On the nonlinear viscosity of the orthotropic bulk rheology
Abstract We compare different ways the bulk flow nonlinearity of glacier ice can be captured in an orthotropic rheology. Specifically, we compare the unapproximated orthotropic rheology, derived from plastic potential theory, to existing approximations that assume either the nonlinear viscosity or f...
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2022
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Online Access: | http://dx.doi.org/10.1017/jog.2022.33 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143022000338 |
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crcambridgeupr:10.1017/jog.2022.33 2024-03-03T08:43:56+00:00 On the nonlinear viscosity of the orthotropic bulk rheology Rathmann, Nicholas M. Lilien, David A. Villum Fonden 2022 http://dx.doi.org/10.1017/jog.2022.33 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143022000338 en eng Cambridge University Press (CUP) https://creativecommons.org/licenses/by/4.0/ Journal of Glaciology volume 68, issue 272, page 1243-1248 ISSN 0022-1430 1727-5652 Earth-Surface Processes journal-article 2022 crcambridgeupr https://doi.org/10.1017/jog.2022.33 2024-02-08T08:37:21Z Abstract We compare different ways the bulk flow nonlinearity of glacier ice can be captured in an orthotropic rheology. Specifically, we compare the unapproximated orthotropic rheology, derived from plastic potential theory, to existing approximations that assume either the nonlinear viscosity or fluidity is identical to that of Glen's isotropic flow law. We find, overall, a reasonable agreement between the three orthotropic rheologies, and with existing Dye 3 ice-core deformation tests, although assuming Glen's viscosity provides the best approximation to the unapproximated rheology. Our results therefore suggest that previous studies based on either approximation to the orthotropic rheology are on relatively safe ground in the sense that both approximations generally agree with the unapproximated rheology and experimental data. Finally, we provide the forward and inverse analytical forms of all three rheologies for use in future numerical ice-flow modelling. Article in Journal/Newspaper Dye 3 Dye-3 ice core Journal of Glaciology Cambridge University Press Journal of Glaciology 1 6 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
topic |
Earth-Surface Processes |
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Earth-Surface Processes Rathmann, Nicholas M. Lilien, David A. On the nonlinear viscosity of the orthotropic bulk rheology |
topic_facet |
Earth-Surface Processes |
description |
Abstract We compare different ways the bulk flow nonlinearity of glacier ice can be captured in an orthotropic rheology. Specifically, we compare the unapproximated orthotropic rheology, derived from plastic potential theory, to existing approximations that assume either the nonlinear viscosity or fluidity is identical to that of Glen's isotropic flow law. We find, overall, a reasonable agreement between the three orthotropic rheologies, and with existing Dye 3 ice-core deformation tests, although assuming Glen's viscosity provides the best approximation to the unapproximated rheology. Our results therefore suggest that previous studies based on either approximation to the orthotropic rheology are on relatively safe ground in the sense that both approximations generally agree with the unapproximated rheology and experimental data. Finally, we provide the forward and inverse analytical forms of all three rheologies for use in future numerical ice-flow modelling. |
author2 |
Villum Fonden |
format |
Article in Journal/Newspaper |
author |
Rathmann, Nicholas M. Lilien, David A. |
author_facet |
Rathmann, Nicholas M. Lilien, David A. |
author_sort |
Rathmann, Nicholas M. |
title |
On the nonlinear viscosity of the orthotropic bulk rheology |
title_short |
On the nonlinear viscosity of the orthotropic bulk rheology |
title_full |
On the nonlinear viscosity of the orthotropic bulk rheology |
title_fullStr |
On the nonlinear viscosity of the orthotropic bulk rheology |
title_full_unstemmed |
On the nonlinear viscosity of the orthotropic bulk rheology |
title_sort |
on the nonlinear viscosity of the orthotropic bulk rheology |
publisher |
Cambridge University Press (CUP) |
publishDate |
2022 |
url |
http://dx.doi.org/10.1017/jog.2022.33 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143022000338 |
genre |
Dye 3 Dye-3 ice core Journal of Glaciology |
genre_facet |
Dye 3 Dye-3 ice core Journal of Glaciology |
op_source |
Journal of Glaciology volume 68, issue 272, page 1243-1248 ISSN 0022-1430 1727-5652 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/jog.2022.33 |
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Journal of Glaciology |
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1 |
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6 |
_version_ |
1792499402619748352 |