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Abstract: The effect of human-induced climate warming on different snow measures in the western United States is compared by calculating the time required to achieve a statistically significant linear trend in the different measures, using time series derived from regionally downscaled global climate models. The measures examined include the water content of the spring snowpack, total cold-season snowfall, fraction of winter precipitation that falls as snow, length of the snow season, and fraction of cold-season precipitation retained in the spring snowpack, as well as temperature and precipitation. Various stakeholders may be interested in different sets of these variables. It is found that temperature and the...
Categories: Publication; Types: Citation; Tags: Southwest CASC, climate, snow
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Snow hardness measurements were collected at camera sites from December 2020 - April 2021, at the same time as snow density. Camera sites were chosen by stratified non-random sampling. Cameras were never closer than 25m to other cameras, nor were they placed facing trails. Measurements were collected every few weeks as logistics allowed. Samples were collected near the camera site in snow visually similar to the snow in the camera viewshed to prevent snow conditions from being disturbed beyond normal camera deployment. Snow hardness was measured using a ram penetrometer or “ramsonde” (Snowmetrics; Fort Collins, CO). A ramsonde is composed of a hammer, anvil, and rod. The hammer is dropped onto the anvil from a known...
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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...
Snow samples were collected in southeastern Idaho over two winters to assess trace element and common ion concentrations in air pollutant fallout across the region. The objectives were to: (1) develop snow sampling and analysis techniques that produce accurate and ultra-low measurements of a broad suite of fallout elements, (2) identify the spatial and temporal trends of the fallout elements across the region, (3) determine if there are unique combinations of fallout elements that are characteristic to the major source areas in the region (source area profiles), and (4) use pattern recognition and multivariate statistical techniques (principal component analysis and classical least squares regression) to investigate...
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Abstract: We present an inverse modeling approach for reconstructing the effective thermal conductivity of snow on a daily basis using air temperature, ground temperature and snow depth measurements. The method is applied to four sites in Alaska. To validate the method we used measured snow densities and snow water equivalents. The modeled thermal conductivities of snow for the two interior Alaska sites have relatively low values and reach their maximum near the end of the snow season, while the conductivities at the two sites on the Alaskan North Slope are higher and reach their maximum earlier in the snow season. We show that the reconstructed daily thermal conductivities allow for more accurate modeling of ground...
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Throughout the Arctic most pregnant polar bears (Ursus maritimus) construct maternity dens in seasonal snowdrifts that form in wind-shadowed areas. We developed and verified a spatial snowdrift polar bearden habitat model (SnowDens-3D) that predicts snowdrift locations and depths along Alaska’s Beaufort Sea coast. SnowDens-3D integrated snow physics, weather data, and a high-resolution digital elevation model (DEM) to produce predictions of the timing, distribution, and growth of snowdrifts suitable for polar bear dens. SnowDens-3D assimilated 18 winters (1995 through 2012) of observed daily meteorological data and a 2.5 m grid-increment DEM covering 337.5 km2 of the Beaufort Sea coast, and described the snowdrift...
Whole air drawn from four heights within the high elevation (3,340 m asl), deep, winter snowpack at Niwot Ridge, Colorado, were sampled into stainless steel canisters, and subsequently analyzed by gas chromatography for 51 volatile inorganic and organic gases. Two adjacent plots with similar snow cover were sampled, one over bare soil and a second one from within a snow-filled chamber where Tedlar/Teflon-film covered the ground and isolated it from the soil. This comparison allowed for studying effects from processes in the snowpack itself versus soil influences on the gas concentrations and fluxes within and through the snowpack. Samples were also collected from ambient air above the snow surface for comparison...
Although freeze?thaw cycles can alter soil physical properties and microbial activity, their overall impact on soil functioning remains unclear. This review addresses the effects of freeze?thaw cycles on soil physical properties, microorganisms, carbon and nutrient dynamics, trace gas losses and higher organisms associated with soil. I discuss how the controlled manipulation of freeze?thaw cycles has varied widely among studies and propose that, despite their value in demonstrating the mechanisms of freeze?thaw action in soils, many studies of soil freeze?thaw cycles have used cycle amplitudes, freezing rates and minimum temperatures that are not relevant to temperature changes across much of the soil profile in...
Dust deposition to mountain snow cover, which has increased since the late 19(th) century, accelerates the rate of snowmelt by increasing the solar radiation absorbed by the snowpack. Snowmelt occurs earlier, but is decoupled from seasonal warming. Climate warming advances the timing of snowmelt and early season phenological events (e.g., the onset of greening and flowering); however, earlier snowmelt without warmer temperatures may have a different effect on phenology. Here, we report the results of a set of snowmelt manipulations in which radiation-absorbing fabric and the addition and removal of dust from the surface of the snowpack advanced or delayed snowmelt in the alpine tundra. These changes in the timing...
This repository contains a package in Program R which allows for snow depth measurements using a "virtual" snow stake. The package detected the edges of a snow stake in a reference image and superimposes the edges of the snow stake onto other images. The R package is also available on GitHub at https://github.com/kaitlynstrickfaden/edger.
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Remote camera data on snow presence, snow depth, and wildlife detections on Moscow Mountain in Latah County, ID, USA. Reconyx Hyperfire I and Hyperfire II cameras were set to take hourly timelapse images and motion-triggered images from October 2020 - May 2021 at 5 elevation categories (800-925m, 925-1050m, 1050-1175m, 1775-1300m, and > 1300m), 4 aspects (N, S, E, and W), and 3 canopy densities (Sparse [0-35%], Moderate [35-75%], and Dense [75-100%]), in duplicate, plus 17 selected microclimates (137 locations total), on Moscow Mountain in Latah County, ID. Images from 27 other locations were part of a pilot experiment during January to May 2020. Data in the CSVs include image metadata, camera site characteristics,...
Abstract (from http://www.sciencedirect.com/science/article/pii/S0165232X1400038X#): We present an inverse modeling approach for reconstructing the effective thermal conductivity of snow on a daily basis using air temperature, ground temperature and snow depth measurements. The method is applied to four sites in Alaska. To validate the method we used measured snow densities and snow water equivalents. The modeled thermal conductivities of snow for the two interior Alaska sites have relatively low values and reach their maximum near the end of the snow season, while the conductivities at the two sites on the Alaskan North Slope are higher and reach their maximum earlier in the snow season. We show that the reconstructed...
The effect of snow cover on surface-atmosphere exchanges of nitrogen oxides (nitrogen oxide (NO) + nitrogen dioxide (NO2); note, here ?NO2? is used as surrogate for a series of oxidized nitrogen gases that were detected by the used monitor in this analysis mode) was investigated at the high elevation, subalpine (3,340 m asl) Soddie site, at Niwot Ridge, Colorado. Vertical (NO + NO2) concentration gradient measurements in interstitial air in the deep (up to ~2.5 m) snowpack were conducted with an automated sampling and analysis system that allowed for continuous observations throughout the snow-covered season. These measurements revealed sustained, highly elevated (NO + NO2) mixing ratios inside the snow. Nitrogen...
Much of the research on the chemistry of snow and surface waters of the western US, Europe, and Asia has been conducted in high-elevation catchments above treeline. Here we provide information on the solute content of the seasonal snowpack at the Soddie site on Niwot Ridge, Colorado, a subalpine site near treeline. We focus on the storage and release of both inorganic and organic solutes to the soils underneath the snowpack, and subsequent effects on the chemical and nutrient content of the underlying soil solution and the adjacent headwater stream. The concentration of inorganic nitrogen (N) stored in the seasonal snowpack at the Soddie site of about 11 μeq L−1 was on the upper end of values reported...
Snow samples were collected in southeastern Idaho over two winters to assess trace element and common ion concentrations in air pollutant fallout across the region. The objectives were to: (1) develop snow sampling and analysis techniques that produce accurate and ultra-low measurements of a broad suite of fallout elements, (2) identify the spatial and temporal trends of the fallout elements across the region, (3) determine if there are unique combinations of fallout elements that are characteristic to the major source areas in the region (source area profiles), and (4) use pattern recognition and multivariate statistical techniques (principal component analysis and classical least squares regression) to investigate...
This spring, a rare combination of exceptionally warm temperatures and near-record lack of precipitation in the western United States caused a rapid change in hydrologic conditions and an unexpectedly early onset of spring conditions.With much of the western U.S. already in its fifth year of drought, an above-average western snowpack on 1 March 2004 provided hope for much-needed abundant runoff. Unfortunately snowmelt began far earlier than anticipated, resulting in dramatic declines in seasonal spring-summer streamflow forecasts as the month proceeded, declines more rapid by some measures than ever before in the past 75 years. With reservoirs near historic lows, many water users have been hard pressed to deal with...
What will the rivers of the Pacific Northwest look like in the future? Will they be stable or unstable? Will the waters be cold and clear or warm and muddy? Will they have salmon or other species? These questions motivated our two-year study of climate warming effects on headwater streams draining the Cascade Mountains. Using a novel combination of snow, geohydrology, and sediment transport models we assessed the vulnerability of stream channels to changing peak streamflow. Our snow modeling shows that with just a 2°C warming, snowfall shifts to rainfall at all elevations, peak snowpacks occur over two months earlier, and snowpacks are reduced by over half of historical values. Our geohydrology modeling shows that...
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Intraspecific variation in the seasonal reproductive timing of Pacific salmon (Oncorhynchus sp.) has importantimplications for the resilience of salmon and for organisms in freshwater and terrestrial communities that dependon salmon resources. Stream temperature has well known associations with salmon spawn timing buthow stream and watershed geomorphology relates to the variation in salmon spawn timing is less understood.We used multivariate statistics applied to five environmental variables to compare conditions across36 watersheds in the Wood River basin in southwest Alaska. We found that the environmental conditionsin the first two axes of a principal components analysis (PCA) explained 76% of the variation in...
map background search result map search result map The Effect of Snow: How to Better Model Ground Surface Temperatures Modeling snowdrift habitat for polar bear dens Watershed geomorphology and snowmelt control stream thermal sensitivity to air temperature. Association between geomorphic attributes of watersheds, water temperature, and salmon spawn timing in Alaskan streams Snow and Wildlife Detections from Remote Camera Stations on Moscow Mountain in Latah County, ID, USA (10/20/20-6/30/21) Snow Hardness Measurements at Remote Camera Stations on Moscow Mountain in Latah County, ID (12/1/20-4/30-21) Snow and Wildlife Detections from Remote Camera Stations on Moscow Mountain in Latah County, ID, USA (10/20/20-6/30/21) Snow Hardness Measurements at Remote Camera Stations on Moscow Mountain in Latah County, ID (12/1/20-4/30-21) The Effect of Snow: How to Better Model Ground Surface Temperatures Modeling snowdrift habitat for polar bear dens Watershed geomorphology and snowmelt control stream thermal sensitivity to air temperature. Association between geomorphic attributes of watersheds, water temperature, and salmon spawn timing in Alaskan streams