Snowfall versus sub-shelf melt: response of an idealized 3D ice-sheet-shelf system to mass redistribution
Surface accumulation and sub-ice-shelf melting are key drivers for the flow dynamics of the Antarctic Ice Sheet and are most likely to change under future warming which leads to 1) higher snowfall and 2) stronger melting below ice shelves. Here we carry out conceptual simulations in which an equilib...
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ftcopernicus:oai:publications.copernicus.org:tcd69195 2023-05-15T13:55:28+02:00 Snowfall versus sub-shelf melt: response of an idealized 3D ice-sheet-shelf system to mass redistribution Feldmann, Johannes Reese, Ronja Winkelmann, Ricarda Levermann, Anders 2018-10-15 application/pdf https://doi.org/10.5194/tc-2018-109 https://tc.copernicus.org/preprints/tc-2018-109/ eng eng doi:10.5194/tc-2018-109 https://tc.copernicus.org/preprints/tc-2018-109/ eISSN: 1994-0424 Text 2018 ftcopernicus https://doi.org/10.5194/tc-2018-109 2020-07-20T16:23:12Z Surface accumulation and sub-ice-shelf melting are key drivers for the flow dynamics of the Antarctic Ice Sheet and are most likely to change under future warming which leads to 1) higher snowfall and 2) stronger melting below ice shelves. Here we carry out conceptual simulations in which an equilibrium ice-sheet-shelf system is perturbed such that the increased sub-shelf melting is compensated by enhanced snowfall. Although the net surface mass balance of the whole system remains unchanged, the redistribution of mass leads to a dynamic response of the ice sheet due to changes in ice thickness, surface slope, ice-shelf backstress and ice discharge. In particular, we show that such forcing can lead to the counter-intuitive situation of a retreating ice sheet which gains mass, thus having a negative sea-level contribution but smaller ice-sheet extent. The ice-sheet evolution and the corresponding steady states are investigated varying relevant parameters that affect ice properties and bed geometry as well as for different magnitudes of mass redistribution. Furthermore, the ice-sheet response is analyzed with respect to the pattern of applied melting, i.e., the area over which melting is distributed and the location where it is applied. We find throughout the ensemble of simulations that after two decades, melting at the lateral ice-shelf margins induces more ice-shelf thinning, resulting in stronger grounding line retreat and transient ice discharge compared to melting adjacent to the central grounding-line section. Analyzing changes in ice-shelf backstress with respect to changes in the ice-shelf length and mean thickness, respectively, we show that a thickness change has up to four times more influence on the backstress of the ice shelf than a length change. Text Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Copernicus Publications: E-Journals Antarctic The Antarctic |
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Copernicus Publications: E-Journals |
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English |
description |
Surface accumulation and sub-ice-shelf melting are key drivers for the flow dynamics of the Antarctic Ice Sheet and are most likely to change under future warming which leads to 1) higher snowfall and 2) stronger melting below ice shelves. Here we carry out conceptual simulations in which an equilibrium ice-sheet-shelf system is perturbed such that the increased sub-shelf melting is compensated by enhanced snowfall. Although the net surface mass balance of the whole system remains unchanged, the redistribution of mass leads to a dynamic response of the ice sheet due to changes in ice thickness, surface slope, ice-shelf backstress and ice discharge. In particular, we show that such forcing can lead to the counter-intuitive situation of a retreating ice sheet which gains mass, thus having a negative sea-level contribution but smaller ice-sheet extent. The ice-sheet evolution and the corresponding steady states are investigated varying relevant parameters that affect ice properties and bed geometry as well as for different magnitudes of mass redistribution. Furthermore, the ice-sheet response is analyzed with respect to the pattern of applied melting, i.e., the area over which melting is distributed and the location where it is applied. We find throughout the ensemble of simulations that after two decades, melting at the lateral ice-shelf margins induces more ice-shelf thinning, resulting in stronger grounding line retreat and transient ice discharge compared to melting adjacent to the central grounding-line section. Analyzing changes in ice-shelf backstress with respect to changes in the ice-shelf length and mean thickness, respectively, we show that a thickness change has up to four times more influence on the backstress of the ice shelf than a length change. |
format |
Text |
author |
Feldmann, Johannes Reese, Ronja Winkelmann, Ricarda Levermann, Anders |
spellingShingle |
Feldmann, Johannes Reese, Ronja Winkelmann, Ricarda Levermann, Anders Snowfall versus sub-shelf melt: response of an idealized 3D ice-sheet-shelf system to mass redistribution |
author_facet |
Feldmann, Johannes Reese, Ronja Winkelmann, Ricarda Levermann, Anders |
author_sort |
Feldmann, Johannes |
title |
Snowfall versus sub-shelf melt: response of an idealized 3D ice-sheet-shelf system to mass redistribution |
title_short |
Snowfall versus sub-shelf melt: response of an idealized 3D ice-sheet-shelf system to mass redistribution |
title_full |
Snowfall versus sub-shelf melt: response of an idealized 3D ice-sheet-shelf system to mass redistribution |
title_fullStr |
Snowfall versus sub-shelf melt: response of an idealized 3D ice-sheet-shelf system to mass redistribution |
title_full_unstemmed |
Snowfall versus sub-shelf melt: response of an idealized 3D ice-sheet-shelf system to mass redistribution |
title_sort |
snowfall versus sub-shelf melt: response of an idealized 3d ice-sheet-shelf system to mass redistribution |
publishDate |
2018 |
url |
https://doi.org/10.5194/tc-2018-109 https://tc.copernicus.org/preprints/tc-2018-109/ |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
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-2018-109 https://tc.copernicus.org/preprints/tc-2018-109/ |
op_doi |
https://doi.org/10.5194/tc-2018-109 |
_version_ |
1766262129639292928 |