Preprints
https://doi.org/10.5194/egusphere-2022-1380
https://doi.org/10.5194/egusphere-2022-1380
09 Jan 2023
 | 09 Jan 2023

The evolution of isolated cavities and hydraulic connection at the glacier bed. Part 1: steady states and friction laws

Christian Schoof

Abstract. 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.

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Journal article(s) based on this preprint

15 Nov 2023
The evolution of isolated cavities and hydraulic connection at the glacier bed – Part 1: Steady states and friction laws
Christian Schoof
The Cryosphere, 17, 4797–4815, https://doi.org/10.5194/tc-17-4797-2023,https://doi.org/10.5194/tc-17-4797-2023, 2023
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

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Computational models that seek to predict the future behaviour of ice sheets and glaciers...
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