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Originally published in Science Express on 17 April 2008
Science 9 May 2008:
Vol. 320. no. 5877, pp. 781 - 783
DOI: 10.1126/science.1153288
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Reports

Seasonal Speedup Along the Western Flank of the Greenland Ice Sheet

Ian Joughin,1* Sarah B. Das,2 Matt A. King,3 Ben E. Smith,1 Ian M. Howat,1{dagger} Twila Moon1

It has been widely hypothesized that a warmer climate in Greenland would increase the volume of lubricating surface meltwater reaching the ice-bedrock interface, accelerating ice flow and increasing mass loss. We have assembled a data set that provides a synoptic-scale view, spanning ice-sheet to outlet-glacier flow, with which to evaluate this hypothesis. On the ice sheet, these data reveal summer speedups (50 to 100%) consistent with, but somewhat larger than, earlier observations. The relative speedup of outlet glaciers, however, is far smaller (<15%). Furthermore, the dominant seasonal influence on Jakobshavn Isbrae's flow is the calving front's annual advance and retreat. With other effects producing outlet-glacier speedups an order of magnitude larger, seasonal melt's influence on ice flow is likely confined to those regions dominated by ice-sheet flow.

1 Polar Science Center, Applied Physics Lab, University of Washington, 1013 NE 40th Street, Seattle, WA 98105–6698, USA.
2 Department of Geology and Geophysics, Woods Hole Oceanographic Institute, Woods Hole, MA02543, USA.
3 School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.

{dagger} Present address: The Ohio State University, 1090 Carmack Road, Columbus, OH 43210–1002, USA.

* To whom correspondence should be addressed. E-mail: ian{at}apl.washington.edu

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THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Large and Rapid Melt-Induced Velocity Changes in the Ablation Zone of the Greenland Ice Sheet.
R. S. W. van de Wal, W. Boot, M. R. van den Broeke, C. J. P. P. Smeets, C. H. Reijmer, J. J. A. Donker, and J. Oerlemans (2008)
Science 321, 111-113
   Abstract »    Full Text »    PDF »
Fracture Propagation to the Base of the Greenland Ice Sheet During Supraglacial Lake Drainage.
S. B. Das, I. Joughin, M. D. Behn, I. M. Howat, M. A. King, D. Lizarralde, and M. P. Bhatia (2008)
Science 320, 778-781
   Abstract »    Full Text »    PDF »


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Science. ISSN 0036-8075 (print), 1095-9203 (online)