Surge dynamics of Shisper Glacier revealed by time-series correlation of optical satellite images and their utility to substantiate a generalized sliding law
Understanding fast ice flow is key to assessing the future of glaciers. Fast ice flow is controlled by sliding at the bed, yet that sliding is poorly understood. A growing number of studies show the relationship between sliding and basal shear stress transitions from an initially rate-strengthening...
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Copernicus Publications
2022
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Online Access: | https://doi.org/10.5194/tc-16-3123-2022 https://doaj.org/article/88faf3a7313440d0944c9619c05dce33 |
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ftdoajarticles:oai:doaj.org/article:88faf3a7313440d0944c9619c05dce33 2023-05-15T18:32:25+02:00 Surge dynamics of Shisper Glacier revealed by time-series correlation of optical satellite images and their utility to substantiate a generalized sliding law F. Beaud S. Aati I. Delaney S. Adhikari J.-P. Avouac 2022-08-01T00:00:00Z https://doi.org/10.5194/tc-16-3123-2022 https://doaj.org/article/88faf3a7313440d0944c9619c05dce33 EN eng Copernicus Publications https://tc.copernicus.org/articles/16/3123/2022/tc-16-3123-2022.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-16-3123-2022 1994-0416 1994-0424 https://doaj.org/article/88faf3a7313440d0944c9619c05dce33 The Cryosphere, Vol 16, Pp 3123-3148 (2022) Environmental sciences GE1-350 Geology QE1-996.5 article 2022 ftdoajarticles https://doi.org/10.5194/tc-16-3123-2022 2022-12-31T02:04:55Z Understanding fast ice flow is key to assessing the future of glaciers. Fast ice flow is controlled by sliding at the bed, yet that sliding is poorly understood. A growing number of studies show the relationship between sliding and basal shear stress transitions from an initially rate-strengthening behavior to a rate-independent or rate-weakening behavior. Studies that have tested a glacier sliding law with data remain rare. Surging glaciers, as we show in this study, can be used as a natural laboratory to inform sliding laws because a single glacier shows extreme velocity variations at a subannual timescale. The present study has two main goals: (1) we introduce a new workflow to produce velocity maps with a high spatiotemporal resolution from remote-sensing data, combining Sentinel-2 (S2) and Landsat 8 (L8) and using the results to describe the recent surge of Shisper Glacier, and (2) we present a generalized sliding law and substantiate the sliding-law behavior using the remote sensing dataset. The quality and spatiotemporal resolution of the velocity time series allow us to identify a gradual amplification of spring speed-up velocities in the 2 years leading up to the surge that started in November 2017. We also find that surface velocity patterns during the surge can be decomposed into three main phases, and each phase appears to be associated with hydraulic changes. Using this dataset, we are able to highlight the rate-independent and rate-weakening relationships between resistive stress and sliding during the surge. We then discuss the importance of the generalized sliding relationship to reconcile observations of fast ice flow, and in particular, different surge behaviors. The approach used in this study remains qualitative, but if coupled with better bed-elevation data and numerical modeling could lead to the widespread quantification of sliding-law parameters. Article in Journal/Newspaper The Cryosphere Directory of Open Access Journals: DOAJ Articles The Cryosphere 16 8 3123 3148 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 F. Beaud S. Aati I. Delaney S. Adhikari J.-P. Avouac Surge dynamics of Shisper Glacier revealed by time-series correlation of optical satellite images and their utility to substantiate a generalized sliding law |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
Understanding fast ice flow is key to assessing the future of glaciers. Fast ice flow is controlled by sliding at the bed, yet that sliding is poorly understood. A growing number of studies show the relationship between sliding and basal shear stress transitions from an initially rate-strengthening behavior to a rate-independent or rate-weakening behavior. Studies that have tested a glacier sliding law with data remain rare. Surging glaciers, as we show in this study, can be used as a natural laboratory to inform sliding laws because a single glacier shows extreme velocity variations at a subannual timescale. The present study has two main goals: (1) we introduce a new workflow to produce velocity maps with a high spatiotemporal resolution from remote-sensing data, combining Sentinel-2 (S2) and Landsat 8 (L8) and using the results to describe the recent surge of Shisper Glacier, and (2) we present a generalized sliding law and substantiate the sliding-law behavior using the remote sensing dataset. The quality and spatiotemporal resolution of the velocity time series allow us to identify a gradual amplification of spring speed-up velocities in the 2 years leading up to the surge that started in November 2017. We also find that surface velocity patterns during the surge can be decomposed into three main phases, and each phase appears to be associated with hydraulic changes. Using this dataset, we are able to highlight the rate-independent and rate-weakening relationships between resistive stress and sliding during the surge. We then discuss the importance of the generalized sliding relationship to reconcile observations of fast ice flow, and in particular, different surge behaviors. The approach used in this study remains qualitative, but if coupled with better bed-elevation data and numerical modeling could lead to the widespread quantification of sliding-law parameters. |
format |
Article in Journal/Newspaper |
author |
F. Beaud S. Aati I. Delaney S. Adhikari J.-P. Avouac |
author_facet |
F. Beaud S. Aati I. Delaney S. Adhikari J.-P. Avouac |
author_sort |
F. Beaud |
title |
Surge dynamics of Shisper Glacier revealed by time-series correlation of optical satellite images and their utility to substantiate a generalized sliding law |
title_short |
Surge dynamics of Shisper Glacier revealed by time-series correlation of optical satellite images and their utility to substantiate a generalized sliding law |
title_full |
Surge dynamics of Shisper Glacier revealed by time-series correlation of optical satellite images and their utility to substantiate a generalized sliding law |
title_fullStr |
Surge dynamics of Shisper Glacier revealed by time-series correlation of optical satellite images and their utility to substantiate a generalized sliding law |
title_full_unstemmed |
Surge dynamics of Shisper Glacier revealed by time-series correlation of optical satellite images and their utility to substantiate a generalized sliding law |
title_sort |
surge dynamics of shisper glacier revealed by time-series correlation of optical satellite images and their utility to substantiate a generalized sliding law |
publisher |
Copernicus Publications |
publishDate |
2022 |
url |
https://doi.org/10.5194/tc-16-3123-2022 https://doaj.org/article/88faf3a7313440d0944c9619c05dce33 |
genre |
The Cryosphere |
genre_facet |
The Cryosphere |
op_source |
The Cryosphere, Vol 16, Pp 3123-3148 (2022) |
op_relation |
https://tc.copernicus.org/articles/16/3123/2022/tc-16-3123-2022.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-16-3123-2022 1994-0416 1994-0424 https://doaj.org/article/88faf3a7313440d0944c9619c05dce33 |
op_doi |
https://doi.org/10.5194/tc-16-3123-2022 |
container_title |
The Cryosphere |
container_volume |
16 |
container_issue |
8 |
container_start_page |
3123 |
op_container_end_page |
3148 |
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1766216529737678848 |