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Louis Sass

Abstract (from http://onlinelibrary.wiley.com/doi/10.1002/2016EF000479/full): Glacier hypsometry provides a first-order approach for assessing a glacier's response to climate forcings. We couple the Randolph Glacier Inventory to a suite of in situ observations and climate model output to examine potential change for the ∼27,000 glaciers in Alaska and northwest Canada through the end of the 21st century. By 2100, based on Representative Concentration Pathways (RCPs) 4.5–8.5 forcings, summer temperatures are predicted to increase between +2.1 and +4.6°C, while solid precipitation (snow) is predicted to decrease by −6 to −11%, despite a +9 to +21% increase in total precipitation. Snow is predicted to undergo a pronounced...
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This dataset contains observations of the distribution of end-of-summer snow cover on approximately 3000 glaciers across Alaska and Northwest Canada. The data are provided as: (1) GeoTIFF rasters indicating the spatial extent of end-of-summer snow cover on each glacier's surface in each year (one raster per glacier per year), and (2) yearly tables with the equilibrium line altitude and the accumulation area ratio of the glaciers derived from the snow cover extent geotiffs. Snow cover was identified in Sentinel-2 imagery using a random forest algorithm trained with a manually-created validation dataset. A series of post-processing steps were used to infill missing data from terrain shadowing and cloud cover, and...
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Assessing the Vulnerability of Alaska’s Glaciers in a Changing Climate
Retreating glaciers are an iconic image of climate change;yet not all glaciers in Alaska are actively retreating, and a few glaciers are even advancing. While this contrasting behavior can be misleading for the casual observer, variable responses between glaciers in a changing climate are expected. Glaciers act as conveyor belts that transport snow and ice from high elevations, where it does not melt, down to low elevations, where it does melt. A change in climate can impact the amount of snow and ice that accumulates (accumulation), the way snow and ice melt (ablation), or the conveyor belt (ice dynamics). While these impacts vary with elevation and glacier shape, glacier changes have major implications for downstream...
Abstract (from http://onlinelibrary.wiley.com/doi/10.1002/2015JF003539/abstract): A quantitative understanding of snow thickness and snow water equivalent (SWE) on glaciers is essential to a wide range of scientific and resource management topics. However, robust SWE estimates are observationally challenging, in part because SWE can vary abruptly over short distances in complex terrain due to interactions between topography and meteorological processes. In spring 2013, we measured snow accumulation on several glaciers around the Gulf of Alaska using both ground- and helicopter-based ground-penetrating radar surveys, complemented by extensive ground truth observations. We found that SWE can be highly variable (40%...
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Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Additional measurements have been made on Lemon Creek Glacier, AK to compliment data collected by the Juneau Icefield Research Program (JIRP; Pelto and others, 2013). Direct field measurements are combined with weather data and imagery analyses to estimate the seasonal and annual mass balance at each glacier in both a conventional and reference surface format (Cogley and others, 2011). High-altitude measurements of meteorological data have been...
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