Stabilizing effect of mélange buttressing on the Marine Ice Cliff Instability of the West Antarctic Ice Sheet
Due to global warming and particularly high regional ocean warming, both Thwaites and Pine Island glaciers in the Amundsen region of the Antarctic Ice Sheet could lose their buttressing ice shelves over time. We analyze the possible consequences using the Parallel Ice Sheet Model (PISM), applying a...
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ftcopernicus:oai:publications.copernicus.org:tcd96646 2023-05-15T14:02:17+02:00 Stabilizing effect of mélange buttressing on the Marine Ice Cliff Instability of the West Antarctic Ice Sheet Schlemm, Tanja Feldmann, Johannes Winkelmann, Ricarda Levermann, Anders 2021-08-12 application/pdf https://doi.org/10.5194/tc-2021-238 https://tc.copernicus.org/preprints/tc-2021-238/ eng eng doi:10.5194/tc-2021-238 https://tc.copernicus.org/preprints/tc-2021-238/ eISSN: 1994-0424 Text 2021 ftcopernicus https://doi.org/10.5194/tc-2021-238 2021-08-16T16:22:27Z Due to global warming and particularly high regional ocean warming, both Thwaites and Pine Island glaciers in the Amundsen region of the Antarctic Ice Sheet could lose their buttressing ice shelves over time. We analyze the possible consequences using the Parallel Ice Sheet Model (PISM), applying a simple cliff-calving parameterization and an ice-mélange-buttressing model. We find that the instantaneous loss of ice-shelf buttressing, due to enforced ice-shelf melting, initiates grounding line retreat and triggers the marine ice sheet instability (MISI). As a consequence, the grounding line progresses into the interior of the West Antarctic Ice Sheet and leads to a sea level contribution of 0.6 m within 100 a. By subjecting the exposed ice cliffs to cliff calving using our simplified parameterization, we also analyze the marine ice cliff instability (MICI). In our simulations it can double or even triple the sea level contribution depending on the only loosely constraint parameter which determines the maximum cliff-calving rate. The speed of MICI depends on this upper bound on the calving rate which is given by the ice mélange buttressing the glacier. However, stabilization of MICI may occur for geometric reasons. Since the embayment geometry changes as MICI advances into the interior of the ice sheet, the upper bound on calving rates is reduced and the progress of MICI is slowed down. Although we cannot claim that our simulations bear relevant quantitative estimates of the effect of ice-mélange buttressing on MICI, the mechanism has the potential to stop the instability. Further research is needed to evaluate its role for the past and future evolution of the Antarctic Ice Sheet. Text Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Copernicus Publications: E-Journals Antarctic Misi ENVELOPE(26.683,26.683,66.617,66.617) The Antarctic West Antarctic Ice Sheet |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Due to global warming and particularly high regional ocean warming, both Thwaites and Pine Island glaciers in the Amundsen region of the Antarctic Ice Sheet could lose their buttressing ice shelves over time. We analyze the possible consequences using the Parallel Ice Sheet Model (PISM), applying a simple cliff-calving parameterization and an ice-mélange-buttressing model. We find that the instantaneous loss of ice-shelf buttressing, due to enforced ice-shelf melting, initiates grounding line retreat and triggers the marine ice sheet instability (MISI). As a consequence, the grounding line progresses into the interior of the West Antarctic Ice Sheet and leads to a sea level contribution of 0.6 m within 100 a. By subjecting the exposed ice cliffs to cliff calving using our simplified parameterization, we also analyze the marine ice cliff instability (MICI). In our simulations it can double or even triple the sea level contribution depending on the only loosely constraint parameter which determines the maximum cliff-calving rate. The speed of MICI depends on this upper bound on the calving rate which is given by the ice mélange buttressing the glacier. However, stabilization of MICI may occur for geometric reasons. Since the embayment geometry changes as MICI advances into the interior of the ice sheet, the upper bound on calving rates is reduced and the progress of MICI is slowed down. Although we cannot claim that our simulations bear relevant quantitative estimates of the effect of ice-mélange buttressing on MICI, the mechanism has the potential to stop the instability. Further research is needed to evaluate its role for the past and future evolution of the Antarctic Ice Sheet. |
format |
Text |
author |
Schlemm, Tanja Feldmann, Johannes Winkelmann, Ricarda Levermann, Anders |
spellingShingle |
Schlemm, Tanja Feldmann, Johannes Winkelmann, Ricarda Levermann, Anders Stabilizing effect of mélange buttressing on the Marine Ice Cliff Instability of the West Antarctic Ice Sheet |
author_facet |
Schlemm, Tanja Feldmann, Johannes Winkelmann, Ricarda Levermann, Anders |
author_sort |
Schlemm, Tanja |
title |
Stabilizing effect of mélange buttressing on the Marine Ice Cliff Instability of the West Antarctic Ice Sheet |
title_short |
Stabilizing effect of mélange buttressing on the Marine Ice Cliff Instability of the West Antarctic Ice Sheet |
title_full |
Stabilizing effect of mélange buttressing on the Marine Ice Cliff Instability of the West Antarctic Ice Sheet |
title_fullStr |
Stabilizing effect of mélange buttressing on the Marine Ice Cliff Instability of the West Antarctic Ice Sheet |
title_full_unstemmed |
Stabilizing effect of mélange buttressing on the Marine Ice Cliff Instability of the West Antarctic Ice Sheet |
title_sort |
stabilizing effect of mélange buttressing on the marine ice cliff instability of the west antarctic ice sheet |
publishDate |
2021 |
url |
https://doi.org/10.5194/tc-2021-238 https://tc.copernicus.org/preprints/tc-2021-238/ |
long_lat |
ENVELOPE(26.683,26.683,66.617,66.617) |
geographic |
Antarctic Misi The Antarctic West Antarctic Ice Sheet |
geographic_facet |
Antarctic Misi The Antarctic West Antarctic Ice Sheet |
genre |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves |
genre_facet |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-2021-238 https://tc.copernicus.org/preprints/tc-2021-238/ |
op_doi |
https://doi.org/10.5194/tc-2021-238 |
_version_ |
1766272455343603712 |