This work was funded by US National Science Foundation (NSF) Office of Polar Programs grants ANT-0423595 and ANT-0233823, the Earth System Modeling program of the Office of Biological and Environmental Research within the US Department of Energy’s Office of Science, and by NSF grant No. ANT-0424589 to the Center for Remote Sensing of Ice Sheets (CReSIS)
Journal of Glaciology
Meltwater -- Antarctica -- McMurdo Dry Valleys, Glaciers -- Antarctica -- McMurdo Dry Valleys, Ablation (Aerothermodynamics)
The 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.
Hoffman, M. J., Fountain, A. G., & Liston, G. E. (2014). Near-surface internal melting: a substantial mass loss on Antarctic Dry Valley glaciers. Journal of Glaciology, 60(220), 361.