Interaction of marine ice-sheet instabilities in two drainage basins: simple scaling of geometry and transition time
The initiation of a marine ice-sheet instability (MISI) is generally discussed from the ocean side of the ice sheet. It has been shown that the reduction in ice-shelf buttressing and softening of the coastal ice can destabilize a marine ice sheet if the bedrock is sloping upward towards the ocean. U...
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ftcopernicus:oai:publications.copernicus.org:tc26684 2023-05-15T16:40:07+02:00 Interaction of marine ice-sheet instabilities in two drainage basins: simple scaling of geometry and transition time Feldmann, J. Levermann, A. 2018-09-27 application/pdf https://doi.org/10.5194/tc-9-631-2015 https://tc.copernicus.org/articles/9/631/2015/ eng eng doi:10.5194/tc-9-631-2015 https://tc.copernicus.org/articles/9/631/2015/ eISSN: 1994-0424 Text 2018 ftcopernicus https://doi.org/10.5194/tc-9-631-2015 2020-07-20T16:24:41Z The initiation of a marine ice-sheet instability (MISI) is generally discussed from the ocean side of the ice sheet. It has been shown that the reduction in ice-shelf buttressing and softening of the coastal ice can destabilize a marine ice sheet if the bedrock is sloping upward towards the ocean. Using a conceptional flow-line geometry, we investigate the possibility of whether a MISI can be triggered from the direction of the ice divide as opposed to coastal forcing and explore the interaction between connected basins. We find that the initiation of a MISI in one basin can induce a destabilization in the other. The underlying mechanism of basin interaction is based on dynamic thinning and a consecutive motion of the ice divide which induces a thinning in the adjacent basin and a successive initiation of the instability. Our simplified and symmetric topographic setup allows scaling both the geometry and the transition time between both instabilities. We find that the ice profile follows a universal shape that is scaled with the horizontal extent of the ice sheet and that the same exponent of 1/2 applies for the scaling relation between central surface elevation and horizontal extent as in the pure shallow ice approximation (Vialov profile). Altering the central bed elevation, we find that the extent of grounding-line retreat in one basin determines the degree of interaction with the other. Different scenarios of basin interaction are discussed based on our modeling results as well as on a conceptual flux-balance analysis. We conclude that for the three-dimensional case, the possibility of drainage basin interaction on timescales on the order of 1 kyr or larger cannot be excluded and hence needs further investigation. Text Ice Sheet Ice Shelf Copernicus Publications: E-Journals Misi ENVELOPE(26.683,26.683,66.617,66.617) The Cryosphere 9 2 631 645 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
The initiation of a marine ice-sheet instability (MISI) is generally discussed from the ocean side of the ice sheet. It has been shown that the reduction in ice-shelf buttressing and softening of the coastal ice can destabilize a marine ice sheet if the bedrock is sloping upward towards the ocean. Using a conceptional flow-line geometry, we investigate the possibility of whether a MISI can be triggered from the direction of the ice divide as opposed to coastal forcing and explore the interaction between connected basins. We find that the initiation of a MISI in one basin can induce a destabilization in the other. The underlying mechanism of basin interaction is based on dynamic thinning and a consecutive motion of the ice divide which induces a thinning in the adjacent basin and a successive initiation of the instability. Our simplified and symmetric topographic setup allows scaling both the geometry and the transition time between both instabilities. We find that the ice profile follows a universal shape that is scaled with the horizontal extent of the ice sheet and that the same exponent of 1/2 applies for the scaling relation between central surface elevation and horizontal extent as in the pure shallow ice approximation (Vialov profile). Altering the central bed elevation, we find that the extent of grounding-line retreat in one basin determines the degree of interaction with the other. Different scenarios of basin interaction are discussed based on our modeling results as well as on a conceptual flux-balance analysis. We conclude that for the three-dimensional case, the possibility of drainage basin interaction on timescales on the order of 1 kyr or larger cannot be excluded and hence needs further investigation. |
format |
Text |
author |
Feldmann, J. Levermann, A. |
spellingShingle |
Feldmann, J. Levermann, A. Interaction of marine ice-sheet instabilities in two drainage basins: simple scaling of geometry and transition time |
author_facet |
Feldmann, J. Levermann, A. |
author_sort |
Feldmann, J. |
title |
Interaction of marine ice-sheet instabilities in two drainage basins: simple scaling of geometry and transition time |
title_short |
Interaction of marine ice-sheet instabilities in two drainage basins: simple scaling of geometry and transition time |
title_full |
Interaction of marine ice-sheet instabilities in two drainage basins: simple scaling of geometry and transition time |
title_fullStr |
Interaction of marine ice-sheet instabilities in two drainage basins: simple scaling of geometry and transition time |
title_full_unstemmed |
Interaction of marine ice-sheet instabilities in two drainage basins: simple scaling of geometry and transition time |
title_sort |
interaction of marine ice-sheet instabilities in two drainage basins: simple scaling of geometry and transition time |
publishDate |
2018 |
url |
https://doi.org/10.5194/tc-9-631-2015 https://tc.copernicus.org/articles/9/631/2015/ |
long_lat |
ENVELOPE(26.683,26.683,66.617,66.617) |
geographic |
Misi |
geographic_facet |
Misi |
genre |
Ice Sheet Ice Shelf |
genre_facet |
Ice Sheet Ice Shelf |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-9-631-2015 https://tc.copernicus.org/articles/9/631/2015/ |
op_doi |
https://doi.org/10.5194/tc-9-631-2015 |
container_title |
The Cryosphere |
container_volume |
9 |
container_issue |
2 |
container_start_page |
631 |
op_container_end_page |
645 |
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1766030484559626240 |