracy requirement of RMSE = 30 mm SWE.", "authors": [ "Thompson, Aaron", "Kelly, Richard" ], "keywords": [ "" ], "year": "2021", "source": "CANADIAN JOURNAL OF REMOTE SENSING", "publication_type": "J", "point2d": [ -66.0643539428711, 1.0165477991104126 ], "cluster": 8.0 }, { "idx": 1115, "title": "Crosstalk analysis and optimization in a compact microwave-microfluidic device towards simultaneous sensing and heating of individual droplets", "abstract": "Non-invasive contactless simultaneous sensing and heating of individual droplets would allow droplet microfluidics to empower a wide range of applications. However, it is challenging to realize simultaneous sensing and heating of individual droplets as the resonance frequency of the droplet fluid, which is decided by its permittivity, must be known so that energy is only supplied at this frequency for droplet heating with one resonator. To tailor the energy transfer in real-life heating applications, the droplet has to be sensed first to identify its corresponding resonance frequency, which is used to dynamically tune the frequency for supplying the required energy for heating this particular droplet. To achieve this goal, two resonators are needed, with one for sensing and one for heating. Integrating multiple resonators into one typical microfluidic device limits placement of the resonators to be as close as possible, which would raise the concern of crosstalk between them. The crosstalk would result in inaccurate sensing and heating. This study focuses on numerically and experimentally investigating the effect of influencing parameters on the crosstalk between two adjacent resonators with the ultimate goal of providing guidance for multiplexing the resonators in a typical microfluidic device. ANSYS HFSS is used to perform the electromagnetic analysis based on the finite element method. Experimental studies are conducted on a microfluidic chip integrated with two resonators to validate the numerical results. An optimal distance between two resonators is suggested, with the recommendation for the resonator size and heating power towards simultaneous sensing and heating of individual droplets.", "authors": [ "Cui, Weijia", "Abbasi, Zahra", "Ren, Carolyn L." ], "keywords": [ "microfluidics", "microwave sensing", "microwave heating", "lab-on-chip", "microwave resonators" ], "year": "2022", "source": "JOURNAL OF MICROMECHANICS AND MICROENGINEERING", "publication_type": "J", "point2d": [ 75.48898315429688, 36.1285285949707 ], "cluster": 6.0 }, { "idx": 1116, "title": "Meteorological and hydrological data from the Alder Creek watershed, SW Ontario", "abstract": "Data for small to mid-sized watersheds are seldom publicly available, but may be representative of diverse types of hydrological contexts when assessing patterns. These types of data may also prove valuable for informing numerical experimentation and practical modelling. This paper presents data collected in the Alder Creek watershed, located within the Grand River basin in Ontario, Canada. The Alder Creek watershed provides source water from the aquifers of the Waterloo Moraine for multiple well fields that supply the cities of Kitchener and Waterloo. Recharge rates and human impacts on streamflow are important topics for the watershed, and many numerical models of the area have been constructed. In order to support these types of analyses, field equipment was deployed within the watershed between 2013 and 2018 to monitor groundwater levels, stream stage, soil moisture, soil temperature, rainfall, and other weather parameters. The available data are described, complementary information is presented, and examples of possible analyses are cited and illustrated. The data presented and described in this paper are available at https://doi.org/10.20383/101.0178 (Wiebe et al., 2019).", "authors": [ "Wiebe, Andrew J.", "Rudolph, David L." ], "keywords": [ "" ], "year": "2022", "source": "EARTH SYSTEM SCIENCE DATA", "publication_type": "J", "point2d": [ 2.748593807220459, -13.266578674316406 ], "cluster": 10.0 }, { "idx": 1117, "title": "Impacts of Event-Based Recharge on the Vulnerability of Public Supply Wells", "abstract": "Dynamic recharge events related to extreme rainfall or snowmelt are becoming more common due to climate change. The vulnerability of public supply wells to water quality degradation may temporarily increase during these types of events. The Walkerton, ON, Canada, tragedy (2000) highlighted the threat to human health associated with the rapid transport of microbial pathogens to public supply wells during dynamic recharge events. Field research at the Thornton (Woodstock, ON, Canada) and Mannheim West (Kitchener, ON, Canada) well fields, situated in glacial overburden aquifers, identified a potential increase in vulnerability due to event-based recharge phenomena. Ephemeral surface water flow and local ponding containing microbial pathogen indicator species were observed and monitored within the capture zones of public supply wells following heavy rain and/or snowmelt. Elevated recharge rates beneath these temporary surface water features were estimated to range between 40 and 710 mm over two-week periods using analytical and numerical modelling based on the water level, soil moisture, and temperature data. Modelling also suggested that such events could reduce contaminant travel times to a supply well, increasing vulnerability to water quality degradation. These studies suggest that event-based recharge processes occurring close to public supply wells may enhance the vulnerability of the wells to surface-sourced contaminants.", "authors": [ "Wiebe, Andrew J.", "Rudolph, David L.", "Pasha, Ehsan", "Brook, Jacqueline M.", "Christie, Mike", "Menkveld, Paul G." ], "keywords": [ "groundwater recharge", "depression focused recharge", "localized recharge", "public supply well", "microbial contamination", "hydrological event", "disease outbreak", "well vulnerability", "overburden aquifer" ], "year": "2021", "source": "SUSTAINABILITY", "publication_type": "J", "point2d": [ 6.909882068634033, -13.836770057678223 ], "cluster": 18.0 }, { "idx": 1118, "title": "Impact of Spectral Resolution on Quantifying Cyanobacteria in Lakes and Reservoirs: A Machine-Learning Assessment", "abstract": "Y Cyanobacterial harmful algal blooms are an increasing threat to coastal and inland waters. These blooms can be detected using optical radiometers due to the presence of phycocyanin (PC) pigments. The spectral resolution of best-available multispectral sensors limits their ability to diagnostically detect PC in the presence of other photosynthetic pigments. To assess the role of spectral resolution in the determination of PC, a large (N = 905) database of colocated in situ radiometric spectra and PC are employed. We first examine the performance of selected widely used machine-learning (ML) models against that of benchmark algorithms for hyperspectral remote sensing reflectance (R-rs) spectra resampled to the spectral configuration of the Hyperspectral Imager for the Coastal Ocean (HICO) with a full-width at half-maximum (FWHM) of < 6 nm. Results show that the multilayer perceptron (MLP) neural network applied to HICO spectral configurations (median errors < 65%) outperforms other ML models. This model is subsequently applied to R-rs spectra resampled to the band configuration of existing satellite instruments and of the one proposed for the next Landsat sensor. These results confirm that employing MLP models to estimate PC from hyperspectral data delivers tangible improvements compared with retrievals from multispectral data and benchmark algorithms (with median errors between similar to 73% and 126%) and shows promise for developing a globally applicable cyanobacteria measurement approach.", "authors": [ "Zolfaghari, Kiana", "Pahlevan, Nima", "Binding, Caren", "Gurlin, Daniela", "Simis, Stefan G. H.", "Ruiz Verdu, Antonio", "Li, Lin", "Crawford, Christopher J.", "VanderWoude, Andrea", "Errera, Reagan", "Zastepa, Arthur", "Duguay, Claude R." ], "keywords": [ "Cyanobacteria harmful algal bloom (Cyano HAB)", "hyperspectral", "machine learning (ML)", "neural network", "phycocyanin (PC)", "spectral resolution" ], "year": "2022", "source": "IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING", "publication_type": "J", "point2d": [ 61.055442810058594, 22.371074676513672 ], "cluster": 19.0 }, { "idx": 1119, "title": "A hybrid analytical-numerical technique for solving soil temperature during the freezing process", "abstract": "The freeze-thaw cycle associated with climatic seasonality is a common phenomenon in cold regions affecting a wide range of subsurface processes. Due to the complex and highly nonlinear nature of the associated hydrologic processes, transient freeze-thaw dynamics are conventionally quantified in a numerical way. Here we present a hybrid analytical-numerical scheme for solving one-dimensional soil (or porous media) temperature profiles when the soil profile is subjected to unidirectional freezing (or thawing) conditions. This scheme divides the partially-frozen soil into multi-layers, each with constant thermal parameters and fixed-temperature boundaries. Temperature profiles within each layer were obtained by solving multiple moving-boundary problems. The proposed hybrid analytical-numerical scheme was tested into a freezing test of silty clay in a permafrost region on the Qinghai-Tibetan Plateau, and its solution was in good agreement with the finite element numerical solution. Results show that the proposed multi-layer method adapted well to the changes in unfrozen water content and thermal properties of soil over a wide range of subzero temperatures. By contrast, the freezing front's migration rate and penetration depth calculated by Neumann's classical solution, which only considers two zones (frozen and unfrozen), was found to be underestimated. As for our proposed multi-layer solution, by dividing the subsurface domain into many layers with smaller proportion ratios (thinner layers close to the freezing front), there was a slower penetration rate of the freezing front resulting in shallower penetration depth. The predicted profiles of temperature, thermal conductivity and diffusivity, heat flux, and dynamics of the freezing front were significantly impacted by the shape of the soil freezing curves and the magnitude of soil grain thermal conductivity, especially for the accuracy of long-term predictions.", "authors": [ "Huang, Xiang", "Rudolph, David L." ], "keywords": [ "Analytical solution", "Heat transfer with phase change", "Freeze-thaw process", "Nonlinearity", "Unfrozen water content", "Temperature-dependent thermal property", "Thermal diffusivity", "Moving boundary problem" ], "year": "2022", "source": "ADVANCES IN WATER RESOURCES", "publication_type": "J", "point2d": [ -38.56746292114258, 24.621170043945312 ], "cluster": 12.0 }, { "idx": 1120, "title": "Microbial Community Compositional Stability in Agricultural Soils During Freeze-Thaw and Fertilizer Stress", "abstract": "Microbial activity persists in cold region agricultural soils during the fall, winter, and spring (i.e., non-growing season) and frozen condition, with peak activity during thaw events. Climate change is expected to change the frequency of freeze-thaw cycles (FTC) and extreme temperature events (i.e, altered timing, extreme heat/cold events) in temperate cold regions, which may hasten microbial consumption of fall-amended fertilizers, decreasing potency come the growing season. We conducted a high-resolution temporal examination of the impacts of freeze-thaw and nutrient stress on microbial communities in agricultural soils across both soil depth and time. Four soil columns were incubated under a climate model of a non-growing season including precipitation, temperature, and thermal gradient with depth over 60 days. Two columns were amended with fertilizer, and two incubated as unamended soil. The impacts of repeated FTC and nutrient stress on bacterial, archaeal, and fungal soil community members were determined, providing a deeply sampled longitudinal view of soil microbial response to non-growing season conditions. Geochemical changes from flow-through leachate and amplicon sequencing of 16S and ITS rRNA genes were used to assess community response. Despite nitrification observed in fertilized columns, there were no significant microbial diversity, core community, or nitrogen cycling population trends in response to nutrient stress. FTC impacts were observable as an increase in alpha diversity during FTC. Community compositions shifted across a longer time frame than individual FTC, with bulk changes to the community in each phase of the experiment. Our results demonstrate microbial community composition remains relatively stable for archaea, bacteria, and fungi through a non-growing season, independent of nutrient availability. This observation contrasts canonical thinking that FTC have significant and prolonged effects on microbial communities. In contrast to permafrost and other soils experiencing rare FTC, in temperate agricultural soils regularly experiencing such perturbations, the response to freeze-thaw and fertilizer stress may be muted by a more resilient community or be controlled at the level of gene expression rather than population turn-over. These results clarify the impacts of winter FTC on fertilizer consumption, with implications for agricultural best practices and modeling of biogeochemical cycling in agroecosystems.", "authors": [ "Jensen, Grant", "Krogstad, Konrad", "Rezanezhad, Fereidoun", "Hug, Laura A." ], "keywords": [ "soil microbiome", "fertlizers", "freeze-thaw (F", "T) cycle", "soil microbial ecology", "nutrient stress" ], "year": "2022", "source": "FRONTIERS IN ENVIRONMENTAL SCIENCE", "publication_type": "J", "point2d": [ 30.20172882080078, 22.72909927368164 ], "cluster": 9.0 }, { "idx": 1123, "title": "Significant underestimation of peatland permafrost along the Labrador Sea coastline in northern Canada", "abstract": "Northern peatlands cover approximately four million km(2), and about half of these peatlands are estimated to contain permafrost and periglacial landforms, like palsas and peat plateaus. In northeastern Canada, peatland permafrost is predicted to be concentrated in the western interior of Labrador but is assumed to be largely absent along the Labrador Sea coastline. However, the paucity of observations of peatland permafrost in the interior, coupled with traditional and ongoing use of perennially frozen peatlands along the coast by Labrador Inuit and Innu, suggests a need for re-evaluation of the reliability of existing peatland permafrost distribution estimates for the region. In this study, we develop a multi-stage consensus-based point inventory of peatland permafrost complexes in coastal Labrador and adjacent parts of Quebec using high-resolution satellite imagery, and we validate it with extensive field visits and low-altitude aerial photography and videography. A subset of 2092 wetland complexes that potentially contained peatland permafrost were inventoried, of which 1119 were classified as likely containing peatland permafrost. Likely peatland permafrost complexes were mostly found in lowlands within 22 km of the coastline, where mean annual air temperatures often exceed +1 ?. A clear gradient in peatland permafrost distribution exists from the outer coasts, where peatland permafrost is more abundant, to inland peatlands, where permafrost is generally absent. This coastal gradient may be attributed to a combination of climatic and geomorphological influences which lead to lower insolation, thinner snowpacks, and poorly drained, frost-susceptible materials along the coast. The results of this study suggest that existing estimates of permafrost distribution for southeastern Labrador require adjustments to better reflect the abundance of peatland permafrost complexes to the south of the regional sporadic discontinuous permafrost limit. This study constitutes the first dedicated peatland permafrost inventory for Labrador and provides an important baseline for future mapping, modelling, and climate change adaptation strategy development in the region.", "authors": [ "Wang, Yifeng", "Way, Robert G.", "Beer, Jordan", "Forget, Anika", "Tutton, Rosamond", "Purcell, Meredith C." ], "keywords": [ "" ], "year": "2023", "source": "CRYOSPHERE", "publication_type": "J", "point2d": [ -24.907203674316406, 45.17341232299805 ], "cluster": 13.0 }, { "idx": 1124, "title": "The effects of roadways on lakes and ponds: a systematic review and assessment of knowledge gaps", "abstract": "As the global population increases, the expansion of road networks has led to the destruction and disturbance of terrestrial and aquatic habitats. Road-related stressors have significant effects on both lotic and lentic habitats. While there are several systematic reviews that evaluate the effects of roads on lotic environments, there are none that consider their effects on lentic habitats only. We conducted a literature review to achieve two objectives: (1) to summarize the effects of roads on the physical, chemical, and biological properties of lentic environments; and (2) to identify biases and gaps in our current knowledge of the effects of roads on lentic habitats, so that we could find promising areas for future research. Our review found 172 papers published between 1970 and 2020. The most frequently studied stressors associated with roads included road salt and heavy metal contamination (67 and 43 papers, respectively), habitat fragmentation (37 papers), and landscape change (14 papers). These stressors can lead to alterations in conductivity and chloride levels, changes in lake stratification patterns, increases in heavy metal concentrations in water and organisms, and significant mortality as amphibians disperse across roadways. We also identified a variety of other stressors that may be understudied based on their frequency of appearance in our search results, including polycyclic aromatic hydrocarbons, road dust, increased accessibility, hydrological changes, noise pollution, dust suppressants, sedimentation, invasive species introductions, and water withdrawal. Our review indicated that there are strong geographic biases in published studies, with 57.0% examining North American sites and 30.2% examining European sites. Furthermore, there were taxonomic biases in the published literature, with most studies focusing on amphibians (41.7%), fish (15.6%), and macroinvertebrates (14.6%), while few considered zooplankton (8.3%), diatoms (7.3%), amoebas (5.2%), water birds (3.1%), reptiles (2.1%), and macrophytes (1.0%). Based on our review, we have identified promising areas for future research for each of the major stressors related to roadways. However, we speculate that rectifying the geographic and taxonomic bias of our current knowledge could significantly advance our understanding of the impacts of roads on lentic environments, thereby better informing environmental management of these important habitats.", "authors": [ "Dixon, Heather J.", "Elmarsafy, Mariam", "Hannan, Natasha", "Gao, Vivian", "Wright, Caitlin", "Khan, Layana", "Gray, Derek K." ], "keywords": [ "lakes", "ponds", "roads", "lentic", "habitat", "anthropogenic stress" ], "year": "2022", "source": "ENVIRONMENTAL REVIEWS", "publication_type": "J", "point2d": [ 57.6878662109375, -4.817724704742432 ], "cluster": 19.0 }, { "idx": 1125, "title": "On estimating long period wind speed return levels from annual maxima", "abstract": "The uniform risk engineering practices that are increasingly being adopted for structural design require estimates of the extreme wind loads with very low annual probabilities of exceedance, corresponding to return periods of up to 3000-years in some cases. These estimates are necessarily based on observational wind data that typically spans only a few decades. The estimates are therefore affected by both large sampling uncertainty and, potentially, non-negligible biases. Design practices that aim to meet mandated structural reliability criteria take the sampling uncertainty of long period wind speed or wind pressure estimates into account, but reliability could be compromised if estimates are also biased. In many circumstances, estimates are obtained by fitting an extreme value distribution to annual maximum wind speed observed over a few decades. A key assumption implicit in doing so is that wind speed annual maxima are max-stable. Departures from max-stability can exacerbate the uncertainty of long-period return level estimates by inducing systematic estimation bias as well. Observational records, however, are generally too short to assess max-stability. We therefore use wind speed data from a large (50-member) ensemble of CanRCM4 historical simulations over North America to assess whether wind speed annual maxima are max-stable. While results are generally reassuring at the continental scale, disquieting evidence of a lack of max-stability is often found in the central and southern parts of the continent. Results show that when annual maximum wind speeds are not max-stable, long period return level extreme wind speeds tend to be underestimated, which would compromise reliability if used to design infrastructure such as tall buildings and towers.", "authors": [ "Ben Alaya, M. A.", "Zwiers, F. W.", "Zhang, X." ], "keywords": [ "Long period wind speed return levels", "Generalized extreme value distribution", "Regional climate model" ], "year": "2021", "source": "WEATHER AND CLIMATE EXTREMES", "publication_type": "J", "point2d": [ -29.90168571472168, -62.01176834106445 ], "cluster": 14.0 }, { "idx": 1126, "title": "Human influence on the 2021 British Columbia floods", "abstract": "A strong atmospheric river made landfall in southwestern British Columbia, Canada on November 14th, 2021, bringing two days of intense precipitation to the region. The resulting floods and landslides led to the loss of at least five lives, cut Vancouver off entirely from the rest of Canada by road and rail, and made this the costliest natural disaster in the province's history. Here we show that when characterised in terms of storm-averaged water vapour transport, the variable typically used to characterise the intensity of atmospheric rivers, westerly atmospheric river events of this magnitude are approximately one in ten year events in the current climate of this region, and that such events have been made at least 60% more likely by the effects of human-induced climate change. Characterised in terms of the associated two-day precipitation, the event is substantially more extreme, approximately a one in fifty to one in a hundred year event, and the probability of events at least this large has been increased by a best estimate of 45% by human-induced climate change. The effects of this precipitation on streamflow were exacerbated by already wet conditions preceding the event, and by rising temperatures during the event that led to significant snowmelt, which led to streamflow maxima exceeding estimated one in a hundred year events in several basins in the region. Based on a large ensemble of simulations with a hydrological model which integrates the effects of multiple climatic drivers, we find that the probability of such extreme streamflow events in October to December has been increased by human-induced climate change by a best estimate of 120-330%. Together these results demonstrate the substantial human influence on this compound extreme event, and help motivate efforts to increase resiliency in the face of more frequent events of this kind in the future.", "authors": [ "Gillett, Nathan P.", "Cannon, Alex J.", "Malinina, Elizaveta", "Schnorbus, Markus", "Anslow, Faron", "Sun, Qiaohong", "Kirchmeier-Young, Megan", "Zwiers, Francis", "Seiler, Christian", "Zhang, Xuebin", "Flato, Greg", "Wan, Hui", "Li, Guilong", "Castellan, Armel" ], "keywords": [ "Event attribution", "Atmospheric river", "Extreme precipitation", "Streamflow", "British Columbia", "Flooding" ], "year": "2022", "source": "WEATHER AND CLIMATE EXTREMES", "publication_type": "J", "point2d": [ -19.16912078857422, -28.33582305908203 ], "cluster": 1.0 }, { "idx": 1127, "title": "Reduction in autumn precipitation over Southwest China by anthropogenic aerosol emissions from eastern China", "abstract": "Impacts of anthropogenic aerosols in China on autumn precipitation over Southwest China were investigated using version 5.1 of the Community Atmosphere Model. Simulations with and without anthropogenic aerosol emissions were compared to examine the effects of anthropogenic aerosols on surface air temperature and precipitation in East Asia. Our results show that the aerosol increase induces strong cooling over East Asia by aerosols' direct effect on radiation and indirect effect on clouds. Substantial reductions in precipitation are found across eastern China, but the largest decrease is in Southwest China. Anthropogenic aerosols cause a considerable increase in the cloud condensation nuclei number concentration and a decline in the cloud droplet effective radius in East Asia. The reduced cloud droplet sizes suppress the formation of precipitation and increase cloud depth and liquid water path. Consequently, aerosols' direct radiative effect as well as indirect effect on cloud depth and albedo significantly reduce the shortwave radiation for all sky between 20 Fand 40N in China. More absorbing aerosols in the lower troposphere increase shortwave radiative heating, which possibly burns off lowlevel convective clouds and could cause significant reductions in condensational heating in the lower troposphere. The patterns of the shortwave heating increase and condensational heating reduction are generally consistent with significant reductions in the convective precipitation over China. We further investigated other factors governing precipitation and found moderate stability enhancement and moisture transport reductions in most of China, both of which partially contribute to a decrease in the convective precipitation in Southwest China. Aerosols' direct and indirect effects reduce the amount of solar radiation reaching the surface and cool the surface and lower troposphere between 20 and 40N, causing anomalous subsidence and reductions in the largescale precipitation over central and eastern China. Both convective and large-scale precipitation are suppressed over Southwest China, leading to a significant decrease in total precipitation over this area.", "authors": [ "Huo, Fei", "Jiang, Zhihong", "Ma, Hongyun", "Li, Zhenhua", "Li, Yanping" ], "keywords": [ "Anthropogenic aerosols", "Monsoons", "Precipitation", "Southwest China" ], "year": "2021", "source": "ATMOSPHERIC RESEARCH", "publication_type": "J", "point2d": [ -43.2081413269043, -61.92081069946289 ], "cluster": 14.0 }, { "idx": 1128, "title": "Climate Model Projections for Canada: A Comparison of CMIP5 and CMIP6", "abstract": "Recent studies have identified stronger warming in the latest generation of climate model simulations globally, and the same is true for projected changes in Canada. This study examines differences for Canada and six sub-regions between simulations from the latest Sixth Coupled Model Intercomparison Project (CMIP6) and its predecessor CMIP5. Ensembles from both experiments are assessed using a set of derived indices calculated from daily precipitation and temperature, with projections compared at fixed future time intervals and fixed levels of global temperature change. For changes calculated at fixed time intervals most temperature indices display higher projected changes in CMIP6 than CMIP5 for most sub-regions, while greater precipitation changes in CMIP6 occur mainly in extreme precipitation indices. When future projections are calculated at fixed levels of global average temperature increase, the size and spread of differences for future projected changes between CMIP6 and CMIP5 are substantially reduced for most indices. Temperature scaling behaviour, or the regional response to increasing global temperatures, is similar in both ensembles, with annual temperature anomalies for Canada and its sub-regions increasing at between 1.5 and 2.5 times the rate of increase globally, depending on the region. The CMIP6 ensemble projections exhibit modestly stronger scaling behaviour for temperature anomalies in northern Canada, as well as for certain indices of moderate and extreme events. Such temperature scaling differences persist even if anomalously warm CMIP6 global climate models are omitted. Comparing the mean and variance of future projections for Canada in CMIP5 and CMIP6 simulations from the same modelling centre suggests CMIP6 models are significantly warmer in Canada than CMIP5 models at the same level of forcing, with some evidence that internal temperature variability in CMIP6 is reduced compared with CMIP5.", "authors": [ "Sobie, S. R.", "Zwiers, F. W.", "Curry, C. L." ], "keywords": [ "CMIP6", "Canada climate change", "model ensembles" ], "year": "2021", "source": "ATMOSPHERE-OCEAN", "publication_type": "J", "point2d": [ -30.856136322021484, -33.84526062011719 ], "cluster": 1.0 }, { "idx": 1129, "title": "Hydrological Evaluation of High-Resolution Precipitation Estimates from the WRF Model in the Third Pole River Basins", "abstract": "In this study, two sets of precipitation estimates that are based on the regional Weather Research and Forecasting (WRF) Model-the high Asia refined analysis (HAR) and outputs with a 9-km resolution from WRF (WRF-9km)-are evaluated at both basin and point scales, and their potential hydrological utilities are investigated by driving the Variable Infiltration Capacity (VIC) large-scale land surface hydrological model in seven Third Pole (TP) basins. The regional climate model (RCM) tends to overestimate the gauge-based estimates by 20%-95% in annual means among the selected basins. Relative to the gauge observations, the RCM precipitation estimates can accurately detect daily precipitation events of varying intensities (with absolute bias < 3 mm). The WRF-9km exhibits a high potential for hydrological application in the monsoon-dominated basins in the southeastern TP (with NSE of 0.7-0.9 and bias from -11% to 3%), whereas the HAR performs well in the upper Indus and upper Brahmaputra basins (with NSE of 0.6 and bias from -15% to -9%). Both of the RCM precipitation estimates can accurately capture the magnitudes of low and moderate daily streamflow but show limited capabilities in flood prediction in most of the TP basins. This study provides a comprehensive evaluation of the strength and limitation of RCMs precipitation in hydrological modeling in the TP with complex terrains and sparse gauge observations.", "authors": [ "Sun, He", "Su, Fengge", "He, Zhihua", "Ou, Tinghai", "Chen, Deliang", "Li, Zhenhua", "Li, Yanping" ], "keywords": [ "Precipitation", "Runoff", "Hydrologic models" ], "year": "2021", "source": "JOURNAL OF HYDROMETEOROLOGY", "publication_type": "J", "point2d": [ -47.12077713012695, -45.36530303955078 ], "cluster": 14.0 }, { "idx": 1130, "title": "Quantifying the Human Influence on the Intensity of Extreme 1-and 5-Day Precipitation Amounts at Global, Continental, and Regional Scales", "abstract": "This study provides a comprehensive analysis of the human contribution to the observed intensification of precipitation extremes at different spatial scales. We consider the annual maxima of the logarithm of 1-day (Rx1day) and 5-day (Rx5day) precipitation amounts for 1950-2014 over the global land area, four continents, and several regions, and compare observed changes with expected responses to external forcings as simulated by CanESM2 in a large-ensemble experiment and by multiple models from phase 6 of the Coupled Model Intercomparison Project (CMIP6). We use a novel detection and attribution analysis method that is applied directly to station data in the areas considered without prior processing such as gridding, spatial or temporal dimension reduction, or transformation to unitless indices and uses climate models only to obtain estimates of the space-time pattern of extreme precipitation response to external forcing. The influence of anthropogenic forcings on extreme precipitation is detected over the global land area, three continental regions (the western Northern Hemisphere, western Eurasia, and eastern Eurasia), and many smaller IPCC regions, including central North America, East Asia, east-central Asia, eastern Europe, eastern North America, northern Europe, and western Siberia for Rx1day, and central North America, eastern Europe, eastern North America, northern Europe, the Russian Arctic region, and western Siberia for Rx5day. Consistent results are obtained using forcing response estimates from either CanESM2 or CMIP6. Anthropogenic influence is estimated to have substantially decreased the approximate waiting time between extreme annual maximum events in regions where anthropogenic influence has been detected, which has important implications for infrastructure design and climate change adaptation policy.", "authors": [ "Sun, Qiaohong", "Zwiers, Francis", "Zhang, Xuebin", "Yan, Jun" ], "keywords": [ "Extreme events", "Pattern detection", "Climate models" ], "year": "2022", "source": "JOURNAL OF CLIMATE", "publication_type": "J", "point2d": [ -40.19820022583008, -62.27853775024414 ], "cluster": 14.0 }, { "idx": 1131, "title": "Assessing past and future hazardous freezing rain and wet snow events in Manitoba, Canada using a pseudo-global warming approach", "abstract": "Freezing precipitation, in the form of freezing rain, freezing drizzle, and/or wet snow, can damage transportation networks, infrastructure, and vegetation. Ten events with freezing precipitation (including freezing rain and wet snow) over the province of Manitoba, Canada were examined using surface observational datasets, reanalysis products and 4-km resolution Weather Research and Forecasting (WRF) products that were both a retrospective control (CTRL) simulation as well as a pseudo-global warming (PGW) simulation. All events tracked to the south and/or east of Manitoba and most (8 of 10) events were associated with a consistent large scale pattern of extratropical cyclone with 500 hPa trough, low surface pressure center nearby, and an atmospheric river. Local factors, such as the 400 m elevated terrain of Riding Mountain, influenced 2 events mainly by altering surface temperature to be favorable for freezing precipitation. These events in the PGW simulation occurred 40-120 km farther north on average, with freezing rain generally being enhanced and wet snow generally being reduced, although wet snow was introduced into events which originally only had freezing rain. This study further showed that power lines aligned west to east, perpendicular to the strongest winds, are most susceptible to the consequences of icing and accretion within the current climate as well as the thermodynamically forced future one.", "authors": [ "Tropea, Brock", "Stewart, Ronald" ], "keywords": [ "Pseudo-global warming", "Freezing precipitation", "Wet snow", "Freezing rain", "Icing", "Power lines" ], "year": "2021", "source": "ATMOSPHERIC RESEARCH", "publication_type": "J", "point2d": [ -55.60307693481445, -26.72381019592285 ], "cluster": 1.0 }, { "idx": 1132, "title": "On the Optimal Design of Field Significance Tests for Changes in Climate Extremes", "abstract": "Field significance tests have been widely used to detect climate change. In most cases, a local test is used to identify significant changes at individual locations, which is then followed by a field significance test that considers the number of locations in a region with locally significant changes. The choice of local test can affect the result, potentially leading to conflicting assessments of the impact of climate change on a region. We demonstrate that when considering changes in the annual extremes of daily precipitation, the simple Mann-Kendall trend test is preferred as the local test over more complex likelihood ratio tests that compare the fits of stationary and nonstationary generalized extreme value distributions. This lesson allows us to report, with enhanced confidence, that the intensification of annual extremes of daily precipitation in China since 1961 became field significant much earlier than previously reported. Plain Language Summary Changes to weather and climate extremes at individual locations can be highly uncertain due to natural variability. Much of the natural variability in precipitation extremes occurs on small spatial scales, and thus analyzing changes at different locations in a region with a field significance test can help extract information about changes in the region that is less affected by natural variability. An important component of doing so is the local test that is used to identify significant changes at individual locations and a field significance test that evaluates whether such changes are found at more locations than would be expected from natural variability in an unchanged climate. By contrasting several common local test methods with varying complexity, we find that the simple Mann-Kendall test tends to yield a field significance test with high power of detection. Based on these lessons, we find that the intensification of extreme precipitation in China became field significant much earlier than previously reported, thereby resolving uncertainty about whether intensification is in fact discernable in China. Key Points Field significance is generally determined by summarizing the results of individual tests conducted at different locations in a domain Inconsistent field significance conclusions can be drawn when using different local test methods For extreme precipitation, field significance determined from the simple Mann-Kendall test performs better than other commonly used ones", "authors": [ "Wang, Jianyu", "Li, Chao", "Zwiers, Francis", "Zhang, Xuebin", "Li, Guilong", "Jiang, Zhihong", "Zhai, Panmao", "Sun, Ying", "Li, Zhen", "Yue, Qun" ], "keywords": [ "Climate change detection", "extreme precipitation", "field significance test" ], "year": "2021", "source": "GEOPHYSICAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -37.279510498046875, -61.684444427490234 ], "cluster": 14.0 }, { "idx": 1133, "title": "Cooling Effects Revealed by Modeling of Wetlands and Land-Atmosphere Interactions", "abstract": "Wetlands are important ecosystems-they provide vital hydrological and ecological services such as regulating floods, storing carbon, and providing wildlife habitat. The ability to simulate their spatial extents and hydrological processes is important for valuing wetlands' function. The purpose of this study is to dynamically represent the spatial extents and hydrological processes of wetlands and investigate their feedback to regional climate in the Prairie Pothole Region (PPR) of North America, where a large number of wetlands exist. In this study, we incorporated a wetland scheme into the Noah-MP land surface model with two major modifications: (a) modifying the subgrid saturation fraction for spatial wetland extent and (b) incorporating a dynamic wetland storage to simulate hydrological processes. This scheme was evaluated at a fen site in central Saskatchewan, Canada and applied regionally in the PPR with 13-year climate forcing produced by a high-resolution convection-permitting model. The differences between wetland and no-wetland simulations are significant, with increasing latent heat and evapotranspiration while suppressing sensible heat and runoff in the wetland scheme. Finally, the dynamic wetland scheme was applied in the Weather Research and Forecasting (WRF) model. The wetlands scheme not only modifies the surface energy balance but also interacts with the lower atmosphere, shallowing the planetary boundary layer height and promoting cloud formation. A cooling effect of 1-3 degrees C in summer temperature is evident where wetlands are abundant. In particular, the wetland simulation shows reduction in the number of hot days for >10 days over the summer of 2006, when a long-lasting heatwave occurred. This research has great implications for land surface/regional climate modeling and wetland conservation, especially in mitigating extreme heatwaves under climate change. Plain Language Summary A large number of wetlands exist in the Prairie Pothole Region (PPR) across the US and Canada. These wetlands are important to our environment as they can provide flood control and wildlife habitat and may cool the temperature, but they are poorly represented in previous land surface model (LSM) studies. In this study, we updated a dynamic wetland module in the Noah-MP LSM to reasonably estimate wetland extent and seasonal variation in the PPR. This wetland module shows significant impacts to the surface environmental conditions and interactions with regional climate. The results show that wetlands would effectively cool the air temperature 1-3 degrees C in summer, especially for regions with high wetland coverage. The implication of this study is very useful for wetland conservation agencies and climate scientists, as this cooling effect could potentially mitigate heat stress under climate change.", "authors": [ "Zhang, Z.", "Chen, F.", "Barlage, M.", "Bortolotti, L. E.", "Famiglietti, J.", "Li, Z.", "Ma, X.", "Li, Y." ], "keywords": [ "" ], "year": "2022", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -16.507118225097656, -7.5106048583984375 ], "cluster": 13.0 }, { "idx": 1134, "title": "A Frequency-Domain Optofluidic Dissolved Oxygen Sensor With Total Internal Reflection Design For in Situ Monitoring", "abstract": "Continuous measurement of dissolved oxygen (DO) variation is important in water monitoring and biomedical applications, which require low-cost and low-maintenance sensors capable of automated operation. A frequency-domain optofluidic DO sensor with total internal reflection (TIR) design has been developed based on fluorescence quenching of Ruthenium complex (Ru(dpp)(3)Cl-2). To minimize artifacts causing drift in fluorescence measurements such as background autofluorescence, photobleaching, optical alignment variation, a low-cost frequency-domain approach is implemented in an optofluidic platform to measure the phase shift between the excitation and emission light. We show that the frequency domain optofluidic DO sensor provides absolute DO concentrations in repeated measurements. TIR design can enhance fluorescence signal in the integrated device and minimize background autofluorescence in the sample, which can subsequently improve overall sensitivity. Furthermore, photobleaching in the samples would be mitigated as the incident light does not enter the microfluidic channel. Our results demonstrate a measurement resolution of 0.2 ppm and response times of less than one minute. In accelerated photobleaching conditions, the long-term drift is shown to be less than +/- 0.4 ppm. These results suggest the potential of this optofluidic DO sensor as an in situ platform for water monitoring and biomedical applications.", "authors": [ "Xiong, Bo", "Mahoney, Eric", "Lo, Joe F.", "Fang, Qiyin" ], "keywords": [ "Fluorescence", "Monitoring", "Frequency-domain analysis", "Biomedical measurement", "Optical sensors", "Pollution measurement", "Dissolved gas analysis", "Fluorescence", "Microfluidics", "Biomedical monitoring", "Environmental monitoring" ], "year": "2021", "source": "IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS", "publication_type": "J", "point2d": [ 66.88273620605469, 43.461246490478516 ], "cluster": 6.0 }, { "idx": 1135, "title": "Dual-Modality Imaging Microfluidic Cytometer for Onsite Detection of Phytoplankton", "abstract": "Phytoplankton monitoring is essential for better understanding and mitigation of phytoplankton bloom formation. We present a microfluidic cytometer with two imaging modalities for onsite detection and identification of phytoplankton: a lensless imaging mode for morphological features, and a fluorescence imaging mode for autofluorescence signal of phytoplankton. Both imaging modes are integrated in a microfluidic device with a field of view (FoV) of 3.7 mm x 2.4 mm and a depth of field (DoF) of 0.8 mm. The particles in the water flow channel can be detected and classified with automated image processing algorithms and machine learning models using their morphology and fluorescence features. The performance of the device was demonstrated by measuring Chlamydomonas, Euglena, and non-fluorescent beads in both separate and mixed flow samples. The recall rates for Chlamydomonas and Euglena ware 93.6% and 94.4%. The dual-modality imaging approach enabled observing both morphology and fluorescence features with a large DoF and FoV which contribute to high-throughput analysis. Moreover, this imaging flow cytometer platform is portable, low-cost, and shows potential in the onsite phytoplankton monitoring.

", "authors": [ "Xiong, Bo", "Hong, Tianqi", "Schellhorn, Herbert", "Fang, Qiyin" ], "keywords": [ "flow cytometry", "phytoplankton", "lensless imaging", "fluorescence imaging", "miniaturization", "microfluidic" ], "year": "2021", "source": "PHOTONICS", "publication_type": "J", "point2d": [ 62.867401123046875, 24.14832878112793 ], "cluster": 6.0 }, { "idx": 1137, "title": "Hydrologic-land surface modelling of the Canadian sporadic-discontinuous permafrost: Initialization and uncertainty propagation", "abstract": "Permafrost thaw has been observed in recent decades in the Northern Hemisphere and is expected to accelerate with continued global warming. Predicting the future of permafrost requires proper representation of the interrelated surface/subsurface thermal and hydrologic regimes. Land surface models (LSMs) are well suited for such predictions, as they couple heat and water interactions across soil-vegetation-atmosphere interfaces and can be applied over large scales. LSMs, however, are challenged by the long-term thermal and hydraulic memories of permafrost and the paucity of historical records to represent permafrost dynamics under transient climate conditions. In this study, we aim to understand better how LSMs function under different spin-up states, which facilitates addressing the challenge of model initialization by characterizing the impact of initial climate conditions and initial soil frozen and liquid water contents on the simulation length required to reach equilibrium. Further, we quantify how the uncertainty in model initialization propagates to simulated permafrost dynamics. Modelling experiments are conducted with the Modelisation Environmentale Communautaire-Surface and Hydrology (MESH) framework and its embedded Canadian land surface scheme (CLASS). The study area is in the Liard River basin in the Northwest Territories of Canada with sporadic and discontinuous regions. Results show that uncertainty in model initialization controls various attributes of simulated permafrost, especially the active layer thickness, which could change by 0.5-1.5 m depending on the initial condition chosen. The least number of spin-up cycles is achieved with near field capacity condition, but the number of cycles varies depending on the spin-up year climate. We advise an extended spin-up of 200-1000 cycles to ensure proper model initialization under different climatic conditions and initial soil moisture contents.", "authors": [ "Abdelhamed, Mohamed S.", "Elshamy, Mohamed E.", "Wheater, Howard S.", "Razavi, Saman" ], "keywords": [ "initialization", "land surface models", "Liard River", "permafrost", "spin-up", "uncertainty" ], "year": "2022", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -29.612224578857422, 0.272579163312912 ], "cluster": 12.0 }, { "idx": 1138, "title": "Modelling the impacts of climate and land use change on water security in a semi-arid forested watershed using InVEST", "abstract": "Water security, a key policy objective for sustainable development, is under stress as a result of land use and climate change, especially in (semi-)arid areas like Iran. Land use change alters surface runoff and affects basin-wide hydrological processes and water consumption, while climate change modifies precipitation and temperature patterns and consequently evapotranspiration and water supply. In this study, water yield, supply and consumption are simulated in a watershed draining into the Caspian Sea in northern Iran, using the water yield model in the Integrated Valuation of Environmental Service and Tradeoffs (InVEST) tool. The novelty of this study is found in the combined modelling of the impacts of climate and land use change scenarios on water security, translating these results into a water stress indicator, and estimating the associated economic costs of reduced future water supply. The results show substantial spatial variation of the negative impacts of water supply and future water security across the watershed, further increasing the pressure on its inhabitants, their economic activities and ecological values. The estimation of the economic costs of increased water insecurity allows us to inform policy and decision-makers about future investments in climate adaptation and mitigation.", "authors": [ "Daneshi, Alireza", "Brouwer, Roy", "Najafinejad, Ali", "Panahi, Mostafa", "Zarandian, Ardavan", "Maghsood, Fatemeh Fadia" ], "keywords": [ "Water security", "Climate change", "InVEST", "Water yield model", "Land use change", "Water stress index", "Water scarcity costs" ], "year": "2021", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ 41.73625946044922, -48.46742248535156 ], "cluster": 11.0 }, { "idx": 1139, "title": "Integrated modelling to assess the impacts of water stress in a transboundary river basin: Bridging local-scale water resource operations to a river basin economy", "abstract": "In this study, we develop a hydro-economic modelling framework for river-basin scales by integrating a water resources system model and an economic model. This framework allows for the representation of both local scale features, such as reservoirs, diversions, and water licenses and priorities, and regional-and provincial scale features, such as cross-sectoral and inter-regional connectedness and trade flows. This framework is able to: (a) represent nonlinearities and interactions that cannot be represented by either of typical water resources or economic models; (b) analyze the sensitivity of macro-scale economy to different local water management decisions (called 'decision levers' herein); and (c) identify water allocation strategies that are economically sound across sectors and regions. This integrated model is applied to the multi-jurisdictional Saskatchewan River Basin in Western Canada. Our findings reveal that an economically optimal water allocation strategy can mitigate the economic losses of water stress up to 80% compared to the existing water allocation strategy. We draw lessons from our analysis and discuss how integrated inter-regional hydro-economic modelling can benefit vulnerability assessment and robust decision making. (c) 2021 Elsevier B.V. All rights reserved.", "authors": [ "Eamen, Leila", "Brouwer, Roy", "Razavi, Saman" ], "keywords": [ "Integrated hydro-economic model", "Vulnerability assessment", "Water allocation", "Water stress", "Robust decision making" ], "year": "2021", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 43.43269729614258, -53.563812255859375 ], "cluster": 11.0 }, { "idx": 1140, "title": "Comparing the applicability of hydro-economic modelling approaches for large-scale decision-making in multi-sectoral and multi-regional river basins", "abstract": "A traditional engineering-based approach to hydro-economic modelling is to connect a partial equilibrium economic assessment, e.g., changes in sectoral production, to a detailed water resources system model. Since the 1990s, another approach emerged where water data are incorporated into a macro-economic model, e.g., a computable general equilibrium or input-output model, to estimate both direct and indirect economic impacts. This study builds on these different approaches and compares the outcomes from three models in the trans-boundary Saskatchewan River Basin in Canada. The economic impacts of drought and socioeconomic develop-ment are estimated using an engineering-based model, a macro-economic model, and a model that integrates a water resources model and a macro-economic model. Findings indicate that although the integrated model is more challenging to develop, its results seem most relevant for water allocation, owing to capturing both regional and sectoral economic interdependencies and key features of the water resources system in more detail.", "authors": [ "Eamen, Leila", "Brouwer, Roy", "Razavi, Saman" ], "keywords": [ "Integrated hydro-economic model", "Supply-side input-output model", "Transboundary water management", "Decision support tool" ], "year": "2022", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 42.747215270996094, -52.78911590576172 ], "cluster": 11.0 }, { "idx": 1141, "title": "Peering into agricultural rebound phenomenon using a global sensitivity analysis approach", "abstract": "Modernizing traditional irrigation systems has long been recognized as a means to reduce water losses. However, empirical evidence shows that this practice may not necessarily reduce water use in the long run; in fact, in many cases, the converse is true-a concept known as the rebound phenomenon. This phenomenon is at the heart of a fundamental research gap in the explicit evaluation of co-evolutionary dynamics and interactions among socioeconomic and hydrologic factors in agricultural systems. This gap calls for the application of systems-based methods to evaluate such dynamics. To address this gap, we use a previously developed Agent-Based Agricultural Water Demand (ABAD) model, applied to the Bow River Basin (BRB) in Canada. We perform a time-varying variance-based global sensitivity analysis (GSA) on the ABAD model to examine the individual effect of factors, as well as their joint effect, that may give rise to the rebound phenomenon in the BRB. Our results show that economic factors dominantly control possible rebounds. Although social interaction among farmers is found to be less influential than the irrigation expansion factor, its interaction effect with other factors becomes more important, indicating the highly interactive nature of the underlying socio-hydrological system. Based on the insights gained via GSA, we discuss several strategies, including community participation and water restrictions, that can be adopted to avoid the rebound phenomenon in irrigation systems. This study demonstrates that a time-varying variance-based GSA can provide a better understanding of the co-evolutionary dynamics of the socio-hydrological systems and can pave the way for better management of water resources.", "authors": [ "Ghoreishi, Mohammad", "Sheikholeslami, Razi", "Elshorbagy, Amin", "Razavi, Saman", "Belcher, Kenneth" ], "keywords": [ "Socio-hydrology", "Time-varying sensitivity analysis", "Agent-based modeling", "Agricultural rebound phenomenon", "Bow River Basin" ], "year": "2021", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ 46.03973388671875, -56.01035690307617 ], "cluster": 11.0 }, { "idx": 1142, "title": "River rhythmicity: A conceptual means of understanding and leveraging the relational values of rivers", "abstract": "River rhythmicity refers to the periodic, recurrent phenomena of a riverscape that are synchronized with the rise and fall of river water, creating regimes of river time. River rhythmicity can serve as a lens into the temporal dimension of river formation and socio-ecological dynamics that are of great interest to many disciplines. In this paper, we introduce river rhythmicity as a conceptual and analytical framework to unify riparian human communities, academic disciplines and water agencies in approaching research and management of rivers. We also explore how the disruptions to riverine rhythms that are experienced by river-dwelling communities, and are often visible in river discharge data through time, reconfigure, hinder or sever relationships between people and rivers. To ground our discussion in practical, lived experience, we provide brief descriptions of regimes of river time to demonstrate how rhythmic patterns established with rivers in north-central Canada and Amazonian Colombia shape the lives of two of our co-authors. By prioritizing holistic accounts of river rhythms, we can elucidate a fuller range of phenomena and their dynamic interactions, revealing riverscape features that are highly valued by local communities yet not often visible to any one discipline. Rhythmicity provides a conceptual framework to help address several challenges facing river conservation and water allocation dilemmas. By emphasizing relationality, it serves to (a) move beyond a biophysical framing of human-nature connectedness by demonstrating that dynamic processes and relationships are constitutive of rivers, not derivative of them; (b) enhance understanding of how the temporal dimensions of riverine relationships and river dwelling are experienced; (c) highlight the socio-cultural consequences of changes to river time and (d) centre socially embedded relationships with rivers forged from generations of observations of care and reciprocity. Read the free Plain Language Summary for this article on the Journal blog.", "authors": [ "Jackson, Sue", "Anderson, Elizabeth P.", "Piland, Natalia C.", "Carriere, Solomon", "Java, Lilia", "Jardine, Timothy D." ], "keywords": [ "Amazon River", "flow", "flow regime", "freshwater conservation", "relationality", "river time", "Saskatchewan River", "temporality" ], "year": "2022", "source": "PEOPLE AND NATURE", "publication_type": "J", "point2d": [ 49.09171676635742, -20.977630615234375 ], "cluster": 4.0 }, { "idx": 1143, "title": "Climate change impact on water supply and hydropower generation potential in Northern Manitoba", "abstract": "Study focus: Hydroelectricity makes up almost 97% of electricity generated in Manitoba, of which over 70% of its generation capacity is installed along the Lower Nelson River (LNR). In this study, 19 climate projections representing ~ 87% of climatic variability over Hudson Bay Drainage Basin are applied to coupled hydrologic-operations models to estimate water supply and hydropower generation potential changes under future climates.New hydrological insights for the region: Future inflow to the forebay of the main hydropower generating stations along LNR is expected to increase in spring and summer but decrease in winter and fall. Consequently, hydropower generation potential is projected to increase for spring, the historical flood season, which may lead to reduced reservoir inflow retention efficiency. In extremely dry climatic simulations, winter seasons see a reduction in reservoir inflow and hydropower generation potential, up to 35% and 37% in 2021-2050 and 2041-2070, respectively. Projected changes in reservoir inflow and hydropower generation potential continue to diverge over time, with dry scenarios becoming drier and wet becoming wetter, yielding high basin climate sensitivity and uncertainty with system supply and generation potential. Despite the presence of statistically significant individual trends and changes, there is a low agreement within the climate ensemble. Analysis of system robustness shows adjustment of the operations along LNR should be considered over time to better leverage changing seasonal water supply.", "authors": [ "Kim, Su Jin", "Asadzadeh, Masoud", "Stadnyk, Tricia A." ], "keywords": [ "Climate change", "Cascade river-reservoir system", "Hydropower", "Hydrologic modeling", "Operations modeling", "Model coupling" ], "year": "2022", "source": "JOURNAL OF HYDROLOGY-REGIONAL STUDIES", "publication_type": "J", "point2d": [ -9.626594543457031, -29.617233276367188 ], "cluster": 16.0 }, { "idx": 1146, "title": "Sensitivity analysis: A discipline coming of age", "abstract": "Sensitivity analysis (SA) as a 'formal' and 'standard' component of scientific development and policy support is relatively young. Many researchers and practitioners from a wide range of disciplines have contributed to SA over the last three decades, and the SAMO (sensitivity analysis of model output) conferences, since 1995, have been the primary driver of breeding a community culture in this heterogeneous population. Now, SA is evolving into a mature and independent field of science, indeed a discipline with emerging applications extending well into new areas such as data science and machine learning. At this growth stage, the present editorial leads a special issue consisting of one Position Paper on The future of sensitivity analysis and 11 research papers on Sensitivity analysis for environmental modelling published in Environmental Modelling & Software in 2020-21.", "authors": [ "Saltelli, Andrea", "Jakeman, Anthony", "Razavi, Saman", "Wu, Qiongli" ], "keywords": [ "Sensitivity analysis", "Uncertainty analysis", "Evidence based policy", "Machine learning", "Validation and verification of mathematical models" ], "year": "2021", "source": "ENVIRONMENTAL MODELLING & SOFTWARE", "publication_type": "J", "point2d": [ 6.533008098602295, -78.08226013183594 ], "cluster": 16.0 }, { "idx": 1147, "title": "Time to Update the Split-Sample Approach in Hydrological Model Calibration", "abstract": "Model calibration and validation are critical in hydrological model robustness assessment. Unfortunately, the commonly used split-sample test (SST) framework for data splitting requires modelers to make subjective decisions without clear guidelines. This large-sample SST assessment study empirically assesses how different data splitting methods influence post-validation model testing period performance, thereby identifying optimal data splitting methods under different conditions. This study investigates the performance of two lumped conceptual hydrological models calibrated and tested in 463 catchments across the United States using 50 different data splitting schemes. These schemes are established regarding the data availability, length and data recentness of continuous calibration sub-periods (CSPs). A full-period CSP is also included in the experiment, which skips model validation. The assessment approach is novel in multiple ways including how model building decisions are framed as a decision tree problem and viewing the model building process as a formal testing period classification problem, aiming to accurately predict model success/failure in the testing period. Results span different climate and catchment conditions across a 35-year period with available data, making conclusions quite generalizable. Calibrating to older data and then validating models on newer data produces inferior model testing period performance in every single analysis conducted and should be avoided. Calibrating to the full available data and skipping model validation entirely is the most robust split-sample decision. Experimental findings remain consistent no matter how model building factors (i.e., catchments, model types, data availability, and testing periods) are varied. Results strongly support revising the traditional split-sample approach in hydrological modeling.", "authors": [ "Shen, Hongren", "Tolson, Bryan A.", "Mai, Juliane" ], "keywords": [ "" ], "year": "2022", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 4.914792060852051, -63.51591110229492 ], "cluster": 16.0 }, { "idx": 1148, "title": "A socio-hydrological framework for understanding conflict and cooperation with respect to transboundary rivers", "abstract": "Increasing hydrological variability, accelerating population growth and urbanisation, and the resurgence of water resources development projects have all indicated increasing tension among the riparian countries of transboundary rivers. While a wide range of disciplines develop their understandings of conflict and cooperation in transboundary river basins, few process-based interdisciplinary approaches are available for investigating the mechanism of conflict and cooperation. This article aims to develop a meta-theoretical socio-hydrological framework that brings the slow and less visible societal processes into existing hydrological-economic models and enables observations of the change in the cooperation process and the societal processes underlying this change, thereby contributing to revealing the mechanism that drives conflict and cooperation. This framework can act as a middle ground, providing a system of constituent disciplinary theories and models for developing formal models according to a specific problem or system under investigation. Its potential applicability is demonstrated in the Nile, Lancang-Mekong, and Columbia rivers.", "authors": [ "Wei, Yongping", "Wei, Jing", "Li, Gen", "Wu, Shuanglei", "Yu, David", "Ghoreishi, Mohammad", "Lu, You", "Souza, Felipe Augusto Arguello", "Sivapalan, Murugesu", "Tian, Fuqiang" ], "keywords": [ "" ], "year": "2022", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ 45.765438079833984, -53.65870666503906 ], "cluster": 11.0 }, { "idx": 1150, "title": "Heterogeneous Changes to Wetlands in the Canadian Prairies Under Future Climate", "abstract": "Numerous wetlands in the prairies of Canada provide important ecosystem services, yet are threatened by climate and land-use changes. Understanding the impacts of climate change on prairie wetlands is critical to effective conservation planning. In this study, we construct a wetland model with surface water balance and ecoregions to project future distribution of wetlands. The climatic conditions downscaled from the Weather Research and Forecasting model were used to drive the Noah-MP land surface model to obtain surface water balance. The climate change perturbation is derived from an ensemble of general circulation models using the pseudo global warming method, under the RCP8.5 emission scenario by the end of 21st century. The results show that climate change impacts on wetland extent are spatiotemporally heterogenous. Future wetter climate in the western Prairies will favor increased wetland abundance in both spring and summer. In the eastern Prairies, particularly in the mixed grassland and mid-boreal upland, wetland areas will increase in spring but experience enhanced declines in summer due to strong evapotranspiration. When these effects of climate change are considered in light of historical drainage, they suggest a need for diverse conservation and restoration strategies. For the mixed grassland in the western Canadian Prairies, wetland restoration will be favorable, while the highly drained eastern Prairies will be challenged by the intensified hydrological cycle. The outcomes of this study will be useful to conservation agencies to ensure that current investments will continue to provide good conservation returns in the future.", "authors": [ "Zhang, Zhe", "Bortolotti, Lauren E.", "Li, Zhenhua", "Armstrong, Llwellyn M.", "Bell, Tom W.", "Li, Yanping" ], "keywords": [ "wetland", "hydrology", "climate change", "Prairie Pothole Region", "waterfowl", "conservation" ], "year": "2021", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -15.989142417907715, -8.12155818939209 ], "cluster": 13.0 }, { "idx": 1151, "title": "Estimating the Total Economic Costs of Nutrient Emission Reduction Policies to Halt Eutrophication in the Great Lakes", "abstract": "The Great Lakes (GL) in North America are among the largest freshwater resources on the planet facing serious eutrophication problems as a result of excessive nutrient loadings due to population and economic growth. More than a third of Canada's GDP is generated in and around the GL. Hence, the economic interests affected by pollution and pollution control are high. New policies to reduce pollution are often insufficiently informed due to the lack of integrated models and methods that provide decision-makers insight into the direct and indirect economic impacts of their policies. This study fills this knowledge gap and estimates the impacts of different total phosphorus (TP) restriction policy scenarios across the GL. A first of its kind multi-regional hydro-economic model is built for the Canadian GL, extended to include TP emissions from point and non-point sources. This optimization model is furthermore extended with a pollution abatement cost function that allows sectors to also take technical measures to meet the imposed pollution reduction targets. The latter is a promising new avenue for extending existing hydro-economic input-output modeling frameworks. The results show decision-makers the least cost-way to achieve different TP emission reduction targets. The estimated cost to reduce TP emissions by 40% in all GL amounts to a total annual cost of 3 billion Canadian dollars or 0.15% of Canada's GDP. The cost structure changes substantially as policy targets become more stringent, increasing the share of indirect costs and affecting not only the economic activities around the GL, but the economy of Canada as a whole due to the tightly interwoven economic structure.", "authors": [ "Garcia-Hernandez, Jorge A.", "Brouwer, Roy", "Pinto, Rute" ], "keywords": [ "Great Lakes", "eutrophication", "economic costs", "phosphorus", "hydro-economic model" ], "year": "2022", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ 40.60612487792969, -57.54640197753906 ], "cluster": 11.0 }, { "idx": 1152, "title": "Stochastic bias correction for RADARSAT-2 soil moisture retrieved over vegetated areas", "abstract": "SAR data provide the high-resolution images useful for monitoring environment, and natural resources. Nevertheless, it has been a great challenge to retrieve soil moisture over vegetated sites from SAR backscatter coefficients, as it is almost impossible to parameterize spatially heterogeneous and time-varying roughness, the effect of rainfall or canopy volume scattering with implicit equations. We suggest a Monte Carlo Method (MCM) as a strategy to mitigate non-linear errors in retrievals arising from rainfall, and vegetation growth. The Advanced Integral Equation Model (AIEM) is repeatedly run in a forward mode for establishing the Gaussian-distributed soil roughness and backscatter coefficients. The mean value of soil moisture ensembles inverted from those was taken as an optimal estimate. Local validations show that Root Mean Square Errors (RMSEs) were 0.05 similar to 0.07 m(3)/m(3) at the stations in Saskatchewan, Canada. Biases were 0.01 m(3)/m(3). Spatial distribution illustrates that the retrieval biases were mitigated, resolving AIEM inversion errors.", "authors": [ "Lee, Ju Hyoung", "Budhathoki, Sujata", "Lindenschmidt, Karl-Erich" ], "keywords": [ "SAR soil moisture", "RADARSAT-2", "time-variant roughness", "stochastic retrievals", "bias correction" ], "year": "2021", "source": "GEOCARTO INTERNATIONAL", "publication_type": "J", "point2d": [ -69.53036499023438, 10.61711597442627 ], "cluster": 8.0 }, { "idx": 1153, "title": "A streamflow-oriented ranking-based methodological framework to combine multiple precipitation datasets across large river basins", "abstract": "Hydrologic-Land Surface Models (H-LSMs) are subject to input uncertainties arising from climate forcing data, especially precipitation. For better streamflow simulations and predictions, the generation of a hybrid dataset by combining existing precipitation products has attracted considerable interest in recent years. To assess the accuracy of the hybrid dataset, in-situ precipitation-gauge stations are used as a reference point. However, the robustness of the hybrid dataset in representing spatial details can be problematic when the evaluation uses only a sparse network of in-situ observations at regional or basin scales. This study aims to develop a methodological framework to generate hybrid precipitation datasets based on the model performance of streamflow simulations that are spatially representative across large river basins. The framework is illustrated using a Canadian H-LSM known as MESH (Modelisation Environmentale communautaire - Surface Hydrology) in the Saskatchewan River basin, Canada, for the period 2002-2010. Five regional and global precipitation products (Global Meteorological Forcing Dataset at Princeton University (Princeton); the WATCH Forcing Data methodology applied to the ERA-Interim (WFDEI) augmented by Climatic Research Unit (WFDEI [CRU]) and Global Precipitation Climatology Centre (WFDEI [GPCC]); North American Regional Reanalysis (NARR); and Canadian Precipitation Analysis (CaPA)) were included as candidates in this study. Results indicate that the generation of a hybrid dataset based on hydrological evaluation was useful for improving H-LSM modelling skills. Hybrid datasets showed a similar or better model performance compared to that of the best basin-wide precipitation product in the headwaters and gradually performed better downstream and at the basin outlet. When multiple products are combined model performance can be further enhanced by considering seasonality with respect to the hydrological regime of the river basin. This study demonstrates the usefulness of hybrid datasets in a large-scale river basin with low climate station network density.", "authors": [ "Wong, Jefferson S.", "Yassin, Fuad", "Famiglietti, James S.", "Pomeroy, John W." ], "keywords": [ "Precipitation combination", "Precipitation datasets", "Hydrological modelling", "Large-scale basins", "Canada" ], "year": "2021", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -30.296676635742188, -28.55437469482422 ], "cluster": 16.0 }, { "idx": 1155, "title": "Proof-of-Concept of a Quasi-2D Water-Quality Modelling Approach to Simulate Transverse Mixing in Rivers", "abstract": "A quasi-two-dimensional (quasi-2D) modelling approach is introduced to mimic transverse mixing of an inflow into a river from one of its banks, either an industrial outfall or a tributary. The concentrations of determinands in the inflow vary greatly from those in the river, leading to very long mixing lengths in the river downstream of the inflow location. Ideally, a two-dimensional (2D) model would be used on a small scale to capture the mixing of the two flow streams. However, for large-scale applications of several hundreds of kilometres of river length, such an approach demands too many computational resources and too much computational time, especially if the application will at some point require ensemble input from climate-change scenario data. However, a one-dimensional (1D) model with variables varying in the longitudinal flow direction but averaged across the cross-sections is too simple of an approach to capture the lateral mixing between different flow streams within the river. Hence, a quasi-2D method is proposed in which a simplified 1D solver is still applied but the discretisation of the model setup can be carried out in such a way as to enable a 2D representation of the model domain. The quasi-2D model setup also allows secondary channels and side lakes in floodplains to be incorporated into the discretisation. To show proof-of-concept, the approach has been tested on a stretch of the lower Athabasca River in Canada flowing through the oil sands region between Fort McMurray and Fort MacKay. A dye tracer and suspended sediments are the constituents modelled in this test case.", "authors": [ "Sabokruhie, Pouya", "Akomeah, Eric", "Rosner, Tammy", "Lindenschmidt, Karl-Erich" ], "keywords": [ "lower Athabasca River", "oil sands region", "quasi-2D modelling", "water-quality analysis simulation program (WASP)", "water-quality modelling" ], "year": "2021", "source": "WATER", "publication_type": "J", "point2d": [ 44.67856216430664, -6.9993414878845215 ], "cluster": 18.0 }, { "idx": 1157, "title": "Hydrometeorological, glaciological and geospatial research data from the Peyto Glacier Research Basin in the Canadian Rockies", "abstract": "This paper presents hydrometeorological, glaciological and geospatial data from the Peyto Glacier Research Basin (PGRB) in the Canadian Rockies. Peyto Glacier has been of interest to glaciological and hydro-logical researchers since the 1960s, when it was chosen as one of five glacier basins in Canada for the study of mass and water balance during the International Hydrological Decade (IHD, 1965-1974). Intensive studies of the glacier and observations of the glacier mass balance continued after the IHD, when the initial seasonal meteorological stations were discontinued, then restarted as continuous stations in the late 1980s. The corresponding hydrometric observations were discontinued in 1977 and restarted in 2013. Datasets presented in this paper include high-resolution, co-registered digital elevation models (DEMs) derived from original air photos and lidar surveys; hourly off-glacier meteorological data recorded from 1987 to the present; precipitation data from the nearby Bow Summit weather station; and long-term hydrological and glaciological model forcing datasets derived from bias-corrected reanalysis products. These data are crucial for studying climate change and variability in the basin and understanding the hydrological responses of the basin to both glacier and climate change. The comprehensive dataset for the PGRB is a valuable and exceptionally long-standing testament to the impacts of climate change on the cryosphere in the high-mountain environment. The dataset is publicly available from Federated Research Data Repository at https://doi.org/10.20383/101.0259 (Pradhananga et al., 2020).", "authors": [ "Pradhananga, Dhiraj", "Pomeroy, John W.", "Aubry-Wake, Caroline", "Munro, D. Scott", "Shea, Joseph", "Demuth, Michael N.", "Kirat, Nammy Hang", "Menounos, Brian", "Mukherjee, Kriti" ], "keywords": [ "" ], "year": "2021", "source": "EARTH SYSTEM SCIENCE DATA", "publication_type": "J", "point2d": [ -32.02305221557617, -9.892276763916016 ], "cluster": 1.0 }, { "idx": 1158, "title": "The spatial extent of hydrological and landscape changes across the mountains and prairies of Canada in the Mackenzie and Nelson River basins based on data from a warm-season time window", "abstract": "East of the Continental Divide in the cold interior of Western Canada, the Mackenzie and Nelson River basins have some of the world's most extreme and variable climates, and the warming climate is changing the landscape, vegetation, cryosphere, and hydrology. Available data consist of streamflow records from a large number (395) of natural (unmanaged) gauged basins, where flow may be perennial or temporary, collected either year-round or during only the warm season, for a different series of years between 1910 and 2012. An annual warm-season time window where observations were available across all stations was used to classify (1) streamflow regime and (2) seasonal trend patterns. Streamflow trends were compared to changes in satellite Normalized Difference Indices. Clustering using dynamic time warping, which overcomes differences in streamflow timing due to latitude or elevation, identified 12 regime types. Streamflow regime types exhibit a strong connection to location; there is a strong distinction between mountains and plains and associated with ecozones. Clustering of seasonal trends resulted in six trend patterns that also follow a distinct spatial organization. The trend patterns include one with decreasing streamflow, four with different patterns of increasing streamflow, and one without structure. The spatial patterns of trends in mean, minimum, and maximum of Normalized Difference Indices of water and snow (NDWI and NDSI) were similar to each other but different from Normalized Difference Index of vegetation (NDVI) trends. Regime types, trend patterns, and satellite indices trends each showed spatially coherent patterns separating the Canadian Rockies and other mountain ranges in the west from the poorly defined drainage basins in the east and north. Three specific areas of change were identified: (i) in the mountains and cold taiga-covered subarctic, streamflow and greenness were increasing while wetness and snowcover were decreasing, (ii) in the forested Boreal Plains, particularly in the mountainous west, streamflows and greenness were decreasing but wetness and snowcover were not changing, and (iii) in the semi-arid to sub-humid agricultural Prairies, three patterns of increasing streamflow and an increase in the wetness index were observed. The largest changes in streamflow occurred in the eastern Canadian Prairies.", "authors": [ "Whitfield, Paul H.", "Kraaijenbrink, Philip D. A.", "Shook, Kevin R.", "Pomeroy, John W." ], "keywords": [ "" ], "year": "2021", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -14.35790729522705, -15.6751127243042 ], "cluster": 1.0 }, { "idx": 1159, "title": "Spatially explicit modeling of wetland conservation costs in Canadian agricultural landscapes", "abstract": "Agriculture is an important source of food, employment, and tax revenue to society. However, agricultural expansion is an important driver of global natural ecosystem degradation, including wetlands. Economic theory shows that wetland loss is caused by a mismatch between the private wetland conservation costs borne by landowners and the public benefits generated. We develop a spatially explicit wetland management model to estimate the private economic benefit of wetland drainage in an agricultural landscape in Alberta, Canada. We estimate a full wetland supply curve and show that the private economic benefits of wetland drainage are highly heterogeneous within a watershed. We then combine these private costs of wetland conservation with non-monetary measures of public ecosystem benefits to assess four wetland conservation policy targeting scenarios. We find a positive correlation between the opportunity cost of wetland conservation on private landowners and the amount of environmental benefits wetlands offer, suggesting that conserving the wetlands that impose the lowest opportunity cost may not be optimal targets for wetland conservation policy. We contribute to wetland conservation economics by demonstrating that targeted wetland conservation policies can be more effective than a uniform conservation policy that assumes wetlands within agricultural landscapes have the same costs and benefits.", "authors": [ "Eric, Asare", "Patrick, Lloyd-Smith", "Kenneth, Belcher" ], "keywords": [ "farm-simulation model", "policy targeting", "wetland conservation" ], "year": "2022", "source": "CANADIAN JOURNAL OF AGRICULTURAL ECONOMICS-REVUE CANADIENNE D AGROECONOMIE", "publication_type": "J", "point2d": [ 49.97323989868164, -44.337440490722656 ], "cluster": 11.0 }, { "idx": 1160, "title": "Increased reliance on insecticide applications in Canada linked to simplified agricultural landscapes", "abstract": "Intensification of agriculture and increased insecticide use have been implicated in global losses of farmland biodiversity and ecosystem services. We hypothesized that increased insecticide applications (proportion of area treated with insecticides) in Canada's expansive agricultural landscapes are due, in part, to shifts toward more simplified landscapes. To assess this relationship, we analyzed data from the Canadian Census of Agriculture spanning 20 years including five census periods (1996-2016) and across 225 census units within the four major agricultural regions of Pacific, Prairie, Central, and Atlantic Canada. Generalized mixed effects models were used to evaluate if changes in landscape simplification - defined as the proportion of farmland in crops (cereals, oilseeds, pulses and fruit/vegetables) - alongside other farming and climatic variables, influenced insecticide applications over time. Bayesian spatial-temporal models were further used to estimate the strength of the relationship with landscape simplification over time. We found that landscape simplification increased in 89% and insecticide applications increased in 70% of the Census Division spatial units during the 1996-2016 period. Nationally, significant increases in landscape simplification were observed in the two most agriculturally intensive regions of Prairie (from 55% to 63%) and Central (from 51% to 60%) Canada. For both regions, landscape simplification was a strong and significant predictor of higher insecticide applications, even after accounting for other factors such as climate, farm economics, farm size and land use practices (e.g., area in cash crops and tillage). If current trends continue, we estimated that insecticide applications will increase another 10%-20% by 2036 as a result of landscape simplification alone. To avoid increased reliance on toxic insecticides, agri-environmental policies need to consider that losing diverse natural habitat can increase insect pest pressure and resistance with negative environmental consequences extending beyond the field.", "authors": [ "Malaj, Egina", "Morrissey, Christy A." ], "keywords": [ "agricultural intensification", "agroecosystems", "biodiversity", "biological pest control", "cropping systems", "ecosystem services", "INLA models", "landscape change", "large-scale analysis", "pesticides", "spatial analysis" ], "year": "2022", "source": "ECOLOGICAL APPLICATIONS", "publication_type": "J", "point2d": [ 37.52357482910156, -22.272817611694336 ], "cluster": 11.0 }, { "idx": 1161, "title": "Assessing hydrological sensitivity of grassland basins in the Canadian Prairies to climate using a basin classification-based virtual modelling approach", "abstract": "Significant challenges from changes in climate and land use face sustainable water use in the Canadian Prairies ecozone. The region has experienced significant warming since the mid-20th century, and continued warming of an additional 2 degrees C by 2050 is expected. This paper aims to enhance understanding of climate controls on Prairie basin hydrology through numerical model experiments. It approaches this by developing a basin-classification-based virtual modelling framework for a portion of the Prairie region and applying the modelling framework to investigate the hydrological sensitivity of one Prairie basin class (High Elevation Grasslands) to changes in climate. High Elevation Grasslands dominate much of central and southern Alberta and parts of south-western Saskatchewan, with outliers in eastern Saskatchewan and western Manitoba. The experiments revealed that High Elevation Grassland snowpacks are highly sensitive to changes in climate but that this varies geographically. Spring maximum snow water equivalent in grasslands decreases 8 % degrees C-1 of warming. Climate scenario simulations indicated that a 2 degrees C increase in temperature requires at least an increase of 20 % in mean annual precipitation for there to be enough additional snowfall to compensate for enhanced melt losses. The sensitivity in runoff is less linear and varies substantially across the study domain center dot simulations using 6 degrees C of warming, and a 30 % increase in mean annual precipitation yields simulated decreases in annual runoff of 40 % in climates of the western Prairie but 55 % increases in climates of eastern portions. These results can be used to identify those areas of the region that are most sensitive to climate change and highlight focus areas for monitoring and adaptation. The results also demonstrate how a basin classification-based virtual modelling framework can be applied to evaluate regional-scale impacts of climate change with relatively high spatial resolution in a robust, effective and efficient manner.", "authors": [ "Spence, Christopher", "He, Zhihua", "Shook, Kevin R.", "Mekonnen, Balew A.", "Pomeroy, John W.", "Whitfield, Colin J.", "Wolfe, Jared D." ], "keywords": [ "" ], "year": "2022", "source": "HYDROLOGY AND EARTH SYSTEM SCIENCES", "publication_type": "J", "point2d": [ -20.34711456298828, -13.257452011108398 ], "cluster": 12.0 }, { "idx": 1162, "title": "A Model for the Soil Freezing Characteristic Curve That Represents the Dominant Role of Salt Exclusion", "abstract": "The phenomenon of freezing point depression in frozen soils results in the co-existence of ice and liquid water in soil pores at temperatures below 273.15 K (0 degrees C), and is thought to have two causes: (a) capillary and adsorption effects, where the phase transition relationship is modified due to soil-air-water-ice interactions, and (b) solute effects, where the presence of salts lowers the freezing temperature. The soil freezing characteristic curve (SFC) characterizes the relationship between liquid water content and temperature in frozen soils. Most hydrological models represent the SFC using only capillary and adsorption effects with a relationship known as the Generalized Clapeyron Equation (GCE). In this study, we develop and test a salt exclusion model for characterizing the SFC, comparing this with the GCE-based model and a combined salt-GCE effect model. We test these models against measured SFCs in laboratory and field experiments with diverse soil textures and salinities. We consistently found that the GCE-based models under-predicted freezing-point depression. We were able to match the observations with the salt exclusion model and the combined model, suggesting that salinity is a dominant control on the SFC in real soils that always contain solutes. In modeling applications where the salinity is unknown, the soil bulk solute concentration can be treated as a single fitting parameter. Improved characterization of the SFC may result in improvements in coupled mass-heat transport models for simulating hydrological processes in cold regions, particularly the hydraulic properties of frozen soils and the hydraulic head in frozen soils that drives cryosuction.", "authors": [ "Amankwah, S. K.", "Ireson, A. M.", "Maule, C.", "Brannen, R.", "Mathias, S. A." ], "keywords": [ "soil freezing characteristic", "frozen soil", "cold regions hydrology", "Generalized Clapeyron Equation", "freezing point depression", "salt exclusion" ], "year": "2021", "source": "WATER RESOURCES RESEARCH", "publication_type": "J", "point2d": [ -38.135780334472656, 21.690832138061523 ], "cluster": 12.0 }, { "idx": 1163, "title": "Using observed soil moisture to constrain the uncertainty of simulated hydrological fluxes", "abstract": "Using data from five long-term field sites measuring soil moisture, we show the limitations of using soil moisture observations alone to constrain modelled hydrological fluxes. We test a land surface model, Modelisation Environnementale communautaire-Surface Hydrology/Canadian Land Surface Scheme, with two configurations: one where the soil hydraulic properties are determined using a pedotransfer function (the texture-based calibration) and one where they are assigned directly (the hydraulic properties-based calibration). The hydraulic properties-based calibration outperforms the texture-based calibration in terms of reproducing changes in soil moisture storage within a 1.6 m deep profile at each site, but both perform reasonably well, especially in the summer months. When the models are constrained using observations of changes in soil moisture, the predicted hydrological fluxes are subject to very large uncertainties associated with equifinality. The uncertainty is larger for the hydraulic properties-based calibration, even though the performance was better. We argue that since the pedotransfer functions constrain the model parameters in the texture-based calibrations in an unrealistic way, the texture-based calibration underestimates the uncertainty in the fluxes. We recommend that reproducing observed cumulative changes in soil moisture storage should be considered a necessary but insufficient criterion of model success. Additional sources of information are needed to reduce uncertainties, and these could include improved estimation of the soil hydraulic properties and direct observations of fluxes, particularly evapotranspiration.", "authors": [ "Ireson, Andrew M.", "Sanchez-Rodriguez, Ines", "Basnet, Sujan", "Brauner, Haley", "Bobenic, Talia", "Brannen, Rosa", "Elrashidy, Mennatullah", "Braaten, Morgan", "Amankwah, Seth K.", "Barr, Alan" ], "keywords": [ "land surface models", "pedotransfer functions", "soil moisture", "uncertainty" ], "year": "2022", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 15.9324312210083, -53.09120178222656 ], "cluster": 16.0 }, { "idx": 1165, "title": "Radial variations in xylem sap flux in a temperate red pine plantation forest", "abstract": "Background Scaling sap flux measurements to whole-tree water use or stand-level transpiration is often done using measurements conducted at a single point in the sapwood of the tree and has the potential to cause significant errors. Previous studies have shown that much of this uncertainty is related to (i) measurement of sapwood area and (ii) variations in sap flow at different depths within the tree sapwood. Results This study measured sap flux density at three depth intervals in the sapwood of 88-year-old red pine (Pinus resinosa) trees to more accurately estimate water-use at the tree- and stand-level in a plantation forest near Lake Erie in Southern Ontario, Canada. Results showed that most of the water transport (65%) occurred in the outermost sapwood, while only 26% and 9% of water was transported in the middle and innermost depths of sapwood, respectively. Conclusions These results suggest that failing to consider radial variations in sap flux density within trees can lead to an overestimation of transpiration by as much as 81%, which may cause large uncertainties in water budgets at the ecosystem and catchment scale. This study will help to improve our understanding of water use dynamics and reduce uncertainties in sap flow measurements in the temperate pine forest ecosystems in the Great Lakes region and help in protecting these forests in the face of climate change.", "authors": [ "Bodo, Alanna V.", "Arain, M. Altaf" ], "keywords": [ "Sap flow", "Transpiration", "Water use", "Red pine", "Temperate forest", "Great Lakes region" ], "year": "2021", "source": "ECOLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -53.94888687133789, 73.16101837158203 ], "cluster": 3.0 }, { "idx": 1166, "title": "Interdecadal variability of streamflow in the Hudson Bay Lowlands watersheds driven by atmospheric circulation", "abstract": "Study region: Hudson Bay Lowlands watersheds, Ontario, Canada. Study Focus: The rivers in the Hudson Bay Lowlands are a major source of freshwater entering the Arctic Ocean and they also cause major floods. In recent decades, this region has been affected by major changes in hydroclimatic processes attributed to climate change and natural climate variability. In this study, we used ERA5 reanalysis data, hydrometric observations, and the hydrological model MESH, to investigate the impact of atmospheric circulation on the inter-decadal variability of streamflow between 1979 and 2018 in the Hudson Bay Lowlands. The natural climate variability was assessed using a weather regimes approach based on the discretization of daily geopotential height anomalies (Z500) from ERA5 reanalysis, as well as large scale oceanic and atmospheric variability modes. New hydrological insights: The results showed an anomalous convergence of atmospheric moisture flux between 1995-2008 that enhanced precipitation and increased streamflow in the western part of the region. This moisture convergence was likely driven by the combination of (i) low pressure anomalies in the East Coast of North America and (ii) low pressure anomalies in western regions of Canada, associated with the cold phase of the pacific decadal oscillation (PDO). Since 2009, streamflow remains high, likely due to more groundwater discharge associated with the degradation of permafrost.", "authors": [ "Champagne, Olivier", "Arain, M. Altaf", "Wang, Shusen", "Leduc, Martin", "Russell, Hazen A. J." ], "keywords": [ "Hudson Bay Lowlands", "Subarctic region", "MESH", "Streamflow", "ERA5", "Atmospheric circulation" ], "year": "2021", "source": "JOURNAL OF HYDROLOGY-REGIONAL STUDIES", "publication_type": "J", "point2d": [ -23.714326858520508, -28.459897994995117 ], "cluster": 1.0 }, { "idx": 1167, "title": "Evaluation of Clumping Effects on the Estimation of Global Terrestrial Evapotranspiration", "abstract": "In terrestrial ecosystems, leaves are aggregated into different spatial structures and their spatial distribution is non-random. Clumping index (CI) is a key canopy structural parameter, characterizing the extent to which leaf deviates from the random distribution. To assess leaf clumping effects on global terrestrial ET, we used a global leaf area index (LAI) map and the latest version of global CI product derived from MODIS BRDF data as well as the Boreal Ecosystem Productivity Simulator (BEPS) to estimate global terrestrial ET. The results show that global terrestrial ET in 2015 was 511.9 +/- 70.1 mm yr(-1) for Case I, where the true LAI and CI are used. Compared to this baseline case, (1) global terrestrial ET is overestimated by 4.7% for Case II where true LAI is used ignoring clumping; (2) global terrestrial ET is underestimated by 13.0% for Case III where effective LAI is used ignoring clumping. Among all plant functional types (PFTs), evergreen needleleaf forests were most affected by foliage clumping for ET estimation in Case II, because they are most clumped with the lowest CI. Deciduous broadleaf forests are affected by leaf clumping most in Case III because they have both high LAI and low CI compared to other PFTs. The leaf clumping effects on ET estimation in both Case II and Case III is robust to the errors in major input parameters. Thus, it is necessary to consider clumping effects in the simulation of global terrestrial ET, which has considerable implications for global water cycle research.", "authors": [ "Chen, Bin", "Lu, Xuehe", "Wang, Shaoqiang", "Chen, Jing M.", "Liu, Yang", "Fang, Hongliang", "Liu, Zhenhai", "Jiang, Fei", "Arain, Muhammad Altaf", "Chen, Jinghua", "Wang, Xiaobo" ], "keywords": [ "canopy structural parameters", "canopy radiation transfer", "two-leaf model", "evapotranspiration", "clumping index", "leaf area index" ], "year": "2021", "source": "REMOTE SENSING", "publication_type": "J", "point2d": [ -60.48558807373047, 63.5903434753418 ], "cluster": 17.0 }, { "idx": 1168, "title": "Explaining the Shortcomings of Log-Transforming the Dependent Variable in Regression Models and Recommending a Better Alternative: Evidence From Soil CO2 Emission Studies", "abstract": "Log-transforming the dependent variable of a regression model, though convenient and frequently used, is accompanied by an under-prediction problem. We found that this underprediction can reach up to 20%, which is significant in studies that aim to estimate annual budgets. The fundamental reason for this problem is simply that the log-function is concave, and it has nothing to do with whether the dependent variable has a log-normal distribution or not. Using field-observed data of soil CO2 emission, soil temperature and soil moisture in a saturated-specification of a regression model for predicting emissions, we revealed that the under-predictions of the log-transformed approach were pervasive and systematically biased. The key determinant of the problem's severity was the coefficient of variation in the dependent variable that differed among different combinations of the values of the explanatory factors. By applying a parsimonious (Gaussian-Gamma) specification of the regression model to data from four different ecosystems, we found that this under-prediction problem was serious to various extents, and that for a relatively weak explanatory factor, the log-transformed approach is prone to yield a physically nonsensical estimated coefficient. Finally, we showed and concluded that the problem can be avoided by switching to the nonlinear approach, which does not require the assumption of homoscedasticity for the error term in computing the standard errors of the estimated coefficients. Plain Language Summary The goal of this study is to persuade empirical researchers to switch from a conventional practice of log-transforming the dependent variable in a regression model to a nonlinear approach, because the conventional practice has a pervasive and systematically biased underprediction problem that can be quite serious. For many decades, this problem was mistakenly assumed to result from the dependent variable being log-normally distributed and hence could not be properly corrected by an adjustment factor derived from this assumption. Using the examples of predicting soil CO2 emission from soil temperature and soil moisture in four ecosystems, we showed (1) that the fundamental reason for this problem is the concavity of the log-function, (2) that the under-predictions by the conventional practice were indeed pervasive and systematically biased, and (3) that the under-prediction problem was quite serious, but could be avoided by switching to a nonlinear approach.", "authors": [ "Liaw, Kao-Lee", "Khomik, Myroslava", "Arain, M. Altaf" ], "keywords": [ "carbon cycle", "desert", "forest", "Gaussian-Gamma model", "grassland", "log-transforming dependent variable", "marsh", "Mediterranean climate", "nonlinear estimation method", "soil CO2 emissions", "soil respiration", "soil temperature", "soil water content", "temperate climate", "under-prediction", "wetland" ], "year": "2021", "source": "JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES", "publication_type": "J", "point2d": [ -24.33491325378418, 59.492469787597656 ], "cluster": 17.0 }, { "idx": 1169, "title": "Species and stand-age driven differences in photochemical reflectance index and light use efficiency across four temperate forests", "abstract": "Photosynthetic light use efficiency (LUE) determines the ability of a plant to assimilate atmospheric carbon dioxide to biomass and is known to be controlled by environmental conditions, light regimes and forest age. The photochemical reflectance index (PRI), derived from leaf or canopy remotely sensed spectra, has been shown to be an effective and accurate estimator of LUE. In this study, we propose a new LUE estimation method that separates the PRI into daily maximal PRI (PRIO) for indicating daily maximal light use efficiency (LUEmax) and Delta PRI, defined as the difference between PRIO and instantaneous PRI, for estimating the diurnal physiological stress (fstress). We develop and apply the method across three temperate pine stands and a deciduous stand of different ages, in Southern Ontario, Canada. Half hourly canopy level spectra were acquired from a tower-based spectro-radiometer system (AMSPEC-III) over the growing season at the four stands. Results show that the PRIG predicted well LUEmax (R-2 > 0.6, p < 0.05) in both coniferous and deciduous stands and was able to track seasonal changes in pigment pools sizes. The Delta PRI was sensitive to short-term meteorological conditions, specifically temperature, vapor pressure deficit (VPD), and light variations resulting in strong correlations (p < 0.05) with fstress and half hourly LUE. This new method significantly improves the estimation accuracy (R(2 )increases from 0.1 to around 0.7) for PRI-based LUE estimation across all four stands of varying age and species composition and suggests that PRI-based LUE estimation has the ability to inform on both the effects of seasonal and diurnal change in photosynthetic efficiency under different meteorological conditions.", "authors": [ "Lin, Shangrong", "Coops, Nicholas C.", "Tortini, Riccardo", "Jia, Wen", "Nesic, Zoran", "Beamesderfer, Eric", "Arain, M. Altaf", "Li, Jing", "Liu, Qinhuo" ], "keywords": [ "Carbon dynamics", "Carbon flux", "Multi-angular remote sensing", "AMSPEC-III" ], "year": "2021", "source": "INTERNATIONAL JOURNAL OF APPLIED EARTH OBSERVATION AND GEOINFORMATION", "publication_type": "J", "point2d": [ -67.02759552001953, 64.2141342163086 ], "cluster": 17.0 }, { "idx": 1170, "title": "Interannual and spatial variability of net ecosystem production in forests explained by an integrated physiological indicator in summer", "abstract": "Understanding the feedback of ecosystem carbon uptake on climate change at temporal and spatial scales is crucial for developing ecosystem models. Previous studies have focused on the role of spring and autumn phenology in regulating carbon sequestration in forest stands, but few on the impact of physiological status in summer. However, plant accumulated the most carbon in summer compared with spring and autumn, therefore, it is of great significance to explore the role of summer phenological metrics on the variability of carbon sequestration. Using 514 site-years of flux data obtained at 40 FLUXNET sites including three forest ecosystems (i.e. evergreen needleleaf forest (ENF), deciduous broadleaf forest (DBF) and mixed forest (MF)) in Europe and North America, we compared the potential of physiological and phenological metrics of Gross Primary Production (GPP) and Ecosystem Respiration (RECO) in explaining the interannual and spatial variability (IAV and SV) of forest net ecosystem production (NEP). In view of the better performance of physiological metrics, we developed the maximum carbon uptake index (MCUI), which integrated the physiology metrics of photosynthesis and respiration in summer, and further explored its ability in explaining the IAV and SV of NEP. The results suggest that the MCUI had a better ability than respiration-growth length ratio (RGR) in predicting NEP for all three forest types. The interpretation of MCUI based on meteorological variables illustrated that the controlling meteorological factors of MCUI differed substantially among ecosystems. The summer shortwave radiation had the greatest influence on MCUI at DBF sites, while the soil water content played an important but opposite role at ENF and DBF sites, and no significant meteorological driver was found at MF sites. The higher potential of MCUI in explaining IAV and SV of NEP highlights the importance of summer physiology in controlling the forest carbon sequestration, and further confirms the significant role of peak plant growth in regulating carbon cycle of forest ecosystems. Understanding the drivers of peak plant growth is therefore of a great significance for further improving the precious of ecosystem model in the future.", "authors": [ "Liu, Ying", "Wu, Chaoyang", "Liu, Lin", "Gu, Chengyan", "Black, T. Andrew", "Jassal, Rachhpal S.", "Hoertnagl, Lukas", "Montagnani, Leonardo", "Moyano, Fernando", "Varlagin, Andrej", "Arain, M. Altaf", "Govind, Ajit" ], "keywords": [ "Physiology", "Phenology", "Forest", "Flux", "Net ecosystem production" ], "year": "2021", "source": "ECOLOGICAL INDICATORS", "publication_type": "J", "point2d": [ -55.97078323364258, 62.627593994140625 ], "cluster": 17.0 }, { "idx": 1171, "title": "The FLUXNET2015 dataset and the ONEFlux processing pipeline for eddy covariance data (vol 7, 225, 2020)", "abstract": "A Correction to this paper has been published: https://doi.org/10.1038/s41597-021-00851-9.", "authors": [ "Pastorello, Gilberto", "Trotta, Carlo", "Canfora, Eleonora", "Chu, Housen", "Christianson, Danielle", "Cheah, You-Wei", "Poindexter, Cristina", "Chen, Jiquan", "Elbashandy, Abdelrahman", "Humphrey, Marty", "Isaac, Peter", "Polidori, Diego", "Reichstein, Markus", "Ribeca, Alessio", "van Ingen, Catharine", "Vuichard, Nicolas", "Zhang, Leiming", "Amiro, Brian", "Ammann, Christof", "Arain, M. Altaf", "Ardo, Jonas", "Arkebauer, Timothy", "Arndt, Stefan K.", "Arriga, Nicola", "Aubinet, Marc", "Aurela, Mika", "Baldocchi, Dennis", "Barr, Alan", "Beamesderfer, Eric", "Marchesini, Luca Belelli", "Bergeron, Onil", "Beringer, Jason", "Bernhofer, Christian", "Berveiller, Daniel", "Billesbach, Dave", "Black, Thomas Andrew", "Blanken, Peter D.", "Bohrer, Gil", "Boike, Julia", "Bolstad, Paul V.", "Bonal, Damien", "Bonnefond, Jean-Marc", "Bowling, David R.", "Bracho, Rosvel", "Brodeur, Jason", "Brummer, Christian", "Buchmann, Nina", "Burban, Benoit", "Burns, Sean P.", "Buysse, Pauline", "Cale, Peter", "Cavagna, Mauro", "Cellier, Pierre", "Chen, Shiping", "Chini, Isaac", "Christensen, Torben R.", "Cleverly, James", "Collalti, Alessio", "Consalvo, Claudia", "Cook, Bruce D.", "Cook, David", "Coursolle, Carole", "Cremonese, Edoardo", "Curtis, Peter S.", "D'Andrea, Ettore", "da Rocha, Humberto", "Dai, Xiaoqin", "Davis, Kenneth J.", "De Cinti, Bruno", "de Grandcourt, Agnes", "De Ligne, Anne", "De Oliveira, Raimundo C.", "Delpierre, Nicolas", "Desai, Ankur R.", "Di Bella, Carlos Marcelo", "di Tommasi, Paul", "Dolman, Han", "Domingo, Francisco", "Dong, Gang", "Dore, Sabina", "Duce, Pierpaolo", "Dufrene, Eric", "Dunn, Allison", "Dusek, Jiri", "Eamus, Derek", "Eichelmann, Uwe", "ElKhidir, Hatim Abdalla M.", "Eugster, Werner", "Ewenz, Cacilia M.", "Ewers, Brent", "Famulari, Daniela", "Fares, Silvano", "Feigenwinter, Iris", "Feitz, Andrew", "Fensholt, Rasmus", "Filippa, Gianluca", "Fischer, Marc", "Frank, John", "Galvagno, Marta", "Gharun, Mana", "Gianelle, Damiano", "Gielen, Bert", "Gioli, Beniamino", "Gitelson, Anatoly", "Goded, Ignacio", "Goeckede, Mathias", "Goldstein, Allen H.", "Gough, Christopher M.", "Goulden, Michael L.", "Graf, Alexander", "Griebel, Anne", "Gruening, Carsten", "Grunwald, Thomas", "Hammerle, Albin", "Han, Shijie", "Han, Xingguo", "Hansen, Birger Ulf", "Hanson, Chad", "Hatakka, Juha", "He, Yongtao", "Hehn, Markus", "Heinesch, Bernard", "Hinko-Najera, Nina", "Hortnagl, Lukas", "Hutley, Lindsay", "Ibrom, Andreas", "Ikawa, Hiroki", "Jackowicz-Korczynski, Marcin", "Janous, Dalibor", "Jans, Wilma", "Jassal, Rachhpal", "Jiang, Shicheng", "Kato, Tomomichi", "Khomik, Myroslava", "Klatt, Janina", "Knohl, Alexander", "Knox, Sara", "Kobayashi, Hideki", "Koerber, Georgia", "Kolle, Olaf", "Kosugi, Yoshiko", "Kotani, Ayumi", "Kowalski, Andrew", "Kruijt, Bart", "Kurbatova, Julia", "Kutsch, Werner L.", "Kwon, Hyojung", "Launiainen, Samuli", "Laurila, Tuomas", "Law, Bev", "Leuning, Ray", "Li, Yingnian", "Liddell, Michael", "Limousin, Jean-Marc", "Lion, Marryanna", "Liska, Adam J.", "Lohila, Annalea", "Lopez-Ballesteros, Ana", "Lopez-Blanco, Efren", "Loubet, Benjamin", "Loustau, Denis", "Lucas-Moffat, Antje", "Luers, Johannes", "Ma, Siyan", "Macfarlane, Craig", "Magliulo, Vincenzo", "Maier, Regine", "Mammarella, Ivan", "Manca, Giovanni", "Marcolla, Barbara", "Margolis, Hank A.", "Marras, Serena", "Massman, William", "Mastepanov, Mikhail", "Matamala, Roser", "Matthes, Jaclyn Hatala", "Mazzenga, Francesco", "McCaughey, Harry", "McHugh, Ian", "McMillan, Andrew M. S.", "Merbold, Lutz", "Meyer, Wayne", "Meyers, Tilden", "Miller, Scott D.", "Minerbi, Stefano", "Moderow, Uta", "Monson, Russell K.", "Montagnani, Leonardo", "Moore, Caitlin E.", "Moors, Eddy", "Moreaux, Virginie", "Moureaux, Christine", "Munger, J. William", "Nakai, Taro", "Neirynck, Johan", "Nesic, Zoran", "Nicolini, Giacomo", "Noormets, Asko", "Northwood, Matthew", "Nosetto, Marcelo", "Nouvellon, Yann", "Novick, Kimberly", "Oechel, Walter", "Olesen, Jorgen Eivind", "Ourcival, Jean-Marc", "Papuga, Shirley A.", "Parmentier, Frans-Jan", "Paul-Limoges, Eugenie", "Pavelka, Marian", "Peichl, Matthias", "Pendall, Elise", "Phillips, Richard P.", "Pilegaard, Kim", "Pirk, Norbert", "Posse, Gabriela", "Powell, Thomas", "Prasse, Heiko", "Prober, Suzanne M.", "Rambal, Serge", "Rannik, Ullar", "Raz-Yaseef, Naama", "Rebmann, Corinna", "Reed, David", "de Dios, Victor Resco", "Restrepo-Coupe, Natalia", "Reverter, Borja R.", "Roland, Marilyn", "Sabbatini, Simone", "Sachs, Torsten", "Saleska, Scott R.", "Sanchez-Canete, Enrique P.", "Sanchez-Mejia, Zulia M.", "Schmid, Hans Peter", "Schmidt, Marius", "Schneider, Karl", "Schrader, Frederik", "Schroder, Ivan", "Scott, Russell L.", "Sedlak, Pavel", "Serrano-Ortiz, Penelope", "Shao, Changliang", "Shi, Peili", "Shironya, Ivan", "Siebicke, Lukas", "Sigut, Ladislav", "Silberstein, Richard", "Sirca, Costantino", "Spano, Donatella", "Steinbrecher, Rainer", "Stevens, Robert M.", "Sturtevant, Cove", "Suyker, Andy", "Tagesson, Torbern", "Takanashi, Satoru", "Tang, Yanhong", "Tapper, Nigel", "Thom, Jonathan", "Tomassucci, Michele", "Tuovinen, Juha-Pekka", "Urbanski, Shawn", "Valentini, Riccardo", "van der Molen, Michiel", "van Gorsel, Eva", "van Huissteden, Ko", "Varlagin, Andrej", "Verfaillie, Joseph", "Vesala, Timo", "Vincke, Caroline", "Vitale, Domenico", "Vygodskaya, Natalia", "Walker, Jeffrey P.", "Walter-Shea, Elizabeth", "Wang, Huimin", "Weber, Robin", "Westermann, Sebastian", "Wille, Christian", "Wofsy, Steven", "Wohlfahrt, Georg", "Wolf, Sebastian", "Woodgate, William", "Li, Yuelin", "Zampedri, Roberto", "Zhang, Junhui", "Zhou, Guoyi", "Zona, Donatella", "Agarwal, Deb", "Biraud, Sebastien", "Torn, Margaret", "Papale, Dario" ], "keywords": [ "" ], "year": "2021", "source": "SCIENTIFIC DATA", "publication_type": "J", "point2d": [ -47.110023498535156, 54.65918731689453 ], "cluster": 17.0 }, { "idx": 1172, "title": "Global transpiration data from sap flow measurements: the SAPFLUXNET database", "abstract": "Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological, energy, and carbon budgets at the land-atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpiration and its response to environmental drivers are currently not well constrained by observations. Here we introduce the first global compilation of whole-plant transpiration data from sap flow measurements (SAPFLUXNET, https://sapfluxnet.creaf.cat/, last access: 8 June 2021). We harmonized and quality-controlled individual datasets supplied by contributors worldwide in a semi-automatic data workflow implemented in the R programming language. Datasets include sub-daily time series of sap flow and hydrometeorological drivers for one or more growing seasons, as well as metadata on the stand characteristics, plant attributes, and technical details of the measurements. SAPFLUXNET contains 202 globally distributed datasets with sap flow time series for 2714 plants, mostly trees, of 174 species. SAPFLUXNET has a broad bioclimatic coverage, with woodland/shrubland and temperate forest biomes especially well represented (80 % of the datasets). The measurements cover a wide variety of stand structural characteristics and plant sizes. The datasets encompass the period between 1995 and 2018, with 50 % of the datasets being at least 3 years long. Accompanying radiation and vapour pressure deficit data are available for most of the datasets, while on-site soil water content is available for 56 % of the datasets. Many datasets contain data for species that make up 90 % or more of the total stand basal area, allowing the estimation of stand transpiration in diverse ecological settings. SAPFLUXNET adds to existing plant trait datasets, ecosystem flux networks, and remote sensing products to help increase our understanding of plant water use, plant responses to drought, and ecohydrological processes. SAPFLUXNET version 0.1.5 is freely available from the Zenodo repository (https://doi.org/10.5281/zenodo.3971689; Poyatos et al., 2020a). The sapfluxnetr R package - designed to access, visualize, and process SAPFLUXNET data - is available from CRAN.", "authors": [ "Poyatos, Rafael", "Granda, Victor", "Flo, Victor", "Adams, Mark A.", "Adorjan, Balazs", "Aguade, David", "Aidar, Marcos P. M.", "Allen, Scott", "Susana Alvarado-Barrientos, M.", "Anderson-Teixeira, Kristina J.", "Aparecido, Luiza Maria", "Arain, M. Altaf", "Aranda, Ismael", "Asbjornsen, Heidi", "Baxter, Robert", "Beamesderfer, Eric", "Berry, Z. Carter", "Berveiller, Daniel", "Blakely, Bethany", "Boggs, Johnny", "Bohrer, Gil", "Bolstad, Paul, V", "Bonal, Damien", "Bracho, Rosvel", "Brito, Patricia", "Brodeur, Jason", "Casanoves, Fernando", "Chave, Jerome", "Chen, Hui", "Cisneros, Cesar", "Clark, Kenneth", "Cremonese, Edoardo", "Dang, Hongzhong", "David, Jorge S.", "David, Teresa S.", "Delpierre, Nicolas", "Desai, Ankur R.", "Do, Frederic C.", "Dohnal, Michal", "Domec, Jean-Christophe", "Dzikiti, Sebinasi", "Edgar, Colin", "Eichstaedt, Rebekka", "El-Madany, Tarek S.", "Elbers, Jan", "Eller, Cleiton B.", "Euskirchen, Eugenie S.", "Ewers, Brent", "Fonti, Patrick", "Forner, Alicia", "Forrester, David, I", "Freitas, Helber C.", "Galvagno, Marta", "Garcia-Tejera, Omar", "Ghimire, Chandra Prasad", "Gimeno, Teresa E.", "Grace, John", "Granier, Andre", "Griebel, Anne", "Guangyu, Yan", "Gush, Mark B.", "Hanson, Paul J.", "Hasselquist, Niles J.", "Heinrich, Ingo", "Hernandez-Santana, Virginia", "Herrmann, Valentine", "Holtta, Teemu", "Holwerda, Friso", "Irvine, James", "Ayutthaya, Supat Isarangkool Na", "Jarvis, Paul G.", "Jochheim, Hubert", "Joly, Carlos A.", "Kaplick, Julia", "Kim, Hyun Seok", "Klemedtsson, Leif", "Kropp, Heather", "Lagergren, Fredrik", "Lane, Patrick", "Lang, Petra", "Lapenas, Andrei", "Lechuga, Victor", "Lee, Minsu", "Leuschner, Christoph", "Limousin, Jean-Marc", "Linares, Juan Carlos", "Linderson, Maj-Lena", "Lindroth, Anders", "Llorens, Pilar", "Lopez-Bernal, Alvaro", "Loranty, Michael M.", "Luttschwager, Dietmar", "Macinnis-Ng, Cate", "Marechaux, Isabelle", "Martin, Timothy A.", "Matheny, Ashley", "McDowell, Nate", "McMahon, Sean", "Meir, Patrick", "Meszaros, Ilona", "Migliavacca, Mirco", "Mitchell, Patrick", "Molder, Meelis", "Montagnani, Leonardo", "Moore, Georgianne W.", "Nakada, Ryogo", "Niu, Furong", "Nolan, Rachael H.", "Norby, Richard", "Novick, Kimberly", "Oberhuber, Walter", "Obojes, Nikolaus", "Oishi, A. Christopher", "Oliveira, Rafael S.", "Oren, Ram", "Ourcival, Jean-Marc", "Paljakka, Teemu", "Perez-Priego, Oscar", "Peri, Pablo L.", "Peters, Richard L.", "Pfautsch, Sebastian", "Pockman, William T.", "Preisler, Yakir", "Rascher, Katherine", "Robinson, George", "Rocha, Humberto", "Rocheteau, Alain", "Roll, Alexander", "Rosado, Bruno H. P.", "Rowland, Lucy", "Rubtsov, Alexey, V", "Sabate, Santiago", "Salmon, Yann", "Salomon, Roberto L.", "Sanchez-Costa, Elisenda", "Schafer, Karina V. R.", "Schuldt, Bernhard", "Shashkin, Alexandr", "Stahl, Clement", "Stojanovic, Marko", "Suarez, Juan Carlos", "Sun, Ge", "Szatniewska, Justyna", "Tatarinov, Fyodor", "Tesar, Miroslav", "Thomas, Frank M.", "Tor-ngern, Pantana", "Urban, Josef", "Valladares, Fernando", "van der Tol, Christiaan", "van Meerveld, Ilja", "Varlagin, Andrej", "Voigt, Holm", "Warren, Jeffrey", "Werner, Christiane", "Werner, Willy", "Wieser, Gerhard", "Wingate, Lisa", "Wullschleger, Stan", "Yi, Koong", "Zweifel, Roman", "Steppe, Kathy", "Mencuccini, Maurizio", "Martinez-Vilalta, Jordi" ], "keywords": [ "" ], "year": "2021", "source": "EARTH SYSTEM SCIENCE DATA", "publication_type": "J", "point2d": [ -58.295692443847656, 50.359474182128906 ], "cluster": 3.0 }, { "idx": 1173, "title": "Seasonal variation in the canopy color of temperate evergreen conifer forests", "abstract": "Evergreen conifer forests are the most prevalent land cover type in North America. Seasonal changes in the color of evergreen forest canopies have been documented with near-surface remote sensing, but the physiological mechanisms underlying these changes, and the implications for photosynthetic uptake, have not been fully elucidated. Here, we integrate on-the-ground phenological observations, leaf-level physiological measurements, near surface hyperspectral remote sensing and digital camera imagery, tower-based CO2 flux measurements, and a predictive model to simulate seasonal canopy color dynamics. We show that seasonal changes in canopy color occur independently of new leaf production, but track changes in chlorophyll fluorescence, the photochemical reflectance index, and leaf pigmentation. We demonstrate that at winter-dormant sites, seasonal changes in canopy color can be used to predict the onset of canopy-level photosynthesis in spring, and its cessation in autumn. Finally, we parameterize a simple temperature-based model to predict the seasonal cycle of canopy greenness, and we show that the model successfully simulates interannual variation in the timing of changes in canopy color. These results provide mechanistic insight into the factors driving seasonal changes in evergreen canopy color and provide opportunities to monitor and model seasonal variation in photosynthetic activity using color-based vegetation indices.", "authors": [ "Seyednasrollah, Bijan", "Bowling, David R.", "Cheng, Rui", "Logan, Barry A.", "Magney, Troy S.", "Frankenberg, Christian", "Yang, Julia C.", "Young, Adam M.", "Hufkens, Koen", "Arain, M. Altaf", "Black, T. Andrew", "Blanken, Peter D.", "Bracho, Rosvel", "Jassal, Rachhpal", "Hollinger, David Y.", "Law, Beverly E.", "Nesic, Zoran", "Richardson, Andrew D." ], "keywords": [ "AmeriFlux", "evergreen conifer", "PhenoCam", "phenology", "PRI", "seasonality", "xanthophyll" ], "year": "2021", "source": "NEW PHYTOLOGIST", "publication_type": "J", "point2d": [ -68.1063003540039, 61.743873596191406 ], "cluster": 17.0 }, { "idx": 1174, "title": "Sensitivity of vegetation dynamics to climate variability in a forest-steppe transition ecozone, north-eastern Inner Mongolia, China", "abstract": "Climate change and land use management were competing explanations for vegetation dynamics in cold and semi-arid region of north-eastern Inner Mongolia, China. In order to reveal the role of human disturbance and clarify the regional climate-vegetation relationship, long-term (1982-2013) datasets of climate variables and vegetation dynamics in a forest-steppe transition zone of north-eastern Inner Mongolia, China were collected. Partial correlation analyses, principal components regression (PCR), and residual analyses were conducted to reveal the vegetation sensitivities to different climate variables and the impact of anthropogenic activities on climate-vegetation relationship. The results showed that. (1) Annual mean air temperature (TMP) significantly increased at a linear slope of 0.08 degrees C per decade, annual precipitation (PRE) had an insignificantly linear slope of -16.42 mm per decade (p = 0.15). The average Normalized Difference Vegetation Index (NDVI) had a significantly negative trend over the past decades. A change point around the year 1998, coincided with the occurrence of an intense global El Nino event was also identified. (2) Regional climate change can be represented by changes in temperature, humidity and radiation. NDVI in the steppes display high sensitivity to moisture availability. Whereas, forests was influenced by the warmth index (WMI), accumulation of monthly temperature above a threshold of 5 degrees C. Partial correlation analyses showed that pixels of positive correlation with PRE (controlling TMP) overlap with the pixels of high partial correlation with minimum temperature (controlling maximum temperature), which suggests a hidden link between minimum temperature and PRE in this region. (3) The spatial distribution of significantly decreased NDVI overlap with cropland expansion, as well as the low residual square (R-2) from PCR analysis. The NDVI decline in these expanded croplands suggests human disturbance on vegetation dynamics. Following climate warming, NDVI of forested land displayed positive trend. Whereas, most of steppe displayed negative trend, possibly resulting from combined effects of climate drying and human disturbance. We conclude that the regional climate change can be characterized as warming and drying. Steppe areas were sensitive to humidity changes while forested land was mostly influenced by growing season warmth. Overall, the regional NDVI displayed significantly negative trend over the past decades. Beyond climate drying, cropland expansion in the transition area between grassland and forested land is also an important driver for decreased NDVI. Further studies on the ecological and hydrological consequences of crop land expansion is necessary.", "authors": [ "You, Guangyong", "Liu, Bo", "Zou, Changxin", "Li, Haidong", "McKenzie, Shawn", "He, Yaqian", "Gao, Jixi", "Jia, Xiru", "Arain, M. Altaf", "Wang, Shusen", "Wang, Zhi", "Xia, Xin", "Xu, Wanggu" ], "keywords": [ "Climate change", "Vegetation dynamics", "Change point", "Sensitivity analysis", "Cropland expansion" ], "year": "2021", "source": "ECOLOGICAL INDICATORS", "publication_type": "J", "point2d": [ -56.585693359375, 42.58758544921875 ], "cluster": 17.0 }, { "idx": 1175, "title": "Seasonality in aerodynamic resistance across a range of North American ecosystems", "abstract": "Surface roughness - a key control on land-atmosphere exchanges of heat and momentum - differs between dormant and growing seasons. However, how surface roughness shifts seasonally at fine time scales (e.g., days) in response to changing canopy conditions is not well understood. This study: (1) explores how aerodynamic resistance changes seasonally; (2) investigates what drives these seasonal shifts, including the role of vegetation phenology; and (3) quantifies the importance of including seasonal changes of aerodynamic resistance in big leaf models of sensible heat flux (H). We evaluated aerodynamic resistance and surface roughness lengths for momentum (z(0m)) and heat (z(0h)) using the kB(-1) parameter (ln(z(0m)/z(0h))). We used AmeriFlux data to obtain surface-roughness estimates, and PhenoCam greenness data for phenology. This analysis included 23 sites and similar to 190 site years from deciduous broadleaf, evergreen needleleaf, woody savanna, cropland, grassland, and shrubland plant-functional types (PFTs). Results indicated clear seasonal patterns in aerodynamic resistance to sensible heat transfer (R-ah). This seasonality tracked PhenoCam-derived start-of-season green-up transitions in PFTs displaying the most significant seasonal changes in canopy structure, with R-ah decreasing near green-up transitions. Conversely, in woody savanna sites and evergreen needleleaf forests, patterns in R-ah were not linked to green-up. Our findings highlight that decreases in kB(-1) are an important control over R-ah, explaining > 50% of seasonal variation in R-ah across most sites. Decreases in kB(-1) during green-up are likely caused by increasing z(0h) in response to higher leaf area index. Accounting for seasonal variation in kB(-1) is key for predicting H as well; assuming kB(-1) to be constant resulted in significant biases that also exhibited strong seasonal patterns. Overall, we found that aerodynamic resistance can be sensitive to phenology in ecosystems having strong seasonality in leaf area, and this linkage is critical for understanding land-atmosphere interactions at seasonal time scales.", "authors": [ "Young, Adam M.", "Friedl, Mark A.", "Seyednasrollah, Bijan", "Beamesderfer, Eric", "Carrillo, Carlos M.", "Li, Xiaolu", "Moon, Minkyu", "Arain, M. Altaf", "Baldocchi, Dennis D.", "Blanken, Peter D.", "Bohrer, Gil", "Burns, Sean P.", "Chu, Housen", "Desai, Ankur R.", "Griffis, Timothy J.", "Hollinger, David Y.", "Litvak, Marcy E.", "Novick, Kim", "Scott, Russell L.", "Suyker, Andrew E.", "Verfaillie, Joseph", "Wood, Jeffrey D.", "Richardson, Andrew D." ], "keywords": [ "Phenology", "AmeriFlux", "PhenoCam", "Aerodynamic resistance", "Land-atmosphere interactions", "Sensible heat flux" ], "year": "2021", "source": "AGRICULTURAL AND FOREST METEOROLOGY", "publication_type": "J", "point2d": [ -52.93033218383789, 54.04677200317383 ], "cluster": 17.0 }, { "idx": 1176, "title": "The Impact of Variable Retention Harvesting on Growth and Carbon Sequestration of a Red Pine (Pinus resinosa Ait.) Plantation Forest in Southern Ontario, Canada", "abstract": "As atmospheric carbon dioxide concentrations continue to rise and global temperatures increase, there is growing concern about the sustainability, health, and carbon sequestration potential of forest ecosystems. Variable retention harvesting (VRH) has been suggested to be a potential method to increase forest biodiversity, growth, and carbon (C) sequestration. A field trial was established in an 88-year-old red pine (Pinus resinosa Ait.) plantation in southern Ontario, Canada, using a completely randomized design to examine the response of tree productivity and other forest values to five harvesting treatments: 33% aggregate retention (33A), 55% aggregate retention (55A), 33% dispersed retention (33D), and 55% dispersed retention (55D) in comparison to an unharvested control (CN). In this study, we explored the impacts of VRH on aboveground stem radial growth and annual C increment. Standard dendrochronological methods and allometric equations were used to quantify tree- and stand-level treatment effects during a five-year pre-harvest (2009-2013) and post-harvest (2014-2018) period. Tree-level growth and C increment were increased by the dispersed retention pattern regardless of retention level. At the stand level, the total C increment was highest at greater retention levels and did not vary with retention pattern. These results suggest that the choice of retention level and pattern can have a large influence on management objectives as they relate to timber production, climate change adaptation, and/or climate change mitigation.", "authors": [ "Zugic, Jessica I.", "Pisaric, Michael F. J.", "McKenzie, Shawn M.", "Parker, William C.", "Elliott, Ken A.", "Arain, M. Altaf" ], "keywords": [ "Pinus resinosa", "forest management", "carbon sequestration", "variable retention harvesting", "dendrochronology", "tree rings" ], "year": "2021", "source": "FRONTIERS IN FORESTS AND GLOBAL CHANGE", "publication_type": "J", "point2d": [ -51.716064453125, 66.89664459228516 ], "cluster": 15.0 }, { "idx": 1177, "title": "Evaluation of observed and projected extreme climate trends for decision making in Six Nations of the Grand River, Canada", "abstract": "Hydrometeorological events have been the predominant type of natural hazards to affect communities across Canada. While climate change is a concern to all Canadians, Indigenous communities in Canada have been disproportionately more affected by these extreme climate events than non-Indigenous communities. As the impacts of climate change intensify, it becomes increasingly important that high-resolution climate services are made available to Indigenous decision makers for the development of climate change adaptation plans. This paper examined extreme climate trends in the Six Nations of the Grand River reserve, the most populated Indigenous community in Canada. A set of 12 indices were used to evaluate changes in extreme climate events from 1951 to 2013, and 2006 to 2099 under Representative Concentration Pathways (RCP) 4.5 and 8.5. Results indicated that from 1951 to 2013, Six Nations became warmer and wetter with an average temperature increase of 0.7 degrees C and precipitation increase of 42 mm. Over this period, the frequency and duration of extreme heat and extreme precipitation events also increased, while extreme cold events decreased. In the future (2006 to 2099), temperature is expected to increase by 3 to 6 degrees C, while seasonal precipitation is expected to increase in winter, early spring, and fall. Projected rate of increase of heatwaves is 0.4 to 1.5 days per year and extreme annual rainfall events is 0.2 to 0.5 mm per year under both RCP scenarios. The climate information and data provide by this study will help Six Nations' decision makers in planning for climate change impacts.", "authors": [ "Deen, Tariq A.", "Arain, M. Altaf", "Champagne, Olivier", "Chow-Fraser, Patricia", "Nagabhatla, Nidhi", "Martin-Hill, Dawn" ], "keywords": [ "Climate change", "Climate change impacts", "Extreme climate events", "Indigenous", "First Nations", "Six Nations of Grand River" ], "year": "2021", "source": "CLIMATE SERVICES", "publication_type": "J", "point2d": [ -37.43564987182617, -32.69044876098633 ], "cluster": 1.0 }, { "idx": 1180, "title": "The sensitivity of snow hydrology to changes in air temperature and precipitation in three North American headwater basins", "abstract": "Whether or not the impact of warming on mountain snow and runoff can be offset by precipitation increases has not been well examined, but it is crucially important for future downstream water supply. Using the physically based Cold Regions Hydrological Modelling Platform (CRHM), elasticity (percent change in runoff divided by change in a climate forcing) and the sensitivity of snow regimes to perturbations were investigated in three well-instrumented mountain research basins spanning the northern North American Cordillera. Hourly meteorological observations were perturbed using air temperature and precipitation changes and were then used to force hydrological models for each basin. In all three basins, lower temperature sensitivities of annual runoff volume (<= 6% degrees C-1) and higher sensitivities of peak snowpack (-17% C-1) showed that annual runoff was far less sensitive to temperature than the snow regime. Higher and lower precipitation elasticities of annual runoff (1.5 - 2.1) and peak snowpack (0.7 - 1.1) indicated that the runoff change is primarily attributed to precipitation change and, secondarily, to warming. A low discrepancy between observed and simulated precipitation elasticities showed that the model results are reliable, and one can conduct sensitivity analysis. The air temperature elasticities, however, must be interpreted with care as the projected warmings range beyond the observed temperatures and, hence, it is not possible to test their reliability. Simulations using multiple elevations showed that the timing of peak snowpack was most sensitive to temperature. For the range of warming expected from North American climate model simulations, the impacts of warming on annual runoff, but not on peak snowpack, can be offset by the size of precipitation increases projected for the near-future period 2041-2070. To offset the impact of 2 degrees C warming on annual runoff, precipitation would need to increase by less than 5% in all three basins. To offset the impact of 2 degrees C warming on peak snowpack, however, precipitation would need to increase by 12% in Wolf Creek in Yukon Territory, 18% in Marmot Creek in the Canadian Rockies, and an amount greater than the maximum projected at Reynolds Mountain in Idaho. The role of increased precipitation as a compensator for the impact of warming on snowpack is more effective at the highest elevations and higher latitudes. Increased precipitation leads to resilient and strongly coupled snow and runoff regimes, contrasting sharply with the sensitive and weakly coupled regimes at low elevations and in temperate climate zones.", "authors": [ "Rasouli, Kabir", "Pomeroy, John W.", "Whitfield, Paul H." ], "keywords": [ "Climate change", "Mountain hydrology", "North American Cordillera", "Hydrological processes", "Runoff elasticity", "Sensitivity analysis" ], "year": "2022", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -34.755096435546875, -13.215299606323242 ], "cluster": 12.0 }, { "idx": 1181, "title": "Simulating site-scale permafrost hydrology: Sensitivity to modelling decisions and air temperature", "abstract": "To predict future hydrological cycling in permafrost-dominated regions requires consideration of complex hydrological interactions that involve cryospheric states and fluxes, and hence thermodynamics. This challenges many hydrological models, particularly those applied in the Arctic. This study presents the implementation and validation of set of algorithms representing permafrost and frozen ground dynamics, coupled into a physically based, modular, cold regions hydrological model at two tundra sites in northern Yukon Territory, Canada. Hydrological processes represented in the model include evapotranspiration, soil moisture dynamics, flow through organic and mineral terrain, ground freeze-thaw, infiltration to frozen and unfrozen soils, snowpack energy balance, and the accumulation, wind redistribution, sublimation, and canopy interception of snow. The model was able to successfully represent observed ground surface temperature, ground thaw and snow accumulation at the two sites without calibration. A sensitivity analysis of simulated ground thaw revealed that the soil properties of the upper organic layer dominated the model response; however, its performance was robust for a range of realistic physical parameters. Different modelling decisions were assessed by removing the physically based algorithms for snowpack dynamics and ground surface temperature and replacing them with empirical approaches. Results demonstrate that more physically based approaches should be pursued to reduce uncertainties in poorly monitored environments. Finally, the model was driven by three climate warming scenarios to assess the sensitivity of snow redistribution and ablation processes and ground thaw to warming temperatures. This showed great sensitivity of snow regime and soil thaw to warming, even in the cold continental climate of the northwestern Canadian Arctic. The results are pertinent to transportation infrastructure and water management in this remote, cold, sparsely gauged region where traditional approaches to hydrological prediction are not possible.", "authors": [ "Krogh, Sebastian A.", "Pomeroy, John W." ], "keywords": [ "Permafrost hydrology", "Arctic", "Cold regions", "Hydrological modelling", "Model uncertainty" ], "year": "2021", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -31.814695358276367, 1.4942868947982788 ], "cluster": 12.0 }, { "idx": 1182, "title": "Diagnosing changes in glacier hydrology from physical principles using a hydrological model with snow redistribution, sublimation, firnification and energy balance ablation algorithms", "abstract": "A comprehensive glacier hydrology model was developed within the Cold Regions Hydrological Modelling platform (CRHM) to include modules representing wind flow over complex terrain, blowing snow redistribution and sublimation by wind, snow redistribution by avalanches, solar irradiance to sloping surfaces, surface sub-limation, glacier mass balance and runoff, meltwater and streamflow routing. The physically based glacier hy-drology model created from these modules in CRHM was applied to simulate the hydrology of the instrumented, glacierized and rapidly deglaciating Peyto and Athabasca glacier research basins in the Canadian Rockies without calibration of parameters from streamflow. It was tested against observed albedo, point and aggregated glacier mass balance, and streamflow and found to successfully simulate surface albedo, snow redistribution, snow and glacier accumulation and ablation, mass balance and streamflow discharge, both when driven by in -situ observations and reanalysis forcing data. Long term modelling results indicate that the increases in discharge from the 1960s to the present are due to increased glacier ice melt contributions, despite declining precipitation and snow melt.", "authors": [ "Pradhananga, Dhiraj", "Pomeroy, John W." ], "keywords": [ "Glacier hydrology", "Energy-budget melt", "Mass balance", "Snow redistribution", "Peyto Glacier", "Athabasca Glacier", "Hydrological modelling" ], "year": "2022", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -28.564537048339844, -12.75227165222168 ], "cluster": 12.0 }, { "idx": 1183, "title": "Glacier recession alters stream water quality characteristics facilitating bloom formation in the benthic diatom Didymosphenia geminata", "abstract": "Glaciers provide cold, turbid runoff to many mountain streams in the late summer and buffer against years with low snowfall. The input of glacial meltwater to streams maintains unique habitats and support a diversity of stream flora and fauna. In western Canada, glaciers are anticipated to retreat by 60-80% by the end of the century, and this retreat will invoke widespread changes in mountain ecosystems. We used a space-for-time substitution along a gradient of glacierization in western Canada to develop insights into changes that may occur in glaciated regions over the coming decades. Here we report on observed changes in physical (temperature, turbidity), and chemical (dissolved and total nutrients) characteristics of mountain streams and the associated shifts in their diatom communities during de-glacierization. Shifts in habitat characteristics across gradients include changes in nutrient concentrations, light penetration, temperatures, and flow, all of which have led to distinct changes in diatom community composition. Importantly, glacial-fed rivers were 3-5 degrees C cooler than rivers without glacial contributions. Declines in glacial meltwater contribution to streams resulted in shifts in the timing of nutrient fluxes and lower concentrations of total phosphorus (TP), soluble reactive phosphorus (SRP), and higher dissolved inorganic nitrogen (DIN) and light penetration. The above set of conditions were linked to the overgrowth of the benthic diatom Didymosphenia geminata. These changes in stream condition and D. geminata colony development primarily occurred in streams with marginal (2-5%) to no glacier cover. Our data support a hypothesis that climate-induced changes in river hydrochemistry and physical condition lead to a phenological mismatch that favors D. geminata bloom development. (C) 2020 Elsevier B.V. All rights reserved.", "authors": [ "Brahney, J.", "Bothwell, M. L.", "Capito, L.", "Gray, C. A.", "Null, S. E.", "Menounos, B.", "Curtis, P. J." ], "keywords": [ "Mountain streams", "Glacier retreat", "Deglacierization", "Climate change", "Nutrients", "Diatoms", "Didymo", "Phenology" ], "year": "2021", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 30.191591262817383, 35.04209518432617 ], "cluster": 19.0 }, { "idx": 1184, "title": "Learning from mistakes-Assessing the performance and uncertainty in process-based models", "abstract": "Typical applications of process- or physically-based models aim to gain a better process understanding or provide the basis for a decision-making process. To adequately represent the physical system, models should include all essential processes. However, model errors can still occur. Other than large systematic observation errors, simplified, misrepresented, inadequately parametrised or missing processes are potential sources of errors. This study presents a set of methods and a proposed workflow for analysing errors of process-based models as a basis for relating them to process representations. The evaluated approach consists of three steps: (1) training a machine-learning (ML) error model using the input data of the process-based model and other available variables, (2) estimation of local explanations (i.e., contributions of each variable to an individual prediction) for each predicted model error using SHapley Additive exPlanations (SHAP) in combination with principal component analysis, (3) clustering of SHAP values of all predicted errors to derive groups with similar error generation characteristics. By analysing these groups of different error-variable association, hypotheses on error generation and corresponding processes can be formulated. That can ultimately lead to improvements in process understanding and prediction. The approach is applied to a process-based stream water temperature model HFLUX in a case study for modelling an alpine stream in the Canadian Rocky Mountains. By using available meteorological and hydrological variables as inputs, the applied ML model is able to predict model residuals. Clustering of SHAP values results in three distinct error groups that are mainly related to shading and vegetation-emitted long wave radiation. Model errors are rarely random and often contain valuable information. Assessing model error associations is ultimately a way of enhancing trust in implemented processes and of providing information on potential areas of improvement to the model.", "authors": [ "Feigl, Moritz", "Roesky, Benjamin", "Herrnegger, Mathew", "Schulz, Karsten", "Hayashi, Masaki" ], "keywords": [ "explainable", "machine learning", "process-based modelling", "stream temperature" ], "year": "2022", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ 5.055197715759277, -57.84438705444336 ], "cluster": 16.0 }, { "idx": 1185, "title": "Quantifying relative contributions of source waters from a subalpine wetland to downstream water bodies", "abstract": "Subalpine regions of the Canadian Rocky Mountains are expected to experience continued changes in hydrometeorological processes due to anthropogenically mediated climate warming. As a result, fresh water supplies are at risk as snowmelt periods occur earlier in the year, and glaciers contribute less annual meltwater, resulting in longer growing seasons and greater reliance on rainfall to generate runoff. In such environments, wetlands are potentially important components that control runoff processes, but due to their location and harsh climates their hydrology is not well studied. We used stable water isotopes of hydrogen and oxygen (delta H-2 and delta O-18), coupled with MixSIAR, a Bayesian mixing model, to understand relative source water contributions and mixing within Burstall Wetland, a subalpine wetland (1900 m a.s.l.), and the larger Burstall Valley. These results were combined with climate data from the Burstall Valley to understand hydrometeorological controls on Burstall Wetland source water dynamics over spatiotemporal timescales. Our results show that the seasonal isotopic patterns within Burstall Wetland reflect greater reliance on snowmelt in spring and rainfall in the peak and post-growing season periods. We found a substantial degree of mixing between precipitation (rain and snow) and stored waters in the landscape, especially during the pre-growing season. These findings suggest that longer growing seasons in subalpine snow-dominated landscapes put wetlands at risk of significant water loss and increased evaporation rates potentially leading to periods of reduced runoff during the peak- growing season and in extreme cases, wetland dry out.", "authors": [ "Hathaway, Julia M.", "Westbrook, Cherie J.", "Rooney, Rebecca C.", "Petrone, Richard M.", "Langs, Lindsey E." ], "keywords": [ "climate", "hydrology", "isotopes", "meteorology", "mixing", "runoff", "subalpine", "wetlands" ], "year": "2022", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -11.628486633300781, 18.60042953491211 ], "cluster": 13.0 }, { "idx": 1186, "title": "Using Stable Water Isotopes to Analyze Spatiotemporal Variability and Hydrometeorological Forcing in Mountain Valley Wetlands", "abstract": "Wetlands in Montane and Subalpine Subregions are increasingly recognized as important hydrologic features that support ecosystem function. However, it is currently not clear how climate trends will impact wetland hydrological processes (e.g., evaporative fluxes) across spatiotemporal scales. Therefore, identifying the factors that influence wetland hydrologic response to climate change is an important step in understanding the sensitivity of these ecosystems to environmental change. We used stable water isotopes of hydrogen and oxygen (delta H-2 and delta O-18), coupled with climate data, to determine the spatiotemporal variability in isotopic signatures of wetland source waters and understand the influence of evaporative fluxes on wetlands in the Kananaskis Valley. Our results show that the primary runoff generation mechanism changes throughout the growing season resulting in considerable mixing in wetland surface waters. We found that evaporative fluxes increased with decreasing elevation and that isotopic values became further removed from meteoric water lines during the late peak- and into the post-growing seasons. These findings suggest that a change in the water balance in favor of enhanced evaporation (due to a warmer and longer summer season than present) will not only lead to greater water loss from the wetlands themselves but may also reduce the water inputs from their catchments.", "authors": [ "Hathaway, Julia M.", "Petrone, Richard M.", "Westbrook, Cherie J.", "Rooney, Rebecca C.", "Langs, Lindsey E." ], "keywords": [ "subalpine", "montane", "isotopes", "evaporation", "wetlands", "Rocky Mountains", "runoff", "deuterium excess" ], "year": "2022", "source": "WATER", "publication_type": "J", "point2d": [ -12.00961971282959, 17.772342681884766 ], "cluster": 13.0 }, { "idx": 1187, "title": "Rapid shrub expansion in a subarctic mountain basin revealed by repeat airborne LiDAR", "abstract": "As a consequence of increasing temperatures, a rapid increase in shrub vegetation has occurred throughout the circumpolar North and is expected to continue. Rates of shrub expansion are highly variable, both at the regional scale and within local study areas. This study uses repeat airborne LiDAR and field surveys to measure changes in shrub vegetation cover along with landscape-scale variations in a well-studied subarctic headwater catchment in Yukon Territory, Canada. Airborne LiDAR surveys were conducted in August 2007 and 2018, whereas vegetation surveys were conducted in summer 2019. Machine learning classification algorithms were used to predict shrub presence/absence in 2018 based on rasterized LiDAR metrics, with the best-performing model applied to the 2007 LiDAR to create binary shrub cover layers to compare between survey years. Results show a 63.3% total increase in detectable shrub cover >= 0.45 m in height between 2007 and 2018, with an average yearly expansion of 5.8%. These changes were compared across terrain derivatives to quantify the influence of topography on shrub expansion. Terrain comparisons show that shrubs are located in and are preferentially expanding into lower and flatter areas near stream networks, at lower slope positions and with a higher potential for topographic wetness. Overall, the findings from this research reinforce the documented increase in pan-Arctic shrub vegetation in recent years, quantify the variation in shrub expansion over terrain derivatives at the landscape scale, and demonstrate the feasibility of using LiDAR to compare changes in shrub properties over time.", "authors": [ "Leipe, Sean C.", "Carey, Sean K." ], "keywords": [ "shrub expansion", "LiDAR", "topography", "Arctic change", "machine learning", "Yukon" ], "year": "2021", "source": "ENVIRONMENTAL RESEARCH COMMUNICATIONS", "publication_type": "J", "point2d": [ -63.89204406738281, 12.795522689819336 ], "cluster": 13.0 }, { "idx": 1188, "title": "Comparison of Soil Nutrient Supply Patterns among Full and Drained Beaver Ponds and Undisturbed Peat in a Rocky Mountain Fen", "abstract": "Beavers are a keystone species known to strategically impound streamflow by building dams. Beaver colonization involves upstream ponding; after abandonment, the dams degrade, and the ponds slowly drain. This ponding-draining cycle likely modifies peatland nutrient availability, which is an important control on vegetation distribution and productivity. We compared soil mineral nutrient supply patterns in a beaver-dammed peatland in the Canadian Rocky Mountains over the growing and senescence study seasons during 2020. We used a nested design, comparing nutrient supply with ion-exchange probes among a full beaver pond (FBP with deep and shallow ponding), a drained beaver pond (DBP at its centre and margin) and unimpacted fen (UF at hummock and hollow hydrologic zones). Overall, FBP had lower soil total inorganic nitrogen (TIN) and nitrate (NO3), and higher ammonium (NH4) and phosphorus (PO4) supplies compared to UF. Interestingly, beaver pond drainage tended to restore the nutrient supply to its original status. The patterns we found in nutrient supply were consistent between the growing and senescence seasons. The key drivers of nutrient dynamics were water table level and soil temperature at 5 cm depth (T-Soil); however, the controls affected each of the nutrients differently. Deepening of the water table level and higher T-Soil non-linearly increased TIN/NO3 but decreased NH4 and PO4. We suggest that the variations in peatland nutrient availabilities in response to the beaver's ponding-draining cycle may support downstream ecosystem heterogeneity and plant community composition diversity at a longer time scale.", "authors": [ "Munir, Tariq M.", "Westbrook, Cherie J." ], "keywords": [ "Beaver pond", "Mineral nutrient", "PRS", "Wetland peatland", "Rocky Mountain", "Castor canadensis" ], "year": "2022", "source": "WETLANDS", "publication_type": "J", "point2d": [ 12.791810035705566, 2.254272222518921 ], "cluster": 13.0 }, { "idx": 1189, "title": "Evapotranspiration and energy partitioning across a forest-shrub vegetation gradient in a subarctic, alpine catchment", "abstract": "As a result of altitude and latitude amplified climate change, widespread changes in vegetation composition, density and distribution have been observed across northern regions. Despite wide documentation of shrub proliferation and treeline advance, few field-based studies have evaluated the hydrological implications of these changes. Quantification of total evapotranspiration (ET) across a range of vegetation gradients is essential for predicting water yield, yet challenging in cold alpine catchments due to heterogeneous land cover, including both boreal forest and shrub taiga ecosystems. Here, we present six years of surface energy balance components and ET dynamics at three sites along an elevational gradient in a subarctic, alpine catchment near Whitehorse, Yukon Territory, Canada. These sites span a gradient of thermal and vegetation regimes, providing a space-fortime comparison for future ecosystem shifts: 1) a low-elevation boreal white spruce forest (similar to 12-20 m), 2) a mid-elevation subalpine taiga comprised of tall, dense willow (Salix) and birch (Betula) shrubs (similar to 1-3 m) and 3) a high-elevation subalpine taiga with short, sparse shrub cover (<0.75 m) and moss, lichen, and bare rock. Eddy covariance instrumentation ran year-round at the forest and during the growing season at the two shrub sites. Total ET decreased and interannual variability increased with elevation, with mean May to September ET totals of 349 (+/- 3) mm at the forest, 249 (+/- 10) mm at the tall, dense shrub site, and 240 (+26) mm at the short, sparse shrub site. Comparatively, over the same period, ET:R ratios were the highest and most variable at the forest (2.19 +/- 0.37) and similar at the tall, dense shrub (1.22 +/- 0.09) and short, sparse shrub (1.14 +/- 0.05) sites. Our results suggest that advances in treeline will increase overall ET and lower interannual variability; however, the large growing season water deficit at the forest indicates strong reliance on soil moisture from late fall and snowmelt recharge. In contrast, ET was considerably less at the cooler higher elevation shrub sites, which exhibited similar ET losses over 6 years despite differences in shrub height and abundance. ET rates between the two shrub sites were similar throughout the year, except during the peak growing season. Greater interannual variability in ET at the short, sparse shrub site indicates the reduced influence of vegetation controls on ET. Results suggest that predicted changes in vegetation type and structure in northern regions will have a considerable impact on water partitioning and will vary in a complex way in response to changing precipitation timing, phase and magnitude, growing season length, and vegetation snow and rain interactions.", "authors": [ "Nicholls, Erin M.", "Carey, Sean K." ], "keywords": [ "Evapotranspiration", "Surface energy balance", "Boreal forest", "Subalpine taiga", "Shrubification", "Vegetation change" ], "year": "2021", "source": "JOURNAL OF HYDROLOGY", "publication_type": "J", "point2d": [ -23.432077407836914, 11.48067569732666 ], "cluster": 3.0 }, { "idx": 1190, "title": "Surface Mass-Balance Gradients From Elevation and Ice Flux Data in the Columbia Basin, Canada", "abstract": "The mass-balance-elevation relation for a given glacier is required for many numerical models of ice flow. Direct measurements of this relation using remotely-sensed methods are complicated by ice dynamics, so observations are currently limited to glaciers where surface mass-balance measurements are routinely made. We test the viability of using the continuity equation to estimate annual surface mass balance between flux-gates in the absence of in situ measurements, on five glaciers in the Columbia Mountains of British Columbia, Canada. Repeat airborne laser scanning surveys of glacier surface elevation, ice penetrating radar surveys and publicly available maps of ice thickness are used to estimate changes in surface elevation and ice flux. We evaluate this approach by comparing modeled to observed mass balance. Modeled mass-balance gradients well-approximate those obtained from direct measurement of surface mass balance, with a mean difference of +6.6 +/- 4%. Regressing modeled mass balance, equilibrium line altitudes are on average 15 m higher than satellite-observations of the transient snow line. Estimates of mass balance over flux bins compare less favorably than the gradients. Average mean error (+0.03 +/- 0.07 m w.e.) between observed and modeled mass balance over flux bins is relatively small, yet mean absolute error (0.55 +/- 0.18 m w.e.) and average modeled mass-balance uncertainty (0.57 m w.e.) are large. Mass conservation, assessed with glaciological data, is respected (when estimates are within 1 sigma uncertainties) for 84% of flux bins representing 86% of total glacier area. Uncertainty on ice velocity, especially for areas where surface velocity is low (< 10 m a(-1)) contributes the greatest error in estimating ice flux. We find that using modeled ice thicknesses yields comparable modeled mass-balance gradients relative to using observations of ice thickness, but we caution against over-interpreting individual flux-bin mass balances due to large mass-balance residuals. Given the performance of modeled ice thickness and the increasing availability of ice velocity and surface topography data, we suggest that similar efforts to produce mass-balance gradients using modern high-resolution datasets are feasible on larger scales.", "authors": [ "Pelto, Ben M.", "Menounos, Brian" ], "keywords": [ "ice flux", "glacier mass balance", "ice velocity", "flux gate", "ice thickness", "balance gradient", "geodetic mass balance" ], "year": "2021", "source": "FRONTIERS IN EARTH SCIENCE", "publication_type": "J", "point2d": [ -49.493106842041016, 6.620257377624512 ], "cluster": 8.0 }, { "idx": 1191, "title": "Effects of lake-groundwater interaction on the thermal regime of a sub-alpine headwater stream", "abstract": "Stream thermal regimes are critical to the stability of freshwater habitats. There is growing concern that climate change will result in stream warming due to rising air temperatures, decreased shading in forested areas due to wildfires, and changes in streamflow. Groundwater plays an important role in controlling stream temperatures in mountain headwaters, where it makes up a considerable portion of discharge. This study investigated the controls on the thermal regime of a headwater stream, and the surrounding groundwater processes, in a catchment on the eastern slopes of the Canadian Rocky Mountains. Groundwater discharge to the headwater spring is partially sourced by a seasonal lake. Spring, stream and lake temperature, water level, discharge and chemistry data were used to build a conceptual model of the system. Meteorological data was used to set up a stream temperature model. This study presents a unique example of an indirectly lake-headed stream, that is, a lake that only has transient subsurface hydrologic connections to the stream and no surface connections. The interaction of groundwater and lake water, and the subsurface connectivity between the lake and the headwater spring determine the resulting stream temperature. Radiation dominated the non-advective fluxes in the stream energy balance. Sensible and latent heat fluxes play a secondary role, but their effects generally cancel out. During snowfall events, the latent heat associated with melting of direct snowfall onto the water surface was responsible for rapid stream cooling. An increase in advective inputs from groundwater and hillslope pathways did not result in observed cooling of stream water during rainfall events. The results from this study will assist water resource and fisheries managers in adapting to stream temperature changes under a warming climate.", "authors": [ "Roesky, Benjamin", "Hayashi, Masaki" ], "keywords": [ "alpine hydrology", "Canadian Rockies", "energy balance", "groundwater-stream interaction", "headwater spring", "seasonal lake", "stream temperature" ], "year": "2022", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -7.6445817947387695, -0.7174121141433716 ], "cluster": 12.0 }, { "idx": 1192, "title": "Beaver dams: How structure, flow state, and landscape setting regulate water storage and release", "abstract": "Beaver (Castor canadensis and Castor fiber) are regarded widely as ecosystem engineers and the dams they create are well-known for their ability to drastically alter the hydrology of rivers. As a result, beaver are increasingly being included in green infrastructure practices to combat the effects of climate change and enhance ecosystem resilience. Both drought and flood mitigation capabilities have been observed in watersheds with beaver dam structures; however, how dams possess contrasting mitigation abilities is not fully understood since most studies neglect to acknowledge variation in beaver dam structures. In this study, an extensive cross-site survey of the physical and hydrologic properties of beaver dams was conducted in the Canadian Rocky Mountains in Alberta. This research aimed to improve the understanding of the hydrology of beaver dams by categorizing dams using their intrinsic properties and landscape settings to identify fundamental patterns that may be applicable across landscape types. The dam flow type classification from Woo and Waddington (1990) was evaluated in this new context and adapted to include two new flow types. The survey of intrinsic beaver dam properties revealed significant differences in dam structure across different sites. Physical differences in dam structure altered the dynamics and variance of pond storage and certain dam attributes related to the landscape setting. For instance, dam material influenced dam height and water source influenced dam length. However, a closer analysis of large rain events showed that the physical structure of dams alters seasonal dynamics of pond storage but not the response to rain events. Overall, this research shows that beaver dams can be both structurally and hydrologically very different from each other. Establishing broadly applicable classifications is vital to understanding the ecosystem resilience and mitigation services beaver dams provide. (c) 2021 Published by Elsevier B.V.", "authors": [ "Ronnquist, Amanda L.", "Westbrook, Cherie J." ], "keywords": [ "Castor", "Ecohydrology", "Green infrastructure", "Stream hydrology", "Rocky Mountains" ], "year": "2021", "source": "SCIENCE OF THE TOTAL ENVIRONMENT", "publication_type": "J", "point2d": [ 10.023056030273438, -1.1642910242080688 ], "cluster": 13.0 }, { "idx": 1193, "title": "Classifying annual daily hydrographs in Western North America using t-distributed stochastic neighbour embedding", "abstract": "Flow regimes are critical for determining physical and biological processes in rivers and their classification and regionalization traditionally seeks to link patterns of flow to physiographic, climate and other information. There are many approaches to, and rationales for, catchment classification, with those focused on streamflow often seeking to relate a particular response characteristic to a physical property or climatic driver. Rationales include such topics as prediction in ungauged basins (PUB), and providing guidance for model selection in poorly understood hydrological systems. The annual daily hydrograph (ADH) is a first-order easily visualized integrated expression of catchment function, and over many years the average ADH is a distinct hydrological signature that differentiate catchments from each other. In this study, we use t-SNE, a state-of-the-art technique of dimensionality reduction, to classify 17 110 ADHs for 304 reference catchments in mountainous Western North America. t-SNE is chosen over other conventional methods of dimensionality reduction (e.g., PCA) as it presents greater separability of ADHs, which are projected on a 2D map where the similarities are evaluated according to their map distance. We then utilize a Deep Learning encoder to upgrade the non-parametric t-SNE to a parametric approach, enhancing its capability to address 'unseen' samples. Results showed that t-SNE successfully clustered ADHs of similar flow regimes on the 2D map and allowed more accurate classification with KNN. In addition, many compact clusters on the 2D map in the coastal Pacific Northwest suggest information redundancy in the local streamflow network. The t-SNE map provides an intuitive way to visualize the similarity of high-dimensional data of ADHs, groups catchments with like characteristics, and avoids the reliance on subjective hydrometric indicators.", "authors": [ "Tang, Weigang", "Carey, Sean K." ], "keywords": [ "hydrograph similarity", "streamflow classification", "t-SNE map" ], "year": "2022", "source": "HYDROLOGICAL PROCESSES", "publication_type": "J", "point2d": [ -22.829849243164062, -61.4466667175293 ], "cluster": 16.0 }, { "idx": 1194, "title": "Effects of microforms on the evaporation of peat-bryophyte-litter column in a montane peatland in Canadian Rocky Mountain", "abstract": "Peatland microtopography contains hummocks (local high points) and hollows (local low points). Little is known about how the evaporation of peat (P), peat-bryophyte (BP), peat-litter (LP) and peat-bryophyte-litter (LBP) columns varies with peatland microforms. That is, whether there are fine-scale variations in peatland evaporation, and if they are critical when being upscaled to the entire peatland ecosystem is yet to be answered. This study found that evaporation was significantly affected by cover type (P, BP, LP or LBP) and the interaction effect of the cover type and microform, based on the field evaporation experiments in a montane peatland in the Canadian Rocky Mountains, during the growing season of 2021. Mean daily evaporation of P-Hummock and P-Hollow is 14.16 and 11.76 g day(-1), respectively; BP-Hummock and BP-Hollow is 9.57 and 14.38 g day(-1), respectively; LBP-Hummock and LBP-Hollow is 9.44 and 9.91 g day(-1), respectively; and evaporation of LP-Hummock and LP-Hollow is 5.68 and 7.64 g day(-1), respectively. Peatland microform indirectly affected evaporation through interactions with cover type, modifying the vertical profile of soil temperature and changing key environmental drivers of evaporation. Moreover, the ability of two widely used models in modelling the spatial variation of peatland evaporation was also tested. It was found that Penman-Monteith (P-M) model and the bryophyte layer model in the Atmosphere-Plant Exchange Simulator (APES) were able to yield satisfactory results based on field measurements of soil temperature and soil moisture. This study supports developing more practical evaluation tools on the hydrological state of peatland ecosystems.", "authors": [ "Wang, Yi", "Petrone, Richard M." ], "keywords": [ "bryophyte", "evaporation", "microform", "modelling", "moss", "peatland" ], "year": "2023", "source": "ECOHYDROLOGY", "publication_type": "J", "point2d": [ -9.607406616210938, 66.04969024658203 ], "cluster": 9.0 }, { "idx": 1195, "title": "The influence of forest fires aerosol and air temperature on glacier albedo, western North America", "abstract": "Over the past decade, western North America glaciers experienced strong mass loss. Regional mass loss during the ablation season is influenced by air temperature, but the importance of other factors such as changes in surface albedo remains uncertain. We examine changes in surface albedo for 17 glaciated regions of western North America as documented in a 20-year record (2000 to 2019) of MODIS daily snow albedo (MOD10A1). Trend analysis reveals that albedo declined for 4% to 81% of the albedo grid cells, and the largest negative trends were situated south of 60 degrees N and in the provinces of British Columbia and Alberta. Sen's slope estimates indicate that 15 of 17 regions showed a decline of which the majority of the largest declines occurred within 100 m of glacier median elevation, suggesting that these declines are driven by a rise of the transient snowline. For most regions, albedo correlates strongly to temperature, and albedo trend in the Chugach region of Alaska, the South Coast, Southern Interior and Central and Southern Rockies of Canada show a significant relationship to aerosols optical depth. Temperature is approximately 2-6 times more predictive of the variation in albedo than AOD for the majority of regions, except the Southern Interior and Southern Rockies where albedo shows a greater dependence on AOD. Investigation of broadband albedo (MCD43A3) for snow grid cells above glacier median elevation in the Central and Southern Rockies shows that declines in the visible and near infrared portions of the spectrum are linked to the presence of forest fire generated aerosols. The results of this study indicate that glacier surface mass balance experiences a regional dependence on forest fire generated light absorbing particles.", "authors": [ "Williamson, Scott N.", "Menounos, Brian" ], "keywords": [ "Albedo", "Forest fire aerosols", "Mountain glaciers", "MODIS", "ERA5 temperature" ], "year": "2021", "source": "REMOTE SENSING OF ENVIRONMENT", "publication_type": "J", "point2d": [ -45.42247772216797, 9.940753936767578 ], "cluster": 8.0 }, { "idx": 1196, "title": "Moisture budget analysis of extreme precipitation associated with different types of atmospheric rivers over western North America", "abstract": "We report on the characteristics of precipitation associated with three types of landfalling atmospheric rivers (ARs) over western North America in the winter season from 1980 to 2004. The ARs are classified according to three landfalling regions as southern, middle and northern types. Two main centers of precipitation are associated with the contributions by the ARs: one over Baja California linked to the southern type of the ARs, and the other over Washington State correlated with the northern and middle types of the ARs. ARs are seen to play a dominant role in the occurrences of extreme precipitation events, with a proportionately greater impact on more extreme events. Moisture flux convergence makes the dominant contribution to precipitation when ARs and extreme precipitation occur simultaneously in the studied areas. Moisture flux convergence in these cases is, in turn, dominated by the mean and transient moisture transported by the transient wind, with greater contribution from the latter, which is mainly concentrated in certain areas. The magnitude and direction of vertically integrated vapor transport (IVT) also play a role in determining the amount of precipitation received in the three regions considered. Larger IVT magnitude corresponds to more precipitation, while an IVT direction of about 220 degrees (0 degrees indicating east wind) is most favorable for high precipitation amount, which is especially obvious for the northern type of the ARs.", "authors": [ "Tan, Yaheng", "Yang, Song", "Zwiers, Francis", "Wang, Ziqian", "Sun, Qiaohong" ], "keywords": [ "Atmospheric rivers", "Extreme precipitation", "Moisture budget", "Diversity", "Interannual variations" ], "year": "2022", "source": "CLIMATE DYNAMICS", "publication_type": "J", "point2d": [ -19.049028396606445, -36.61613464355469 ], "cluster": 14.0 }, { "idx": 1197, "title": "Changes in the frequency of global high mountain rain-on-snow events due to climate warming", "abstract": "Rain-on-snow (ROS) events can trigger severe floods in mountain regions. There is high uncertainty about how the frequency of ROS events (ROS) and associated floods will change as climate warms. Previous research has found considerable spatial variability in ROS responses to climate change. Detailed global assessments have not been conducted. Here, atmospheric reanalysis data was used to drive a physically based snow hydrology model to simulate the snowpack and the streamflow response to climate warming of a 5.25 km(2) virtual basin (VB) applied to different high mountain climates around the world. Results confirm that the sensitivity of ROS to climate warming is highly variable among sites, and also with different elevations, aspects and slopes in each basin. The hydrological model predicts a decrease in the frequency of ROS with warming in 30 out 40 of the VBs analyzed; the rest have increasing ROS. The dominant phase of precipitation, duration of snow cover and average temperature of each basin are the main factors that explain this variation in the sensitivity of ROS to climate warming. Within each basin, the largest decreases in ROS were predicted to be at lower elevations and on slopes with sunward aspects. Although the overall frequency of ROS drops, the hydrological importance of ROS is not expected to decline. Peak streamflows due to ROS are predicted to increase due to more rapid melting from enhanced energy inputs, and warmer snowpacks during future ROS.", "authors": [ "Lopez-Moreno, J., I", "Pomeroy, J. W.", "Moran-Tejeda, E.", "Revuelto, J.", "Navarro-Serrano, F. M.", "Vidaller, I", "Alonso-Gonzalez, E." ], "keywords": [ "rain on snow events (ROS)", "sensitivity analysis", "climate warming", "snow hydrology", "hydrological modelling", "high mountains" ], "year": "2021", "source": "ENVIRONMENTAL RESEARCH LETTERS", "publication_type": "J", "point2d": [ -37.933868408203125, -13.338815689086914 ], "cluster": 12.0 } ]