Agulhas Leakage Predominantly Responds to the Southern Hemisphere Westerlies
The Agulhas Current plays a crucial role in the thermohaline circulation through its leakage into the South Atlantic. Under both past and present climates, the trade winds and westerlies could have the ability to modulate the amount of Indian-Atlantic inflow. Compelling arguments have been put forwa...
Published in: | Journal of Physical Oceanography |
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Online Access: | https://oceanrep.geomar.de/id/eprint/22060/ https://oceanrep.geomar.de/id/eprint/22060/1/Durgadoo.pdf https://oceanrep.geomar.de/id/eprint/22060/7/jpo-d-13-047.1.pdf https://doi.org/10.1175/JPO-D-13-047.1 |
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ftoceanrep:oai:oceanrep.geomar.de:22060 2023-05-15T13:37:40+02:00 Agulhas Leakage Predominantly Responds to the Southern Hemisphere Westerlies Durgadoo, Jonathan V. Loveday, Benjamin R. Reason, Chris J. C. Penven, Pierrick Biastoch, Arne 2013-10-01 text https://oceanrep.geomar.de/id/eprint/22060/ https://oceanrep.geomar.de/id/eprint/22060/1/Durgadoo.pdf https://oceanrep.geomar.de/id/eprint/22060/7/jpo-d-13-047.1.pdf https://doi.org/10.1175/JPO-D-13-047.1 en eng AMS (American Meteorological Society) https://oceanrep.geomar.de/id/eprint/22060/1/Durgadoo.pdf https://oceanrep.geomar.de/id/eprint/22060/7/jpo-d-13-047.1.pdf Durgadoo, J. V. , Loveday, B. R., Reason, C. J. C., Penven, P. and Biastoch, A. (2013) Agulhas Leakage Predominantly Responds to the Southern Hemisphere Westerlies. Open Access Journal of Physical Oceanography, 43 (10). pp. 2113-2131. DOI 10.1175/JPO-D-13-047.1 <https://doi.org/10.1175/JPO-D-13-047.1>. doi:10.1175/JPO-D-13-047.1 info:eu-repo/semantics/openAccess Article PeerReviewed info:eu-repo/semantics/article 2013 ftoceanrep https://doi.org/10.1175/JPO-D-13-047.1 2023-04-07T15:10:22Z The Agulhas Current plays a crucial role in the thermohaline circulation through its leakage into the South Atlantic. Under both past and present climates, the trade winds and westerlies could have the ability to modulate the amount of Indian-Atlantic inflow. Compelling arguments have been put forward suggesting that trade winds alone have little impact on the magnitude of Agulhas leakage. Here, employing three ocean models for robust analysis – a global coarse resolution, a regional eddy-permitting and a nested high-resolution eddy-resolving configuration – and systematically altering the position and intensity of the westerly wind belt in a series of sensitivity experiments, it is shown that the westerlies, in particular their intensity, control the leakage. Leakage responds proportionally to the westerlies intensity up to a certain point. Beyond this, through the adjustment of the large-scale circulation, energetic interactions occur between the Agulhas Return Current and the Antarctic Circumpolar Current that result in a state where leakage no longer increases. This adjustment takes place within 1 to 2 decades. Contrary to previous assertions, our results further show that an equatorward (poleward) shift in westerlies increases (decreases) leakage. This occurs due to the redistribution of momentum input by the winds. It is concluded that the reported present-day leakage increase could therefore reflect an unadjusted oceanic response mainly to the strengthening westerlies over the last few decades. Article in Journal/Newspaper Antarc* Antarctic OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Antarctic Indian The Antarctic Journal of Physical Oceanography 43 10 2113 2131 |
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Open Polar |
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OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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ftoceanrep |
language |
English |
description |
The Agulhas Current plays a crucial role in the thermohaline circulation through its leakage into the South Atlantic. Under both past and present climates, the trade winds and westerlies could have the ability to modulate the amount of Indian-Atlantic inflow. Compelling arguments have been put forward suggesting that trade winds alone have little impact on the magnitude of Agulhas leakage. Here, employing three ocean models for robust analysis – a global coarse resolution, a regional eddy-permitting and a nested high-resolution eddy-resolving configuration – and systematically altering the position and intensity of the westerly wind belt in a series of sensitivity experiments, it is shown that the westerlies, in particular their intensity, control the leakage. Leakage responds proportionally to the westerlies intensity up to a certain point. Beyond this, through the adjustment of the large-scale circulation, energetic interactions occur between the Agulhas Return Current and the Antarctic Circumpolar Current that result in a state where leakage no longer increases. This adjustment takes place within 1 to 2 decades. Contrary to previous assertions, our results further show that an equatorward (poleward) shift in westerlies increases (decreases) leakage. This occurs due to the redistribution of momentum input by the winds. It is concluded that the reported present-day leakage increase could therefore reflect an unadjusted oceanic response mainly to the strengthening westerlies over the last few decades. |
format |
Article in Journal/Newspaper |
author |
Durgadoo, Jonathan V. Loveday, Benjamin R. Reason, Chris J. C. Penven, Pierrick Biastoch, Arne |
spellingShingle |
Durgadoo, Jonathan V. Loveday, Benjamin R. Reason, Chris J. C. Penven, Pierrick Biastoch, Arne Agulhas Leakage Predominantly Responds to the Southern Hemisphere Westerlies |
author_facet |
Durgadoo, Jonathan V. Loveday, Benjamin R. Reason, Chris J. C. Penven, Pierrick Biastoch, Arne |
author_sort |
Durgadoo, Jonathan V. |
title |
Agulhas Leakage Predominantly Responds to the Southern Hemisphere Westerlies |
title_short |
Agulhas Leakage Predominantly Responds to the Southern Hemisphere Westerlies |
title_full |
Agulhas Leakage Predominantly Responds to the Southern Hemisphere Westerlies |
title_fullStr |
Agulhas Leakage Predominantly Responds to the Southern Hemisphere Westerlies |
title_full_unstemmed |
Agulhas Leakage Predominantly Responds to the Southern Hemisphere Westerlies |
title_sort |
agulhas leakage predominantly responds to the southern hemisphere westerlies |
publisher |
AMS (American Meteorological Society) |
publishDate |
2013 |
url |
https://oceanrep.geomar.de/id/eprint/22060/ https://oceanrep.geomar.de/id/eprint/22060/1/Durgadoo.pdf https://oceanrep.geomar.de/id/eprint/22060/7/jpo-d-13-047.1.pdf https://doi.org/10.1175/JPO-D-13-047.1 |
geographic |
Antarctic Indian The Antarctic |
geographic_facet |
Antarctic Indian The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_relation |
https://oceanrep.geomar.de/id/eprint/22060/1/Durgadoo.pdf https://oceanrep.geomar.de/id/eprint/22060/7/jpo-d-13-047.1.pdf Durgadoo, J. V. , Loveday, B. R., Reason, C. J. C., Penven, P. and Biastoch, A. (2013) Agulhas Leakage Predominantly Responds to the Southern Hemisphere Westerlies. Open Access Journal of Physical Oceanography, 43 (10). pp. 2113-2131. DOI 10.1175/JPO-D-13-047.1 <https://doi.org/10.1175/JPO-D-13-047.1>. doi:10.1175/JPO-D-13-047.1 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1175/JPO-D-13-047.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
43 |
container_issue |
10 |
container_start_page |
2113 |
op_container_end_page |
2131 |
_version_ |
1766095745494024192 |