The effect of anisotropy on simulated ice dynamics: an idealised ice shelf example using the Ice Sheet System Model
An essential component of an ice sheet model is its description of how ice deforms under applied stresses itsmaterial constitutive relation. Current large-scale ice sheet models routinely rely on Glens flow relation, whichis an isotropic material constitutive relation that is not dependent on the ch...
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ftunivtasecite:oai:ecite.utas.edu.au:125963 2023-05-15T16:40:00+02:00 The effect of anisotropy on simulated ice dynamics: an idealised ice shelf example using the Ice Sheet System Model Graham, F Morlighem, M Warner, RC Treverrow, A 2017 application/pdf http://ecite.utas.edu.au/125963 en eng Copernicus GmbH http://ecite.utas.edu.au/125963/1/2017_Graham_EGU_abstract.pdf Graham, F and Morlighem, M and Warner, RC and Treverrow, A, The effect of anisotropy on simulated ice dynamics: an idealised ice shelf example using the Ice Sheet System Model, Geophysical Research Abstracts, 23-28 April, Vienna, Austria, pp. 157. ISSN 1607-7962 (2017) [Conference Extract] http://ecite.utas.edu.au/125963 Earth Sciences Physical Geography and Environmental Geoscience Glaciology Conference Extract NonPeerReviewed 2017 ftunivtasecite 2019-12-13T22:24:25Z An essential component of an ice sheet model is its description of how ice deforms under applied stresses itsmaterial constitutive relation. Current large-scale ice sheet models routinely rely on Glens flow relation, whichis an isotropic material constitutive relation that is not dependent on the character of the stress applied. However,laboratory experiments subjecting ice to simultaneous simple shear and compressive stresses (a typical situationin ice sheets) show that with sustained deformation under constant stresses, steady state viscous creep becomesanisotropic. For various combinations of simple shear and compression, results show that flow enhancement furtherincreases as the stress configuration becomes dominated by simple shear. The empirical, scalar, tertiary, anisotropicrheology (ESTAR) is a computationally-efficient flow relation that incorporates anisotropic effects through a parameterisationfor a flow enhancement factor that takes into account the proportion of simple shear in the overallstress regime. Here, we use the Ice Sheet System Model to investigate the impact of anisotropy on the dynamics ofan idealized ice shelf by comparing simulated flow fields using ESTAR with those of the standard (isotropic) Glenflow relation. When enhanced to match simple shear flow rates, the Glen flow relation overestimates velocities atthe ice-ocean front by up to 36%. Significantly, no single Glen enhancement factor accurately captures the spatialvariations in flow over the ice shelf produced by ESTAR. Our results have implications for reconstructions andprojections of sea level using ice sheet models that do not account for anisotropy. Conference Object Ice Sheet Ice Shelf eCite UTAS (University of Tasmania) |
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eCite UTAS (University of Tasmania) |
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ftunivtasecite |
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English |
topic |
Earth Sciences Physical Geography and Environmental Geoscience Glaciology |
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Earth Sciences Physical Geography and Environmental Geoscience Glaciology Graham, F Morlighem, M Warner, RC Treverrow, A The effect of anisotropy on simulated ice dynamics: an idealised ice shelf example using the Ice Sheet System Model |
topic_facet |
Earth Sciences Physical Geography and Environmental Geoscience Glaciology |
description |
An essential component of an ice sheet model is its description of how ice deforms under applied stresses itsmaterial constitutive relation. Current large-scale ice sheet models routinely rely on Glens flow relation, whichis an isotropic material constitutive relation that is not dependent on the character of the stress applied. However,laboratory experiments subjecting ice to simultaneous simple shear and compressive stresses (a typical situationin ice sheets) show that with sustained deformation under constant stresses, steady state viscous creep becomesanisotropic. For various combinations of simple shear and compression, results show that flow enhancement furtherincreases as the stress configuration becomes dominated by simple shear. The empirical, scalar, tertiary, anisotropicrheology (ESTAR) is a computationally-efficient flow relation that incorporates anisotropic effects through a parameterisationfor a flow enhancement factor that takes into account the proportion of simple shear in the overallstress regime. Here, we use the Ice Sheet System Model to investigate the impact of anisotropy on the dynamics ofan idealized ice shelf by comparing simulated flow fields using ESTAR with those of the standard (isotropic) Glenflow relation. When enhanced to match simple shear flow rates, the Glen flow relation overestimates velocities atthe ice-ocean front by up to 36%. Significantly, no single Glen enhancement factor accurately captures the spatialvariations in flow over the ice shelf produced by ESTAR. Our results have implications for reconstructions andprojections of sea level using ice sheet models that do not account for anisotropy. |
format |
Conference Object |
author |
Graham, F Morlighem, M Warner, RC Treverrow, A |
author_facet |
Graham, F Morlighem, M Warner, RC Treverrow, A |
author_sort |
Graham, F |
title |
The effect of anisotropy on simulated ice dynamics: an idealised ice shelf example using the Ice Sheet System Model |
title_short |
The effect of anisotropy on simulated ice dynamics: an idealised ice shelf example using the Ice Sheet System Model |
title_full |
The effect of anisotropy on simulated ice dynamics: an idealised ice shelf example using the Ice Sheet System Model |
title_fullStr |
The effect of anisotropy on simulated ice dynamics: an idealised ice shelf example using the Ice Sheet System Model |
title_full_unstemmed |
The effect of anisotropy on simulated ice dynamics: an idealised ice shelf example using the Ice Sheet System Model |
title_sort |
effect of anisotropy on simulated ice dynamics: an idealised ice shelf example using the ice sheet system model |
publisher |
Copernicus GmbH |
publishDate |
2017 |
url |
http://ecite.utas.edu.au/125963 |
genre |
Ice Sheet Ice Shelf |
genre_facet |
Ice Sheet Ice Shelf |
op_relation |
http://ecite.utas.edu.au/125963/1/2017_Graham_EGU_abstract.pdf Graham, F and Morlighem, M and Warner, RC and Treverrow, A, The effect of anisotropy on simulated ice dynamics: an idealised ice shelf example using the Ice Sheet System Model, Geophysical Research Abstracts, 23-28 April, Vienna, Austria, pp. 157. ISSN 1607-7962 (2017) [Conference Extract] http://ecite.utas.edu.au/125963 |
_version_ |
1766030358222995456 |