Exceptionally high heat flux needed to sustain the Northeast Greenland Ice Stream
The Northeast Greenland Ice Stream (NEGIS) currently drains more than 10 % of the Greenland Ice Sheet area and has recently undergone significant dynamic changes. It is therefore critical to accurately represent this feature when assessing the future contribution of Greenland to sea level rise. At p...
Published in: | The Cryosphere |
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Language: | English |
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Online Access: | https://doi.org/10.5194/tc-14-841-2020 https://tc.copernicus.org/articles/14/841/2020/ |
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ftcopernicus:oai:publications.copernicus.org:tc79971 2023-05-15T16:03:53+02:00 Exceptionally high heat flux needed to sustain the Northeast Greenland Ice Stream Smith-Johnsen, Silje Fleurian, Basile Schlegel, Nicole Seroussi, Helene Nisancioglu, Kerim 2020-03-06 info:eu-repo/semantics/application/pdf https://doi.org/10.5194/tc-14-841-2020 https://tc.copernicus.org/articles/14/841/2020/ eng eng info:eu-repo/grantAgreement/EC/FP7/610055 doi:10.5194/tc-14-841-2020 https://tc.copernicus.org/articles/14/841/2020/ info:eu-repo/semantics/openAccess eISSN: 1994-0424 info:eu-repo/semantics/Text 2020 ftcopernicus https://doi.org/10.5194/tc-14-841-2020 2020-07-20T16:22:22Z The Northeast Greenland Ice Stream (NEGIS) currently drains more than 10 % of the Greenland Ice Sheet area and has recently undergone significant dynamic changes. It is therefore critical to accurately represent this feature when assessing the future contribution of Greenland to sea level rise. At present, NEGIS is reproduced in ice sheet models by inferring basal conditions using observed surface velocities. This approach helps estimate conditions at the base of the ice sheet but cannot be used to estimate the evolution of basal drag in time, so it is not a good representation of the evolution of the ice sheet in future climate warming scenarios. NEGIS is suggested to be initiated by a geothermal heat flux anomaly close to the ice divide, left behind by the movement of Greenland over the Icelandic plume. However, the heat flux underneath the ice sheet is largely unknown, except for a few direct measurements from deep ice core drill sites. Using the Ice Sheet System Model (ISSM), with ice dynamics coupled to a subglacial hydrology model, we investigate the possibility of initiating NEGIS by inserting heat flux anomalies with various locations and intensities. In our model experiment, a minimum heat flux value of 970 mW m −2 located close to the East Greenland Ice-core Project (EGRIP) is required locally to reproduce the observed NEGIS velocities, giving basal melt rates consistent with previous estimates. The value cannot be attributed to geothermal heat flux alone and we suggest hydrothermal circulation as a potential explanation for the high local heat flux. By including high heat flux and the effect of water on sliding, we successfully reproduce the main characteristics of NEGIS in an ice sheet model without using data assimilation. Other/Unknown Material East Greenland East Greenland Ice-core Project Greenland Greenland ice core Greenland Ice core Project ice core Ice Sheet Copernicus Publications: E-Journals Greenland The Cryosphere 14 3 841 854 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
The Northeast Greenland Ice Stream (NEGIS) currently drains more than 10 % of the Greenland Ice Sheet area and has recently undergone significant dynamic changes. It is therefore critical to accurately represent this feature when assessing the future contribution of Greenland to sea level rise. At present, NEGIS is reproduced in ice sheet models by inferring basal conditions using observed surface velocities. This approach helps estimate conditions at the base of the ice sheet but cannot be used to estimate the evolution of basal drag in time, so it is not a good representation of the evolution of the ice sheet in future climate warming scenarios. NEGIS is suggested to be initiated by a geothermal heat flux anomaly close to the ice divide, left behind by the movement of Greenland over the Icelandic plume. However, the heat flux underneath the ice sheet is largely unknown, except for a few direct measurements from deep ice core drill sites. Using the Ice Sheet System Model (ISSM), with ice dynamics coupled to a subglacial hydrology model, we investigate the possibility of initiating NEGIS by inserting heat flux anomalies with various locations and intensities. In our model experiment, a minimum heat flux value of 970 mW m −2 located close to the East Greenland Ice-core Project (EGRIP) is required locally to reproduce the observed NEGIS velocities, giving basal melt rates consistent with previous estimates. The value cannot be attributed to geothermal heat flux alone and we suggest hydrothermal circulation as a potential explanation for the high local heat flux. By including high heat flux and the effect of water on sliding, we successfully reproduce the main characteristics of NEGIS in an ice sheet model without using data assimilation. |
format |
Other/Unknown Material |
author |
Smith-Johnsen, Silje Fleurian, Basile Schlegel, Nicole Seroussi, Helene Nisancioglu, Kerim |
spellingShingle |
Smith-Johnsen, Silje Fleurian, Basile Schlegel, Nicole Seroussi, Helene Nisancioglu, Kerim Exceptionally high heat flux needed to sustain the Northeast Greenland Ice Stream |
author_facet |
Smith-Johnsen, Silje Fleurian, Basile Schlegel, Nicole Seroussi, Helene Nisancioglu, Kerim |
author_sort |
Smith-Johnsen, Silje |
title |
Exceptionally high heat flux needed to sustain the Northeast Greenland Ice Stream |
title_short |
Exceptionally high heat flux needed to sustain the Northeast Greenland Ice Stream |
title_full |
Exceptionally high heat flux needed to sustain the Northeast Greenland Ice Stream |
title_fullStr |
Exceptionally high heat flux needed to sustain the Northeast Greenland Ice Stream |
title_full_unstemmed |
Exceptionally high heat flux needed to sustain the Northeast Greenland Ice Stream |
title_sort |
exceptionally high heat flux needed to sustain the northeast greenland ice stream |
publishDate |
2020 |
url |
https://doi.org/10.5194/tc-14-841-2020 https://tc.copernicus.org/articles/14/841/2020/ |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
East Greenland East Greenland Ice-core Project Greenland Greenland ice core Greenland Ice core Project ice core Ice Sheet |
genre_facet |
East Greenland East Greenland Ice-core Project Greenland Greenland ice core Greenland Ice core Project ice core Ice Sheet |
op_source |
eISSN: 1994-0424 |
op_relation |
info:eu-repo/grantAgreement/EC/FP7/610055 doi:10.5194/tc-14-841-2020 https://tc.copernicus.org/articles/14/841/2020/ |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/tc-14-841-2020 |
container_title |
The Cryosphere |
container_volume |
14 |
container_issue |
3 |
container_start_page |
841 |
op_container_end_page |
854 |
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1766399581918068736 |