Rapid basal melting of the Greenland Ice Sheet from surface meltwater drainage.
Subglacial hydrologic systems regulate ice sheet flow, causing acceleration or deceleration, depending on hydraulic efficiency and the rate at which surface meltwater is delivered to the bed. Because these systems are rarely observed, ice sheet basal drainage represents a poorly integrated and uncer...
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Proceedings of the National Academy of Sciences
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ftunivcam:oai:www.repository.cam.ac.uk:1810/331405 2024-01-14T10:07:02+01:00 Rapid basal melting of the Greenland Ice Sheet from surface meltwater drainage. Young, Tun Christoffersen, Poul Bougamont, Marion Tulaczyk, Slawek M Hubbard, Bryn Mankoff, Kenneth D Nicholls, Keith W Stewart, Craig L 2021-12-13T13:13:31Z application/pdf https://www.repository.cam.ac.uk/handle/1810/331405 https://doi.org/10.17863/CAM.78858 eng eng Proceedings of the National Academy of Sciences Department of Geography Proc Natl Acad Sci U S A https://doi.org/10.17863/CAM.80852 https://www.repository.cam.ac.uk/handle/1810/331405 doi:10.17863/CAM.78858 Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/ Article 2021 ftunivcam https://doi.org/10.17863/CAM.7885810.17863/CAM.80852 2023-12-21T23:27:06Z Subglacial hydrologic systems regulate ice sheet flow, causing acceleration or deceleration, depending on hydraulic efficiency and the rate at which surface meltwater is delivered to the bed. Because these systems are rarely observed, ice sheet basal drainage represents a poorly integrated and uncertain component of models used to predict sea level changes. Here, we report radar-derived basal melt rates and unexpectedly warm subglacial conditions beneath a large Greenlandic outlet glacier. The basal melt rates averaged 14 mm ⋅d-1 over 4 months, peaking at 57 mm ⋅d-1 when basal water temperature reached +0.88 ∘C in a nearby borehole. We attribute both observations to the conversion of potential energy of surface water to heat in the basal drainage system, which peaked during a period of rainfall and intense surface melting. Our findings reveal limitations in the theory of channel formation, and we show that viscous dissipation far surpasses other basal heat sources, even in a distributed, high-pressure system. EU Horizon 2020 Article in Journal/Newspaper glacier Greenland greenlandic Ice Sheet Apollo - University of Cambridge Repository Greenland |
institution |
Open Polar |
collection |
Apollo - University of Cambridge Repository |
op_collection_id |
ftunivcam |
language |
English |
description |
Subglacial hydrologic systems regulate ice sheet flow, causing acceleration or deceleration, depending on hydraulic efficiency and the rate at which surface meltwater is delivered to the bed. Because these systems are rarely observed, ice sheet basal drainage represents a poorly integrated and uncertain component of models used to predict sea level changes. Here, we report radar-derived basal melt rates and unexpectedly warm subglacial conditions beneath a large Greenlandic outlet glacier. The basal melt rates averaged 14 mm ⋅d-1 over 4 months, peaking at 57 mm ⋅d-1 when basal water temperature reached +0.88 ∘C in a nearby borehole. We attribute both observations to the conversion of potential energy of surface water to heat in the basal drainage system, which peaked during a period of rainfall and intense surface melting. Our findings reveal limitations in the theory of channel formation, and we show that viscous dissipation far surpasses other basal heat sources, even in a distributed, high-pressure system. EU Horizon 2020 |
format |
Article in Journal/Newspaper |
author |
Young, Tun Christoffersen, Poul Bougamont, Marion Tulaczyk, Slawek M Hubbard, Bryn Mankoff, Kenneth D Nicholls, Keith W Stewart, Craig L |
spellingShingle |
Young, Tun Christoffersen, Poul Bougamont, Marion Tulaczyk, Slawek M Hubbard, Bryn Mankoff, Kenneth D Nicholls, Keith W Stewart, Craig L Rapid basal melting of the Greenland Ice Sheet from surface meltwater drainage. |
author_facet |
Young, Tun Christoffersen, Poul Bougamont, Marion Tulaczyk, Slawek M Hubbard, Bryn Mankoff, Kenneth D Nicholls, Keith W Stewart, Craig L |
author_sort |
Young, Tun |
title |
Rapid basal melting of the Greenland Ice Sheet from surface meltwater drainage. |
title_short |
Rapid basal melting of the Greenland Ice Sheet from surface meltwater drainage. |
title_full |
Rapid basal melting of the Greenland Ice Sheet from surface meltwater drainage. |
title_fullStr |
Rapid basal melting of the Greenland Ice Sheet from surface meltwater drainage. |
title_full_unstemmed |
Rapid basal melting of the Greenland Ice Sheet from surface meltwater drainage. |
title_sort |
rapid basal melting of the greenland ice sheet from surface meltwater drainage. |
publisher |
Proceedings of the National Academy of Sciences |
publishDate |
2021 |
url |
https://www.repository.cam.ac.uk/handle/1810/331405 https://doi.org/10.17863/CAM.78858 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
glacier Greenland greenlandic Ice Sheet |
genre_facet |
glacier Greenland greenlandic Ice Sheet |
op_relation |
https://doi.org/10.17863/CAM.80852 https://www.repository.cam.ac.uk/handle/1810/331405 doi:10.17863/CAM.78858 |
op_rights |
Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.17863/CAM.7885810.17863/CAM.80852 |
_version_ |
1788061453791526912 |