Does sea ice influence Greenland ice sheet surface-melt?
Asa K. Rennermalm1, Laurence C. Smith1,2, Julienne C. Stroeve3 and Vena W. Chu1
1 Department of Geography, University of California Los Angeles, 1255 Bunche Hall, Box 951525, Los Angeles, CA 90095-1524, USA
2 Department of Earth and Space Sciences, University of California Los Angeles, Los Angeles, CA, USA
3 National Snow and Ice Data Center, Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
e-mail: akr@ucla.edu
Received 27 January 2009; accepted 3 June 2009; published 19 June 2009.
Abstract
Recent decreases in Arctic sea ice and increases in Greenland ice sheet surface-melt may have global impacts, but the interactions between these two processes are unknown. Using microwave satellite data, we explore the spatial and temporal covariance of sea ice extent and ice sheet surface-melt around Greenland from 1979 to 2007. Significant covariance is discovered in several loci in the late summer, with the strongest covariance in western Greenland, particularly in the southwest (Kangerlussuaq). In this region, wind direction patterns and a statistical lag analysis of ice retreat/advance and surface-melt event timings suggest that sea ice extent change is a potential driver of ice sheet melt. Here, late summer wind directions facilitate onshore advection of ocean heat, and enhanced melting on the ice sheet commonly occurs after reductions in offshore sea ice. Hence, this study identifies for the first time the covariability patterns of sea ice and ice sheet melt and suggests that a retreating sea ice margin may enhance melting over the ice sheet.
Link: http://iopscience.iop.org/1748-9326/4/2/024011/fulltext
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