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Ice-stream stability on a reverse bed slope.

Jamieson, S.S.R. and Vieli, A. and Livingstone, S.J. and Ó Cofaigh, C. and Stokes, C.R. and Hillenbrand, C-D. and Dowdeswell, J.A. (2012) 'Ice-stream stability on a reverse bed slope.', Nature geoscience. .

Abstract

Marine-based ice streams whose beds deepen inland are thought to be inherently unstable. This instability is of particular concern because significant portions of the marine-based West Antarctic and Greenland ice sheets are losing mass and their retreat could contribute significantly to future sea-level rise. However, the present understanding of ice-stream stability is limited by observational records that are too short to resolve multi-decadal to millennial-scale behaviour or to validate numerical models8. Here we present a dynamic numerical simulation of Antarctic ice-stream retreat since the Last Glacial Maximum (LGM), constrained by geophysical data, whose behaviour is consistent with the geomorphological record. We find that retreat of Marguerite Bay Ice Stream following the LGM was highly nonlinear and was interrupted by stabilizations on a reverse-sloping bed, where theory predicts rapid unstable retreat. We demonstrate that these transient stabilizations were caused by enhanced lateral drag as the ice stream narrowed. We conclude that, as well as bed topography, ice-stream width and long-term retreat history are crucial for understanding decadal- to centennial-scale ice-stream behaviour and marine ice-sheet vulnerability.

Item Type:Article
Additional Information:Read Durham University's press release about this article, available at: http://www.dur.ac.uk/news/newsitem/?itemno=15572
Full text:PDF - Accepted Version (1605Kb)
Status:Peer-reviewed
Publisher Web site:http://dx.doi.org/10.1038/ngeo1600
Record Created:16 Oct 2012 16:20
Last Modified:20 Oct 2013 00:30

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