Boundary layer models for calving marine outlet glaciers
We consider the flow of marine-terminating outlet glaciers that are laterally confined in a channel of prescribed width. In that case, the drag exerted by the channel side walls on a floating ice shelf can reduce extensional stress at the grounding line. If ice flux through the grounding line increa...
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ftdoajarticles:oai:doaj.org/article:01f4f10b3836473699e7295d7e3ceef4 2023-05-15T16:41:55+02:00 Boundary layer models for calving marine outlet glaciers C. Schoof A. D. Davis T. V. Popa 2017-10-01T00:00:00Z https://doi.org/10.5194/tc-11-2283-2017 https://doaj.org/article/01f4f10b3836473699e7295d7e3ceef4 EN eng Copernicus Publications https://www.the-cryosphere.net/11/2283/2017/tc-11-2283-2017.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-11-2283-2017 1994-0416 1994-0424 https://doaj.org/article/01f4f10b3836473699e7295d7e3ceef4 The Cryosphere, Vol 11, Pp 2283-2303 (2017) Environmental sciences GE1-350 Geology QE1-996.5 article 2017 ftdoajarticles https://doi.org/10.5194/tc-11-2283-2017 2023-01-08T01:26:36Z We consider the flow of marine-terminating outlet glaciers that are laterally confined in a channel of prescribed width. In that case, the drag exerted by the channel side walls on a floating ice shelf can reduce extensional stress at the grounding line. If ice flux through the grounding line increases with both ice thickness and extensional stress, then a longer shelf can reduce ice flux by decreasing extensional stress. Consequently, calving has an effect on flux through the grounding line by regulating the length of the shelf. In the absence of a shelf, it plays a similar role by controlling the above-flotation height of the calving cliff. Using two calving laws, one due to Nick et al. (2010) based on a model for crevasse propagation due to hydrofracture and the other simply asserting that calving occurs where the glacier ice becomes afloat, we pose and analyse a flowline model for a marine-terminating glacier by two methods: direct numerical solution and matched asymptotic expansions. The latter leads to a boundary layer formulation that predicts flux through the grounding line as a function of depth to bedrock, channel width, basal drag coefficient, and a calving parameter. By contrast with unbuttressed marine ice sheets, we find that flux can decrease with increasing depth to bedrock at the grounding line, reversing the usual stability criterion for steady grounding line location. Stable steady states can then have grounding lines located on retrograde slopes. We show how this anomalous behaviour relates to the strength of lateral versus basal drag on the grounded portion of the glacier and to the specifics of the calving law used. Article in Journal/Newspaper Ice Shelf The Cryosphere Directory of Open Access Journals: DOAJ Articles The Cryosphere 11 5 2283 2303 |
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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 |
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Environmental sciences GE1-350 Geology QE1-996.5 C. Schoof A. D. Davis T. V. Popa Boundary layer models for calving marine outlet glaciers |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
We consider the flow of marine-terminating outlet glaciers that are laterally confined in a channel of prescribed width. In that case, the drag exerted by the channel side walls on a floating ice shelf can reduce extensional stress at the grounding line. If ice flux through the grounding line increases with both ice thickness and extensional stress, then a longer shelf can reduce ice flux by decreasing extensional stress. Consequently, calving has an effect on flux through the grounding line by regulating the length of the shelf. In the absence of a shelf, it plays a similar role by controlling the above-flotation height of the calving cliff. Using two calving laws, one due to Nick et al. (2010) based on a model for crevasse propagation due to hydrofracture and the other simply asserting that calving occurs where the glacier ice becomes afloat, we pose and analyse a flowline model for a marine-terminating glacier by two methods: direct numerical solution and matched asymptotic expansions. The latter leads to a boundary layer formulation that predicts flux through the grounding line as a function of depth to bedrock, channel width, basal drag coefficient, and a calving parameter. By contrast with unbuttressed marine ice sheets, we find that flux can decrease with increasing depth to bedrock at the grounding line, reversing the usual stability criterion for steady grounding line location. Stable steady states can then have grounding lines located on retrograde slopes. We show how this anomalous behaviour relates to the strength of lateral versus basal drag on the grounded portion of the glacier and to the specifics of the calving law used. |
format |
Article in Journal/Newspaper |
author |
C. Schoof A. D. Davis T. V. Popa |
author_facet |
C. Schoof A. D. Davis T. V. Popa |
author_sort |
C. Schoof |
title |
Boundary layer models for calving marine outlet glaciers |
title_short |
Boundary layer models for calving marine outlet glaciers |
title_full |
Boundary layer models for calving marine outlet glaciers |
title_fullStr |
Boundary layer models for calving marine outlet glaciers |
title_full_unstemmed |
Boundary layer models for calving marine outlet glaciers |
title_sort |
boundary layer models for calving marine outlet glaciers |
publisher |
Copernicus Publications |
publishDate |
2017 |
url |
https://doi.org/10.5194/tc-11-2283-2017 https://doaj.org/article/01f4f10b3836473699e7295d7e3ceef4 |
genre |
Ice Shelf The Cryosphere |
genre_facet |
Ice Shelf The Cryosphere |
op_source |
The Cryosphere, Vol 11, Pp 2283-2303 (2017) |
op_relation |
https://www.the-cryosphere.net/11/2283/2017/tc-11-2283-2017.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-11-2283-2017 1994-0416 1994-0424 https://doaj.org/article/01f4f10b3836473699e7295d7e3ceef4 |
op_doi |
https://doi.org/10.5194/tc-11-2283-2017 |
container_title |
The Cryosphere |
container_volume |
11 |
container_issue |
5 |
container_start_page |
2283 |
op_container_end_page |
2303 |
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1766032393081192448 |