Evidence for a water system transition beneath Thwaites Glacier, West Antarctica
Thwaites Glacier is one of the largest, most rapidly changing glaciers on Earth, and its landward-sloping bed reaches the interior of the marine West Antarctic Ice Sheet, which impounds enough ice to yield meters of sea-level rise. Marine ice sheets with landward-sloping beds have a potentially unst...
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ftpubmed:oai:pubmedcentral.nih.gov:3725042 2023-05-15T13:59:46+02:00 Evidence for a water system transition beneath Thwaites Glacier, West Antarctica Schroeder, Dustin M. Blankenship, Donald D. Young, Duncan A. 2013-07-23 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3725042 http://www.ncbi.nlm.nih.gov/pubmed/23836631 https://doi.org/10.1073/pnas.1302828110 en eng National Academy of Sciences http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3725042 http://www.ncbi.nlm.nih.gov/pubmed/23836631 http://dx.doi.org/10.1073/pnas.1302828110 Freely available online through the PNAS open access option. Physical Sciences Text 2013 ftpubmed https://doi.org/10.1073/pnas.1302828110 2013-09-05T03:03:16Z Thwaites Glacier is one of the largest, most rapidly changing glaciers on Earth, and its landward-sloping bed reaches the interior of the marine West Antarctic Ice Sheet, which impounds enough ice to yield meters of sea-level rise. Marine ice sheets with landward-sloping beds have a potentially unstable configuration in which acceleration can initiate or modulate grounding-line retreat and ice loss. Subglacial water has been observed and theorized to accelerate the flow of overlying ice dependent on whether it is hydrologically distributed or concentrated. However, the subglacial water systems of Thwaites Glacier and their control on ice flow have not been characterized by geophysical analysis. The only practical means of observing these water systems is airborne ice-penetrating radar, but existing radar analysis approaches cannot discriminate between their dynamically critical states. We use the angular distribution of energy in radar bed echoes to characterize both the extent and hydrologic state of subglacial water systems across Thwaites Glacier. We validate this approach with radar imaging, showing that substantial water volumes are ponding in a system of distributed canals upstream of a bedrock ridge that is breached and bordered by a system of concentrated channels. The transition between these systems occurs with increasing surface slope, melt-water flux, and basal shear stress. This indicates a feedback between the subglacial water system and overlying ice dynamics, which raises the possibility that subglacial water could trigger or facilitate a grounding-line retreat in Thwaites Glacier capable of spreading into the interior of the West Antarctic Ice Sheet. Text Antarc* Antarctic Antarctica Ice Sheet Thwaites Glacier West Antarctica PubMed Central (PMC) Antarctic Thwaites Glacier ENVELOPE(-106.750,-106.750,-75.500,-75.500) West Antarctic Ice Sheet West Antarctica Proceedings of the National Academy of Sciences 110 30 12225 12228 |
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Physical Sciences Schroeder, Dustin M. Blankenship, Donald D. Young, Duncan A. Evidence for a water system transition beneath Thwaites Glacier, West Antarctica |
topic_facet |
Physical Sciences |
description |
Thwaites Glacier is one of the largest, most rapidly changing glaciers on Earth, and its landward-sloping bed reaches the interior of the marine West Antarctic Ice Sheet, which impounds enough ice to yield meters of sea-level rise. Marine ice sheets with landward-sloping beds have a potentially unstable configuration in which acceleration can initiate or modulate grounding-line retreat and ice loss. Subglacial water has been observed and theorized to accelerate the flow of overlying ice dependent on whether it is hydrologically distributed or concentrated. However, the subglacial water systems of Thwaites Glacier and their control on ice flow have not been characterized by geophysical analysis. The only practical means of observing these water systems is airborne ice-penetrating radar, but existing radar analysis approaches cannot discriminate between their dynamically critical states. We use the angular distribution of energy in radar bed echoes to characterize both the extent and hydrologic state of subglacial water systems across Thwaites Glacier. We validate this approach with radar imaging, showing that substantial water volumes are ponding in a system of distributed canals upstream of a bedrock ridge that is breached and bordered by a system of concentrated channels. The transition between these systems occurs with increasing surface slope, melt-water flux, and basal shear stress. This indicates a feedback between the subglacial water system and overlying ice dynamics, which raises the possibility that subglacial water could trigger or facilitate a grounding-line retreat in Thwaites Glacier capable of spreading into the interior of the West Antarctic Ice Sheet. |
format |
Text |
author |
Schroeder, Dustin M. Blankenship, Donald D. Young, Duncan A. |
author_facet |
Schroeder, Dustin M. Blankenship, Donald D. Young, Duncan A. |
author_sort |
Schroeder, Dustin M. |
title |
Evidence for a water system transition beneath Thwaites Glacier, West Antarctica |
title_short |
Evidence for a water system transition beneath Thwaites Glacier, West Antarctica |
title_full |
Evidence for a water system transition beneath Thwaites Glacier, West Antarctica |
title_fullStr |
Evidence for a water system transition beneath Thwaites Glacier, West Antarctica |
title_full_unstemmed |
Evidence for a water system transition beneath Thwaites Glacier, West Antarctica |
title_sort |
evidence for a water system transition beneath thwaites glacier, west antarctica |
publisher |
National Academy of Sciences |
publishDate |
2013 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3725042 http://www.ncbi.nlm.nih.gov/pubmed/23836631 https://doi.org/10.1073/pnas.1302828110 |
long_lat |
ENVELOPE(-106.750,-106.750,-75.500,-75.500) |
geographic |
Antarctic Thwaites Glacier West Antarctic Ice Sheet West Antarctica |
geographic_facet |
Antarctic Thwaites Glacier West Antarctic Ice Sheet West Antarctica |
genre |
Antarc* Antarctic Antarctica Ice Sheet Thwaites Glacier West Antarctica |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet Thwaites Glacier West Antarctica |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3725042 http://www.ncbi.nlm.nih.gov/pubmed/23836631 http://dx.doi.org/10.1073/pnas.1302828110 |
op_rights |
Freely available online through the PNAS open access option. |
op_doi |
https://doi.org/10.1073/pnas.1302828110 |
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Proceedings of the National Academy of Sciences |
container_volume |
110 |
container_issue |
30 |
container_start_page |
12225 |
op_container_end_page |
12228 |
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1766268540519710720 |