Stirring across the Antarctic Circumpolar Current's Southern Boundary at the Greenwich Meridian, Weddell Sea
At the Southern Boundary of the Antarctic Circumpolar Current (ACC), relatively warm ACC waters encounter the colder waters surrounding Antarctica. Strong density gradients across the Southern Boundary indicate the presence of a frontal jet and are thought to modulate the southward heat transport ac...
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Copernicus Publications
2023
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Online Access: | https://doi.org/10.5194/egusphere-2022-1527 https://noa.gwlb.de/receive/cop_mods_00064266 https://egusphere.copernicus.org/preprints/egusphere-2022-1527/egusphere-2022-1527.pdf |
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00064266 2023-05-15T13:49:22+02:00 Stirring across the Antarctic Circumpolar Current's Southern Boundary at the Greenwich Meridian, Weddell Sea Oelerich, Ria Heywood, Karen J. Damerell, Gillian M. du Plessis, Marcel Biddle, Louise C. Swart, Sebastiaan 2023-01 electronic https://doi.org/10.5194/egusphere-2022-1527 https://noa.gwlb.de/receive/cop_mods_00064266 https://egusphere.copernicus.org/preprints/egusphere-2022-1527/egusphere-2022-1527.pdf eng eng Copernicus Publications https://doi.org/10.5194/egusphere-2022-1527 https://noa.gwlb.de/receive/cop_mods_00064266 https://egusphere.copernicus.org/preprints/egusphere-2022-1527/egusphere-2022-1527.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/restrictedAccess CC-BY article Verlagsveröffentlichung article Text doc-type:article 2023 ftnonlinearchiv https://doi.org/10.5194/egusphere-2022-1527 2023-01-09T00:13:12Z At the Southern Boundary of the Antarctic Circumpolar Current (ACC), relatively warm ACC waters encounter the colder waters surrounding Antarctica. Strong density gradients across the Southern Boundary indicate the presence of a frontal jet and are thought to modulate the southward heat transport across the front. In this study, the Southern Boundary in the Weddell Sea sector at the Greenwich Meridian is surveyed for the first time in high resolution over an entire austral summer with underwater gliders transecting the front on 5 occasions. The 5 transects show that the frontal structure (i.e., hydrography, velocities and lateral density gradients) varies temporally. The results demonstrate significant, quite rapid (a few weeks) variability of the Southern Boundary and its frontal jet in location, strength and width. A mesoscale cold-core eddy is identified to disrupt the Southern Boundary’s frontal structure and strengthen lateral density gradients across the front. The front’s barrier properties are assessed using mixing length scales and potential vorticity to establish the cross-frontal exchange of properties between the Southern Boundary and the Weddell Gyre. The results show that stronger lateral density gradients caused by the mesoscale eddy strengthen the barrier-like properties of the front through reduced mixing length scales and pronounced gradients of potential vorticity. In contrast, the barrier-like properties of the Southern Boundary are reduced when no mesoscale eddy is influencing the density gradients across the front. Using altimetry, we further demonstrate that the barrier properties over the past decade have strengthened as a result of increased meridional gradients of absolute dynamic topography and increased frontal jet speeds in comparison to previous decades. Our results emphasize that locally and rapidly changing barrier properties of the Southern Boundary are important to quantify the cross-frontal exchange, which is particularly relevant in regions where the Southern Boundary is ... Article in Journal/Newspaper Antarc* Antarctic Antarctica Weddell Sea Niedersächsisches Online-Archiv NOA Antarctic Austral Greenwich The Antarctic Weddell Weddell Sea |
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Open Polar |
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Niedersächsisches Online-Archiv NOA |
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ftnonlinearchiv |
language |
English |
topic |
article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Oelerich, Ria Heywood, Karen J. Damerell, Gillian M. du Plessis, Marcel Biddle, Louise C. Swart, Sebastiaan Stirring across the Antarctic Circumpolar Current's Southern Boundary at the Greenwich Meridian, Weddell Sea |
topic_facet |
article Verlagsveröffentlichung |
description |
At the Southern Boundary of the Antarctic Circumpolar Current (ACC), relatively warm ACC waters encounter the colder waters surrounding Antarctica. Strong density gradients across the Southern Boundary indicate the presence of a frontal jet and are thought to modulate the southward heat transport across the front. In this study, the Southern Boundary in the Weddell Sea sector at the Greenwich Meridian is surveyed for the first time in high resolution over an entire austral summer with underwater gliders transecting the front on 5 occasions. The 5 transects show that the frontal structure (i.e., hydrography, velocities and lateral density gradients) varies temporally. The results demonstrate significant, quite rapid (a few weeks) variability of the Southern Boundary and its frontal jet in location, strength and width. A mesoscale cold-core eddy is identified to disrupt the Southern Boundary’s frontal structure and strengthen lateral density gradients across the front. The front’s barrier properties are assessed using mixing length scales and potential vorticity to establish the cross-frontal exchange of properties between the Southern Boundary and the Weddell Gyre. The results show that stronger lateral density gradients caused by the mesoscale eddy strengthen the barrier-like properties of the front through reduced mixing length scales and pronounced gradients of potential vorticity. In contrast, the barrier-like properties of the Southern Boundary are reduced when no mesoscale eddy is influencing the density gradients across the front. Using altimetry, we further demonstrate that the barrier properties over the past decade have strengthened as a result of increased meridional gradients of absolute dynamic topography and increased frontal jet speeds in comparison to previous decades. Our results emphasize that locally and rapidly changing barrier properties of the Southern Boundary are important to quantify the cross-frontal exchange, which is particularly relevant in regions where the Southern Boundary is ... |
format |
Article in Journal/Newspaper |
author |
Oelerich, Ria Heywood, Karen J. Damerell, Gillian M. du Plessis, Marcel Biddle, Louise C. Swart, Sebastiaan |
author_facet |
Oelerich, Ria Heywood, Karen J. Damerell, Gillian M. du Plessis, Marcel Biddle, Louise C. Swart, Sebastiaan |
author_sort |
Oelerich, Ria |
title |
Stirring across the Antarctic Circumpolar Current's Southern Boundary at the Greenwich Meridian, Weddell Sea |
title_short |
Stirring across the Antarctic Circumpolar Current's Southern Boundary at the Greenwich Meridian, Weddell Sea |
title_full |
Stirring across the Antarctic Circumpolar Current's Southern Boundary at the Greenwich Meridian, Weddell Sea |
title_fullStr |
Stirring across the Antarctic Circumpolar Current's Southern Boundary at the Greenwich Meridian, Weddell Sea |
title_full_unstemmed |
Stirring across the Antarctic Circumpolar Current's Southern Boundary at the Greenwich Meridian, Weddell Sea |
title_sort |
stirring across the antarctic circumpolar current's southern boundary at the greenwich meridian, weddell sea |
publisher |
Copernicus Publications |
publishDate |
2023 |
url |
https://doi.org/10.5194/egusphere-2022-1527 https://noa.gwlb.de/receive/cop_mods_00064266 https://egusphere.copernicus.org/preprints/egusphere-2022-1527/egusphere-2022-1527.pdf |
geographic |
Antarctic Austral Greenwich The Antarctic Weddell Weddell Sea |
geographic_facet |
Antarctic Austral Greenwich The Antarctic Weddell Weddell Sea |
genre |
Antarc* Antarctic Antarctica Weddell Sea |
genre_facet |
Antarc* Antarctic Antarctica Weddell Sea |
op_relation |
https://doi.org/10.5194/egusphere-2022-1527 https://noa.gwlb.de/receive/cop_mods_00064266 https://egusphere.copernicus.org/preprints/egusphere-2022-1527/egusphere-2022-1527.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-2022-1527 |
_version_ |
1766251249945018368 |