Sensitivity of submarine melting on North East Greenland towards ocean forcing
The Nioghalvfjerdsbræ (79NG) is a floating ice tongue on Northeast Greenland draining a large part of the Greenland Ice Sheet. A CTD profile from a rift on the ice tongue close to the northern front shows that Atlantic Water (AW) is present in the cavity below, with maximum temperature of approximat...
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ftcopernicus:oai:publications.copernicus.org:tcd74696 2023-05-15T16:03:53+02:00 Sensitivity of submarine melting on North East Greenland towards ocean forcing Anhaus, Philipp Smedsrud, Lars H. Årthun, Marius Straneo, Fiammetta 2019-04-10 application/pdf https://doi.org/10.5194/tc-2019-35 https://tc.copernicus.org/preprints/tc-2019-35/ eng eng doi:10.5194/tc-2019-35 https://tc.copernicus.org/preprints/tc-2019-35/ eISSN: 1994-0424 Text 2019 ftcopernicus https://doi.org/10.5194/tc-2019-35 2020-07-20T16:22:53Z The Nioghalvfjerdsbræ (79NG) is a floating ice tongue on Northeast Greenland draining a large part of the Greenland Ice Sheet. A CTD profile from a rift on the ice tongue close to the northern front shows that Atlantic Water (AW) is present in the cavity below, with maximum temperature of approximately 1 °C at 610 m depth. The AW present in the cavity thus has the potential to drive submarine melting along the ice base. Here, we simulate melt rates from the 79NG with a 1D numerical Ice Shelf Water (ISW) plume model. A meltwater plume is initiated at the grounding line depth (600 m) and rises along the ice base as a result of buoyancy contrast to the underlying AW. Ice melts as the plume entrains the warm AW. Maximum simulated melt rates are 50–76 m yr −1 within 10 km of the grounding line. Within a zone of rapid decay between 10 km and 20 km melt rates drop to roughly 6 m yr −1 . Further downstream, melt rates are between 15 m yr −1 and 6 m yr −1 . The melt-rate sensitivity to variations in AW temperatures is assessed by forcing the model with AW temperatures between 0.1–1.4 °C, as identified from the ECCOv4 ocean state estimate. The melt rates increase linearly with rising AW temperature, ranging from 10 m yr −1 to 21 m yr −1 along the centerline. The corresponding freshwater flux ranges between 11 km 3 yr −1 (0.4 mSv) and 30 km 3 yr −1 (1.0 mSv), which is 5 % and 12 % of the total freshwater flux from the Greenland Ice Sheet since 1995, respectively. Our results improve the understanding of processes driving submarine melting of marine-terminating glaciers around Greenland, and its sensitivity to changing ocean conditions. Text East Greenland Greenland Ice Sheet Ice Shelf Copernicus Publications: E-Journals Greenland |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
The Nioghalvfjerdsbræ (79NG) is a floating ice tongue on Northeast Greenland draining a large part of the Greenland Ice Sheet. A CTD profile from a rift on the ice tongue close to the northern front shows that Atlantic Water (AW) is present in the cavity below, with maximum temperature of approximately 1 °C at 610 m depth. The AW present in the cavity thus has the potential to drive submarine melting along the ice base. Here, we simulate melt rates from the 79NG with a 1D numerical Ice Shelf Water (ISW) plume model. A meltwater plume is initiated at the grounding line depth (600 m) and rises along the ice base as a result of buoyancy contrast to the underlying AW. Ice melts as the plume entrains the warm AW. Maximum simulated melt rates are 50–76 m yr −1 within 10 km of the grounding line. Within a zone of rapid decay between 10 km and 20 km melt rates drop to roughly 6 m yr −1 . Further downstream, melt rates are between 15 m yr −1 and 6 m yr −1 . The melt-rate sensitivity to variations in AW temperatures is assessed by forcing the model with AW temperatures between 0.1–1.4 °C, as identified from the ECCOv4 ocean state estimate. The melt rates increase linearly with rising AW temperature, ranging from 10 m yr −1 to 21 m yr −1 along the centerline. The corresponding freshwater flux ranges between 11 km 3 yr −1 (0.4 mSv) and 30 km 3 yr −1 (1.0 mSv), which is 5 % and 12 % of the total freshwater flux from the Greenland Ice Sheet since 1995, respectively. Our results improve the understanding of processes driving submarine melting of marine-terminating glaciers around Greenland, and its sensitivity to changing ocean conditions. |
format |
Text |
author |
Anhaus, Philipp Smedsrud, Lars H. Årthun, Marius Straneo, Fiammetta |
spellingShingle |
Anhaus, Philipp Smedsrud, Lars H. Årthun, Marius Straneo, Fiammetta Sensitivity of submarine melting on North East Greenland towards ocean forcing |
author_facet |
Anhaus, Philipp Smedsrud, Lars H. Årthun, Marius Straneo, Fiammetta |
author_sort |
Anhaus, Philipp |
title |
Sensitivity of submarine melting on North East Greenland towards ocean forcing |
title_short |
Sensitivity of submarine melting on North East Greenland towards ocean forcing |
title_full |
Sensitivity of submarine melting on North East Greenland towards ocean forcing |
title_fullStr |
Sensitivity of submarine melting on North East Greenland towards ocean forcing |
title_full_unstemmed |
Sensitivity of submarine melting on North East Greenland towards ocean forcing |
title_sort |
sensitivity of submarine melting on north east greenland towards ocean forcing |
publishDate |
2019 |
url |
https://doi.org/10.5194/tc-2019-35 https://tc.copernicus.org/preprints/tc-2019-35/ |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
East Greenland Greenland Ice Sheet Ice Shelf |
genre_facet |
East Greenland Greenland Ice Sheet Ice Shelf |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-2019-35 https://tc.copernicus.org/preprints/tc-2019-35/ |
op_doi |
https://doi.org/10.5194/tc-2019-35 |
_version_ |
1766399582272487424 |