Observational verification of predicted increase in bedrock-to-surface amplitude transfer during a glacier surge
The amplitude ratio between surface and bedrock topography has been predicted to depend strongly on the ratio of deformational velocity to mean basal sliding velocity. Observations made prior to and during a surge of Tungnaárjökull, Vatnajökull ice cap, Iceland, allow this prediction to be tested. D...
Published in: | Annals of Glaciology |
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International Glaciological Society
2003
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Online Access: | https://nrl.northumbria.ac.uk/id/eprint/38010/ https://doi.org/10.3189/172756403781816248 |
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ftunivnorthumb:oai:nrl.northumbria.ac.uk:38010 2023-05-15T13:29:24+02:00 Observational verification of predicted increase in bedrock-to-surface amplitude transfer during a glacier surge Gudmundsson, Hilmar Aðalgeirsdóttir, Guðefinna Björnsson, Helgi 2003 https://nrl.northumbria.ac.uk/id/eprint/38010/ https://doi.org/10.3189/172756403781816248 unknown International Glaciological Society Gudmundsson, Hilmar, Aðalgeirsdóttir, Guðefinna and Björnsson, Helgi (2003) Observational verification of predicted increase in bedrock-to-surface amplitude transfer during a glacier surge. Annals of Glaciology, 36. pp. 91-96. ISSN 0260-3055 F800 Physical and Terrestrial Geographical and Environmental Sciences Article PeerReviewed 2003 ftunivnorthumb https://doi.org/10.3189/172756403781816248 2022-09-25T06:09:12Z The amplitude ratio between surface and bedrock topography has been predicted to depend strongly on the ratio of deformational velocity to mean basal sliding velocity. Observations made prior to and during a surge of Tungnaárjökull, Vatnajökull ice cap, Iceland, allow this prediction to be tested. During the surge, the ratio of internal deformational velocity and basal sliding (slip ratio) changed from about unity to a few hundred. The amplitude ratio changed from about 0.1 to about 0.7. This increase in amplitude ratio is in good overall agreement with predictions based on an analytical perturbation analysis for a linearly viscous medium which includes the effects of horizontal deviatoric stresses on glacier flow. An increase in amplitude ratio of this magnitude is not predicted by a similarly linearized analysis that employs the commonly used shallow-ice approximation. The strong increase in transfer amplitude observed in the surge of Tungnaárjökull is a clear illustration of the effects of horizontal stress transmission on glacier flow reported here for the first time. Article in Journal/Newspaper Annals of Glaciology glacier Ice cap Iceland Vatnajökull Northumbria University, Newcastle: Northumbria Research Link (NRL) Tungnaárjökull ENVELOPE(-18.022,-18.022,64.319,64.319) Vatnajökull ENVELOPE(-16.823,-16.823,64.420,64.420) Annals of Glaciology 36 91 96 |
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Open Polar |
collection |
Northumbria University, Newcastle: Northumbria Research Link (NRL) |
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ftunivnorthumb |
language |
unknown |
topic |
F800 Physical and Terrestrial Geographical and Environmental Sciences |
spellingShingle |
F800 Physical and Terrestrial Geographical and Environmental Sciences Gudmundsson, Hilmar Aðalgeirsdóttir, Guðefinna Björnsson, Helgi Observational verification of predicted increase in bedrock-to-surface amplitude transfer during a glacier surge |
topic_facet |
F800 Physical and Terrestrial Geographical and Environmental Sciences |
description |
The amplitude ratio between surface and bedrock topography has been predicted to depend strongly on the ratio of deformational velocity to mean basal sliding velocity. Observations made prior to and during a surge of Tungnaárjökull, Vatnajökull ice cap, Iceland, allow this prediction to be tested. During the surge, the ratio of internal deformational velocity and basal sliding (slip ratio) changed from about unity to a few hundred. The amplitude ratio changed from about 0.1 to about 0.7. This increase in amplitude ratio is in good overall agreement with predictions based on an analytical perturbation analysis for a linearly viscous medium which includes the effects of horizontal deviatoric stresses on glacier flow. An increase in amplitude ratio of this magnitude is not predicted by a similarly linearized analysis that employs the commonly used shallow-ice approximation. The strong increase in transfer amplitude observed in the surge of Tungnaárjökull is a clear illustration of the effects of horizontal stress transmission on glacier flow reported here for the first time. |
format |
Article in Journal/Newspaper |
author |
Gudmundsson, Hilmar Aðalgeirsdóttir, Guðefinna Björnsson, Helgi |
author_facet |
Gudmundsson, Hilmar Aðalgeirsdóttir, Guðefinna Björnsson, Helgi |
author_sort |
Gudmundsson, Hilmar |
title |
Observational verification of predicted increase in bedrock-to-surface amplitude transfer during a glacier surge |
title_short |
Observational verification of predicted increase in bedrock-to-surface amplitude transfer during a glacier surge |
title_full |
Observational verification of predicted increase in bedrock-to-surface amplitude transfer during a glacier surge |
title_fullStr |
Observational verification of predicted increase in bedrock-to-surface amplitude transfer during a glacier surge |
title_full_unstemmed |
Observational verification of predicted increase in bedrock-to-surface amplitude transfer during a glacier surge |
title_sort |
observational verification of predicted increase in bedrock-to-surface amplitude transfer during a glacier surge |
publisher |
International Glaciological Society |
publishDate |
2003 |
url |
https://nrl.northumbria.ac.uk/id/eprint/38010/ https://doi.org/10.3189/172756403781816248 |
long_lat |
ENVELOPE(-18.022,-18.022,64.319,64.319) ENVELOPE(-16.823,-16.823,64.420,64.420) |
geographic |
Tungnaárjökull Vatnajökull |
geographic_facet |
Tungnaárjökull Vatnajökull |
genre |
Annals of Glaciology glacier Ice cap Iceland Vatnajökull |
genre_facet |
Annals of Glaciology glacier Ice cap Iceland Vatnajökull |
op_relation |
Gudmundsson, Hilmar, Aðalgeirsdóttir, Guðefinna and Björnsson, Helgi (2003) Observational verification of predicted increase in bedrock-to-surface amplitude transfer during a glacier surge. Annals of Glaciology, 36. pp. 91-96. ISSN 0260-3055 |
op_doi |
https://doi.org/10.3189/172756403781816248 |
container_title |
Annals of Glaciology |
container_volume |
36 |
container_start_page |
91 |
op_container_end_page |
96 |
_version_ |
1766000369615241216 |