Bed topography and marine ice-sheet stability
This paper examines the effect of basal topography and strength on the grounding-line position, flux and stability of rapidly-sliding ice streams. It does so by supposing that the buoyancy of the ice stream is small, and of the same order as the longitudinal stress gradient. Making this scaling assu...
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ftucl:oai:eprints.ucl.ac.uk.OAI2:10132440 2023-12-24T10:17:35+01:00 Bed topography and marine ice-sheet stability Sergienko, OV Wingham, DJ 2021-07-09 text https://discovery.ucl.ac.uk/id/eprint/10132440/1/Wingham_Bed%20topography%20and%20marine%20ice-sheet%20stability_AOP.pdf https://discovery.ucl.ac.uk/id/eprint/10132440/ eng eng https://discovery.ucl.ac.uk/id/eprint/10132440/1/Wingham_Bed%20topography%20and%20marine%20ice-sheet%20stability_AOP.pdf https://discovery.ucl.ac.uk/id/eprint/10132440/ open Journal of Glaciology (2021) (In press). Ice dynamics ice-sheet modelling ice streams Article 2021 ftucl 2023-11-27T13:07:27Z This paper examines the effect of basal topography and strength on the grounding-line position, flux and stability of rapidly-sliding ice streams. It does so by supposing that the buoyancy of the ice stream is small, and of the same order as the longitudinal stress gradient. Making this scaling assumption makes the role of the basal gradient and accumulation rate explicit in the lowest order expression for the ice flux at the grounding line and also provides the transcendental equation for the grounding-line position. It also introduces into the stability condition terms in the basal curvature and accumulation-rate gradient. These expressions revert to well-established expressions in circumstances in which the thickness gradient is large at the grounding line, a result which is shown to be the consequence of the non-linearity of the flow. The behaviour of the grounding-line flux is illustrated for a range of bed topographies and strengths. We show that, when bed topography at a horizontal scale of several tens of ice thicknesses is present, the grounding-line flux and stability have more complex dependencies on bed gradient than that associated with the ‘marine ice-sheet instability hypothesis’, and that unstable grounding-line positions can occur on prograde beds as well as stable positions on retrograde beds. Article in Journal/Newspaper Ice Sheet Journal of Glaciology University College London: UCL Discovery |
institution |
Open Polar |
collection |
University College London: UCL Discovery |
op_collection_id |
ftucl |
language |
English |
topic |
Ice dynamics ice-sheet modelling ice streams |
spellingShingle |
Ice dynamics ice-sheet modelling ice streams Sergienko, OV Wingham, DJ Bed topography and marine ice-sheet stability |
topic_facet |
Ice dynamics ice-sheet modelling ice streams |
description |
This paper examines the effect of basal topography and strength on the grounding-line position, flux and stability of rapidly-sliding ice streams. It does so by supposing that the buoyancy of the ice stream is small, and of the same order as the longitudinal stress gradient. Making this scaling assumption makes the role of the basal gradient and accumulation rate explicit in the lowest order expression for the ice flux at the grounding line and also provides the transcendental equation for the grounding-line position. It also introduces into the stability condition terms in the basal curvature and accumulation-rate gradient. These expressions revert to well-established expressions in circumstances in which the thickness gradient is large at the grounding line, a result which is shown to be the consequence of the non-linearity of the flow. The behaviour of the grounding-line flux is illustrated for a range of bed topographies and strengths. We show that, when bed topography at a horizontal scale of several tens of ice thicknesses is present, the grounding-line flux and stability have more complex dependencies on bed gradient than that associated with the ‘marine ice-sheet instability hypothesis’, and that unstable grounding-line positions can occur on prograde beds as well as stable positions on retrograde beds. |
format |
Article in Journal/Newspaper |
author |
Sergienko, OV Wingham, DJ |
author_facet |
Sergienko, OV Wingham, DJ |
author_sort |
Sergienko, OV |
title |
Bed topography and marine ice-sheet stability |
title_short |
Bed topography and marine ice-sheet stability |
title_full |
Bed topography and marine ice-sheet stability |
title_fullStr |
Bed topography and marine ice-sheet stability |
title_full_unstemmed |
Bed topography and marine ice-sheet stability |
title_sort |
bed topography and marine ice-sheet stability |
publishDate |
2021 |
url |
https://discovery.ucl.ac.uk/id/eprint/10132440/1/Wingham_Bed%20topography%20and%20marine%20ice-sheet%20stability_AOP.pdf https://discovery.ucl.ac.uk/id/eprint/10132440/ |
genre |
Ice Sheet Journal of Glaciology |
genre_facet |
Ice Sheet Journal of Glaciology |
op_source |
Journal of Glaciology (2021) (In press). |
op_relation |
https://discovery.ucl.ac.uk/id/eprint/10132440/1/Wingham_Bed%20topography%20and%20marine%20ice-sheet%20stability_AOP.pdf https://discovery.ucl.ac.uk/id/eprint/10132440/ |
op_rights |
open |
_version_ |
1786205832123252736 |