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...
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ftdoajarticles:oai:doaj.org/article:70a6ef54f17440f68210124ad57f2c85 2023-05-15T16:03:54+02:00 Exceptionally high heat flux needed to sustain the Northeast Greenland Ice Stream S. Smith-Johnsen B. de Fleurian N. Schlegel H. Seroussi K. Nisancioglu 2020-03-01T00:00:00Z https://doi.org/10.5194/tc-14-841-2020 https://doaj.org/article/70a6ef54f17440f68210124ad57f2c85 EN eng Copernicus Publications https://www.the-cryosphere.net/14/841/2020/tc-14-841-2020.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-14-841-2020 1994-0416 1994-0424 https://doaj.org/article/70a6ef54f17440f68210124ad57f2c85 The Cryosphere, Vol 14, Pp 841-854 (2020) Environmental sciences GE1-350 Geology QE1-996.5 article 2020 ftdoajarticles https://doi.org/10.5194/tc-14-841-2020 2022-12-31T03:10:35Z 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. Article in Journal/Newspaper East Greenland East Greenland Ice-core Project Greenland Greenland ice core Greenland Ice core Project ice core Ice Sheet The Cryosphere Directory of Open Access Journals: DOAJ Articles Greenland The Cryosphere 14 3 841 854 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 S. Smith-Johnsen B. de Fleurian N. Schlegel H. Seroussi K. Nisancioglu Exceptionally high heat flux needed to sustain the Northeast Greenland Ice Stream |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
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 |
Article in Journal/Newspaper |
author |
S. Smith-Johnsen B. de Fleurian N. Schlegel H. Seroussi K. Nisancioglu |
author_facet |
S. Smith-Johnsen B. de Fleurian N. Schlegel H. Seroussi K. Nisancioglu |
author_sort |
S. Smith-Johnsen |
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 |
publisher |
Copernicus Publications |
publishDate |
2020 |
url |
https://doi.org/10.5194/tc-14-841-2020 https://doaj.org/article/70a6ef54f17440f68210124ad57f2c85 |
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 The Cryosphere |
genre_facet |
East Greenland East Greenland Ice-core Project Greenland Greenland ice core Greenland Ice core Project ice core Ice Sheet The Cryosphere |
op_source |
The Cryosphere, Vol 14, Pp 841-854 (2020) |
op_relation |
https://www.the-cryosphere.net/14/841/2020/tc-14-841-2020.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-14-841-2020 1994-0416 1994-0424 https://doaj.org/article/70a6ef54f17440f68210124ad57f2c85 |
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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1766399588185407488 |