The evolution of isolated cavities and hydraulic connection at the glacier bed – Part 1: Steady states and friction laws
<p>Models of subglacial drainage and of cavity formation generally assume that the glacier bed is pervasively hydraulically connected. A growing body of field observations indicates that this assumption is frequently violated in practice. In this paper, I use an extension of existing models...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2023-11-01
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| Series: | The Cryosphere |
| Online Access: | https://tc.copernicus.org/articles/17/4797/2023/tc-17-4797-2023.pdf |
| _version_ | 1827762312366260224 |
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| author | C. Schoof |
| author_facet | C. Schoof |
| author_sort | C. Schoof |
| collection | DOAJ |
| description | <p>Models of subglacial drainage and of cavity formation generally assume that the glacier bed is pervasively hydraulically connected. A growing body of field observations indicates that this assumption is frequently violated in practice. In this paper, I use an extension of existing models of steady-state cavitation to study the formation of hydraulically isolated, uncavitated, low-pressure regions of the bed, which would become flooded if they had access to the subglacial drainage system. I also study their natural counterpart, hydraulically isolated cavities that would drain if they had access to the subglacial drainage system. I show that connections to the drainage system are made at two different sets of critical effective pressure, a lower one at which uncavitated low-pressure regions connect to the drainage system and a higher one at which isolated cavities do the same. I also show that the extent of cavitation, determined by the history of connections made at the bed, has a dominant effect on basal drag while remaining outside the realm of previously employed basal friction laws: changes in basal effective pressure alone may have a minor effect on basal drag until a connection between a cavity and an uncavitated low-pressure region of the bed is made, at which point a drastic and irreversible drop in drag occurs. These results point to the need to expand basal friction and drainage models to include a description of basal connectivity.</p> |
| first_indexed | 2024-03-11T10:27:48Z |
| format | Article |
| id | doaj.art-9475592bab55476397c51159322ce5de |
| institution | Directory Open Access Journal |
| issn | 1994-0416 1994-0424 |
| language | English |
| last_indexed | 2024-03-11T10:27:48Z |
| publishDate | 2023-11-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | The Cryosphere |
| spelling | doaj.art-9475592bab55476397c51159322ce5de2023-11-15T10:06:10ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242023-11-01174797481510.5194/tc-17-4797-2023The evolution of isolated cavities and hydraulic connection at the glacier bed – Part 1: Steady states and friction lawsC. Schoof<p>Models of subglacial drainage and of cavity formation generally assume that the glacier bed is pervasively hydraulically connected. A growing body of field observations indicates that this assumption is frequently violated in practice. In this paper, I use an extension of existing models of steady-state cavitation to study the formation of hydraulically isolated, uncavitated, low-pressure regions of the bed, which would become flooded if they had access to the subglacial drainage system. I also study their natural counterpart, hydraulically isolated cavities that would drain if they had access to the subglacial drainage system. I show that connections to the drainage system are made at two different sets of critical effective pressure, a lower one at which uncavitated low-pressure regions connect to the drainage system and a higher one at which isolated cavities do the same. I also show that the extent of cavitation, determined by the history of connections made at the bed, has a dominant effect on basal drag while remaining outside the realm of previously employed basal friction laws: changes in basal effective pressure alone may have a minor effect on basal drag until a connection between a cavity and an uncavitated low-pressure region of the bed is made, at which point a drastic and irreversible drop in drag occurs. These results point to the need to expand basal friction and drainage models to include a description of basal connectivity.</p>https://tc.copernicus.org/articles/17/4797/2023/tc-17-4797-2023.pdf |
| spellingShingle | C. Schoof The evolution of isolated cavities and hydraulic connection at the glacier bed – Part 1: Steady states and friction laws The Cryosphere |
| title | The evolution of isolated cavities and hydraulic connection at the glacier bed – Part 1: Steady states and friction laws |
| title_full | The evolution of isolated cavities and hydraulic connection at the glacier bed – Part 1: Steady states and friction laws |
| title_fullStr | The evolution of isolated cavities and hydraulic connection at the glacier bed – Part 1: Steady states and friction laws |
| title_full_unstemmed | The evolution of isolated cavities and hydraulic connection at the glacier bed – Part 1: Steady states and friction laws |
| title_short | The evolution of isolated cavities and hydraulic connection at the glacier bed – Part 1: Steady states and friction laws |
| title_sort | evolution of isolated cavities and hydraulic connection at the glacier bed part 1 steady states and friction laws |
| url | https://tc.copernicus.org/articles/17/4797/2023/tc-17-4797-2023.pdf |
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