Thermal controls on ice stream shear margins
<jats:title>Abstract</jats:title><jats:p>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 visc...
| Main Authors: | , , , , |
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| פורמט: | Article |
| שפה: | English |
| יצא לאור: |
Cambridge University Press (CUP)
2021
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| גישה מקוונת: | https://hdl.handle.net/1721.1/133820 |
| _version_ | 1826214345217933312 |
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| author | Hunter, Pierce Meyer, Colin Minchew, Brent Haseloff, Marianne Rempel, Alan |
| author_facet | Hunter, Pierce Meyer, Colin Minchew, Brent Haseloff, Marianne Rempel, Alan |
| author_sort | Hunter, Pierce |
| collection | MIT |
| description | <jats:title>Abstract</jats:title><jats:p>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.</jats:p> |
| first_indexed | 2024-09-23T16:03:54Z |
| format | Article |
| id | mit-1721.1/133820 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T16:03:54Z |
| publishDate | 2021 |
| publisher | Cambridge University Press (CUP) |
| record_format | dspace |
| spelling | mit-1721.1/1338202021-10-28T03:13:54Z Thermal controls on ice stream shear margins Hunter, Pierce Meyer, Colin Minchew, Brent Haseloff, Marianne Rempel, Alan <jats:title>Abstract</jats:title><jats:p>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.</jats:p> 2021-10-27T19:56:49Z 2021-10-27T19:56:49Z 2021 2021-09-17T16:08:15Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/133820 en 10.1017/JOG.2020.118 Journal of Glaciology Creative Commons Attribution 4.0 International license https://creativecommons.org/licenses/by/4.0/ application/pdf Cambridge University Press (CUP) Cambridge University Press |
| spellingShingle | Hunter, Pierce Meyer, Colin Minchew, Brent Haseloff, Marianne Rempel, Alan Thermal controls on ice stream shear margins |
| 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 |
| url | https://hdl.handle.net/1721.1/133820 |
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