Precursor of disintegration of Greenland's largest floating ice tongue
The largest floating tongue of Greenland’s ice sheet, Nioghalvfjerdsbræ, has so far been relatively stable with respect to areal retreat. Curiously, it experienced significant less thinning and ice flow acceleration than its neighbour Zacharias Isbræ. Draining more than 6 % of the ice sheet, Nioghal...
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ftcopernicus:oai:publications.copernicus.org:tcd106042 2023-05-15T16:40:38+02:00 Precursor of disintegration of Greenland's largest floating ice tongue Humbert, Angelika Helm, Veit Neckel, Niklas Zeising, Ole Rückamp, Martin Khan, Shfaqat Abbas Loebel, Erik Gross, Dietmar Sondershaus, Rabea Müller, Ralf 2022-09-19 application/pdf https://doi.org/10.5194/tc-2022-171 https://tc.copernicus.org/preprints/tc-2022-171/ eng eng doi:10.5194/tc-2022-171 https://tc.copernicus.org/preprints/tc-2022-171/ eISSN: 1994-0424 Text 2022 ftcopernicus https://doi.org/10.5194/tc-2022-171 2022-09-26T16:22:42Z The largest floating tongue of Greenland’s ice sheet, Nioghalvfjerdsbræ, has so far been relatively stable with respect to areal retreat. Curiously, it experienced significant less thinning and ice flow acceleration than its neighbour Zacharias Isbræ. Draining more than 6 % of the ice sheet, Nioghalvfjerdsbræ might become a large contributor to sea level rise in the future. Therefore, the stability of the floating tongue is a focus of this study. We employ a suite of observational methods to detect recent changes. We found that the calving style has changed at the southern part of the eastern calving front from normal tongue-type calving to a crack evolution initiated at frontal ice rises reaching 5–7 km and progressing further upstream compared to 2010. The calving front area is further weakened by a substantial increase of a zone of fragments and open water at the tongue’s southern margin, leading to the formation of a narrow ice bridge. These geometric and mechanical changes are a precursor of instability of the floating tongue. We complement our study by numerical ice flow simulations to estimate the impact of future break-up or disintegration events on the ice discharge. These idealised scenarios reveal that a loss of the south-eastern area would lead to 1 % of increase of ice discharge at the grounding line, while a sudden collapse of the frontal area (46 % of the floating tongue area) will enhance the ice discharge by 8.3 % due to loss in buttressing. Text Ice Sheet Copernicus Publications: E-Journals |
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Copernicus Publications: E-Journals |
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English |
description |
The largest floating tongue of Greenland’s ice sheet, Nioghalvfjerdsbræ, has so far been relatively stable with respect to areal retreat. Curiously, it experienced significant less thinning and ice flow acceleration than its neighbour Zacharias Isbræ. Draining more than 6 % of the ice sheet, Nioghalvfjerdsbræ might become a large contributor to sea level rise in the future. Therefore, the stability of the floating tongue is a focus of this study. We employ a suite of observational methods to detect recent changes. We found that the calving style has changed at the southern part of the eastern calving front from normal tongue-type calving to a crack evolution initiated at frontal ice rises reaching 5–7 km and progressing further upstream compared to 2010. The calving front area is further weakened by a substantial increase of a zone of fragments and open water at the tongue’s southern margin, leading to the formation of a narrow ice bridge. These geometric and mechanical changes are a precursor of instability of the floating tongue. We complement our study by numerical ice flow simulations to estimate the impact of future break-up or disintegration events on the ice discharge. These idealised scenarios reveal that a loss of the south-eastern area would lead to 1 % of increase of ice discharge at the grounding line, while a sudden collapse of the frontal area (46 % of the floating tongue area) will enhance the ice discharge by 8.3 % due to loss in buttressing. |
format |
Text |
author |
Humbert, Angelika Helm, Veit Neckel, Niklas Zeising, Ole Rückamp, Martin Khan, Shfaqat Abbas Loebel, Erik Gross, Dietmar Sondershaus, Rabea Müller, Ralf |
spellingShingle |
Humbert, Angelika Helm, Veit Neckel, Niklas Zeising, Ole Rückamp, Martin Khan, Shfaqat Abbas Loebel, Erik Gross, Dietmar Sondershaus, Rabea Müller, Ralf Precursor of disintegration of Greenland's largest floating ice tongue |
author_facet |
Humbert, Angelika Helm, Veit Neckel, Niklas Zeising, Ole Rückamp, Martin Khan, Shfaqat Abbas Loebel, Erik Gross, Dietmar Sondershaus, Rabea Müller, Ralf |
author_sort |
Humbert, Angelika |
title |
Precursor of disintegration of Greenland's largest floating ice tongue |
title_short |
Precursor of disintegration of Greenland's largest floating ice tongue |
title_full |
Precursor of disintegration of Greenland's largest floating ice tongue |
title_fullStr |
Precursor of disintegration of Greenland's largest floating ice tongue |
title_full_unstemmed |
Precursor of disintegration of Greenland's largest floating ice tongue |
title_sort |
precursor of disintegration of greenland's largest floating ice tongue |
publishDate |
2022 |
url |
https://doi.org/10.5194/tc-2022-171 https://tc.copernicus.org/preprints/tc-2022-171/ |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-2022-171 https://tc.copernicus.org/preprints/tc-2022-171/ |
op_doi |
https://doi.org/10.5194/tc-2022-171 |
_version_ |
1766031039553077248 |