A Coupled Marine Ice-Stream – Ice-Shelf Model
Abstract Evidence as to the potential roles of marine ice flows in the dramatic climatological changes which have occurred from the late Pleistocene to the present is reviewed, indicating the need for careful modeling studies to evaluate several crucial hypotheses. A scale analysis of the flow of a...
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Language: | English |
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Cambridge University Press (CUP)
1987
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Online Access: | http://dx.doi.org/10.1017/s0022143000005281 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000005281 |
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crcambridgeupr:10.1017/s0022143000005281 2024-03-03T08:45:29+00:00 A Coupled Marine Ice-Stream – Ice-Shelf Model Muszynski, Isabelle Birchfield, G. E. 1987 http://dx.doi.org/10.1017/s0022143000005281 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000005281 en eng Cambridge University Press (CUP) Journal of Glaciology volume 33, issue 113, page 3-15 ISSN 0022-1430 1727-5652 Earth-Surface Processes journal-article 1987 crcambridgeupr https://doi.org/10.1017/s0022143000005281 2024-02-08T08:40:23Z Abstract Evidence as to the potential roles of marine ice flows in the dramatic climatological changes which have occurred from the late Pleistocene to the present is reviewed, indicating the need for careful modeling studies to evaluate several crucial hypotheses. A scale analysis of the flow of a marine ice stream coupled to a freely floating ice shelf is presented, in two dimensions and ignoring thermodynamic effects. With these limitations, the most important control of the dynamics of the ice stream is associated with first-order buoyancy effects related to the density contrast ∆ ρ / ρ w between ice and sea-water. It is shown that longitudinal stretching, arising from large gradients in basal sliding velocity, dominates shearing deformation provided the aspect ratio ω 2 « ∆ ρ / ρ w . The buoyancy control is established through the necessity of having continuously varying longitudinal strain-rates in the neighborhood of the grounding line. The scale analysis is the basis for derivation of a simplified model of a fast-flowing ice stream coupled to a freely floating ice shelf. The distance in the ice stream up-stream from the grounding line over which the above dynamic regime extends is estimated and found to be relatively insensitive to the basal sliding velocity and to the rheological constant of ice. A further potentially important feed-back mechanism between ice stream and ice shelf is associated with buoyancy corrections to the longitudinal deviatoric stress field. Article in Journal/Newspaper Ice Shelf Journal of Glaciology Cambridge University Press Journal of Glaciology 33 113 3 15 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
topic |
Earth-Surface Processes |
spellingShingle |
Earth-Surface Processes Muszynski, Isabelle Birchfield, G. E. A Coupled Marine Ice-Stream – Ice-Shelf Model |
topic_facet |
Earth-Surface Processes |
description |
Abstract Evidence as to the potential roles of marine ice flows in the dramatic climatological changes which have occurred from the late Pleistocene to the present is reviewed, indicating the need for careful modeling studies to evaluate several crucial hypotheses. A scale analysis of the flow of a marine ice stream coupled to a freely floating ice shelf is presented, in two dimensions and ignoring thermodynamic effects. With these limitations, the most important control of the dynamics of the ice stream is associated with first-order buoyancy effects related to the density contrast ∆ ρ / ρ w between ice and sea-water. It is shown that longitudinal stretching, arising from large gradients in basal sliding velocity, dominates shearing deformation provided the aspect ratio ω 2 « ∆ ρ / ρ w . The buoyancy control is established through the necessity of having continuously varying longitudinal strain-rates in the neighborhood of the grounding line. The scale analysis is the basis for derivation of a simplified model of a fast-flowing ice stream coupled to a freely floating ice shelf. The distance in the ice stream up-stream from the grounding line over which the above dynamic regime extends is estimated and found to be relatively insensitive to the basal sliding velocity and to the rheological constant of ice. A further potentially important feed-back mechanism between ice stream and ice shelf is associated with buoyancy corrections to the longitudinal deviatoric stress field. |
format |
Article in Journal/Newspaper |
author |
Muszynski, Isabelle Birchfield, G. E. |
author_facet |
Muszynski, Isabelle Birchfield, G. E. |
author_sort |
Muszynski, Isabelle |
title |
A Coupled Marine Ice-Stream – Ice-Shelf Model |
title_short |
A Coupled Marine Ice-Stream – Ice-Shelf Model |
title_full |
A Coupled Marine Ice-Stream – Ice-Shelf Model |
title_fullStr |
A Coupled Marine Ice-Stream – Ice-Shelf Model |
title_full_unstemmed |
A Coupled Marine Ice-Stream – Ice-Shelf Model |
title_sort |
coupled marine ice-stream – ice-shelf model |
publisher |
Cambridge University Press (CUP) |
publishDate |
1987 |
url |
http://dx.doi.org/10.1017/s0022143000005281 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000005281 |
genre |
Ice Shelf Journal of Glaciology |
genre_facet |
Ice Shelf Journal of Glaciology |
op_source |
Journal of Glaciology volume 33, issue 113, page 3-15 ISSN 0022-1430 1727-5652 |
op_doi |
https://doi.org/10.1017/s0022143000005281 |
container_title |
Journal of Glaciology |
container_volume |
33 |
container_issue |
113 |
container_start_page |
3 |
op_container_end_page |
15 |
_version_ |
1792501046569861120 |