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...

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Main Authors: Hunter, Pierce, Meyer, Colin, Minchew, Brent, Haseloff, Marianne, Rempel, Alan
פורמט: Article
שפה:English
יצא לאור: Cambridge University Press (CUP) 2021
גישה מקוונת:https://hdl.handle.net/1721.1/133820
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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>
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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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AT meyercolin thermalcontrolsonicestreamshearmargins
AT minchewbrent thermalcontrolsonicestreamshearmargins
AT haseloffmarianne thermalcontrolsonicestreamshearmargins
AT rempelalan thermalcontrolsonicestreamshearmargins