Can unconfined ice shelves provide buttressing via hoop stresses?
The stress balance within an ice shelf is key to the resistance, or buttressing, it can provide and in part controls the rate of ice discharge from the upstream ice sheet. Unconfined ice shelves are widely assumed to provide no buttressing. However, theory and laboratory-scale analogue experiments h...
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Cambridge University Press
2020
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Online Access: | https://doi.org/10.1017/jog.2019.101 https://doaj.org/article/58f9d9f986ef4b119c88b76648fd34a0 |
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ftdoajarticles:oai:doaj.org/article:58f9d9f986ef4b119c88b76648fd34a0 2023-05-15T14:13:30+02:00 Can unconfined ice shelves provide buttressing via hoop stresses? Martin G. Wearing Jonathan Kingslake M. Grae Worster 2020-06-01T00:00:00Z https://doi.org/10.1017/jog.2019.101 https://doaj.org/article/58f9d9f986ef4b119c88b76648fd34a0 EN eng Cambridge University Press https://www.cambridge.org/core/product/identifier/S0022143019001011/type/journal_article https://doaj.org/toc/0022-1430 https://doaj.org/toc/1727-5652 doi:10.1017/jog.2019.101 0022-1430 1727-5652 https://doaj.org/article/58f9d9f986ef4b119c88b76648fd34a0 Journal of Glaciology, Vol 66, Pp 349-361 (2020) Antarctic glaciology ice shelves ice velocity ice dynamics ice-shelf break-up Environmental sciences GE1-350 Meteorology. Climatology QC851-999 article 2020 ftdoajarticles https://doi.org/10.1017/jog.2019.101 2023-03-12T01:30:57Z The stress balance within an ice shelf is key to the resistance, or buttressing, it can provide and in part controls the rate of ice discharge from the upstream ice sheet. Unconfined ice shelves are widely assumed to provide no buttressing. However, theory and laboratory-scale analogue experiments have shown that unconfined, floating viscous flows generate buttressing via hoop stresses. Hoop stress results from the viscous resistance to spreading perpendicular to the flow direction in a diverging flow. We build on theoretical work to explore the controls on the magnitude of hoop-stress buttressing, deducing that buttressing increases with increasing effective viscosity and increasing divergence. We use an idealised model calibrated to unconfined sections of Antarctic ice shelves and find that many shelves have low effective viscosity, most likely due to extensive damage resulting from high extensional stresses. Therefore, they are unable to sustain the large hoop stresses required to resist flow. Some ice shelves that are surrounded by sea ice year-round have a greater effective viscosity and can provide buttressing, suggesting that sea ice reduces fracturing. However, we find that most unconfined ice shelves provide insignificant buttressing today, even when hoop stresses are considered in the stress balance. Article in Journal/Newspaper Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Journal of Glaciology Sea ice Directory of Open Access Journals: DOAJ Articles Antarctic Journal of Glaciology 66 257 349 361 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Antarctic glaciology ice shelves ice velocity ice dynamics ice-shelf break-up Environmental sciences GE1-350 Meteorology. Climatology QC851-999 |
spellingShingle |
Antarctic glaciology ice shelves ice velocity ice dynamics ice-shelf break-up Environmental sciences GE1-350 Meteorology. Climatology QC851-999 Martin G. Wearing Jonathan Kingslake M. Grae Worster Can unconfined ice shelves provide buttressing via hoop stresses? |
topic_facet |
Antarctic glaciology ice shelves ice velocity ice dynamics ice-shelf break-up Environmental sciences GE1-350 Meteorology. Climatology QC851-999 |
description |
The stress balance within an ice shelf is key to the resistance, or buttressing, it can provide and in part controls the rate of ice discharge from the upstream ice sheet. Unconfined ice shelves are widely assumed to provide no buttressing. However, theory and laboratory-scale analogue experiments have shown that unconfined, floating viscous flows generate buttressing via hoop stresses. Hoop stress results from the viscous resistance to spreading perpendicular to the flow direction in a diverging flow. We build on theoretical work to explore the controls on the magnitude of hoop-stress buttressing, deducing that buttressing increases with increasing effective viscosity and increasing divergence. We use an idealised model calibrated to unconfined sections of Antarctic ice shelves and find that many shelves have low effective viscosity, most likely due to extensive damage resulting from high extensional stresses. Therefore, they are unable to sustain the large hoop stresses required to resist flow. Some ice shelves that are surrounded by sea ice year-round have a greater effective viscosity and can provide buttressing, suggesting that sea ice reduces fracturing. However, we find that most unconfined ice shelves provide insignificant buttressing today, even when hoop stresses are considered in the stress balance. |
format |
Article in Journal/Newspaper |
author |
Martin G. Wearing Jonathan Kingslake M. Grae Worster |
author_facet |
Martin G. Wearing Jonathan Kingslake M. Grae Worster |
author_sort |
Martin G. Wearing |
title |
Can unconfined ice shelves provide buttressing via hoop stresses? |
title_short |
Can unconfined ice shelves provide buttressing via hoop stresses? |
title_full |
Can unconfined ice shelves provide buttressing via hoop stresses? |
title_fullStr |
Can unconfined ice shelves provide buttressing via hoop stresses? |
title_full_unstemmed |
Can unconfined ice shelves provide buttressing via hoop stresses? |
title_sort |
can unconfined ice shelves provide buttressing via hoop stresses? |
publisher |
Cambridge University Press |
publishDate |
2020 |
url |
https://doi.org/10.1017/jog.2019.101 https://doaj.org/article/58f9d9f986ef4b119c88b76648fd34a0 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Journal of Glaciology Sea ice |
genre_facet |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Journal of Glaciology Sea ice |
op_source |
Journal of Glaciology, Vol 66, Pp 349-361 (2020) |
op_relation |
https://www.cambridge.org/core/product/identifier/S0022143019001011/type/journal_article https://doaj.org/toc/0022-1430 https://doaj.org/toc/1727-5652 doi:10.1017/jog.2019.101 0022-1430 1727-5652 https://doaj.org/article/58f9d9f986ef4b119c88b76648fd34a0 |
op_doi |
https://doi.org/10.1017/jog.2019.101 |
container_title |
Journal of Glaciology |
container_volume |
66 |
container_issue |
257 |
container_start_page |
349 |
op_container_end_page |
361 |
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1766285966047182848 |