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Ice-stream stability on a reverse bed slope

Jamieson, Stewart S.R.; Vieli, Andreas; Livingstone, Stephen J.; Ó Cofaigh, Colm; Stokes, Chris; Hillenbrand, Claus-Dieter; Dowdeswell, Julian A.. 2012 Ice-stream stability on a reverse bed slope. Nature Geoscience, 5 (11). 799-802. 10.1038/NGEO1600

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Abstract/Summary

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 marinebased 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 icestream stability is limited by observational records that are too short to resolve multi-decadal to millennial-scale behaviour or to validate numerical models. 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: Publication - Article
Digital Object Identifier (DOI): 10.1038/NGEO1600
Programmes: BAS Programmes > Polar Science for Planet Earth (2009 - ) > Ice Sheets
ISSN: 1752-0894
Additional Keywords: Climate science, Geomorphology, Cryospheric science, Palaeoclimate and palaeoceanography
NORA Subject Terms: Glaciology
Date made live: 02 Apr 2012 08:20 +0 (UTC)
URI: http://nora.nerc.ac.uk/id/eprint/17541

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