Ice Shelves: A Review
Abstract Ice shelves form where ice flows off the Antarctic ice sheet onto the sea to produce rather flat slabs of floating ice which, for the theoretician, are the simplest of all large ice masses. Boundary conditions are well defined, conditions change very slowly over distances that are large com...
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Online Access: | http://dx.doi.org/10.1017/s0022143000014799 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000014799 |
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crcambridgeupr:10.1017/s0022143000014799 2024-09-09T18:59:27+00:00 Ice Shelves: A Review Thomas, Robert H. 1979 http://dx.doi.org/10.1017/s0022143000014799 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000014799 en eng Cambridge University Press (CUP) Journal of Glaciology volume 24, issue 90, page 273-286 ISSN 0022-1430 1727-5652 journal-article 1979 crcambridgeupr https://doi.org/10.1017/s0022143000014799 2024-07-24T04:02:51Z Abstract Ice shelves form where ice flows off the Antarctic ice sheet onto the sea to produce rather flat slabs of floating ice which, for the theoretician, are the simplest of all large ice masses. Boundary conditions are well defined, conditions change very slowly over distances that are large compared with ice thickness, and horizontal velocities are independent of depth. Unconfined ice shelves can be used as giant creep machines to investigate the ice flow law at low stresses. Further inland, where movement is hampered by obstructions such as grounded ice rises and by shear between the ice shelf and its sides, the ice shelf transmits a backpressure which tends to restrict drainage from the ice sheets that feed it. Wastage from ice shelves is principally by calving and by bottom melting. There has been no direct measurement of bottom-melting rates, but indirect evidence suggests that, near the seaward edges of ice shelves, bottom-melting rates may exceed one metre per year, with significant melting within about 100 km of the ice front. Further inland there may be bottom freezing, and analysis of cores taken from the Amery Ice Shelf indicate that bottom-freezing rates average 0.5 m a –1 over a distance of 200 km. Such high freezing-rates are probably exceptional, and, beneath the Ross Ice Shelf, freezing appears to be insignificant even at a distance of 400 km from the ice front. Because of their accessibility ice shelves have been studied in considerable detail, but many problems remain. In particular we need to improve our understanding of basal flux, ice-shelf dynamics near the grounding line, the calving of icebergs, and the state of equilibrium of ice rises. In addition there is a clear need for basic data from the Filchner-Ronne ice shelf. Article in Journal/Newspaper Amery Ice Shelf Antarc* Antarctic Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Sheet Ice Shelf Ice Shelves Iceberg* Journal of Glaciology Ronne Ice Shelf Ross Ice Shelf Cambridge University Press Amery ENVELOPE(-94.063,-94.063,56.565,56.565) Amery Ice Shelf ENVELOPE(71.000,71.000,-69.750,-69.750) Antarctic Ronne Ice Shelf ENVELOPE(-61.000,-61.000,-78.500,-78.500) Ross Ice Shelf The Antarctic Journal of Glaciology 24 90 273 286 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
Abstract Ice shelves form where ice flows off the Antarctic ice sheet onto the sea to produce rather flat slabs of floating ice which, for the theoretician, are the simplest of all large ice masses. Boundary conditions are well defined, conditions change very slowly over distances that are large compared with ice thickness, and horizontal velocities are independent of depth. Unconfined ice shelves can be used as giant creep machines to investigate the ice flow law at low stresses. Further inland, where movement is hampered by obstructions such as grounded ice rises and by shear between the ice shelf and its sides, the ice shelf transmits a backpressure which tends to restrict drainage from the ice sheets that feed it. Wastage from ice shelves is principally by calving and by bottom melting. There has been no direct measurement of bottom-melting rates, but indirect evidence suggests that, near the seaward edges of ice shelves, bottom-melting rates may exceed one metre per year, with significant melting within about 100 km of the ice front. Further inland there may be bottom freezing, and analysis of cores taken from the Amery Ice Shelf indicate that bottom-freezing rates average 0.5 m a –1 over a distance of 200 km. Such high freezing-rates are probably exceptional, and, beneath the Ross Ice Shelf, freezing appears to be insignificant even at a distance of 400 km from the ice front. Because of their accessibility ice shelves have been studied in considerable detail, but many problems remain. In particular we need to improve our understanding of basal flux, ice-shelf dynamics near the grounding line, the calving of icebergs, and the state of equilibrium of ice rises. In addition there is a clear need for basic data from the Filchner-Ronne ice shelf. |
format |
Article in Journal/Newspaper |
author |
Thomas, Robert H. |
spellingShingle |
Thomas, Robert H. Ice Shelves: A Review |
author_facet |
Thomas, Robert H. |
author_sort |
Thomas, Robert H. |
title |
Ice Shelves: A Review |
title_short |
Ice Shelves: A Review |
title_full |
Ice Shelves: A Review |
title_fullStr |
Ice Shelves: A Review |
title_full_unstemmed |
Ice Shelves: A Review |
title_sort |
ice shelves: a review |
publisher |
Cambridge University Press (CUP) |
publishDate |
1979 |
url |
http://dx.doi.org/10.1017/s0022143000014799 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000014799 |
long_lat |
ENVELOPE(-94.063,-94.063,56.565,56.565) ENVELOPE(71.000,71.000,-69.750,-69.750) ENVELOPE(-61.000,-61.000,-78.500,-78.500) |
geographic |
Amery Amery Ice Shelf Antarctic Ronne Ice Shelf Ross Ice Shelf The Antarctic |
geographic_facet |
Amery Amery Ice Shelf Antarctic Ronne Ice Shelf Ross Ice Shelf The Antarctic |
genre |
Amery Ice Shelf Antarc* Antarctic Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Sheet Ice Shelf Ice Shelves Iceberg* Journal of Glaciology Ronne Ice Shelf Ross Ice Shelf |
genre_facet |
Amery Ice Shelf Antarc* Antarctic Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Sheet Ice Shelf Ice Shelves Iceberg* Journal of Glaciology Ronne Ice Shelf Ross Ice Shelf |
op_source |
Journal of Glaciology volume 24, issue 90, page 273-286 ISSN 0022-1430 1727-5652 |
op_doi |
https://doi.org/10.1017/s0022143000014799 |
container_title |
Journal of Glaciology |
container_volume |
24 |
container_issue |
90 |
container_start_page |
273 |
op_container_end_page |
286 |
_version_ |
1809933827458465792 |