On the drivers of regime shifts in the Antarctic marginal seas, exemplified by the Weddell Sea
Recent studies have found evidence for a potential future tipping point, when the density of Antarctic continental shelf waters, specifically in the southern Weddell Sea, will allow for the onshore flow of warm waters of open ocean origin. A cold-to-warm regime shift in the adjacent ice shelf caviti...
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Copernicus Publications
2023
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Online Access: | https://doi.org/10.5194/os-19-1529-2023 https://noa.gwlb.de/receive/cop_mods_00069721 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00068096/os-19-1529-2023.pdf https://os.copernicus.org/articles/19/1529/2023/os-19-1529-2023.pdf |
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00069721 2023-12-10T09:42:55+01:00 On the drivers of regime shifts in the Antarctic marginal seas, exemplified by the Weddell Sea Haid, Verena Timmermann, Ralph Gürses, Özgür Hellmer, Hartmut H. 2023-11 electronic https://doi.org/10.5194/os-19-1529-2023 https://noa.gwlb.de/receive/cop_mods_00069721 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00068096/os-19-1529-2023.pdf https://os.copernicus.org/articles/19/1529/2023/os-19-1529-2023.pdf eng eng Copernicus Publications Ocean Science -- http://www.bibliothek.uni-regensburg.de/ezeit/?2183769 -- http://www.copernicus.org/EGU/os/os.html -- 1812-0792 https://doi.org/10.5194/os-19-1529-2023 https://noa.gwlb.de/receive/cop_mods_00069721 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00068096/os-19-1529-2023.pdf https://os.copernicus.org/articles/19/1529/2023/os-19-1529-2023.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2023 ftnonlinearchiv https://doi.org/10.5194/os-19-1529-2023 2023-11-13T00:22:47Z Recent studies have found evidence for a potential future tipping point, when the density of Antarctic continental shelf waters, specifically in the southern Weddell Sea, will allow for the onshore flow of warm waters of open ocean origin. A cold-to-warm regime shift in the adjacent ice shelf cavities entails a strong enhancement of ice shelf basal melt rates and could trigger instabilities in the ice sheet. From a suite of numerical experiments, aimed to force such a regime shift on the continental shelf, we identified the density balance between the shelf waters formed by sea ice production and the warmer water at the shelf break as the defining element of a tipping into a warm state. In our experiments, this process is reversible but there is evidence for hysteresis behaviour. Using HadCM3 20th-century output as atmospheric forcing, the resulting state of the Filchner–Ronne cavity depends on the initial state. In contrast, ERA Interim forcing pushes even a warm-initialized cavity into a cold state, i.e. it pushes the system back across the reversal threshold to the cold side. However, it turns out that for forcing data perturbations of a realistic magnitude, a unique and universal recipe for triggering a regime shift in Antarctic marginal seas was not found; instead, various ocean states can lead to an intrusion of off-shelf waters onto the continental shelf and into the cavities. Whether or not any given forcing or perturbation yields a density imbalance and thus allows for the inflow of warm water depends on the complex interplay between bottom topography, mean ocean state, sea ice processes, and atmospheric conditions. Article in Journal/Newspaper Antarc* Antarctic Ice Sheet Ice Shelf Sea ice Weddell Sea Niedersächsisches Online-Archiv NOA Antarctic The Antarctic Weddell Sea Weddell Ocean Science 19 6 1529 1544 |
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Open Polar |
collection |
Niedersächsisches Online-Archiv NOA |
op_collection_id |
ftnonlinearchiv |
language |
English |
topic |
article Verlagsveröffentlichung |
spellingShingle |
article Verlagsveröffentlichung Haid, Verena Timmermann, Ralph Gürses, Özgür Hellmer, Hartmut H. On the drivers of regime shifts in the Antarctic marginal seas, exemplified by the Weddell Sea |
topic_facet |
article Verlagsveröffentlichung |
description |
Recent studies have found evidence for a potential future tipping point, when the density of Antarctic continental shelf waters, specifically in the southern Weddell Sea, will allow for the onshore flow of warm waters of open ocean origin. A cold-to-warm regime shift in the adjacent ice shelf cavities entails a strong enhancement of ice shelf basal melt rates and could trigger instabilities in the ice sheet. From a suite of numerical experiments, aimed to force such a regime shift on the continental shelf, we identified the density balance between the shelf waters formed by sea ice production and the warmer water at the shelf break as the defining element of a tipping into a warm state. In our experiments, this process is reversible but there is evidence for hysteresis behaviour. Using HadCM3 20th-century output as atmospheric forcing, the resulting state of the Filchner–Ronne cavity depends on the initial state. In contrast, ERA Interim forcing pushes even a warm-initialized cavity into a cold state, i.e. it pushes the system back across the reversal threshold to the cold side. However, it turns out that for forcing data perturbations of a realistic magnitude, a unique and universal recipe for triggering a regime shift in Antarctic marginal seas was not found; instead, various ocean states can lead to an intrusion of off-shelf waters onto the continental shelf and into the cavities. Whether or not any given forcing or perturbation yields a density imbalance and thus allows for the inflow of warm water depends on the complex interplay between bottom topography, mean ocean state, sea ice processes, and atmospheric conditions. |
format |
Article in Journal/Newspaper |
author |
Haid, Verena Timmermann, Ralph Gürses, Özgür Hellmer, Hartmut H. |
author_facet |
Haid, Verena Timmermann, Ralph Gürses, Özgür Hellmer, Hartmut H. |
author_sort |
Haid, Verena |
title |
On the drivers of regime shifts in the Antarctic marginal seas, exemplified by the Weddell Sea |
title_short |
On the drivers of regime shifts in the Antarctic marginal seas, exemplified by the Weddell Sea |
title_full |
On the drivers of regime shifts in the Antarctic marginal seas, exemplified by the Weddell Sea |
title_fullStr |
On the drivers of regime shifts in the Antarctic marginal seas, exemplified by the Weddell Sea |
title_full_unstemmed |
On the drivers of regime shifts in the Antarctic marginal seas, exemplified by the Weddell Sea |
title_sort |
on the drivers of regime shifts in the antarctic marginal seas, exemplified by the weddell sea |
publisher |
Copernicus Publications |
publishDate |
2023 |
url |
https://doi.org/10.5194/os-19-1529-2023 https://noa.gwlb.de/receive/cop_mods_00069721 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00068096/os-19-1529-2023.pdf https://os.copernicus.org/articles/19/1529/2023/os-19-1529-2023.pdf |
geographic |
Antarctic The Antarctic Weddell Sea Weddell |
geographic_facet |
Antarctic The Antarctic Weddell Sea Weddell |
genre |
Antarc* Antarctic Ice Sheet Ice Shelf Sea ice Weddell Sea |
genre_facet |
Antarc* Antarctic Ice Sheet Ice Shelf Sea ice Weddell Sea |
op_relation |
Ocean Science -- http://www.bibliothek.uni-regensburg.de/ezeit/?2183769 -- http://www.copernicus.org/EGU/os/os.html -- 1812-0792 https://doi.org/10.5194/os-19-1529-2023 https://noa.gwlb.de/receive/cop_mods_00069721 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00068096/os-19-1529-2023.pdf https://os.copernicus.org/articles/19/1529/2023/os-19-1529-2023.pdf |
op_rights |
https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/os-19-1529-2023 |
container_title |
Ocean Science |
container_volume |
19 |
container_issue |
6 |
container_start_page |
1529 |
op_container_end_page |
1544 |
_version_ |
1784885960395194368 |