Suppression of marine ice sheet instability
A long-standing open question in glaciology concerns the propensity for ice sheets that lie predominantly submerged in the ocean (marine ice sheets) to destabilise under buoyancy. This paper addresses the processes by which a buoyancy-driven mechanism for the retreat and ultimate collapse of such ic...
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ftleedsuniv:oai:eprints.whiterose.ac.uk:137914 2023-05-15T13:57:46+02:00 Suppression of marine ice sheet instability Pegler, SS 2018-12-25 text https://eprints.whiterose.ac.uk/137914/ https://eprints.whiterose.ac.uk/137914/1/AAV_Pegler2018_P2.pdf en eng Cambridge University Press https://eprints.whiterose.ac.uk/137914/1/AAV_Pegler2018_P2.pdf Pegler, SS orcid.org/0000-0001-8373-2693 (2018) Suppression of marine ice sheet instability. Journal of Fluid Mechanics, 857. pp. 648-680. ISSN 0022-1120 Article NonPeerReviewed 2018 ftleedsuniv 2023-01-30T22:12:08Z A long-standing open question in glaciology concerns the propensity for ice sheets that lie predominantly submerged in the ocean (marine ice sheets) to destabilise under buoyancy. This paper addresses the processes by which a buoyancy-driven mechanism for the retreat and ultimate collapse of such ice sheets – the marine ice sheet instability – is suppressed by lateral stresses acting on its floating component (the ice shelf). The key results are to demonstrate the transition between a mode of stable (easily reversible) retreat along a stable steady-state branch created by ice-shelf buttressing to tipped (almost irreversible) retreat across a critical parametric threshold. The conditions for triggering tipped retreat can be controlled by the calving position and other properties of the ice-shelf profile and can be largely independent of basal stress, in contrast to principles established from studies of unbuttressed grounding-line dynamics. The stability and recovery conditions introduced by lateral stresses are analysed by developing a method of constructing grounding-line stability (bifurcation) diagrams, which provide a rapid assessment of the steady-state positions, their natures and the conditions for secondary grounding, giving clear visualisations of global stabilisation conditions. A further result is to reveal the possibility of a third structural component of a marine ice sheet that lies intermediate to the fully grounded and floating components. The region forms an extended grounding area in which the ice sheet lies very close to flotation, and there is no clearly distinguished grounding line. The formation of this region generates an upsurge in buttressing that provides the most feasible mechanism for reversal of a tipped grounding line. The results of this paper provide conceptual insight into the phenomena controlling the stability of the West Antarctic Ice Sheet, the collapse of which has the potential to dominate future contributions to global sea-level rise. Article in Journal/Newspaper Antarc* Antarctic Ice Sheet Ice Shelf White Rose Research Online (Universities of Leeds, Sheffield & York) Antarctic West Antarctic Ice Sheet |
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White Rose Research Online (Universities of Leeds, Sheffield & York) |
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ftleedsuniv |
language |
English |
description |
A long-standing open question in glaciology concerns the propensity for ice sheets that lie predominantly submerged in the ocean (marine ice sheets) to destabilise under buoyancy. This paper addresses the processes by which a buoyancy-driven mechanism for the retreat and ultimate collapse of such ice sheets – the marine ice sheet instability – is suppressed by lateral stresses acting on its floating component (the ice shelf). The key results are to demonstrate the transition between a mode of stable (easily reversible) retreat along a stable steady-state branch created by ice-shelf buttressing to tipped (almost irreversible) retreat across a critical parametric threshold. The conditions for triggering tipped retreat can be controlled by the calving position and other properties of the ice-shelf profile and can be largely independent of basal stress, in contrast to principles established from studies of unbuttressed grounding-line dynamics. The stability and recovery conditions introduced by lateral stresses are analysed by developing a method of constructing grounding-line stability (bifurcation) diagrams, which provide a rapid assessment of the steady-state positions, their natures and the conditions for secondary grounding, giving clear visualisations of global stabilisation conditions. A further result is to reveal the possibility of a third structural component of a marine ice sheet that lies intermediate to the fully grounded and floating components. The region forms an extended grounding area in which the ice sheet lies very close to flotation, and there is no clearly distinguished grounding line. The formation of this region generates an upsurge in buttressing that provides the most feasible mechanism for reversal of a tipped grounding line. The results of this paper provide conceptual insight into the phenomena controlling the stability of the West Antarctic Ice Sheet, the collapse of which has the potential to dominate future contributions to global sea-level rise. |
format |
Article in Journal/Newspaper |
author |
Pegler, SS |
spellingShingle |
Pegler, SS Suppression of marine ice sheet instability |
author_facet |
Pegler, SS |
author_sort |
Pegler, SS |
title |
Suppression of marine ice sheet instability |
title_short |
Suppression of marine ice sheet instability |
title_full |
Suppression of marine ice sheet instability |
title_fullStr |
Suppression of marine ice sheet instability |
title_full_unstemmed |
Suppression of marine ice sheet instability |
title_sort |
suppression of marine ice sheet instability |
publisher |
Cambridge University Press |
publishDate |
2018 |
url |
https://eprints.whiterose.ac.uk/137914/ https://eprints.whiterose.ac.uk/137914/1/AAV_Pegler2018_P2.pdf |
geographic |
Antarctic West Antarctic Ice Sheet |
geographic_facet |
Antarctic West Antarctic Ice Sheet |
genre |
Antarc* Antarctic Ice Sheet Ice Shelf |
genre_facet |
Antarc* Antarctic Ice Sheet Ice Shelf |
op_relation |
https://eprints.whiterose.ac.uk/137914/1/AAV_Pegler2018_P2.pdf Pegler, SS orcid.org/0000-0001-8373-2693 (2018) Suppression of marine ice sheet instability. Journal of Fluid Mechanics, 857. pp. 648-680. ISSN 0022-1120 |
_version_ |
1766265664056590336 |