Hysteretic evolution of ice rises and ice rumples in response to variations in sea level
Ice rises and ice rumples are locally grounded features found in coastal Antarctica and are surrounded by otherwise freely floating ice shelves. An ice rise has an independent flow regime, whereas the flow regime of an ice rumple conforms to that of the ice shelf and merely slows the flow of ice. In bot...
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00060741 2023-05-15T13:49:21+02:00 Hysteretic evolution of ice rises and ice rumples in response to variations in sea level Henry, A. Clara J. Drews, Reinhard Schannwell, Clemens Višnjević, Vjeran 2022-04 electronic https://doi.org/10.5194/egusphere-2022-128 https://noa.gwlb.de/receive/cop_mods_00060741 https://egusphere.copernicus.org/preprints/egusphere-2022-128/egusphere-2022-128.pdf eng eng Copernicus Publications https://doi.org/10.5194/egusphere-2022-128 https://noa.gwlb.de/receive/cop_mods_00060741 https://egusphere.copernicus.org/preprints/egusphere-2022-128/egusphere-2022-128.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/restrictedAccess CC-BY article Verlagsveröffentlichung article Text doc-type:article 2022 ftnonlinearchiv https://doi.org/10.5194/egusphere-2022-128 2022-05-01T23:09:44Z Ice rises and ice rumples are locally grounded features found in coastal Antarctica and are surrounded by otherwise freely floating ice shelves. An ice rise has an independent flow regime, whereas the flow regime of an ice rumple conforms to that of the ice shelf and merely slows the flow of ice. In both cases, local highs in the bathymetry are in contact with the ice shelf from below, thereby regulating the large-scale ice flow, with implications for the upstream continental grounding line position. This buttressing effect, paired with the suitability of ice rises as a climate archive, necessitates a better understanding of the transition between ice rise and ice rumple, their evolution in response to a change in sea level, and their dynamic interaction with the surrounding ice shelf. We investigate this behaviour using a three-dimensional full Stokes ice flow model. The simulations span end-member basal friction scenarios of almost stagnant and fully sliding ice at the ice-bed interface. We analyse the coupling with the surrounding ice shelf by comparing the deviations between the non-local full Stokes surface velocities and the local shallow ice approximation (SIA). Deviations are generally high at the ice divides and small on the lee sides. On the stoss side, where ice rise and ice shelf have opposing flow directions, deviations can be significant. Differences are negligible in the absence of basal sliding where the corresponding steady state ice rise is larger and develops a fully independent flow regime that is well described by SIA. When sea level is increased and a transition from ice rise to ice rumple is approached, the divide migration is more abrupt the higher the basal friction. In each scenario, the transition occurs after the stoss side grounding line has moved over the bed high and is positioned on a retrograde slope. We identify a hysteretic response of ice rises and ice rumples to changes in sea level, with grounded area being larger in a sea level increase scenario than in a sea level decrease scenario. This hysteresis not only shows irreversibility following an equal increase and subsequent decrease in sea level, but also has important implications for ice flow model initialisation. The initial grounded area needs to be carefully considered, as this will determine the formation of either an ice rise or an ice rumple, thereby causing different buttressing effects. Article in Journal/Newspaper Antarc* Antarctica Ice Shelf Ice Shelves Niedersächsisches Online-Archiv NOA |
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English |
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article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Henry, A. Clara J. Drews, Reinhard Schannwell, Clemens Višnjević, Vjeran Hysteretic evolution of ice rises and ice rumples in response to variations in sea level |
topic_facet |
article Verlagsveröffentlichung |
description |
Ice rises and ice rumples are locally grounded features found in coastal Antarctica and are surrounded by otherwise freely floating ice shelves. An ice rise has an independent flow regime, whereas the flow regime of an ice rumple conforms to that of the ice shelf and merely slows the flow of ice. In both cases, local highs in the bathymetry are in contact with the ice shelf from below, thereby regulating the large-scale ice flow, with implications for the upstream continental grounding line position. This buttressing effect, paired with the suitability of ice rises as a climate archive, necessitates a better understanding of the transition between ice rise and ice rumple, their evolution in response to a change in sea level, and their dynamic interaction with the surrounding ice shelf. We investigate this behaviour using a three-dimensional full Stokes ice flow model. The simulations span end-member basal friction scenarios of almost stagnant and fully sliding ice at the ice-bed interface. We analyse the coupling with the surrounding ice shelf by comparing the deviations between the non-local full Stokes surface velocities and the local shallow ice approximation (SIA). Deviations are generally high at the ice divides and small on the lee sides. On the stoss side, where ice rise and ice shelf have opposing flow directions, deviations can be significant. Differences are negligible in the absence of basal sliding where the corresponding steady state ice rise is larger and develops a fully independent flow regime that is well described by SIA. When sea level is increased and a transition from ice rise to ice rumple is approached, the divide migration is more abrupt the higher the basal friction. In each scenario, the transition occurs after the stoss side grounding line has moved over the bed high and is positioned on a retrograde slope. We identify a hysteretic response of ice rises and ice rumples to changes in sea level, with grounded area being larger in a sea level increase scenario than in a sea level decrease scenario. This hysteresis not only shows irreversibility following an equal increase and subsequent decrease in sea level, but also has important implications for ice flow model initialisation. The initial grounded area needs to be carefully considered, as this will determine the formation of either an ice rise or an ice rumple, thereby causing different buttressing effects. |
format |
Article in Journal/Newspaper |
author |
Henry, A. Clara J. Drews, Reinhard Schannwell, Clemens Višnjević, Vjeran |
author_facet |
Henry, A. Clara J. Drews, Reinhard Schannwell, Clemens Višnjević, Vjeran |
author_sort |
Henry, A. Clara J. |
title |
Hysteretic evolution of ice rises and ice rumples in response to variations in sea level |
title_short |
Hysteretic evolution of ice rises and ice rumples in response to variations in sea level |
title_full |
Hysteretic evolution of ice rises and ice rumples in response to variations in sea level |
title_fullStr |
Hysteretic evolution of ice rises and ice rumples in response to variations in sea level |
title_full_unstemmed |
Hysteretic evolution of ice rises and ice rumples in response to variations in sea level |
title_sort |
hysteretic evolution of ice rises and ice rumples in response to variations in sea level |
publisher |
Copernicus Publications |
publishDate |
2022 |
url |
https://doi.org/10.5194/egusphere-2022-128 https://noa.gwlb.de/receive/cop_mods_00060741 https://egusphere.copernicus.org/preprints/egusphere-2022-128/egusphere-2022-128.pdf |
genre |
Antarc* Antarctica Ice Shelf Ice Shelves |
genre_facet |
Antarc* Antarctica Ice Shelf Ice Shelves |
op_relation |
https://doi.org/10.5194/egusphere-2022-128 https://noa.gwlb.de/receive/cop_mods_00060741 https://egusphere.copernicus.org/preprints/egusphere-2022-128/egusphere-2022-128.pdf |
op_rights |
https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/restrictedAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/egusphere-2022-128 |
_version_ |
1766251222977740800 |