Affiliation:
1. Geophysical Institute University of Alaska Fairbanks Fairbanks AK USA
Abstract
AbstractFrom April through June in 2019 and 2022, we monitored snow melt at three sites near Utqiaġvik, Alaska. Along 200‐m lines we measured snow depth, density, stratigraphy, snow‐covered area, and spectral albedo. Site 1 (ARM) was sloped tundra drained by water tracks. Site 2 (BEO) was flat polygonal tundra. Site 3 (ICE) was on undeformed landfast sea ice. All three sites were within a 6 km radius. Despite similar pre‐melt snow distributions and weather, the melt progression differed markedly between sites. In 2019, by mid‐melt, there was 40% less snow‐covered area at ARM versus ICE, and 34% less snow‐covered area at ARM versus BEO. The 2022 melt started 2 weeks later than in 2019 and was rapid, so smaller differences in snow‐covered areas developed. In both years meltout dates varied by up to 25 days between sites, and more than 20 days within sites, with melt rates at locations only meters apart differing by up to a factor of seven. This melt diachroneity led to highly heterogeneous meltout patterns at all three sites. Our measurements and observations indicate that, in addition to reductions in snow reflective properties and wind‐driven heat advection, the fate of meltwater plays a key role in producing melt diachroneity. We identify seven snow‐water mechanisms that can enhance or inhibit melt rates, all largely controlled by the local topography and the nature of the substrate. These mechanisms are important because the most rapid changes in albedo coincide with the peak of water‐snow melt interactions.
Publisher
American Geophysical Union (AGU)
Reference88 articles.
1. Agisoft Metashape Pro Version 1.7.2. (2021).Downloads. Agisoft Metashape 1.7.2. Retrieved fromhttps://www.agisoft.com/downloads/installer/
2. Multilevel thresholding of images with improved Otsu thresholding by black widow optimization algorithm
3. Bulk volumetric liquid water content in a seasonal snowpack: modeling its dynamics in different climatic conditions
4. Benson C. S.(1960).Stratigraphic studies in the snow and firn of the Greenland ice sheet. Research Report 70.Cold Regions Research and Engineering Laboratory.