Inland migration of near-surface crevasses in the Amundsen Sea Sector, West Antarctica
Since distributed satellite observations of elevation change and velocity became available in the 1990s, Thwaites, Pine Island, Haynes, Pope, and Kohler Glaciers, located in Antarctica’s Amundsen Sea Embayment, have thinned and accelerated in response to ocean-induced melting and grounding-line retr...
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Copernicus Publications
2024
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00070854 2024-02-04T09:52:47+01:00 Inland migration of near-surface crevasses in the Amundsen Sea Sector, West Antarctica Hoffman, Andrew O. Christianson, Knut Lai, Ching-Yao Joughin, Ian Holschuh, Nicholas Case, Elizabeth Kingslake, Jonathan 2024-01 electronic https://doi.org/10.5194/egusphere-2023-2956 https://noa.gwlb.de/receive/cop_mods_00070854 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00069183/egusphere-2023-2956.pdf https://egusphere.copernicus.org/preprints/2024/egusphere-2023-2956/egusphere-2023-2956.pdf eng eng Copernicus Publications https://doi.org/10.5194/egusphere-2023-2956 https://noa.gwlb.de/receive/cop_mods_00070854 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00069183/egusphere-2023-2956.pdf https://egusphere.copernicus.org/preprints/2024/egusphere-2023-2956/egusphere-2023-2956.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2024 ftnonlinearchiv https://doi.org/10.5194/egusphere-2023-2956 2024-01-08T00:22:45Z Since distributed satellite observations of elevation change and velocity became available in the 1990s, Thwaites, Pine Island, Haynes, Pope, and Kohler Glaciers, located in Antarctica’s Amundsen Sea Embayment, have thinned and accelerated in response to ocean-induced melting and grounding-line retreat. We develop a crevasse image segmentation algorithm to identify and map surface crevasses on the grounded portions of Thwaites, Pine Island, Haynes, Pope, and Kohler Glaciers between 2015 and 2022 using Sentinel-1A satellite synthetic aperture radar (SAR) imagery. We also develop a geometric model for firn tensile strength dependent on porosity and the tensile strength of ice. On Pine Island and Thwaites Glaciers, which have both accelerated since 2015, crevassing has expanded tens of kilometers upstream of the 2015 extent. From the crevasse time series, we find that crevassing is strongly linked to principal surface stresses and consistent with von Mises fracture theory predictions. Our geometric model, analysis of SAR, and optical imagery, together with ice-penetrating radar data, suggest that these crevasses are near-surface features restricted to the firn. The porosity dependence of the near-surface tensile strength of the ice sheet may explain discrepancies between the tensile strength inferred from remotely-sensed surface crevasse observations and tensile strength measured in laboratory experiments, which often focus on ice (rather than firn) fracture. The near-surface nature of these features suggests that the expansion of crevasses inland has a limited direct impact on glacier mechanics. Article in Journal/Newspaper Amundsen Sea Antarc* Antarctica Ice Sheet Pine Island West Antarctica Niedersächsisches Online-Archiv NOA Amundsen Sea West Antarctica |
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Open Polar |
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Niedersächsisches Online-Archiv NOA |
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ftnonlinearchiv |
language |
English |
topic |
article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Hoffman, Andrew O. Christianson, Knut Lai, Ching-Yao Joughin, Ian Holschuh, Nicholas Case, Elizabeth Kingslake, Jonathan Inland migration of near-surface crevasses in the Amundsen Sea Sector, West Antarctica |
topic_facet |
article Verlagsveröffentlichung |
description |
Since distributed satellite observations of elevation change and velocity became available in the 1990s, Thwaites, Pine Island, Haynes, Pope, and Kohler Glaciers, located in Antarctica’s Amundsen Sea Embayment, have thinned and accelerated in response to ocean-induced melting and grounding-line retreat. We develop a crevasse image segmentation algorithm to identify and map surface crevasses on the grounded portions of Thwaites, Pine Island, Haynes, Pope, and Kohler Glaciers between 2015 and 2022 using Sentinel-1A satellite synthetic aperture radar (SAR) imagery. We also develop a geometric model for firn tensile strength dependent on porosity and the tensile strength of ice. On Pine Island and Thwaites Glaciers, which have both accelerated since 2015, crevassing has expanded tens of kilometers upstream of the 2015 extent. From the crevasse time series, we find that crevassing is strongly linked to principal surface stresses and consistent with von Mises fracture theory predictions. Our geometric model, analysis of SAR, and optical imagery, together with ice-penetrating radar data, suggest that these crevasses are near-surface features restricted to the firn. The porosity dependence of the near-surface tensile strength of the ice sheet may explain discrepancies between the tensile strength inferred from remotely-sensed surface crevasse observations and tensile strength measured in laboratory experiments, which often focus on ice (rather than firn) fracture. The near-surface nature of these features suggests that the expansion of crevasses inland has a limited direct impact on glacier mechanics. |
format |
Article in Journal/Newspaper |
author |
Hoffman, Andrew O. Christianson, Knut Lai, Ching-Yao Joughin, Ian Holschuh, Nicholas Case, Elizabeth Kingslake, Jonathan |
author_facet |
Hoffman, Andrew O. Christianson, Knut Lai, Ching-Yao Joughin, Ian Holschuh, Nicholas Case, Elizabeth Kingslake, Jonathan |
author_sort |
Hoffman, Andrew O. |
title |
Inland migration of near-surface crevasses in the Amundsen Sea Sector, West Antarctica |
title_short |
Inland migration of near-surface crevasses in the Amundsen Sea Sector, West Antarctica |
title_full |
Inland migration of near-surface crevasses in the Amundsen Sea Sector, West Antarctica |
title_fullStr |
Inland migration of near-surface crevasses in the Amundsen Sea Sector, West Antarctica |
title_full_unstemmed |
Inland migration of near-surface crevasses in the Amundsen Sea Sector, West Antarctica |
title_sort |
inland migration of near-surface crevasses in the amundsen sea sector, west antarctica |
publisher |
Copernicus Publications |
publishDate |
2024 |
url |
https://doi.org/10.5194/egusphere-2023-2956 https://noa.gwlb.de/receive/cop_mods_00070854 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00069183/egusphere-2023-2956.pdf https://egusphere.copernicus.org/preprints/2024/egusphere-2023-2956/egusphere-2023-2956.pdf |
geographic |
Amundsen Sea West Antarctica |
geographic_facet |
Amundsen Sea West Antarctica |
genre |
Amundsen Sea Antarc* Antarctica Ice Sheet Pine Island West Antarctica |
genre_facet |
Amundsen Sea Antarc* Antarctica Ice Sheet Pine Island West Antarctica |
op_relation |
https://doi.org/10.5194/egusphere-2023-2956 https://noa.gwlb.de/receive/cop_mods_00070854 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00069183/egusphere-2023-2956.pdf https://egusphere.copernicus.org/preprints/2024/egusphere-2023-2956/egusphere-2023-2956.pdf |
op_rights |
https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/egusphere-2023-2956 |
_version_ |
1789960928915095552 |