Evaluating different geothermal heat-flow maps as basal boundary conditions during spin-up of the Greenland ice sheet
There is currently poor scientific agreement on whether the ice–bed interface is frozen or thawed beneath approximately one third of the Greenland ice sheet. This disagreement in basal thermal state results, at least partly, from differences in the subglacial geothermal heat-flow basal boundary cond...
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ftdoajarticles:oai:doaj.org/article:6050159ef68a4a6f947cc59289590521 2024-02-27T08:41:06+00:00 Evaluating different geothermal heat-flow maps as basal boundary conditions during spin-up of the Greenland ice sheet T. Zhang W. Colgan A. Wansing A. Løkkegaard G. Leguy W. H. Lipscomb C. Xiao 2024-01-01T00:00:00Z https://doi.org/10.5194/tc-18-387-2024 https://doaj.org/article/6050159ef68a4a6f947cc59289590521 EN eng Copernicus Publications https://tc.copernicus.org/articles/18/387/2024/tc-18-387-2024.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-18-387-2024 1994-0416 1994-0424 https://doaj.org/article/6050159ef68a4a6f947cc59289590521 The Cryosphere, Vol 18, Pp 387-402 (2024) Environmental sciences GE1-350 Geology QE1-996.5 article 2024 ftdoajarticles https://doi.org/10.5194/tc-18-387-2024 2024-01-28T01:36:58Z There is currently poor scientific agreement on whether the ice–bed interface is frozen or thawed beneath approximately one third of the Greenland ice sheet. This disagreement in basal thermal state results, at least partly, from differences in the subglacial geothermal heat-flow basal boundary condition used in different ice-flow models. Here, we employ seven widely used Greenland geothermal heat-flow maps in 10 000-year spin-ups of the Community Ice Sheet Model (CISM). We perform two spin-ups: one nudged toward thickness observations and the other unconstrained. Across the seven heat-flow maps, and regardless of unconstrained or nudged spin-up, the spread in basal ice temperatures exceeds 10 ∘ C over large areas of the ice–bed interface. For a given heat-flow map, the thawed-bed ice-sheet area is consistently larger under unconstrained spin-ups than nudged spin-ups. Under the unconstrained spin-up, thawed-bed area ranges from 33.5 % to 60.0 % across the seven heat-flow maps. Perhaps counterintuitively, the highest iceberg calving fluxes are associated with the lowest heat flows (and vice versa) for both unconstrained and nudged spin-ups. These results highlight the direct, and non-trivial, influence of the heat-flow boundary condition on the simulated equilibrium thermal state of the ice sheet. We suggest that future ice-flow model intercomparisons should employ a range of basal heat-flow maps, and limit direct intercomparisons with simulations using a common heat-flow map. Article in Journal/Newspaper Greenland Ice Sheet The Cryosphere Directory of Open Access Journals: DOAJ Articles Greenland The Cryosphere 18 1 387 402 |
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 T. Zhang W. Colgan A. Wansing A. Løkkegaard G. Leguy W. H. Lipscomb C. Xiao Evaluating different geothermal heat-flow maps as basal boundary conditions during spin-up of the Greenland ice sheet |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
There is currently poor scientific agreement on whether the ice–bed interface is frozen or thawed beneath approximately one third of the Greenland ice sheet. This disagreement in basal thermal state results, at least partly, from differences in the subglacial geothermal heat-flow basal boundary condition used in different ice-flow models. Here, we employ seven widely used Greenland geothermal heat-flow maps in 10 000-year spin-ups of the Community Ice Sheet Model (CISM). We perform two spin-ups: one nudged toward thickness observations and the other unconstrained. Across the seven heat-flow maps, and regardless of unconstrained or nudged spin-up, the spread in basal ice temperatures exceeds 10 ∘ C over large areas of the ice–bed interface. For a given heat-flow map, the thawed-bed ice-sheet area is consistently larger under unconstrained spin-ups than nudged spin-ups. Under the unconstrained spin-up, thawed-bed area ranges from 33.5 % to 60.0 % across the seven heat-flow maps. Perhaps counterintuitively, the highest iceberg calving fluxes are associated with the lowest heat flows (and vice versa) for both unconstrained and nudged spin-ups. These results highlight the direct, and non-trivial, influence of the heat-flow boundary condition on the simulated equilibrium thermal state of the ice sheet. We suggest that future ice-flow model intercomparisons should employ a range of basal heat-flow maps, and limit direct intercomparisons with simulations using a common heat-flow map. |
format |
Article in Journal/Newspaper |
author |
T. Zhang W. Colgan A. Wansing A. Løkkegaard G. Leguy W. H. Lipscomb C. Xiao |
author_facet |
T. Zhang W. Colgan A. Wansing A. Løkkegaard G. Leguy W. H. Lipscomb C. Xiao |
author_sort |
T. Zhang |
title |
Evaluating different geothermal heat-flow maps as basal boundary conditions during spin-up of the Greenland ice sheet |
title_short |
Evaluating different geothermal heat-flow maps as basal boundary conditions during spin-up of the Greenland ice sheet |
title_full |
Evaluating different geothermal heat-flow maps as basal boundary conditions during spin-up of the Greenland ice sheet |
title_fullStr |
Evaluating different geothermal heat-flow maps as basal boundary conditions during spin-up of the Greenland ice sheet |
title_full_unstemmed |
Evaluating different geothermal heat-flow maps as basal boundary conditions during spin-up of the Greenland ice sheet |
title_sort |
evaluating different geothermal heat-flow maps as basal boundary conditions during spin-up of the greenland ice sheet |
publisher |
Copernicus Publications |
publishDate |
2024 |
url |
https://doi.org/10.5194/tc-18-387-2024 https://doaj.org/article/6050159ef68a4a6f947cc59289590521 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice Sheet The Cryosphere |
genre_facet |
Greenland Ice Sheet The Cryosphere |
op_source |
The Cryosphere, Vol 18, Pp 387-402 (2024) |
op_relation |
https://tc.copernicus.org/articles/18/387/2024/tc-18-387-2024.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-18-387-2024 1994-0416 1994-0424 https://doaj.org/article/6050159ef68a4a6f947cc59289590521 |
op_doi |
https://doi.org/10.5194/tc-18-387-2024 |
container_title |
The Cryosphere |
container_volume |
18 |
container_issue |
1 |
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387 |
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402 |
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1792048349267886080 |