Rapid fragmentation of Thwaites Eastern Ice Shelf

Ice shelves play a key role in the dynamics of marine ice sheets by buttressing grounded ice and limiting rates of ice flux to the oceans. In response to recent climatic and oceanic change, ice shelves fringing the West Antarctic Ice Sheet (WAIS) have begun to fragment and retreat, with major implic...

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Published in:The Cryosphere
Main Authors: Benn, Douglas I., Luckman, Adrian, Åström, Jan A., Crawford, Anna J., Cornford, Stephen L., Bevan, Suzanne L., Zwinger, Thomas, Gladstone, Rupert, Alley, Karen, Pettit, Erin, Bassis, Jeremy
Format: Text
Language:English
Published: 2022
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Online Access:https://doi.org/10.5194/tc-16-2545-2022
https://tc.copernicus.org/articles/16/2545/2022/
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spelling ftcopernicus:oai:publications.copernicus.org:tc97652 2023-05-15T14:02:18+02:00 Rapid fragmentation of Thwaites Eastern Ice Shelf Benn, Douglas I. Luckman, Adrian Åström, Jan A. Crawford, Anna J. Cornford, Stephen L. Bevan, Suzanne L. Zwinger, Thomas Gladstone, Rupert Alley, Karen Pettit, Erin Bassis, Jeremy 2022-06-27 application/pdf https://doi.org/10.5194/tc-16-2545-2022 https://tc.copernicus.org/articles/16/2545/2022/ eng eng doi:10.5194/tc-16-2545-2022 https://tc.copernicus.org/articles/16/2545/2022/ eISSN: 1994-0424 Text 2022 ftcopernicus https://doi.org/10.5194/tc-16-2545-2022 2022-07-04T16:22:43Z Ice shelves play a key role in the dynamics of marine ice sheets by buttressing grounded ice and limiting rates of ice flux to the oceans. In response to recent climatic and oceanic change, ice shelves fringing the West Antarctic Ice Sheet (WAIS) have begun to fragment and retreat, with major implications for ice-sheet stability. Here, we focus on the Thwaites Eastern Ice Shelf (TEIS), the remaining pinned floating extension of Thwaites Glacier. We show that TEIS has undergone a process of fragmentation in the last 5 years, including brittle failure along a major shear zone, formation of tensile cracks on the main body of the shelf, and a release of tabular bergs on both the eastern and western flanks. Simulations with the Helsinki Discrete Element Model (HiDEM) show that this pattern of failure is associated with high backstress from a submarine pinning point at the distal edge of the shelf. We show that a significant zone of shear, upstream of the main pinning point, developed in response to the rapid acceleration of the shelf between 2002 and 2006, seeding damage on the shelf. Subsequently, basal melting and positive feedback between damage and strain rates weakened TEIS, allowing damage to accumulate. Thus, although backstress on TEIS has likely diminished over time as the pinning point shrunk, accumulation of damage has ensured that the ice in the shear zone remained the weakest link in the system. Experiments with the BISICLES ice-sheet model indicate that additional damage to or unpinning of TEIS is unlikely to trigger significantly increased ice loss from WAIS, but the calving response to the loss of TEIS remains highly uncertain. It is widely recognised that ice-shelf fragmentation and collapse can be triggered by hydrofracturing and/or unpinning from ice-shelf margins or grounding points. Our results indicate a third mechanism, backstress triggered failure , that can occur if and when an ice shelf is no longer able to withstand stress imposed by pinning points. In most circumstances, pinning points are ... Text Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Thwaites Glacier Copernicus Publications: E-Journals Antarctic Thwaites Glacier ENVELOPE(-106.750,-106.750,-75.500,-75.500) West Antarctic Ice Sheet The Cryosphere 16 6 2545 2564
institution Open Polar
collection Copernicus Publications: E-Journals
op_collection_id ftcopernicus
language English
description Ice shelves play a key role in the dynamics of marine ice sheets by buttressing grounded ice and limiting rates of ice flux to the oceans. In response to recent climatic and oceanic change, ice shelves fringing the West Antarctic Ice Sheet (WAIS) have begun to fragment and retreat, with major implications for ice-sheet stability. Here, we focus on the Thwaites Eastern Ice Shelf (TEIS), the remaining pinned floating extension of Thwaites Glacier. We show that TEIS has undergone a process of fragmentation in the last 5 years, including brittle failure along a major shear zone, formation of tensile cracks on the main body of the shelf, and a release of tabular bergs on both the eastern and western flanks. Simulations with the Helsinki Discrete Element Model (HiDEM) show that this pattern of failure is associated with high backstress from a submarine pinning point at the distal edge of the shelf. We show that a significant zone of shear, upstream of the main pinning point, developed in response to the rapid acceleration of the shelf between 2002 and 2006, seeding damage on the shelf. Subsequently, basal melting and positive feedback between damage and strain rates weakened TEIS, allowing damage to accumulate. Thus, although backstress on TEIS has likely diminished over time as the pinning point shrunk, accumulation of damage has ensured that the ice in the shear zone remained the weakest link in the system. Experiments with the BISICLES ice-sheet model indicate that additional damage to or unpinning of TEIS is unlikely to trigger significantly increased ice loss from WAIS, but the calving response to the loss of TEIS remains highly uncertain. It is widely recognised that ice-shelf fragmentation and collapse can be triggered by hydrofracturing and/or unpinning from ice-shelf margins or grounding points. Our results indicate a third mechanism, backstress triggered failure , that can occur if and when an ice shelf is no longer able to withstand stress imposed by pinning points. In most circumstances, pinning points are ...
format Text
author Benn, Douglas I.
Luckman, Adrian
Åström, Jan A.
Crawford, Anna J.
Cornford, Stephen L.
Bevan, Suzanne L.
Zwinger, Thomas
Gladstone, Rupert
Alley, Karen
Pettit, Erin
Bassis, Jeremy
spellingShingle Benn, Douglas I.
Luckman, Adrian
Åström, Jan A.
Crawford, Anna J.
Cornford, Stephen L.
Bevan, Suzanne L.
Zwinger, Thomas
Gladstone, Rupert
Alley, Karen
Pettit, Erin
Bassis, Jeremy
Rapid fragmentation of Thwaites Eastern Ice Shelf
author_facet Benn, Douglas I.
Luckman, Adrian
Åström, Jan A.
Crawford, Anna J.
Cornford, Stephen L.
Bevan, Suzanne L.
Zwinger, Thomas
Gladstone, Rupert
Alley, Karen
Pettit, Erin
Bassis, Jeremy
author_sort Benn, Douglas I.
title Rapid fragmentation of Thwaites Eastern Ice Shelf
title_short Rapid fragmentation of Thwaites Eastern Ice Shelf
title_full Rapid fragmentation of Thwaites Eastern Ice Shelf
title_fullStr Rapid fragmentation of Thwaites Eastern Ice Shelf
title_full_unstemmed Rapid fragmentation of Thwaites Eastern Ice Shelf
title_sort rapid fragmentation of thwaites eastern ice shelf
publishDate 2022
url https://doi.org/10.5194/tc-16-2545-2022
https://tc.copernicus.org/articles/16/2545/2022/
long_lat ENVELOPE(-106.750,-106.750,-75.500,-75.500)
geographic Antarctic
Thwaites Glacier
West Antarctic Ice Sheet
geographic_facet Antarctic
Thwaites Glacier
West Antarctic Ice Sheet
genre Antarc*
Antarctic
Ice Sheet
Ice Shelf
Ice Shelves
Thwaites Glacier
genre_facet Antarc*
Antarctic
Ice Sheet
Ice Shelf
Ice Shelves
Thwaites Glacier
op_source eISSN: 1994-0424
op_relation doi:10.5194/tc-16-2545-2022
https://tc.copernicus.org/articles/16/2545/2022/
op_doi https://doi.org/10.5194/tc-16-2545-2022
container_title The Cryosphere
container_volume 16
container_issue 6
container_start_page 2545
op_container_end_page 2564
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