Characterizing spatiotemporal dynamics of wetted soils across a polar desert landscape, McMurdo Dry Valleys Antarctica

The McMurdo Dry Valleys is a landscape characterized by open expanses of bare soils, alpine and piedmont glaciers, and ice-covered lakes on the valley floors, all underlain by permafrost. There is contemporary evidence of changes to the near-surface hydrology of the Dry Valleys as extensive wet soil patches are being observed extensively throughout the valleys. The availability and movement of water across this landscape may drive important shifts in the interactions among meteorology, hydrology and biogeochemical processes. Wetted soils are generally found adjacent to streams and lakes, but have also been observed far from lake shorelines and channels. The relative contributions of water to the development of wetted zones from glaciers, ablated snow patches and melted permafrost has not been established. We evaluate the spatio-temporal variability of wet soil patches using high resolution optical data from Quickbird and Wordview satellites to document the occurrence, dimensions, and growth of the patches during the 2009-10, 2010-11, and 2011-12 austral summers over Taylor Valley, Wright Valley, Victoria Valley, Garwood Valley, Marshall Valley, Miers Valley, and Hidden Valley.  We compare the patterns in wet soil patches to those in snow accumulation and ablation as well as proximity to glacier termini for identifying the sources.