Sliding over anisotropic beds
Many glacier beds are anisotropic, by which is meant that the dominant wavelengths are different in the two map-plane directions. A largely unexplored consequence of Nye-Kamb sliding theory is the fact that an anisotropic bed can produce a sliding velocity not parallel to the tangential traction vec...
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2000
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ftnerc:oai:nora.nerc.ac.uk:20577 2023-05-15T13:29:19+02:00 Sliding over anisotropic beds Hindmarsh, Richard C.A. 2000 http://nora.nerc.ac.uk/id/eprint/20577/ https://doi.org/10.3189/172756400781820840 unknown International Glaciological Society Hindmarsh, Richard C.A. orcid:0000-0003-1633-2416 . 2000 Sliding over anisotropic beds. Annals of Glaciology, 30 (1). 137-145. https://doi.org/10.3189/172756400781820840 <https://doi.org/10.3189/172756400781820840> Publication - Article PeerReviewed 2000 ftnerc https://doi.org/10.3189/172756400781820840 2023-02-04T19:33:00Z Many glacier beds are anisotropic, by which is meant that the dominant wavelengths are different in the two map-plane directions. A largely unexplored consequence of Nye-Kamb sliding theory is the fact that an anisotropic bed can produce a sliding velocity not parallel to the tangential traction vector. This has important consequences, since observations of non-parallel flow are often taken as indications that the shallow-ice approximation has broken down, whereas this need not be the case with an anisotropic bed. Mathematically, this effect can be incorporated through the use of a sliding tensor. The mathematical properties of this tensor are outlined, and the correct "invariant" for the sliding law, a quadratic form, is deduced. Nye-Kamb theory for anisotropic beds is discussed. Flow on the infinite plane and the properties of surface-topography diffusion are elucidated. The properities of kinematic waves and shock waves are discussed. Kinematic waves can have a lateral component. Numerical computations of ice-sheet flow on beds with anisotropic roughness are presented, with emphasis placed on how this affects divide-ridge structure. It is suggested that cold-based ice sheets, which have an anisotropic bed affecting the shear layer, may also show non-parallelism of surface slope and velocity. Article in Journal/Newspaper Annals of Glaciology Ice Sheet Natural Environment Research Council: NERC Open Research Archive Annals of Glaciology 30 137 145 |
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Natural Environment Research Council: NERC Open Research Archive |
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Many glacier beds are anisotropic, by which is meant that the dominant wavelengths are different in the two map-plane directions. A largely unexplored consequence of Nye-Kamb sliding theory is the fact that an anisotropic bed can produce a sliding velocity not parallel to the tangential traction vector. This has important consequences, since observations of non-parallel flow are often taken as indications that the shallow-ice approximation has broken down, whereas this need not be the case with an anisotropic bed. Mathematically, this effect can be incorporated through the use of a sliding tensor. The mathematical properties of this tensor are outlined, and the correct "invariant" for the sliding law, a quadratic form, is deduced. Nye-Kamb theory for anisotropic beds is discussed. Flow on the infinite plane and the properties of surface-topography diffusion are elucidated. The properities of kinematic waves and shock waves are discussed. Kinematic waves can have a lateral component. Numerical computations of ice-sheet flow on beds with anisotropic roughness are presented, with emphasis placed on how this affects divide-ridge structure. It is suggested that cold-based ice sheets, which have an anisotropic bed affecting the shear layer, may also show non-parallelism of surface slope and velocity. |
format |
Article in Journal/Newspaper |
author |
Hindmarsh, Richard C.A. |
spellingShingle |
Hindmarsh, Richard C.A. Sliding over anisotropic beds |
author_facet |
Hindmarsh, Richard C.A. |
author_sort |
Hindmarsh, Richard C.A. |
title |
Sliding over anisotropic beds |
title_short |
Sliding over anisotropic beds |
title_full |
Sliding over anisotropic beds |
title_fullStr |
Sliding over anisotropic beds |
title_full_unstemmed |
Sliding over anisotropic beds |
title_sort |
sliding over anisotropic beds |
publisher |
International Glaciological Society |
publishDate |
2000 |
url |
http://nora.nerc.ac.uk/id/eprint/20577/ https://doi.org/10.3189/172756400781820840 |
genre |
Annals of Glaciology Ice Sheet |
genre_facet |
Annals of Glaciology Ice Sheet |
op_relation |
Hindmarsh, Richard C.A. orcid:0000-0003-1633-2416 . 2000 Sliding over anisotropic beds. Annals of Glaciology, 30 (1). 137-145. https://doi.org/10.3189/172756400781820840 <https://doi.org/10.3189/172756400781820840> |
op_doi |
https://doi.org/10.3189/172756400781820840 |
container_title |
Annals of Glaciology |
container_volume |
30 |
container_start_page |
137 |
op_container_end_page |
145 |
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1765999915669913600 |