干旱区生态环境知识资源中心

Liquid water is scarce across the landscape of the McMurdo Dry Valleys (MDV), Antarctica, a 3800 km(2) ice-free region, and is chiefly associated with soils that are adjacent to streams and lakes (i.e. wetted margins) during the annual thaw season. However, isolated wetted soils have been observed at locations distal from water bodies. The source of water for the isolated patches of wet soil is potentially generated by a combination of infiltration from melting snowpacks, melting of pore ice at the ice table, and melting of buried segregation ice formed during winter freezing. High resolution remote sensing data gathered several times per summer in the MDV region were used to determine the spatial and temporal distribution of wet soils. The spatial consistency with which the wet soils occurred was assessed for the 2009-10 to 2011-12 summers. The remote sensing analyses reveal that cumulative area and number of wet soil patches varies among summers. The 2010-11 summer provided the most wetted soil area (10.21 km(2)) and 2009-10 covered the least (5.38 km(2)). These data suggest that wet soils are a significant component of the MDV cold desert land system and may become more prevalent as regional climate changes.