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Variable deceleration of Whillans Ice Stream, West Antarctica
Citation
Beem, LH and Tulaczyk, SM and King, MA and Bougamont, M and Fricker, HA and Christoffersen, P, Variable deceleration of Whillans Ice Stream, West Antarctica, Journal of Geophysical Research: Earth Surface, 119, (2) pp. 212-224. ISSN 2169-9003 (2014) [Refereed Article]
Copyright Statement
Copyright 2014 American Geophysical Union
Abstract
The Whillans Ice Stream Ice Plain (WIP) has been slowing since at least 1963. Prior constraints on this slowdown were consistent with a constant long-term deceleration rate. New observations of ice velocity from 11 continuous and 3 seasonal GPS sites indicate the deceleration rate varies through time including on interannual time scales. Between 2009 and 2012 WIP decelerated at a rate (6.1 to 10.9 ± 2 m/yr2) that was double the multidecadal average (3.0 to 5.6 ± 2 m/yr2). To identify the causes of slowdown, we used new and prior velocity estimates to constrain longitudinal and transverse force budget models as well as a higher-order inverse model. All model results support the conclusion that the observed deceleration of WIP is caused by an increase in basal resistance to motion at a rate of 10 to 40 Pa/yr. Subglacial processes that may be responsible for strengthening the ice stream bed include basal freeze on, changes in subglacial hydrology, or increases in the area of resistant basal substrate through differential erosion. The observed variability in WIP deceleration rate suggests that dynamics in subglacial hydrology, plausibly driven by basal freeze on and/or activity of subglacial lakes, plays a key role in modulating basal resistance to ice motion in the region.
Item Details
Item Type: | Refereed Article |
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Keywords: | Antarctica, ice sheets |
Research Division: | Earth Sciences |
Research Group: | Geophysics |
Research Field: | Geodesy |
Objective Division: | Environmental Policy, Climate Change and Natural Hazards |
Objective Group: | Understanding climate change |
Objective Field: | Effects of climate change on Antarctic and sub-Antarctic environments (excl. social impacts) |
UTAS Author: | King, MA (Professor Matt King) |
ID Code: | 93182 |
Year Published: | 2014 |
Funding Support: | Australian Research Council (FT110100207) |
Web of Science® Times Cited: | 33 |
Deposited By: | Geography and Environmental Studies |
Deposited On: | 2014-07-15 |
Last Modified: | 2017-10-24 |
Downloads: | 0 |
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