Thermal controls on ice stream shear margins
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 s...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Cambridge University Press
2021-06-01
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| Series: | Journal of Glaciology |
| Subjects: | |
| Online Access: | https://www.cambridge.org/core/product/identifier/S0022143020001185/type/journal_article |
| _version_ | 1811155803594293248 |
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| author | Pierce Hunter Colin Meyer Brent Minchew Marianne Haseloff Alan Rempel |
| author_facet | Pierce Hunter Colin Meyer Brent Minchew Marianne Haseloff Alan Rempel |
| author_sort | Pierce Hunter |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-04-10T04:39:42Z |
| format | Article |
| id | doaj.art-82fe2d65459d4061900643df0ba442e6 |
| institution | Directory Open Access Journal |
| issn | 0022-1430 1727-5652 |
| language | English |
| last_indexed | 2024-04-10T04:39:42Z |
| publishDate | 2021-06-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Journal of Glaciology |
| spelling | doaj.art-82fe2d65459d4061900643df0ba442e62023-03-09T12:41:06ZengCambridge University PressJournal of Glaciology0022-14301727-56522021-06-016743544910.1017/jog.2020.118Thermal controls on ice stream shear marginsPierce Hunter0Colin Meyer1https://orcid.org/0000-0002-1209-1881Brent Minchew2https://orcid.org/0000-0002-5991-3926Marianne Haseloff3Alan Rempel4Department of Earth Sciences, University of Oregon, Eugene, OR, USAThayer School of Engineering, Dartmouth College, Hanover, NH, USAEarth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USAGeography and Environmental Sciences, Northumbria University, Newcastle upon Tyne, UKDepartment of Earth Sciences, University of Oregon, Eugene, OR, USAIce 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.https://www.cambridge.org/core/product/identifier/S0022143020001185/type/journal_articleAntarctic glaciologyglacial rheologyglacier flowglacier mechanicsice streams |
| spellingShingle | Pierce Hunter Colin Meyer Brent Minchew Marianne Haseloff Alan Rempel Thermal controls on ice stream shear margins Journal of Glaciology Antarctic glaciology glacial rheology glacier flow glacier mechanics ice streams |
| title | 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_short | Thermal controls on ice stream shear margins |
| title_sort | thermal controls on ice stream shear margins |
| topic | Antarctic glaciology glacial rheology glacier flow glacier mechanics ice streams |
| url | https://www.cambridge.org/core/product/identifier/S0022143020001185/type/journal_article |
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