Shear-margin melting causes stronger transient ice discharge than ice-stream melting in idealized simulations
Basal ice-shelf melting is the key driver of Antarctica's increasing sea-level contribution. In diminishing the buttressing force of the ice shelves that fringe the ice sheet, the melting increases the ice discharge into the ocean. Here we contrast the influence of basal melting in two differen...
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ftleibnizopen:oai:oai.leibnizopen.de:GFu78IgBdbrxVwz6mJws 2023-07-16T03:54:36+02:00 Shear-margin melting causes stronger transient ice discharge than ice-stream melting in idealized simulations Feldmann, Johannes Reese, Ronja Winkelmann, Ricarda Levermann, Anders 2022 application/pdf https://oa.tib.eu/renate/handle/123456789/11863 https://doi.org/10.34657/10896 eng eng Katlenburg-Lindau : Copernicus CC BY 4.0 Unported https://creativecommons.org/licenses/by/4.0 The Cryosphere : TC 16 (2022), Nr. 5 basal melting ice shelf ice stream simulation 910 article Text 2022 ftleibnizopen https://doi.org/10.34657/10896 2023-06-25T23:15:39Z Basal ice-shelf melting is the key driver of Antarctica's increasing sea-level contribution. In diminishing the buttressing force of the ice shelves that fringe the ice sheet, the melting increases the ice discharge into the ocean. Here we contrast the influence of basal melting in two different ice-shelf regions on the time-dependent response of an isothermal, inherently buttressed ice-sheet-shelf system. In the idealized numerical simulations, the basal-melt perturbations are applied close to the grounding line in the ice-shelf's (1) ice-stream region, where the ice shelf is fed by the fastest ice masses that stream through the upstream bed trough and (2) shear margins, where the ice flow is slower. The results show that melting below one or both of the shear margins can cause a decadal to centennial increase in ice discharge that is more than twice as large compared to a similar perturbation in the ice-stream region. We attribute this to the fact that melt-induced ice-shelf thinning in the central grounding-line region is attenuated very effectively by the fast flow of the central ice stream. In contrast, the much slower ice dynamics in the lateral shear margins of the ice shelf facilitate sustained ice-shelf thinning and thereby foster buttressing reduction. Regardless of the melt location, a higher melt concentration toward the grounding line generally goes along with a stronger response. Our results highlight the vulnerability of outlet glaciers to basal melting in stagnant, buttressing-relevant ice-shelf regions, a mechanism that may gain importance under future global warming. Leibniz_Fonds publishedVersion Article in Journal/Newspaper Antarc* Ice Sheet Ice Shelf Ice Shelves The Cryosphere LeibnizOpen (The Leibniz Association) |
institution |
Open Polar |
collection |
LeibnizOpen (The Leibniz Association) |
op_collection_id |
ftleibnizopen |
language |
English |
topic |
basal melting ice shelf ice stream simulation 910 |
spellingShingle |
basal melting ice shelf ice stream simulation 910 Feldmann, Johannes Reese, Ronja Winkelmann, Ricarda Levermann, Anders Shear-margin melting causes stronger transient ice discharge than ice-stream melting in idealized simulations |
topic_facet |
basal melting ice shelf ice stream simulation 910 |
description |
Basal ice-shelf melting is the key driver of Antarctica's increasing sea-level contribution. In diminishing the buttressing force of the ice shelves that fringe the ice sheet, the melting increases the ice discharge into the ocean. Here we contrast the influence of basal melting in two different ice-shelf regions on the time-dependent response of an isothermal, inherently buttressed ice-sheet-shelf system. In the idealized numerical simulations, the basal-melt perturbations are applied close to the grounding line in the ice-shelf's (1) ice-stream region, where the ice shelf is fed by the fastest ice masses that stream through the upstream bed trough and (2) shear margins, where the ice flow is slower. The results show that melting below one or both of the shear margins can cause a decadal to centennial increase in ice discharge that is more than twice as large compared to a similar perturbation in the ice-stream region. We attribute this to the fact that melt-induced ice-shelf thinning in the central grounding-line region is attenuated very effectively by the fast flow of the central ice stream. In contrast, the much slower ice dynamics in the lateral shear margins of the ice shelf facilitate sustained ice-shelf thinning and thereby foster buttressing reduction. Regardless of the melt location, a higher melt concentration toward the grounding line generally goes along with a stronger response. Our results highlight the vulnerability of outlet glaciers to basal melting in stagnant, buttressing-relevant ice-shelf regions, a mechanism that may gain importance under future global warming. Leibniz_Fonds publishedVersion |
format |
Article in Journal/Newspaper |
author |
Feldmann, Johannes Reese, Ronja Winkelmann, Ricarda Levermann, Anders |
author_facet |
Feldmann, Johannes Reese, Ronja Winkelmann, Ricarda Levermann, Anders |
author_sort |
Feldmann, Johannes |
title |
Shear-margin melting causes stronger transient ice discharge than ice-stream melting in idealized simulations |
title_short |
Shear-margin melting causes stronger transient ice discharge than ice-stream melting in idealized simulations |
title_full |
Shear-margin melting causes stronger transient ice discharge than ice-stream melting in idealized simulations |
title_fullStr |
Shear-margin melting causes stronger transient ice discharge than ice-stream melting in idealized simulations |
title_full_unstemmed |
Shear-margin melting causes stronger transient ice discharge than ice-stream melting in idealized simulations |
title_sort |
shear-margin melting causes stronger transient ice discharge than ice-stream melting in idealized simulations |
publisher |
Katlenburg-Lindau : Copernicus |
publishDate |
2022 |
url |
https://oa.tib.eu/renate/handle/123456789/11863 https://doi.org/10.34657/10896 |
genre |
Antarc* Ice Sheet Ice Shelf Ice Shelves The Cryosphere |
genre_facet |
Antarc* Ice Sheet Ice Shelf Ice Shelves The Cryosphere |
op_source |
The Cryosphere : TC 16 (2022), Nr. 5 |
op_rights |
CC BY 4.0 Unported https://creativecommons.org/licenses/by/4.0 |
op_doi |
https://doi.org/10.34657/10896 |
_version_ |
1771540862061248512 |