A unified model for transient subglacial water pressure and basal sliding
Abstract Changes in water pressure at the beds of glaciers greatly modify their sliding rate, affecting rates of ice mass loss and sea level change. However, there is still no agreement about the physics of subglacial sliding or how water affects it. Here, we present a new simplified physical model...
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Cambridge University Press (CUP)
2021
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Online Access: | http://dx.doi.org/10.1017/jog.2021.103 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143021001039 |
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crcambridgeupr:10.1017/jog.2021.103 2024-09-30T14:35:23+00:00 A unified model for transient subglacial water pressure and basal sliding Tsai, Victor C. Smith, Laurence C. Gardner, Alex S. Seroussi, Helene National Aeronautics and Space Administration 2021 http://dx.doi.org/10.1017/jog.2021.103 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143021001039 en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0/ Journal of Glaciology volume 68, issue 268, page 390-400 ISSN 0022-1430 1727-5652 journal-article 2021 crcambridgeupr https://doi.org/10.1017/jog.2021.103 2024-09-18T04:03:15Z Abstract Changes in water pressure at the beds of glaciers greatly modify their sliding rate, affecting rates of ice mass loss and sea level change. However, there is still no agreement about the physics of subglacial sliding or how water affects it. Here, we present a new simplified physical model for the effect of transient subglacial hydrology on basal ice velocity. This model assumes that a fraction of the glacier bed is connected by an active hydrologic system that, when averaged over an appropriate scale, is governed by two parameters with limited spatial variability. The sliding model is reminiscent of Budd's empirical sliding law but with fundamental differences including a dependence on the fractional area of the active hydrologic system. With periodic surface meltwater forcing, the model displays classic diffusion-wave behavior, with a downstream time lag and decay of subglacial water pressure perturbations. Testing the model against Greenland observations suggests that, despite its simplicity, it captures key features of observed proglacial discharges and ice velocities with reasonable physical parameter values. Given these encouraging findings, including this sliding model in predictive ice-sheet models may improve their ability to predict time-evolving velocities and associated sea level change and reduce the related uncertainties. Article in Journal/Newspaper glacier Greenland Ice Sheet Journal of Glaciology Cambridge University Press Greenland Journal of Glaciology 1 11 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
Abstract Changes in water pressure at the beds of glaciers greatly modify their sliding rate, affecting rates of ice mass loss and sea level change. However, there is still no agreement about the physics of subglacial sliding or how water affects it. Here, we present a new simplified physical model for the effect of transient subglacial hydrology on basal ice velocity. This model assumes that a fraction of the glacier bed is connected by an active hydrologic system that, when averaged over an appropriate scale, is governed by two parameters with limited spatial variability. The sliding model is reminiscent of Budd's empirical sliding law but with fundamental differences including a dependence on the fractional area of the active hydrologic system. With periodic surface meltwater forcing, the model displays classic diffusion-wave behavior, with a downstream time lag and decay of subglacial water pressure perturbations. Testing the model against Greenland observations suggests that, despite its simplicity, it captures key features of observed proglacial discharges and ice velocities with reasonable physical parameter values. Given these encouraging findings, including this sliding model in predictive ice-sheet models may improve their ability to predict time-evolving velocities and associated sea level change and reduce the related uncertainties. |
author2 |
National Aeronautics and Space Administration |
format |
Article in Journal/Newspaper |
author |
Tsai, Victor C. Smith, Laurence C. Gardner, Alex S. Seroussi, Helene |
spellingShingle |
Tsai, Victor C. Smith, Laurence C. Gardner, Alex S. Seroussi, Helene A unified model for transient subglacial water pressure and basal sliding |
author_facet |
Tsai, Victor C. Smith, Laurence C. Gardner, Alex S. Seroussi, Helene |
author_sort |
Tsai, Victor C. |
title |
A unified model for transient subglacial water pressure and basal sliding |
title_short |
A unified model for transient subglacial water pressure and basal sliding |
title_full |
A unified model for transient subglacial water pressure and basal sliding |
title_fullStr |
A unified model for transient subglacial water pressure and basal sliding |
title_full_unstemmed |
A unified model for transient subglacial water pressure and basal sliding |
title_sort |
unified model for transient subglacial water pressure and basal sliding |
publisher |
Cambridge University Press (CUP) |
publishDate |
2021 |
url |
http://dx.doi.org/10.1017/jog.2021.103 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143021001039 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
glacier Greenland Ice Sheet Journal of Glaciology |
genre_facet |
glacier Greenland Ice Sheet Journal of Glaciology |
op_source |
Journal of Glaciology volume 68, issue 268, page 390-400 ISSN 0022-1430 1727-5652 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/jog.2021.103 |
container_title |
Journal of Glaciology |
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1 |
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11 |
_version_ |
1811638680697176064 |