01831nas a2200157   4500008004100000245009400041210006900135260001200204300001200216490000700228520126700235100001501502700002401517700001401541856011801555       2014                        eng d00aNear-Surface Internal Melting - a Substantial Mass Loss on Antarctic Dry Valley Glaciers.0 aNearSurface Internal Melting a Substantial Mass Loss on Antarcti  c04/2014  a361-3740 v603 aThe McMurdo Dry Valleys, southern Victoria Land, East Antarctica, are a polar desert, and melt from glacial ice is the primary source of water to streams, lakes and associated ecosystems. Previous work found that to adequately model glacier ablation and subsurface ice temperatures with a surface energy-balance model required including the transmission of solar radiation into the ice. Here we investigate the contribution of subsurface melt to the mass balance of (and runoff from) Dry Valley glaciers by including a drainage process in the model and applying the model to three glacier sites using 13years of hourly meteorological data. Model results for the smooth glacier surfaces common to many glaciers in the Dry Valleys showed that sublimation was typically the largest component of surface lowering, with rare episodes of surface melting, consistent with anecdotal field observations. Results also showed extensive internal melting 5-15 cm below the ice surface, the drainage of which accounted for 50% of summer ablation. This is consistent with field observations of subsurface streams and formation of a weathering crust. We identify an annual cycle of weathering crust formation in summer and its removal during the 10 months of winter sublimation.1 aHoffman, M1 aFountain, Andrew, G1 aListon, G  uhttps://mcm.lternet.edu/content/near-surface-internal-melting-substantial-mass-loss-antarctic-dry-valley-glaciers