Seasonal dynamics of Totten Ice Shelf controlled by sea ice buttressing
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Published:2018-09-06
Issue:9
Volume:12
Page:2869-2882
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ISSN:1994-0424
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Container-title:The Cryosphere
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language:en
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Short-container-title:The Cryosphere
Author:
Greene Chad A.ORCID, Young Duncan A.ORCID, Gwyther David E.ORCID, Galton-Fenzi Benjamin K.ORCID, Blankenship Donald D.
Abstract
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 100 m yr−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.
Funder
Division of Polar Programs G. Unger Vetlesen Foundation Australian Research Council
Publisher
Copernicus GmbH
Subject
Earth-Surface Processes,Water Science and Technology
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