Seasonal variability in Antarctic ice shelf velocities forced by sea surface height variations
Antarctica’s ice shelves resist the flow of grounded ice towards the ocean through “buttressing” arising from their contact with ice rises, rumples, and lateral margins. Ice shelf thinning and retreat reduces buttressing, leading to increased delivery of mass to the ocean that adds to global sea lev...
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ftcopernicus:oai:publications.copernicus.org:tcd105338 2023-05-15T13:38:41+02:00 Seasonal variability in Antarctic ice shelf velocities forced by sea surface height variations Mosbeux, Cyrille Padman, Laurie Klein, Emilie Bromirski, Peter B. Fricker, Helen A. 2022-08-09 application/pdf https://doi.org/10.5194/tc-2022-153 https://tc.copernicus.org/preprints/tc-2022-153/ eng eng doi:10.5194/tc-2022-153 https://tc.copernicus.org/preprints/tc-2022-153/ eISSN: 1994-0424 Text 2022 ftcopernicus https://doi.org/10.5194/tc-2022-153 2022-08-15T16:22:54Z Antarctica’s ice shelves resist the flow of grounded ice towards the ocean through “buttressing” arising from their contact with ice rises, rumples, and lateral margins. Ice shelf thinning and retreat reduces buttressing, leading to increased delivery of mass to the ocean that adds to global sea level. Ice shelf response to large annual cycles in atmospheric and oceanic processes provide opportunities to examine how environmental changes affect dynamics of both ice shelves and the buttressed grounded ice. Here, we explore whether seasonal variability of sea surface height (SSH) can explain observed seasonal variability of ice velocity. We investigate this hypothesis using several time series of ice velocity from Ross Ice Shelf (RIS), satellite-based estimates of SSH seaward of the RIS front, ocean models of SSH under and near RIS, and a viscous ice sheet model. The observed annual changes in RIS velocity are of order 1–10 metres per year (roughly 1 % of mean flow). The ice sheet model, forced by the observed and modelled range of SSH of about 10 cm, reproduces the observed velocity changes when visco-elastic effects near the grounding line are parameterized in our viscous model. The model response is dominated by grounding line migration, but with a significant contribution from SSH-induced tilt of the ice shelf. Improvements in measurements and models of SSH, including under ice shelves, combined with additional long-term GNSS records of ice shelf velocities, will provide further insights into longer term ice shelf and ice sheet response to future changes in sea level. Text Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Ross Ice Shelf Copernicus Publications: E-Journals Antarctic Ross Ice Shelf |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Antarctica’s ice shelves resist the flow of grounded ice towards the ocean through “buttressing” arising from their contact with ice rises, rumples, and lateral margins. Ice shelf thinning and retreat reduces buttressing, leading to increased delivery of mass to the ocean that adds to global sea level. Ice shelf response to large annual cycles in atmospheric and oceanic processes provide opportunities to examine how environmental changes affect dynamics of both ice shelves and the buttressed grounded ice. Here, we explore whether seasonal variability of sea surface height (SSH) can explain observed seasonal variability of ice velocity. We investigate this hypothesis using several time series of ice velocity from Ross Ice Shelf (RIS), satellite-based estimates of SSH seaward of the RIS front, ocean models of SSH under and near RIS, and a viscous ice sheet model. The observed annual changes in RIS velocity are of order 1–10 metres per year (roughly 1 % of mean flow). The ice sheet model, forced by the observed and modelled range of SSH of about 10 cm, reproduces the observed velocity changes when visco-elastic effects near the grounding line are parameterized in our viscous model. The model response is dominated by grounding line migration, but with a significant contribution from SSH-induced tilt of the ice shelf. Improvements in measurements and models of SSH, including under ice shelves, combined with additional long-term GNSS records of ice shelf velocities, will provide further insights into longer term ice shelf and ice sheet response to future changes in sea level. |
format |
Text |
author |
Mosbeux, Cyrille Padman, Laurie Klein, Emilie Bromirski, Peter B. Fricker, Helen A. |
spellingShingle |
Mosbeux, Cyrille Padman, Laurie Klein, Emilie Bromirski, Peter B. Fricker, Helen A. Seasonal variability in Antarctic ice shelf velocities forced by sea surface height variations |
author_facet |
Mosbeux, Cyrille Padman, Laurie Klein, Emilie Bromirski, Peter B. Fricker, Helen A. |
author_sort |
Mosbeux, Cyrille |
title |
Seasonal variability in Antarctic ice shelf velocities forced by sea surface height variations |
title_short |
Seasonal variability in Antarctic ice shelf velocities forced by sea surface height variations |
title_full |
Seasonal variability in Antarctic ice shelf velocities forced by sea surface height variations |
title_fullStr |
Seasonal variability in Antarctic ice shelf velocities forced by sea surface height variations |
title_full_unstemmed |
Seasonal variability in Antarctic ice shelf velocities forced by sea surface height variations |
title_sort |
seasonal variability in antarctic ice shelf velocities forced by sea surface height variations |
publishDate |
2022 |
url |
https://doi.org/10.5194/tc-2022-153 https://tc.copernicus.org/preprints/tc-2022-153/ |
geographic |
Antarctic Ross Ice Shelf |
geographic_facet |
Antarctic Ross Ice Shelf |
genre |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Ross Ice Shelf |
genre_facet |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Ross Ice Shelf |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-2022-153 https://tc.copernicus.org/preprints/tc-2022-153/ |
op_doi |
https://doi.org/10.5194/tc-2022-153 |
_version_ |
1766109480040267776 |