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Abstract

Previous studies of Totten Ice Shelf have employed surface velocity measurements to estimate its mass balance and understand its sensitivities to interannual changes in climate forcing. However, displacement measurements acquired over timescales of days to weeks may not accurately characterize long-term flow rates wherein ice velocity fluctuates with the seasons. Quantifying annual mass budgets or analyzing interannual changes in ice velocity requires knowing when and where observations of glacier velocity could be aliased by subannual variability. Here, we analyze 16 years of velocity data for Totten Ice Shelf, which we generate at subannual resolution by applying feature-tracking algorithms to several hundred satellite image pairs. We identify a seasonal cycle characterized by a spring to autumn speedup of more than 100myr−1 close to the ice front. The amplitude of the seasonal cycle diminishes with distance from the open ocean, suggesting the presence of a resistive back stress at the ice front that is strongest in winter. Springtime acceleration precedes summer surface melt and is not attributable to thinning from basal melt. We attribute the onset of ice shelf acceleration each spring to the loss of buttressing from the breakup of seasonal landfast sea ice.

Item Type:	Article
Authors/Creators:	Greene, CA and Young, DA and Gwyther, DE and Galton-Fenzi, BK and Blankenship, DD
Keywords:	Antarctica, Totten Glacier, ice sheet, sea ice
Journal or Publication Title:	Cryosphere
Publisher:	Copernicus GmbH
ISSN:	1994-0416
DOI / ID Number:	https://doi.org/10.5194/tc-12-2869-2018
Copyright Information:	Copyright 2018 the authors. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/
Related URLs:	Google Scholar: Gwyther, DE UTAS Profile: Gwyther, DE
Item Statistics:	View statistics for this item

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