Ocean regulation hypothesis for glacier dynamics in southeast Greenland and implications for ice sheet mass changes

Murray, T. and Scharrer, K. and James, T. D. and Dye, S. R. and Hanna, E. and Booth, A. D. and Selmes, N. and Luckman, A. and Hughes, A. L. C. and Cook, S. and Huybrechts, P. (2010) Ocean regulation hypothesis for glacier dynamics in southeast Greenland and implications for ice sheet mass changes. Journal of Geophysical Research: Earth Surface, 115 (3). ISSN 2169-9011

Full content URL: https://doi.org/10.1029/2009JF001522

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Abstract

Synchronous acceleration and thinning of southeast (SE) Greenland glaciers during the early 2000s was the main contributor that resulted in the doubling of annual discharge from the ice sheet. We show that this acceleration was followed by a synchronized and widespread slowdown of the same glaciers, in many cases associated with a decrease in thinning rates, and we propose that ice sheet-ocean interactions are the first-order regional control on these recent mass changes. Sea surface temperature and mooring data show that the preceding dynamic thinning coincides with a brief decline in the cold East Greenland Coastal Current (EGCC) and East Greenland Current. We suggest this decline was partly induced by a reduction in ice sheet runoff, which allowed warm water from the Irminger Current to reach the SE Greenland coast. A restrengthening of the cold waters coincides with the glaciers' subsequent slowdown. We argue that this warming and subsequent cooling of the coastal waters was the cause of the glaciers' dynamic changes. We further suggest that the restrengthening of the EGCC resulted in part from cold water input by increased glacier calving during the speedup and increased ice sheet runoff. We hypothesize that the main mechanism for ice sheet mass loss in SE Greenland is highly sensitive to ocean conditions and is likely subject to negative feedback mechanisms. Copyright 2010 by the American Geophysical Union.

Keywords:feedback mechanism, glacier dynamics, glacier flow, glacier mass balance, glacier retreat, glacier surge, ice sheet, ice-ocean interaction, iceberg calving, sea ice, Arctic, Arctic Ocean, East Greenland Current, Greenland, Greenland Ice Sheet
Subjects:F Physical Sciences > F890 Geographical and Environmental Sciences not elsewhere classified
Divisions:College of Science > School of Geography
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ID Code:26043
Deposited On:22 Feb 2017 17:06

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