Asa Rennermalm, Assistant Professor, Department of Geography, Rutgers University, on the hydrology of the Arctic region, particularly the Greenland Ice Sheet.
Greenland ice sheet water release, and the magnitude of sub- and englacial storage, firn densification, internal refreezing and other hydrologic processes that delay or reduce true water export to the global ocean remain poorly understood. This problem is compounded by scant hydrometerological measurements. Here, ice sheet surface meltwater runoff and proglacial river discharge determined between 2008 and 2012 for three sites near Kangerlussuaq, western Greenland were used to establish the water budget for a small ice sheet watershed. The water budget could not be closed in the three years, even when uncertainty ranges were considered. Instead, between 12% and 53% of ice sheet surface runoff is retained within the catchment each melt year (time between onset of ice sheet runoff in two consecutive years) most likely in en- and subglacial storages. Evidence suggests that while some holdover summer meltwater may escape during the cold-season, this water volume is too small to close the budget. Thus, this study indicates that the Greenland ice sheet cryo-hydrologic system may remain active year round, and that meltwater may be retained in the pro glacial area, internally, or in firn layers for prolonged time periods before release to the ocean.
Åsa Rennermalm is assistant professor at the Department of Geography at Rutgers, The State University of New Jersey. Her research interest is hydrology of the Arctic region. Currently she is discovering how water is transported and retained within the Greenland ice sheet, for better understanding how much meltwater escapes to the ocean and raising global sea levels. Her work involves modeling, satellite and in situ data analysis, and fieldwork. She has participated several field expeditions to the Arctic, including Alaska and Greenland.
Sponsored by the Dickey Center's Institute of Arctic Studies.
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