‘Stable’ and ‘unstable’ are not useful descriptions of marine ice sheets in the Earth's climate system
Investigations of the time-dependent behavior of marine ice sheets and their sensitivity to basal conditions require numerical models because existing theoretical analyses focus only on steady-state configurations primarily with a power-law basal shear stress. Numerical results indicate that the cho...
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Cambridge University Press (CUP)
2023
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Online Access: | http://dx.doi.org/10.1017/jog.2023.40 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143023000400 |
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crcambridgeupr:10.1017/jog.2023.40 2024-09-30T14:36:37+00:00 ‘Stable’ and ‘unstable’ are not useful descriptions of marine ice sheets in the Earth's climate system Sergienko, Olga Haseloff, Marianne Climate Program Office National Science Foundation 2023 http://dx.doi.org/10.1017/jog.2023.40 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143023000400 en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0/ Journal of Glaciology volume 69, issue 277, page 1483-1499 ISSN 0022-1430 1727-5652 journal-article 2023 crcambridgeupr https://doi.org/10.1017/jog.2023.40 2024-09-18T04:03:33Z Investigations of the time-dependent behavior of marine ice sheets and their sensitivity to basal conditions require numerical models because existing theoretical analyses focus only on steady-state configurations primarily with a power-law basal shear stress. Numerical results indicate that the choice of the sliding law strongly affects ice-sheet dynamic behavior. Although observed or simulated grounding-line retreat is typically interpreted as an indication of marine ice sheet instability introduced by Weertman (1974), this (in)stability is a characteristic of the ice sheet's steady states – not time-variant behavior. To bridge the gap between theoretical and numerical results, we develop a framework to investigate grounding line dynamics with generalized basal and lateral stresses (i.e. the functional dependencies are not specified). Motivated by observations of internal variability of the Southern Ocean conditions we explore the grounding-line response to stochastic variability. We find that adding stochastic variability to submarine melt rates that produced stable steady-state configurations leads to intermittently advancing and retreating grounding lines. They can also retreat in an unstoppable manner on time-scales significantly longer than the stochastic correlation time-scales. These results suggest that at any given time of their evolution, the transient behavior of marine ice sheets cannot be described in terms of ‘stable’ or ‘unstable’. Article in Journal/Newspaper Ice Sheet Journal of Glaciology Southern Ocean Cambridge University Press Southern Ocean Weertman ENVELOPE(-67.753,-67.753,-66.972,-66.972) Journal of Glaciology 69 277 1483 1499 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
Investigations of the time-dependent behavior of marine ice sheets and their sensitivity to basal conditions require numerical models because existing theoretical analyses focus only on steady-state configurations primarily with a power-law basal shear stress. Numerical results indicate that the choice of the sliding law strongly affects ice-sheet dynamic behavior. Although observed or simulated grounding-line retreat is typically interpreted as an indication of marine ice sheet instability introduced by Weertman (1974), this (in)stability is a characteristic of the ice sheet's steady states – not time-variant behavior. To bridge the gap between theoretical and numerical results, we develop a framework to investigate grounding line dynamics with generalized basal and lateral stresses (i.e. the functional dependencies are not specified). Motivated by observations of internal variability of the Southern Ocean conditions we explore the grounding-line response to stochastic variability. We find that adding stochastic variability to submarine melt rates that produced stable steady-state configurations leads to intermittently advancing and retreating grounding lines. They can also retreat in an unstoppable manner on time-scales significantly longer than the stochastic correlation time-scales. These results suggest that at any given time of their evolution, the transient behavior of marine ice sheets cannot be described in terms of ‘stable’ or ‘unstable’. |
author2 |
Climate Program Office National Science Foundation |
format |
Article in Journal/Newspaper |
author |
Sergienko, Olga Haseloff, Marianne |
spellingShingle |
Sergienko, Olga Haseloff, Marianne ‘Stable’ and ‘unstable’ are not useful descriptions of marine ice sheets in the Earth's climate system |
author_facet |
Sergienko, Olga Haseloff, Marianne |
author_sort |
Sergienko, Olga |
title |
‘Stable’ and ‘unstable’ are not useful descriptions of marine ice sheets in the Earth's climate system |
title_short |
‘Stable’ and ‘unstable’ are not useful descriptions of marine ice sheets in the Earth's climate system |
title_full |
‘Stable’ and ‘unstable’ are not useful descriptions of marine ice sheets in the Earth's climate system |
title_fullStr |
‘Stable’ and ‘unstable’ are not useful descriptions of marine ice sheets in the Earth's climate system |
title_full_unstemmed |
‘Stable’ and ‘unstable’ are not useful descriptions of marine ice sheets in the Earth's climate system |
title_sort |
‘stable’ and ‘unstable’ are not useful descriptions of marine ice sheets in the earth's climate system |
publisher |
Cambridge University Press (CUP) |
publishDate |
2023 |
url |
http://dx.doi.org/10.1017/jog.2023.40 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143023000400 |
long_lat |
ENVELOPE(-67.753,-67.753,-66.972,-66.972) |
geographic |
Southern Ocean Weertman |
geographic_facet |
Southern Ocean Weertman |
genre |
Ice Sheet Journal of Glaciology Southern Ocean |
genre_facet |
Ice Sheet Journal of Glaciology Southern Ocean |
op_source |
Journal of Glaciology volume 69, issue 277, page 1483-1499 ISSN 0022-1430 1727-5652 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/jog.2023.40 |
container_title |
Journal of Glaciology |
container_volume |
69 |
container_issue |
277 |
container_start_page |
1483 |
op_container_end_page |
1499 |
_version_ |
1811639650637316096 |