Stirring across the Antarctic Circumpolar Current's southern boundary at the prime 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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Online Access: | https://hdl.handle.net/11250/3145326 https://doi.org/10.5194/os-19-1465-2023 |
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ftunivbergen:oai:bora.uib.no:11250/3145326 2024-09-15T17:44:48+00:00 Stirring across the Antarctic Circumpolar Current's southern boundary at the prime meridian, Weddell Sea Oelerich, Ria Heywood, Karen J. Damerell, Gillian Mary Du Plessis, Marcel Biddle, Louise C. Swart, Sebastiaan 2023 application/pdf https://hdl.handle.net/11250/3145326 https://doi.org/10.5194/os-19-1465-2023 eng eng Copernicus Publications urn:issn:1812-0784 https://hdl.handle.net/11250/3145326 https://doi.org/10.5194/os-19-1465-2023 cristin:2215861 Ocean Science. 2023, 19 (5), 1465-1482. Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no Copyright 2023 The Author(s) Ocean Science 1465-1482 19 5 Journal article Peer reviewed 2023 ftunivbergen https://doi.org/10.5194/os-19-1465-2023 2024-08-13T23:41:38Z 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 prime meridian is surveyed for the first time in high resolution over 2 months during an austral summer with underwater gliders occupying a transect across the front on five occasions. The five transects show that the frontal structure (i.e. hydrography, velocities and lateral density gradients) varies temporally. The results demonstrate significant, transient (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 ACC 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 satellite 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 emphasise 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 ... Article in Journal/Newspaper Antarc* Antarctic Antarctica Weddell Sea University of Bergen: Bergen Open Research Archive (BORA-UiB) Ocean Science 19 5 1465 1482 |
institution |
Open Polar |
collection |
University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
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 prime meridian is surveyed for the first time in high resolution over 2 months during an austral summer with underwater gliders occupying a transect across the front on five occasions. The five transects show that the frontal structure (i.e. hydrography, velocities and lateral density gradients) varies temporally. The results demonstrate significant, transient (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 ACC 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 satellite 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 emphasise 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 ... |
format |
Article in Journal/Newspaper |
author |
Oelerich, Ria Heywood, Karen J. Damerell, Gillian Mary Du Plessis, Marcel Biddle, Louise C. Swart, Sebastiaan |
spellingShingle |
Oelerich, Ria Heywood, Karen J. Damerell, Gillian Mary Du Plessis, Marcel Biddle, Louise C. Swart, Sebastiaan Stirring across the Antarctic Circumpolar Current's southern boundary at the prime meridian, Weddell Sea |
author_facet |
Oelerich, Ria Heywood, Karen J. Damerell, Gillian Mary Du Plessis, Marcel Biddle, Louise C. Swart, Sebastiaan |
author_sort |
Oelerich, Ria |
title |
Stirring across the Antarctic Circumpolar Current's southern boundary at the prime meridian, Weddell Sea |
title_short |
Stirring across the Antarctic Circumpolar Current's southern boundary at the prime meridian, Weddell Sea |
title_full |
Stirring across the Antarctic Circumpolar Current's southern boundary at the prime meridian, Weddell Sea |
title_fullStr |
Stirring across the Antarctic Circumpolar Current's southern boundary at the prime meridian, Weddell Sea |
title_full_unstemmed |
Stirring across the Antarctic Circumpolar Current's southern boundary at the prime meridian, Weddell Sea |
title_sort |
stirring across the antarctic circumpolar current's southern boundary at the prime meridian, weddell sea |
publisher |
Copernicus Publications |
publishDate |
2023 |
url |
https://hdl.handle.net/11250/3145326 https://doi.org/10.5194/os-19-1465-2023 |
genre |
Antarc* Antarctic Antarctica Weddell Sea |
genre_facet |
Antarc* Antarctic Antarctica Weddell Sea |
op_source |
Ocean Science 1465-1482 19 5 |
op_relation |
urn:issn:1812-0784 https://hdl.handle.net/11250/3145326 https://doi.org/10.5194/os-19-1465-2023 cristin:2215861 Ocean Science. 2023, 19 (5), 1465-1482. |
op_rights |
Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no Copyright 2023 The Author(s) |
op_doi |
https://doi.org/10.5194/os-19-1465-2023 |
container_title |
Ocean Science |
container_volume |
19 |
container_issue |
5 |
container_start_page |
1465 |
op_container_end_page |
1482 |
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1810492471873896448 |