Cyclic Surging of Glaciers
Abstract A partly phenomenological theory and model are constructed of cyclically surging glaciers. During the after-surge portion of a surge cycle the lower portion of a glacier becomes increasingly stagnant. The upper part of the glacier gradually becomes more active as both its thickness and the...
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Language: | English |
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Cambridge University Press (CUP)
1973
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Online Access: | http://dx.doi.org/10.1017/s002214300002267x https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S002214300002267X |
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crcambridgeupr:10.1017/s002214300002267x 2024-09-15T18:15:39+00:00 Cyclic Surging of Glaciers Robin, G. de Q. Weertman, J. 1973 http://dx.doi.org/10.1017/s002214300002267x https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S002214300002267X en eng Cambridge University Press (CUP) Journal of Glaciology volume 12, issue 64, page 3-18 ISSN 0022-1430 1727-5652 journal-article 1973 crcambridgeupr https://doi.org/10.1017/s002214300002267x 2024-07-17T04:03:25Z Abstract A partly phenomenological theory and model are constructed of cyclically surging glaciers. During the after-surge portion of a surge cycle the lower portion of a glacier becomes increasingly stagnant. The upper part of the glacier gradually becomes more active as both its thickness and the magnitude of its basal shear stress increase. In the region between these two parts, called by us the trigger zone, the value of the derivative of the basal shear stress in the longitudinal direction of the glacier gradually increases with time. The pressure gradient in the water at the base of a glacier is related to the derivative of the basal shear stress. The pressure gradient decreases as the basal shear-stress gradient increases. The pressure gradient actually can take on negative values, a condition which produces “up-hill” water flow at the base of a glacier. A surge is started in the trigger zone when water is dammed there by a zero water-pressure gradient. The zone of fast-sliding velocities propagates up the glacier from the trigger zone with a velocity of the order of a surge velocity. The fast-sliding velocity zone also propagates down the glacier because of increased melt-water production. Article in Journal/Newspaper Journal of Glaciology Cambridge University Press Journal of Glaciology 12 64 3 18 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
Abstract A partly phenomenological theory and model are constructed of cyclically surging glaciers. During the after-surge portion of a surge cycle the lower portion of a glacier becomes increasingly stagnant. The upper part of the glacier gradually becomes more active as both its thickness and the magnitude of its basal shear stress increase. In the region between these two parts, called by us the trigger zone, the value of the derivative of the basal shear stress in the longitudinal direction of the glacier gradually increases with time. The pressure gradient in the water at the base of a glacier is related to the derivative of the basal shear stress. The pressure gradient decreases as the basal shear-stress gradient increases. The pressure gradient actually can take on negative values, a condition which produces “up-hill” water flow at the base of a glacier. A surge is started in the trigger zone when water is dammed there by a zero water-pressure gradient. The zone of fast-sliding velocities propagates up the glacier from the trigger zone with a velocity of the order of a surge velocity. The fast-sliding velocity zone also propagates down the glacier because of increased melt-water production. |
format |
Article in Journal/Newspaper |
author |
Robin, G. de Q. Weertman, J. |
spellingShingle |
Robin, G. de Q. Weertman, J. Cyclic Surging of Glaciers |
author_facet |
Robin, G. de Q. Weertman, J. |
author_sort |
Robin, G. de Q. |
title |
Cyclic Surging of Glaciers |
title_short |
Cyclic Surging of Glaciers |
title_full |
Cyclic Surging of Glaciers |
title_fullStr |
Cyclic Surging of Glaciers |
title_full_unstemmed |
Cyclic Surging of Glaciers |
title_sort |
cyclic surging of glaciers |
publisher |
Cambridge University Press (CUP) |
publishDate |
1973 |
url |
http://dx.doi.org/10.1017/s002214300002267x https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S002214300002267X |
genre |
Journal of Glaciology |
genre_facet |
Journal of Glaciology |
op_source |
Journal of Glaciology volume 12, issue 64, page 3-18 ISSN 0022-1430 1727-5652 |
op_doi |
https://doi.org/10.1017/s002214300002267x |
container_title |
Journal of Glaciology |
container_volume |
12 |
container_issue |
64 |
container_start_page |
3 |
op_container_end_page |
18 |
_version_ |
1810453561059835904 |