Thermal Regulation of Glacier Surging
Abstract A necessary condition for a glacier to surge by thermal instability is that the glacier be cold with basal ice at or near the melting point. Deep temperature measurements show that two small surge-type glaciers in the Yukon Territory meet this requirement, but shallow measurements in three...
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Cambridge University Press (CUP)
1976
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crcambridgeupr:10.1017/s0022143000031567 2024-09-15T18:15:39+00:00 Thermal Regulation of Glacier Surging Clarke, Garry K.C. 1976 http://dx.doi.org/10.1017/s0022143000031567 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000031567 en eng Cambridge University Press (CUP) Journal of Glaciology volume 16, issue 74, page 231-250 ISSN 0022-1430 1727-5652 journal-article 1976 crcambridgeupr https://doi.org/10.1017/s0022143000031567 2024-07-31T04:04:11Z Abstract A necessary condition for a glacier to surge by thermal instability is that the glacier be cold with basal ice at or near the melting point. Deep temperature measurements show that two small surge-type glaciers in the Yukon Territory meet this requirement, but shallow measurements in three other surge-type glaciers suggest a temperate regime. If the latter observations are accepted, not all surges are thermally controlled: if a single mechanism accounts for all surges it cannot be thermal instability. In this paper it is argued that thermal instability remains a viable mechanism for explaining surges of many cold glaciers, and that regardless of the underlying mechanism, thermal processes must at least have a major influence on the surge behavior of cold glaciers. Two numerical modelling experiments are described. The first involves a one-dimensional model which shows that thermal control can account for the remarkably constant surge cycle found in some glaciers. The second, a two-dimensional model of the time-dependent temperature structure of a surge-type glacier, shows that the relative amounts of temperate and cold basal ice can change considerably as the surge cycle progresses. This variation alone may be sufficient to explain surges, but even if this is not the case, thermal processes must affect the timing of surges in many cold glaciers. A compelling feature of the thermal instability mechanism is that it offers an explanation of the factors controlling the non-random geographical distribution of surge-type glaciers. For a glacier to have a cold surface and near-temperate bed, the ice thickness, temperature, and geothermal flux must be fortuitously related. Article in Journal/Newspaper Journal of Glaciology Yukon Cambridge University Press Journal of Glaciology 16 74 231 250 |
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Cambridge University Press |
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language |
English |
description |
Abstract A necessary condition for a glacier to surge by thermal instability is that the glacier be cold with basal ice at or near the melting point. Deep temperature measurements show that two small surge-type glaciers in the Yukon Territory meet this requirement, but shallow measurements in three other surge-type glaciers suggest a temperate regime. If the latter observations are accepted, not all surges are thermally controlled: if a single mechanism accounts for all surges it cannot be thermal instability. In this paper it is argued that thermal instability remains a viable mechanism for explaining surges of many cold glaciers, and that regardless of the underlying mechanism, thermal processes must at least have a major influence on the surge behavior of cold glaciers. Two numerical modelling experiments are described. The first involves a one-dimensional model which shows that thermal control can account for the remarkably constant surge cycle found in some glaciers. The second, a two-dimensional model of the time-dependent temperature structure of a surge-type glacier, shows that the relative amounts of temperate and cold basal ice can change considerably as the surge cycle progresses. This variation alone may be sufficient to explain surges, but even if this is not the case, thermal processes must affect the timing of surges in many cold glaciers. A compelling feature of the thermal instability mechanism is that it offers an explanation of the factors controlling the non-random geographical distribution of surge-type glaciers. For a glacier to have a cold surface and near-temperate bed, the ice thickness, temperature, and geothermal flux must be fortuitously related. |
format |
Article in Journal/Newspaper |
author |
Clarke, Garry K.C. |
spellingShingle |
Clarke, Garry K.C. Thermal Regulation of Glacier Surging |
author_facet |
Clarke, Garry K.C. |
author_sort |
Clarke, Garry K.C. |
title |
Thermal Regulation of Glacier Surging |
title_short |
Thermal Regulation of Glacier Surging |
title_full |
Thermal Regulation of Glacier Surging |
title_fullStr |
Thermal Regulation of Glacier Surging |
title_full_unstemmed |
Thermal Regulation of Glacier Surging |
title_sort |
thermal regulation of glacier surging |
publisher |
Cambridge University Press (CUP) |
publishDate |
1976 |
url |
http://dx.doi.org/10.1017/s0022143000031567 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000031567 |
genre |
Journal of Glaciology Yukon |
genre_facet |
Journal of Glaciology Yukon |
op_source |
Journal of Glaciology volume 16, issue 74, page 231-250 ISSN 0022-1430 1727-5652 |
op_doi |
https://doi.org/10.1017/s0022143000031567 |
container_title |
Journal of Glaciology |
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16 |
container_issue |
74 |
container_start_page |
231 |
op_container_end_page |
250 |
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1810453570790621184 |