Hydraulic run-away: a mechanism for thermally regulated surges of ice sheets
Abstract By using a simple parameterized model of thermomechanically coupled flow in cold ice sheets, together with a physically based sliding law which includes a description of basal drainage, we show that relationships between ice flux and ice thickness can realistically be multi-valued, and henc...
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Language: | English |
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Cambridge University Press (CUP)
1995
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Online Access: | http://dx.doi.org/10.1017/s002214300003478x https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S002214300003478X |
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crcambridgeupr:10.1017/s002214300003478x 2024-09-15T18:11:06+00:00 Hydraulic run-away: a mechanism for thermally regulated surges of ice sheets Fowler, A. C. Johnson, Clare 1995 http://dx.doi.org/10.1017/s002214300003478x https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S002214300003478X en eng Cambridge University Press (CUP) Journal of Glaciology volume 41, issue 139, page 554-561 ISSN 0022-1430 1727-5652 journal-article 1995 crcambridgeupr https://doi.org/10.1017/s002214300003478x 2024-07-17T04:04:14Z Abstract By using a simple parameterized model of thermomechanically coupled flow in cold ice sheets, together with a physically based sliding law which includes a description of basal drainage, we show that relationships between ice flux and ice thickness can realistically be multi-valued, and hence that hydraulically induced surges can occur. We term this mechanism hydraulic run-away , as it relies on the positive feed-back between sliding velocity and basal melt production. For this feedback to operate, it is essential that water pressure increases with water storage. This is consistent with various recent ideas concerning drainage, under ice sheets, be it through a system of canals, a distnbuted film or a subglacial aquifer. For confined flows, such as valley glaciers (e.g. Trapridge Glacier) or topographically constrained ice streams (e.g. Hudson Strait in the Laurentide ice sheet), which are underlain by sufficiently deformable sediment, we can expect thermally regulated surges to occur, while in a laterally unconfined drainage basin (such as that which flows into the Ross Ice Shelf), we might expect ice streams to develop. Article in Journal/Newspaper Hudson Strait Ice Sheet Ice Shelf Journal of Glaciology Ross Ice Shelf Cambridge University Press Journal of Glaciology 41 139 554 561 |
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Open Polar |
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Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
Abstract By using a simple parameterized model of thermomechanically coupled flow in cold ice sheets, together with a physically based sliding law which includes a description of basal drainage, we show that relationships between ice flux and ice thickness can realistically be multi-valued, and hence that hydraulically induced surges can occur. We term this mechanism hydraulic run-away , as it relies on the positive feed-back between sliding velocity and basal melt production. For this feedback to operate, it is essential that water pressure increases with water storage. This is consistent with various recent ideas concerning drainage, under ice sheets, be it through a system of canals, a distnbuted film or a subglacial aquifer. For confined flows, such as valley glaciers (e.g. Trapridge Glacier) or topographically constrained ice streams (e.g. Hudson Strait in the Laurentide ice sheet), which are underlain by sufficiently deformable sediment, we can expect thermally regulated surges to occur, while in a laterally unconfined drainage basin (such as that which flows into the Ross Ice Shelf), we might expect ice streams to develop. |
format |
Article in Journal/Newspaper |
author |
Fowler, A. C. Johnson, Clare |
spellingShingle |
Fowler, A. C. Johnson, Clare Hydraulic run-away: a mechanism for thermally regulated surges of ice sheets |
author_facet |
Fowler, A. C. Johnson, Clare |
author_sort |
Fowler, A. C. |
title |
Hydraulic run-away: a mechanism for thermally regulated surges of ice sheets |
title_short |
Hydraulic run-away: a mechanism for thermally regulated surges of ice sheets |
title_full |
Hydraulic run-away: a mechanism for thermally regulated surges of ice sheets |
title_fullStr |
Hydraulic run-away: a mechanism for thermally regulated surges of ice sheets |
title_full_unstemmed |
Hydraulic run-away: a mechanism for thermally regulated surges of ice sheets |
title_sort |
hydraulic run-away: a mechanism for thermally regulated surges of ice sheets |
publisher |
Cambridge University Press (CUP) |
publishDate |
1995 |
url |
http://dx.doi.org/10.1017/s002214300003478x https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S002214300003478X |
genre |
Hudson Strait Ice Sheet Ice Shelf Journal of Glaciology Ross Ice Shelf |
genre_facet |
Hudson Strait Ice Sheet Ice Shelf Journal of Glaciology Ross Ice Shelf |
op_source |
Journal of Glaciology volume 41, issue 139, page 554-561 ISSN 0022-1430 1727-5652 |
op_doi |
https://doi.org/10.1017/s002214300003478x |
container_title |
Journal of Glaciology |
container_volume |
41 |
container_issue |
139 |
container_start_page |
554 |
op_container_end_page |
561 |
_version_ |
1810448705513324544 |