Thermal controls on ice stream shear margins
Abstract Ice stream discharge responds to a balance between gravity, basal friction and lateral drag. Appreciable viscous heating occurs in shear margins between ice streams and adjacent slow-moving ice ridges, altering the temperature-dependent viscosity distribution that connects lateral drag to m...
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Cambridge University Press (CUP)
2021
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Online Access: | http://dx.doi.org/10.1017/jog.2020.118 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143020001185 |
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crcambridgeupr:10.1017/jog.2020.118 2024-06-23T07:47:49+00:00 Thermal controls on ice stream shear margins Hunter, Pierce Meyer, Colin Minchew, Brent Haseloff, Marianne Rempel, Alan 2021 http://dx.doi.org/10.1017/jog.2020.118 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143020001185 en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0/ Journal of Glaciology volume 67, issue 263, page 435-449 ISSN 0022-1430 1727-5652 journal-article 2021 crcambridgeupr https://doi.org/10.1017/jog.2020.118 2024-06-05T04:04:35Z Abstract Ice stream discharge responds to a balance between gravity, basal friction and lateral drag. Appreciable viscous heating occurs in shear margins between ice streams and adjacent slow-moving ice ridges, altering the temperature-dependent viscosity distribution that connects lateral drag to marginal strain rates and ice stream velocity. Warmer ice deforms more easily and accommodates faster flow, whereas cold ice supplied from ice ridges drives advective cooling that counteracts viscous heating. Here, we present a two-dimensional (three velocity component), steady-state model designed to explore the thermal controls on ice stream shear margins. We validate our treatment through comparison with observed velocities for Bindschadler Ice Stream and verify that calculated temperatures are consistent with results from previous studies. Sweeping through a parameter range that encompasses conditions representative of ice streams in Antarctica, we show that modeled steady-state velocity has a modest response to different choices in forcing up until temperate zones develop in the shear margins. When temperate zones are present, velocity is much more sensitive to changes in forcing. We identify key scalings for the emergence of temperate conditions in our idealized treatment that can be used to identify where thermo-mechanical feedbacks influence the evolution of the ice sheet. Article in Journal/Newspaper Antarc* Antarctica Bindschadler Ice Stream Ice Sheet Journal of Glaciology Cambridge University Press Bindschadler Ice Stream ENVELOPE(-142.000,-142.000,-81.000,-81.000) Journal of Glaciology 67 263 435 449 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
Abstract Ice stream discharge responds to a balance between gravity, basal friction and lateral drag. Appreciable viscous heating occurs in shear margins between ice streams and adjacent slow-moving ice ridges, altering the temperature-dependent viscosity distribution that connects lateral drag to marginal strain rates and ice stream velocity. Warmer ice deforms more easily and accommodates faster flow, whereas cold ice supplied from ice ridges drives advective cooling that counteracts viscous heating. Here, we present a two-dimensional (three velocity component), steady-state model designed to explore the thermal controls on ice stream shear margins. We validate our treatment through comparison with observed velocities for Bindschadler Ice Stream and verify that calculated temperatures are consistent with results from previous studies. Sweeping through a parameter range that encompasses conditions representative of ice streams in Antarctica, we show that modeled steady-state velocity has a modest response to different choices in forcing up until temperate zones develop in the shear margins. When temperate zones are present, velocity is much more sensitive to changes in forcing. We identify key scalings for the emergence of temperate conditions in our idealized treatment that can be used to identify where thermo-mechanical feedbacks influence the evolution of the ice sheet. |
format |
Article in Journal/Newspaper |
author |
Hunter, Pierce Meyer, Colin Minchew, Brent Haseloff, Marianne Rempel, Alan |
spellingShingle |
Hunter, Pierce Meyer, Colin Minchew, Brent Haseloff, Marianne Rempel, Alan Thermal controls on ice stream shear margins |
author_facet |
Hunter, Pierce Meyer, Colin Minchew, Brent Haseloff, Marianne Rempel, Alan |
author_sort |
Hunter, Pierce |
title |
Thermal controls on ice stream shear margins |
title_short |
Thermal controls on ice stream shear margins |
title_full |
Thermal controls on ice stream shear margins |
title_fullStr |
Thermal controls on ice stream shear margins |
title_full_unstemmed |
Thermal controls on ice stream shear margins |
title_sort |
thermal controls on ice stream shear margins |
publisher |
Cambridge University Press (CUP) |
publishDate |
2021 |
url |
http://dx.doi.org/10.1017/jog.2020.118 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143020001185 |
long_lat |
ENVELOPE(-142.000,-142.000,-81.000,-81.000) |
geographic |
Bindschadler Ice Stream |
geographic_facet |
Bindschadler Ice Stream |
genre |
Antarc* Antarctica Bindschadler Ice Stream Ice Sheet Journal of Glaciology |
genre_facet |
Antarc* Antarctica Bindschadler Ice Stream Ice Sheet Journal of Glaciology |
op_source |
Journal of Glaciology volume 67, issue 263, page 435-449 ISSN 0022-1430 1727-5652 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/jog.2020.118 |
container_title |
Journal of Glaciology |
container_volume |
67 |
container_issue |
263 |
container_start_page |
435 |
op_container_end_page |
449 |
_version_ |
1802637999963373568 |