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Morphological evidence and direct estimates of rapid melting beneath Totten Glacier Ice Shelf, East Antarctica
Citation
Greenbaum, J and Schroeder, D and Grima, C and Habbal, F and Dow, C and Roberts, J and Gwyther, D and van Ommen, TD and Siegert, M and Blankenship, D, Morphological evidence and direct estimates of rapid melting beneath Totten Glacier Ice Shelf, East Antarctica, Geophysical Research Abstracts, 23-28 April, Vienna, Austria, pp. 1559. ISSN 1607-7962 (2017) [Conference Extract]
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Abstract
Totten Glacier drains at least 3.5 meters of eustatic sea level potential from marine-based ice in the Aurora Subglacial
Basin (ASB) in East Antarctica, more than the combined total of all glaciers in West Antarctica. Totten
Glacier has been the most rapidly thinning glacier in East Antarctica since satellite altimetry time series began
and the nature of the thinning suggests that it is driven by enhanced basal melting due to ocean processes. While
grounded ice thinning rates have been steady, recent work has shown that Totten’s floating ice shelf may not have
the same thinning behavior; as a result, it is critical to observe ice shelf and cavity boundary conditions and basal
processes to understand this apparent discrepancy. Warm Modified Circumpolar Deep Water (MCDW), which has
been linked to glacier retreat in West Antarctica, has been observed in summer and winter on the nearby Sabrina
Coast continental shelf and deep depressions in the seafloor provide access for MCDW to reach the ice shelf cavity.
Given its northern latitude, numerical ice sheet modeling indicates that Totten Glacier may be prone to retreat
caused by hydrofracture in a warming climate, so it is important to understand how intruding MCDW is affecting
thinning of Totten Glacier’s ice shelf. Here we use post-processed, focused airborne radar observations of the Totten
Glacier Ice Shelf to delineate multi-km wide basal channels and flat basal terraces associated with high basal
reflectivity and specularity (flatness) anomalies and correspondingly large ice surface depressions that indicate
active basal melting. Using a simple temperature-attenuation model, and basal roughness corrections, we present
basal melt rates associated with the radar reflection and specularity anomalies and compare them to those derived
from numerical ocean circulation modeling and an ice flow divergence calculation. Sub-ice shelf ocean circulation
modeling and under-ice robotic observations of Pine Island Glacier Ice Shelf in West Antarctica and the Petermann
Glacier Ice Shelf in Greenland have shown that basal terraces associated with large basal channels are an indication
of rapidly melting ice shelves. In this context, these new results identify an East Antarctic example of rapid basal
melting processes and demonstrate that airborne radar can be used to identify basal characteristics and processes
relevant to ice shelf stability.
Item Details
Item Type: | Conference Extract |
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Keywords: | Antarctica, melting, Totten Glacier |
Research Division: | Earth Sciences |
Research Group: | Oceanography |
Research Field: | Physical oceanography |
Objective Division: | Environmental Management |
Objective Group: | Management of Antarctic and Southern Ocean environments |
Objective Field: | Antarctic and Southern Ocean oceanic processes |
UTAS Author: | Roberts, J (Dr Jason Roberts) |
UTAS Author: | Gwyther, D (Dr David Gwyther) |
UTAS Author: | van Ommen, TD (Dr Tas van Ommen) |
ID Code: | 116899 |
Year Published: | 2017 |
Deposited By: | Oceans and Cryosphere |
Deposited On: | 2017-05-24 |
Last Modified: | 2019-09-25 |
Downloads: | 0 |
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