The evolution of isolated cavities and hydraulic connection at the glacier bed – Part 2: A dynamic viscoelastic model
Many large-scale subglacial drainage models implicitly or explicitly assume that the distributed part of the drainage system consists of subglacial cavities. Few of these models, however, consider the possibility of hydraulic disconnection, where cavities exist but are not numerous or large enough t...
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Copernicus Publications
2023
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ftdoajarticles:oai:doaj.org/article:ec8078bcdd17418a96004eef8771da99 2023-12-31T10:23:39+01:00 The evolution of isolated cavities and hydraulic connection at the glacier bed – Part 2: A dynamic viscoelastic model C. Schoof 2023-11-01T00:00:00Z https://doi.org/10.5194/tc-17-4817-2023 https://doaj.org/article/ec8078bcdd17418a96004eef8771da99 EN eng Copernicus Publications https://tc.copernicus.org/articles/17/4817/2023/tc-17-4817-2023.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-17-4817-2023 1994-0416 1994-0424 https://doaj.org/article/ec8078bcdd17418a96004eef8771da99 The Cryosphere, Vol 17, Pp 4817-4836 (2023) Environmental sciences GE1-350 Geology QE1-996.5 article 2023 ftdoajarticles https://doi.org/10.5194/tc-17-4817-2023 2023-12-03T01:39:04Z Many large-scale subglacial drainage models implicitly or explicitly assume that the distributed part of the drainage system consists of subglacial cavities. Few of these models, however, consider the possibility of hydraulic disconnection, where cavities exist but are not numerous or large enough to be pervasively connected with one another so that water can flow. Here I use a process-scale model for subglacial cavities to explore their evolution, focusing on the dynamics of connections that are made between cavities. The model uses a viscoelastic representation of ice and computes the pressure gradients that are necessary to move water around basal cavities as they grow or shrink. The latter model component sets the work here apart from previous studies of subglacial cavities and permits the model to represent the behaviour of isolated cavities as well as of uncavitated parts of the bed at low normal stress. I show that connections between cavities are made dynamically when the cavitation ratio (the fraction of the bed occupied by cavities) reaches a critical value due to decreases in effective pressure. I also show that existing simple models for cavitation ratio and for water sheet thickness (defined as mean water depth) fail to even qualitatively capture the behaviour predicted by the present model. Article in Journal/Newspaper The Cryosphere Directory of Open Access Journals: DOAJ Articles The Cryosphere 17 11 4817 4836 |
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Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 C. Schoof The evolution of isolated cavities and hydraulic connection at the glacier bed – Part 2: A dynamic viscoelastic model |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
Many large-scale subglacial drainage models implicitly or explicitly assume that the distributed part of the drainage system consists of subglacial cavities. Few of these models, however, consider the possibility of hydraulic disconnection, where cavities exist but are not numerous or large enough to be pervasively connected with one another so that water can flow. Here I use a process-scale model for subglacial cavities to explore their evolution, focusing on the dynamics of connections that are made between cavities. The model uses a viscoelastic representation of ice and computes the pressure gradients that are necessary to move water around basal cavities as they grow or shrink. The latter model component sets the work here apart from previous studies of subglacial cavities and permits the model to represent the behaviour of isolated cavities as well as of uncavitated parts of the bed at low normal stress. I show that connections between cavities are made dynamically when the cavitation ratio (the fraction of the bed occupied by cavities) reaches a critical value due to decreases in effective pressure. I also show that existing simple models for cavitation ratio and for water sheet thickness (defined as mean water depth) fail to even qualitatively capture the behaviour predicted by the present model. |
format |
Article in Journal/Newspaper |
author |
C. Schoof |
author_facet |
C. Schoof |
author_sort |
C. Schoof |
title |
The evolution of isolated cavities and hydraulic connection at the glacier bed – Part 2: A dynamic viscoelastic model |
title_short |
The evolution of isolated cavities and hydraulic connection at the glacier bed – Part 2: A dynamic viscoelastic model |
title_full |
The evolution of isolated cavities and hydraulic connection at the glacier bed – Part 2: A dynamic viscoelastic model |
title_fullStr |
The evolution of isolated cavities and hydraulic connection at the glacier bed – Part 2: A dynamic viscoelastic model |
title_full_unstemmed |
The evolution of isolated cavities and hydraulic connection at the glacier bed – Part 2: A dynamic viscoelastic model |
title_sort |
evolution of isolated cavities and hydraulic connection at the glacier bed – part 2: a dynamic viscoelastic model |
publisher |
Copernicus Publications |
publishDate |
2023 |
url |
https://doi.org/10.5194/tc-17-4817-2023 https://doaj.org/article/ec8078bcdd17418a96004eef8771da99 |
genre |
The Cryosphere |
genre_facet |
The Cryosphere |
op_source |
The Cryosphere, Vol 17, Pp 4817-4836 (2023) |
op_relation |
https://tc.copernicus.org/articles/17/4817/2023/tc-17-4817-2023.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-17-4817-2023 1994-0416 1994-0424 https://doaj.org/article/ec8078bcdd17418a96004eef8771da99 |
op_doi |
https://doi.org/10.5194/tc-17-4817-2023 |
container_title |
The Cryosphere |
container_volume |
17 |
container_issue |
11 |
container_start_page |
4817 |
op_container_end_page |
4836 |
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1786835393584300032 |