Transient evolution of basal drag during glacier slip
Abstract Glacier slip is usually described using steady-state sliding laws that relate drag, slip velocity and effective pressure, but where subglacial conditions vary rapidly transient effects may influence slip dynamics. Here we use results from a set of laboratory experiments to examine the trans...
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Cambridge University Press (CUP)
2021
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Online Access: | http://dx.doi.org/10.1017/jog.2021.131 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143021001313 |
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crcambridgeupr:10.1017/jog.2021.131 2024-09-30T14:35:22+00:00 Transient evolution of basal drag during glacier slip Zoet, Lucas K. Iverson, Neal R. Andrews, Lauren Helanow, Christian National Science Foundation National Science Foundation National Science Foundation 2021 http://dx.doi.org/10.1017/jog.2021.131 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143021001313 en eng Cambridge University Press (CUP) https://creativecommons.org/licenses/by/4.0/ Journal of Glaciology volume 68, issue 270, page 741-750 ISSN 0022-1430 1727-5652 journal-article 2021 crcambridgeupr https://doi.org/10.1017/jog.2021.131 2024-09-04T04:03:30Z Abstract Glacier slip is usually described using steady-state sliding laws that relate drag, slip velocity and effective pressure, but where subglacial conditions vary rapidly transient effects may influence slip dynamics. Here we use results from a set of laboratory experiments to examine the transient response of glacier slip over a hard bed to velocity perturbations. The drag and cavity evolution from lab experiments are used to parameterize a rate-and-state drag model that is applied to observations of surface velocity and ice-bed separation from the Greenland ice sheet. The drag model successfully predicts observed lags between changes in ice-bed separation and sliding speed. These lags result from the time (or displacement) required for cavities to evolve from one steady-state condition to another. In comparing drag estimates resulting from applying rate-and-state and steady-state slip laws to transient data, we find the peaks in drag are out of phase. This suggests that in locations where subglacial conditions vary on timescales shorter than those needed for cavity adjustment transient slip processes control basal drag. Article in Journal/Newspaper glacier Greenland Ice Sheet Journal of Glaciology Cambridge University Press Greenland Journal of Glaciology 1 10 |
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Open Polar |
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Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
Abstract Glacier slip is usually described using steady-state sliding laws that relate drag, slip velocity and effective pressure, but where subglacial conditions vary rapidly transient effects may influence slip dynamics. Here we use results from a set of laboratory experiments to examine the transient response of glacier slip over a hard bed to velocity perturbations. The drag and cavity evolution from lab experiments are used to parameterize a rate-and-state drag model that is applied to observations of surface velocity and ice-bed separation from the Greenland ice sheet. The drag model successfully predicts observed lags between changes in ice-bed separation and sliding speed. These lags result from the time (or displacement) required for cavities to evolve from one steady-state condition to another. In comparing drag estimates resulting from applying rate-and-state and steady-state slip laws to transient data, we find the peaks in drag are out of phase. This suggests that in locations where subglacial conditions vary on timescales shorter than those needed for cavity adjustment transient slip processes control basal drag. |
author2 |
National Science Foundation National Science Foundation National Science Foundation |
format |
Article in Journal/Newspaper |
author |
Zoet, Lucas K. Iverson, Neal R. Andrews, Lauren Helanow, Christian |
spellingShingle |
Zoet, Lucas K. Iverson, Neal R. Andrews, Lauren Helanow, Christian Transient evolution of basal drag during glacier slip |
author_facet |
Zoet, Lucas K. Iverson, Neal R. Andrews, Lauren Helanow, Christian |
author_sort |
Zoet, Lucas K. |
title |
Transient evolution of basal drag during glacier slip |
title_short |
Transient evolution of basal drag during glacier slip |
title_full |
Transient evolution of basal drag during glacier slip |
title_fullStr |
Transient evolution of basal drag during glacier slip |
title_full_unstemmed |
Transient evolution of basal drag during glacier slip |
title_sort |
transient evolution of basal drag during glacier slip |
publisher |
Cambridge University Press (CUP) |
publishDate |
2021 |
url |
http://dx.doi.org/10.1017/jog.2021.131 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143021001313 |
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 270, page 741-750 ISSN 0022-1430 1727-5652 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/jog.2021.131 |
container_title |
Journal of Glaciology |
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1 |
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10 |
_version_ |
1811638670529134592 |