Seasonal controls on snow distribution and aerial ablation at the snow-patch and landscape scales, McMurdo Dry Valleys, Antarctica

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TitleSeasonal controls on snow distribution and aerial ablation at the snow-patch and landscape scales, McMurdo Dry Valleys, Antarctica
Publication TypeJournal Article
Year of Publication2012
AuthorsEveland, J, Gooseff, MN, Lampkin, DJ, Barrett, JE, Takacs-Vesbach, C
JournalThe Cryosphere Discussions
Volume6
Issue5
Pagination3823 - 3862
Date Published2012
Abstract

Accumulated snow in the McMurdo Dry Valleys, while limited, has great ecological significance to subnivian soil environments. Though sublimation dominates the ablation process in this region, measurable increases in soil moisture and insulation from temperature extremes provide more favorable conditions with respect to subnivian soil communities. While precipitation is not substantial, significant amounts of snow can accumulate, via aeolian redistribution, in topographic lees along the valley bottoms, forming thousands of discontinuous snow patches. These patches have the potential to act as significant sources of local melt water, controlling biogeochemical cycling and the landscape distribution of microbial communities. Therefore, determining the spatial and temporal dynamics of snow at multiple scales is imperative to understanding the broader ecological role of snow in this region. High-resolution satellite imagery acquired during the 2009-2010 and 2010-2011 austral summers was used to quantify the distribution of snow across Taylor and Wright Valleys. Extracted snow-covered area from the imagery was used as the basis for assessing seasonal variability and seasonal controls on accumulation and ablation of snow at multiple scales. In addition, fifteen 1 km2 plots (3 in each of 5 study regions) were selected to assess the prevalence of snow cover at finer spatial scales. Results confirm that snow patches tend to form in the same locations each year with some minor deviations observed. At the snow-patch scale, neighboring patches often exhibit considerable differences in aerial ablation rates, and particular snow patches do not reflect trends for snow-covered area observed at the landscape scale. These differences are presumably related to microtopographic influences over snow depth and exposure. This highlights the importance of both the landscape and snow-patch scales in assessing the effects of snow cover on biogeochemical cycling and microbial communities.

DOI10.5194/tcd-6-3823-2012