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There is a great deal of interest in whether and how Alaska’s precipitation is changing but little agreement in the existing peer-reviewed literature. To provide insight on this question, we have selected three commonly used 0.5° resolution gridded precipitation products that have long-term monthly data coverage (Climatic Research Unit TS3.10.1, Global Precipitation Climatology Centre Full Data Reanalysis version 5, and University of Delaware version 2.01) and evaluated their homogeneity and trends with multiple methods over two periods, 1950–2008 and 1980–2008. All three data sets displayed common broadscale features of Alaska’s precipitation climatology, but there were substantial differences between them in terms...
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Floods, spatially complex water flows, and organism movements all generate important fluxes of aquatic-derived materials into terrestrial habitats, counteracting the gravity-driven downhill transport of matter from terrestrial-to-aquatic ecosystems. The magnitude of these aquatic subsidies isoften smaller than terrestrial subsidies to aquatic ecosystems but higher in nutritional quality, energy density, and nutrient concentration. The lateral extent of biological aquatic subsidies is typically small, extending only a few meters into riparian habitat; however, terrestrial consumers often aggregate on shorelines to capitalize on these high-quality resources. Although the ecological effects of aquatic subsidies remain...
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How local geomorphic and hydrologic features mediate the sensitivity of stream thermal regimes to variation in climatic conditions remains a critical uncertainty in understanding aquatic ecosystem responses to climate change. We used stable isotopes of hydrogen and oxygen to estimate contributions of snow and rainfall to 80 boreal streams and show that differences in snow contribution are controlled by watershed topography. Time series analysis of stream thermal regimes revealed that streams in rain-dominated, low-elevation watersheds were 5–8 times more sensitive to variation in summer air temperature compared to streams draining steeper topography whose flows were dominated by snowmelt. This effect was more pronounced...
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Interactions and feedbacks between abundant surface waters and permafrost fundamentally shapelowland Arctic landscapes. Sublake permafrost is maintained when the maximum ice thickness (MIT) exceedslake depth and mean annual bed temperatures (MABTs) remain below freezing. However, decliningMIT since the1970s is likely causing talik development below shallow lakes. Here we show high-temperature sensitivity towinter ice growth at the water-sediment interface of shallow lakes based on year-round lake sensor data.Empirical model experiments suggest that shallow (1m depth) lakes have warmed substantially over the last30years (2.4°C), withMABT above freezing5 of the last 7years.This is incomparison to slower ratesofwarming...
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In this first worldwide synthesis of in situ and satellite-derived lake data, we find that lakesummer surface water temperatures rose rapidly (global mean = 0.34°C decade1) between 1985 and2009. Our analyses show that surface water warming rates are dependent on combinations of climate andlocal characteristics, rather than just lake location, leading to the counterintuitive result that regionalconsistency in lake warming is the exception, rather than the rule. The most rapidly warming lakes are widelygeographically distributed, and their warming is associated with interactions among different climatic factors—from seasonally ice-covered lakes in areas where temperature and solar radiation are increasing whilecloud...
An integrated high resolution tide and storm surge model has been developedfor all of coastal Alaska. The model uses the ADCIRC basin-to-channelscale unstructured grid circulation code. Tidal forcing from global tidal modelsand meteorological forcing from the Climate Forecast System Reanalysisare used. The model’s tidal solution has been validated at 121 shelf andnearshore stations. The model’s skill has been investigated for summer, falland winter storms. Sea ice has been incorporated through a parameterizedwind drag coefficient which modifies the air-sea drag under ice coverage.Three large storms with distinctly different ice coverages were chosen to exhibitthe effect of sea ice on the resulting storm surge. The...
Categories: Data, Publication; Types: Citation; Tags: Academics & scientific researchers, COASTAL AREAS, COASTAL AREAS, COASTAL PROCESSES, COASTAL PROCESSES, All tags...
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Numerous studies have evaluated precipitation trends in Alaska and come to different conclusions. These studies differ in analysis period and methodology and do not address the issue of temporal homogeneity. To reconcile these conflicting results, we selected 29 stations with largely complete monthly records, screened them for homogeneity, and then evaluated trend over two analysis periods (1950–2010 and 1980–2010) using three methods: least absolute deviation regression, ordinary least squares regression (with and without transformation), and Mann-Kendall trend testing following removal of first-order autocorrelation. We found that differences in analytical period had a significant impact on trends and that the...
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This paper explores the impacts of shrinking glaciers on downstream ecosystems in the Arctic National Wildlife Refuge. Glaciers here are losing mass at an accelerating rate and will largely disappear in the next 50–100 years if current trends continue. We believe this will have a measurable and possibly important impact on the terrestrial and estuarine ecosystems and the associated bird and fish species within these glaciated watersheds.
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The Yukon–Kuskokwim Delta of Alaska,USAis a globally important region for numerous avianspecies including millions of migrating and nesting waterbirds.However, data on the current spatial distributionof critical nesting areas and the importance of environmental variables in the selection of nest locations aregenerally lacking for waterbirds in this region.We modeled nest densities for 6 species of geese and eiders thatcommonly breed on the Yukon–Kuskokwim Delta, including cackling goose (Branta hutchinsii minima),emperor goose (Chen canagica), black brant (B. bernicla nigricans), greater white-fronted goose (Anser albifronsfrontalis), spectacled eider (Somateria fischeri), and common eider (S. mollissima).Thedata...
Categories: Data, Publication; Types: Citation, Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: BIRDS, BIRDS, CLIMATE CHANGE IMPACT ASSESSMENT MODELS, CLIMATE CHANGE IMPACT ASSESSMENT MODELS, DELTAS, All tags...
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When resources are spatially and temporally variable, consumers can increasetheir foraging success by moving to track ephemeral feeding opportunitiesas these shift across the landscape; the best examples derive from herbivore–plant systems, where grazers migrate to capitalize on the seasonal waves ofvegetation growth. We evaluated whether analogous processes occur in watershedssupporting spawning sockeye salmon (Oncorhynchus nerka), askingwhether seasonal activities ofpredators and scavengers shift spatial distributionsto capitalize on asynchronous spawning among populations of salmon. Bothglaucous-winged gulls and coastal brown bears showed distinct shifts in theirspatial distributions over the course of the summer,...
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Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structureand function. Recent studies have suggested significant warming of water temperatures in individual lakesacross many different regions around the world. However, the spatial and temporal coherence associatedwith the magnitude of these trends remains unclear. Thus, a global data set of water temperature isrequired to understand and synthesize global, long-term trends in surface water temperatures of inlandbodies of water. We assembled a database of summer lake surface temperatures for 291 lakes collectedin situ and/or by satellites for the period 1985–2009. In addition, corresponding climatic drivers (airtemperatures,...
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How local geomorphic and hydrologic features mediate the sensitivity of stream thermal regimesto variation in climatic conditions remains a critical uncertainty in understanding aquatic ecosystem responsesto climate change.We used stable isotopes of hydrogen and oxygen to estimate contributions of snow and rainfallto 80 boreal streams and show that differences in snow contribution are controlled by watershed topography.Time series analysis of streamthermal regimes revealed that streams in rain-dominated, low-elevation watershedswere 5–8 times more sensitive to variation in summer air temperature compared to streams draining steepertopography whose flows were dominated by snowmelt. This effect wasmore pronounced...
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The Weather Research and Forecasting (WRF) model was used to downscale select general circulation models (GCMs) that participated in the Coupled Model Intercomparison Project (CMIP5). WRF was used to produce output at a 2-km horizontal resolution for Puerto Rico and the US Virgin Islands by applying a 30-km/10- km/2-km one-way nest. Data from each nest was archived. Two twenty-year time slices from two CMIP5 GCMs were dynamically downscaled using WRF, a historical time slice (1985-2005) and a future time slice (2040-2060). The CMIP5 GCMs downscaled included the Community Climate System Model (CCSM4) and the Centre National de Recherches Meteorologiques-CERFACS (CNRM). The high Greenhouse Gas Emission Scenario, RCP8.5,...
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The potential ecological and economic effects of climate change for tropical islands were studied using output from 12 statistically downscaled general circulation models (GCMs) taking Puerto Rico as a test case. Two model selection/model averaging strategies were used: the average of all available GCMs and the average of the models that are able to reproduce the observed large-scale dynamics that control precipitation over the Caribbean. Five island-wide and multidecadal averages of daily precipitation and temperature wereestimated by way of a climatology-informed interpolation of the site-specific downscaled climate model output. Annual cooling degree-days (CDD) were calculated as a proxy index for air-conditioning...
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ire-induced permafrost degradation is well documented in boreal forests, but the role of fires in initiating thermokarst development in Arctic tundra is less well understood. Here we show that Arctic tundra fires may induce widespread thaw subsidence of permafrost terrain in the first seven years following the disturbance. Quantitative analysis of airborne LiDAR data acquired two and seven years post-fire, detected permafrost thaw subsidence across 34% of the burned tundra area studied, compared to less than 1% in similar undisturbed, ice-rich tundra terrain units. The variability in thermokarst development appears to be influenced by the interaction of tundra fire burn severity and near-surface, ground-ice content....
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This dataset represents data collected at 120 quadrat locations (points) within 12 selected cedar glades and contains measurements of relative humidity (percent) at the ground surface for each point. Measurements were obtained on the following dates (which correspond to the fields in the dataset): February 6, 2012; March 5, 2012; April 2, 2012; April 23, 2012; May 25, 2012; June 21, 2012; July 19, 2012; August 23, 2012; September 27, 2012; November 5, 2012; December 17, 2012; January 21,2013; February 18, 2013; March 19, 2013; April 15, 2013; and May 13, 2013. Points classified into four groups (identified by the field "Group") and were visited on a rotating sampling schedule, such that each group of points was...
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This dataset contains data collected within limestone cedar glades at Stones River National Battlefield (STRI) near Murfreesboro, Tennessee. This dataset represents interpolated estimates of precipitation (in decimal inches) for 120 quadrat locations (points) within 12 selected cedar glades, for a period of time from 6 days (144 hours) prior to the field visit day up until 3 days (72 hours) prior to the field visit day. At each field visit, precipitation data was collected at four rain gauges installed at STRI. Rain gauge measurements were obtained on the following dates (which correspond to 3 days prior to the fields in the dataset): February 3, 2012; March 2, 2012; March 30, 2012; April 20, 2012; May 22, 2012;...
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An important unresolved question is how populations of coldwater-dependent fishes will respond to rapidly warming water temperatures. For example, the culturally and economically important group, Pacific salmon (Oncorhynchus spp.), experience site-specific thermal regimes during early development that could be disrupted by warming. To test for thermal local adaptation and heritable phenotypic plasticity in Pacific salmon embryos, we measured the developmental rate, survival, and body size at hatching in two populations of sockeye salmon (Oncorhynchus nerka) that overlap in timing of spawning but incubate in contrasting natural thermal regimes. Using a split half-sibling design, we exposed embryos of 10 families...
Categories: Data, Publication; Types: Citation, Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: Academics & scientific researchers, CLIMATE CHANGE IMPACT ASSESSMENT MODELS, CLIMATE CHANGE IMPACT ASSESSMENT MODELS, DATA REFORMATTING, DATA REFORMATTING, All tags...
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Spawning migrations of Pacific salmon (Oncorhynchus spp.) to coastal watersheds provide a rich resource subsidy to freshwater consumers. However, variation in thermal regimes and spawning activity across the landscape constrain the ability of poikilothermic consumers to assimilate eggs and carcasses. We investigated how sockeye salmon (Oncorhynchus nerka) spawning density and stream temperature affect the growth, body condition, and fatty acid composition of juvenile coho salmon (Oncorhynchus kisutch), a known egg predator, in seven tributaries of the Wood River in Southwest Alaska. We compared mean body size of juvenile coho salmon in late summer among 3–7 years per stream and found that the largest mean size occurred...


map background search result map search result map Interpolated precipitation data (first interval) for 120 point locations within limestone cedar glades at Stones River National Battlefield near Murfreesboro, Tennessee Relative humidity data for 120 point locations within limestone cedar glades at Stones River National Battlefield near Murfreesboro, Tennessee Weather Research and Forecasting (WRF): Puerto Rico & US Virgin Islands Dynamical Downscaled Climate Change Projections Threshold sensitivity of shallow Arctic lakes and sublake permafrost to changing winter climate Reconciling precipitation trends in Alaska: 2. Gridded data analyses Watershed geomorphology and snowmelt control stream thermal sensitivity to air temperature. Rapid and highly variable warming of lake surface waters around the globe Watershed geomorphology and snowmelt control stream thermal sensitivity to air temperature Thermal adaptation and phenotypic plasticity in a warming world: Insights from common garden experiments on Alaskan sockeye salmon Thermal constraints on stream consumer responses to a marine resource subsidy Riding the crimson tide: mobile terrestrial consumers track phenological variation in spawning of an anadromous fish Subsidies of Aquatic Resources in Terrestrial Ecosystems A global database of lake surface temperatures collected by in situ and satellite methods from 1985–2009 Predicting the Impact of Glacier Loss Reconciling precipitation trends in Alaska: 1. Station-based analyses Recent Arctic tundra fire initiates widespread thermokarst development Climate Change Implications for Tropical Islands: Interpolating and Interpreting Statistically Downscaled GCM Projections for Management and Planning Predicting Waterbird Nest Distributions on the Yukon–Kuskokwim Delta of Alaska Interpolated precipitation data (first interval) for 120 point locations within limestone cedar glades at Stones River National Battlefield near Murfreesboro, Tennessee Relative humidity data for 120 point locations within limestone cedar glades at Stones River National Battlefield near Murfreesboro, Tennessee Predicting Waterbird Nest Distributions on the Yukon–Kuskokwim Delta of Alaska Predicting the Impact of Glacier Loss Climate Change Implications for Tropical Islands: Interpolating and Interpreting Statistically Downscaled GCM Projections for Management and Planning Threshold sensitivity of shallow Arctic lakes and sublake permafrost to changing winter climate Thermal adaptation and phenotypic plasticity in a warming world: Insights from common garden experiments on Alaskan sockeye salmon Watershed geomorphology and snowmelt control stream thermal sensitivity to air temperature. Riding the crimson tide: mobile terrestrial consumers track phenological variation in spawning of an anadromous fish Rapid and highly variable warming of lake surface waters around the globe Watershed geomorphology and snowmelt control stream thermal sensitivity to air temperature Thermal constraints on stream consumer responses to a marine resource subsidy Subsidies of Aquatic Resources in Terrestrial Ecosystems A global database of lake surface temperatures collected by in situ and satellite methods from 1985–2009 Recent Arctic tundra fire initiates widespread thermokarst development Weather Research and Forecasting (WRF): Puerto Rico & US Virgin Islands Dynamical Downscaled Climate Change Projections Reconciling precipitation trends in Alaska: 2. Gridded data analyses Reconciling precipitation trends in Alaska: 1. Station-based analyses