Subseasonal changes observed in subglacial channel pressure, size, and sediment transport
Water that pressurizes the base of glaciers and ice sheets enhances glacier velocities and modulates glacial erosion. Predicting ice flow and erosion therefore requires knowledge of subglacial channel evolution, which remains observationally limited. Here we demonstrate that detailed analysis of sei...
Published in: | Geophysical Research Letters |
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American Geophysical Union
2016
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ftcaltechauth:oai:authors.library.caltech.edu:69059 2023-05-15T16:20:25+02:00 Subseasonal changes observed in subglacial channel pressure, size, and sediment transport Gimbert, Florent Tsai, Victor C. Amundson, Jason M. Bartholomaus, Timothy C. Walter, Jacob I. 2016-04-28 application/pdf https://authors.library.caltech.edu/69059/ https://authors.library.caltech.edu/69059/1/Gimbert_et_al-2016-Geophysical_Research_Letters.pdf https://authors.library.caltech.edu/69059/2/grl54301-sup-0001-supinfo.pdf https://resolver.caltech.edu/CaltechAUTHORS:20160715-111120593 en eng American Geophysical Union https://authors.library.caltech.edu/69059/1/Gimbert_et_al-2016-Geophysical_Research_Letters.pdf https://authors.library.caltech.edu/69059/2/grl54301-sup-0001-supinfo.pdf Gimbert, Florent and Tsai, Victor C. and Amundson, Jason M. and Bartholomaus, Timothy C. and Walter, Jacob I. (2016) Subseasonal changes observed in subglacial channel pressure, size, and sediment transport. Geophysical Research Letters, 43 (8). pp. 3786-3794. ISSN 0094-8276. doi:10.1002/2016GL068337. https://resolver.caltech.edu/CaltechAUTHORS:20160715-111120593 <https://resolver.caltech.edu/CaltechAUTHORS:20160715-111120593> other Article PeerReviewed 2016 ftcaltechauth https://doi.org/10.1002/2016GL068337 2021-11-18T18:38:27Z Water that pressurizes the base of glaciers and ice sheets enhances glacier velocities and modulates glacial erosion. Predicting ice flow and erosion therefore requires knowledge of subglacial channel evolution, which remains observationally limited. Here we demonstrate that detailed analysis of seismic ground motion caused by subglacial water flow at Mendenhall Glacier (Alaska) allows for continuous measurement of daily to subseasonal changes in basal water pressure gradient, channel size, and sediment transport. We observe intermittent subglacial water pressure gradient changes during the melt season, at odds with common assumptions of slowly varying, low-pressure channels. These observations indicate that changes in channel size do not keep pace with changes in discharge. This behavior strongly affects glacier dynamics and subglacial channel erosion at Mendenhall Glacier, where episodic periods of high water pressure gradients enhance glacier surface velocity and channel sediment transport by up to 30% and 50%, respectively. We expect the application of this framework to future seismic observations acquired at glaciers worldwide to improve our understanding of subglacial processes. Article in Journal/Newspaper glacier glaciers Alaska Caltech Authors (California Institute of Technology) Geophysical Research Letters 43 8 3786 3794 |
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Open Polar |
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Caltech Authors (California Institute of Technology) |
op_collection_id |
ftcaltechauth |
language |
English |
description |
Water that pressurizes the base of glaciers and ice sheets enhances glacier velocities and modulates glacial erosion. Predicting ice flow and erosion therefore requires knowledge of subglacial channel evolution, which remains observationally limited. Here we demonstrate that detailed analysis of seismic ground motion caused by subglacial water flow at Mendenhall Glacier (Alaska) allows for continuous measurement of daily to subseasonal changes in basal water pressure gradient, channel size, and sediment transport. We observe intermittent subglacial water pressure gradient changes during the melt season, at odds with common assumptions of slowly varying, low-pressure channels. These observations indicate that changes in channel size do not keep pace with changes in discharge. This behavior strongly affects glacier dynamics and subglacial channel erosion at Mendenhall Glacier, where episodic periods of high water pressure gradients enhance glacier surface velocity and channel sediment transport by up to 30% and 50%, respectively. We expect the application of this framework to future seismic observations acquired at glaciers worldwide to improve our understanding of subglacial processes. |
format |
Article in Journal/Newspaper |
author |
Gimbert, Florent Tsai, Victor C. Amundson, Jason M. Bartholomaus, Timothy C. Walter, Jacob I. |
spellingShingle |
Gimbert, Florent Tsai, Victor C. Amundson, Jason M. Bartholomaus, Timothy C. Walter, Jacob I. Subseasonal changes observed in subglacial channel pressure, size, and sediment transport |
author_facet |
Gimbert, Florent Tsai, Victor C. Amundson, Jason M. Bartholomaus, Timothy C. Walter, Jacob I. |
author_sort |
Gimbert, Florent |
title |
Subseasonal changes observed in subglacial channel pressure, size, and sediment transport |
title_short |
Subseasonal changes observed in subglacial channel pressure, size, and sediment transport |
title_full |
Subseasonal changes observed in subglacial channel pressure, size, and sediment transport |
title_fullStr |
Subseasonal changes observed in subglacial channel pressure, size, and sediment transport |
title_full_unstemmed |
Subseasonal changes observed in subglacial channel pressure, size, and sediment transport |
title_sort |
subseasonal changes observed in subglacial channel pressure, size, and sediment transport |
publisher |
American Geophysical Union |
publishDate |
2016 |
url |
https://authors.library.caltech.edu/69059/ https://authors.library.caltech.edu/69059/1/Gimbert_et_al-2016-Geophysical_Research_Letters.pdf https://authors.library.caltech.edu/69059/2/grl54301-sup-0001-supinfo.pdf https://resolver.caltech.edu/CaltechAUTHORS:20160715-111120593 |
genre |
glacier glaciers Alaska |
genre_facet |
glacier glaciers Alaska |
op_relation |
https://authors.library.caltech.edu/69059/1/Gimbert_et_al-2016-Geophysical_Research_Letters.pdf https://authors.library.caltech.edu/69059/2/grl54301-sup-0001-supinfo.pdf Gimbert, Florent and Tsai, Victor C. and Amundson, Jason M. and Bartholomaus, Timothy C. and Walter, Jacob I. (2016) Subseasonal changes observed in subglacial channel pressure, size, and sediment transport. Geophysical Research Letters, 43 (8). pp. 3786-3794. ISSN 0094-8276. doi:10.1002/2016GL068337. https://resolver.caltech.edu/CaltechAUTHORS:20160715-111120593 <https://resolver.caltech.edu/CaltechAUTHORS:20160715-111120593> |
op_rights |
other |
op_doi |
https://doi.org/10.1002/2016GL068337 |
container_title |
Geophysical Research Letters |
container_volume |
43 |
container_issue |
8 |
container_start_page |
3786 |
op_container_end_page |
3794 |
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1766008344119607296 |