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CHARACTERIZATION OF BURIED SUPRAGLACIAL LAKES OVER THE GREENLAND ICE SHEET

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Monday, 5 January 2015
Casey A. Joseph, University of Maryland College Park, Easton, MD; and L. S. Koenig and D. J. Lampkin

The changing mass of the Greenland Ice Sheet (GIS) represents a large unknown in the assessment of future global sea level rise. GIS has experienced a rapid increase in the extent and magnitude of surface melt resulting in pronounced surface runoff and the proliferation of surface lakes which can transfer surface melt water to the bedrock influencing ice flow behavior and mass balance. Supraglacial lakes, their relationships to the evolution of englacial and subglacial hydrologic systems responsible for dynamic changes in ice sheet mass flux is not well understood. The recent discovery of sub-surface melt water in supraglacial lake basins retained through the winter has complicated our understanding of the ice sheet hydrology. Backscatter data from a Frequency Modulated Continuous Wave (FMCW) radar operating from 2-6 GHz derived from NASA's Operation Ice Bridge Mission from 2009-2013, are used to detect stored sub-surface lakes over GIS. The depth to sub-surface water is extracted for each buried lake. Panchromatic LANDSAT ETM+ imagery is used to monitor the spatio-temporal variability of lakes with buried melt water over the analysis period. This effort quantifies the relationship between buried lake depths and the temporal variability of lake area over the Jakobshavn IsbrŠ and ZachariŠ Isstr°m outlet glacier regions.