Recent ice dynamic and surface mass balance of Union glacier in the west antarctic ice sheet
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Date
2014-08-06
Journal Title
Journal ISSN
Volume Title
Publisher
Copernicus Publications
Abstract
Here we present the results of a comprehensive
glaciological investigation of Union Glacier
(79°460 S/83°240 W) in theWest Antarctic Ice Sheet (WAIS),
a major outlet glacier within the Ellsworth Mountains. Union
Glacier flows into the Ronne Ice Shelf, where recent models
have indicated the potential for significant grounding line
zone (GLZ) migrations in response to changing climate and
ocean conditions. To elaborate a glaciological base line that
can help to evaluate the potential impact of this GLZ change
scenario, we installed an array of stakes on Union Glacier in
2007. The stake network has been surveyed repeatedly for elevation,
velocity, and net surface mass balance. The region of
the stake measurements is in near-equilibrium, and ice speeds
are 10 to 33ma−1. Ground-penetrating radars (GPR) have
been used to map the subglacial topography, internal structure,
and crevasse frequency and depth along surveyed tracks
in the stake site area. The bedrock in this area has a minimum
elevation of −858ma.s.l., significantly deeper than
shown by BEDMAP2 data. However, between this deeper
area and the local GLZ, there is a threshold where the subglacial
topography shows a maximum altitude of 190 m. This
subglacial condition implies that an upstream migration of
the GLZ will not have strong effects on Union Glacier until
it passes beyond this shallow ice pinning point.
Description
Keywords
Ciencia, Flow, Reassessment, Stream
Citation
The Cryosphere, 8, 1445–1456, 2014