Wind Forcing Controls on Antarctic Bottom Water Export from the Weddell Sea via Bottom Boundary Layer Processes
The Antarctic Bottom Water (AABW) exported from the Weddell Sea has experienced warming and contraction in the past 30 yrs. Superposed on this decadal trend is substantial annual and interannual variability in the volume and properties of Weddell-sourced AABW. Several mechanisms have been suggested...
Published in: | Journal of Geophysical Research: Oceans |
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Main Authors: | , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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American Geophysical Union
2024
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Online Access: | http://nora.nerc.ac.uk/id/eprint/535837/ https://nora.nerc.ac.uk/id/eprint/535837/1/JGR%20Oceans%20-%202024%20-%20Auckland%20-%20Wind%20Forcing%20Controls%20on%20Antarctic%20Bottom%20Water%20Export%20From%20the%20Weddell%20Sea%20via%20Bottom.pdf https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024JC021089 |
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ftnerc:oai:nora.nerc.ac.uk:535837 2024-09-09T19:10:05+00:00 Wind Forcing Controls on Antarctic Bottom Water Export from the Weddell Sea via Bottom Boundary Layer Processes Auckland, C.D.J. Abrahamsen, E.P. Meredith, M. Naveira Garabato, A.C. Spingys, C.P. Frajka-Williams, E. Gordon, A.L. 2024-08-06 text http://nora.nerc.ac.uk/id/eprint/535837/ https://nora.nerc.ac.uk/id/eprint/535837/1/JGR%20Oceans%20-%202024%20-%20Auckland%20-%20Wind%20Forcing%20Controls%20on%20Antarctic%20Bottom%20Water%20Export%20From%20the%20Weddell%20Sea%20via%20Bottom.pdf https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024JC021089 en eng American Geophysical Union https://nora.nerc.ac.uk/id/eprint/535837/1/JGR%20Oceans%20-%202024%20-%20Auckland%20-%20Wind%20Forcing%20Controls%20on%20Antarctic%20Bottom%20Water%20Export%20From%20the%20Weddell%20Sea%20via%20Bottom.pdf Auckland, C.D.J. orcid:0000-0001-7613-6789 Abrahamsen, E.P. orcid:0000-0001-5924-5350 Meredith, M. orcid:0000-0002-7342-7756 Naveira Garabato, A.C.; Spingys, C.P.; Frajka-Williams, E.; Gordon, A.L. 2024 Wind Forcing Controls on Antarctic Bottom Water Export from the Weddell Sea via Bottom Boundary Layer Processes. Journal of Geophysical Research: Oceans, 129 (8), e2024JC021089. 21, pp. https://doi.org/10.1029/2024JC021089 <https://doi.org/10.1029/2024JC021089> cc_by_4 Publication - Article PeerReviewed 2024 ftnerc https://doi.org/10.1029/2024JC021089 2024-08-27T23:40:53Z The Antarctic Bottom Water (AABW) exported from the Weddell Sea has experienced warming and contraction in the past 30 yrs. Superposed on this decadal trend is substantial annual and interannual variability in the volume and properties of Weddell-sourced AABW. Several mechanisms have been suggested to explain these variations, many of which highlight a role of wind stress, but the comparative importance and possible simultaneity of the different mechanisms remains unclear. Using data from two mooring sites within the Weddell Sea, we find a rapid intensification of the abyssal boundary current carrying AABW through Orkney Passage (OP), the most direct export pathway of AABW from the Weddell Sea, in response to periods of strong zonal wind stress and anomalous wind stress curl along the South Scotia Ridge upstream of OP. This acceleration is concomitant with a 40% reduction in northward AABW transport in late 2015. The changes in transport follow anomalous wind forcing by approximately 3 months, with the short timescale indicative of a barotropic response in the flow through OP. The bottom boundary layer over the OP's sloping topography is found to have a key role in regulating export on monthly to interannual timescales. Increased boundary current velocity leading up to the passage forms a thickened bottom boundary layer, resulting in reduced AABW thickness and density, and thus restricting northward transport of AABW through the passage. Whilst other processes are likely to dominate on longer (decadal) periods, the dynamics identified here can explain significant variability on timescales up to interannual. Article in Journal/Newspaper Antarc* Antarctic Weddell Sea Natural Environment Research Council: NERC Open Research Archive Antarctic Curl ENVELOPE(-63.071,-63.071,-70.797,-70.797) South Scotia Ridge ENVELOPE(-46.500,-46.500,-60.000,-60.000) The Antarctic Weddell Weddell Sea Journal of Geophysical Research: Oceans 129 8 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
The Antarctic Bottom Water (AABW) exported from the Weddell Sea has experienced warming and contraction in the past 30 yrs. Superposed on this decadal trend is substantial annual and interannual variability in the volume and properties of Weddell-sourced AABW. Several mechanisms have been suggested to explain these variations, many of which highlight a role of wind stress, but the comparative importance and possible simultaneity of the different mechanisms remains unclear. Using data from two mooring sites within the Weddell Sea, we find a rapid intensification of the abyssal boundary current carrying AABW through Orkney Passage (OP), the most direct export pathway of AABW from the Weddell Sea, in response to periods of strong zonal wind stress and anomalous wind stress curl along the South Scotia Ridge upstream of OP. This acceleration is concomitant with a 40% reduction in northward AABW transport in late 2015. The changes in transport follow anomalous wind forcing by approximately 3 months, with the short timescale indicative of a barotropic response in the flow through OP. The bottom boundary layer over the OP's sloping topography is found to have a key role in regulating export on monthly to interannual timescales. Increased boundary current velocity leading up to the passage forms a thickened bottom boundary layer, resulting in reduced AABW thickness and density, and thus restricting northward transport of AABW through the passage. Whilst other processes are likely to dominate on longer (decadal) periods, the dynamics identified here can explain significant variability on timescales up to interannual. |
format |
Article in Journal/Newspaper |
author |
Auckland, C.D.J. Abrahamsen, E.P. Meredith, M. Naveira Garabato, A.C. Spingys, C.P. Frajka-Williams, E. Gordon, A.L. |
spellingShingle |
Auckland, C.D.J. Abrahamsen, E.P. Meredith, M. Naveira Garabato, A.C. Spingys, C.P. Frajka-Williams, E. Gordon, A.L. Wind Forcing Controls on Antarctic Bottom Water Export from the Weddell Sea via Bottom Boundary Layer Processes |
author_facet |
Auckland, C.D.J. Abrahamsen, E.P. Meredith, M. Naveira Garabato, A.C. Spingys, C.P. Frajka-Williams, E. Gordon, A.L. |
author_sort |
Auckland, C.D.J. |
title |
Wind Forcing Controls on Antarctic Bottom Water Export from the Weddell Sea via Bottom Boundary Layer Processes |
title_short |
Wind Forcing Controls on Antarctic Bottom Water Export from the Weddell Sea via Bottom Boundary Layer Processes |
title_full |
Wind Forcing Controls on Antarctic Bottom Water Export from the Weddell Sea via Bottom Boundary Layer Processes |
title_fullStr |
Wind Forcing Controls on Antarctic Bottom Water Export from the Weddell Sea via Bottom Boundary Layer Processes |
title_full_unstemmed |
Wind Forcing Controls on Antarctic Bottom Water Export from the Weddell Sea via Bottom Boundary Layer Processes |
title_sort |
wind forcing controls on antarctic bottom water export from the weddell sea via bottom boundary layer processes |
publisher |
American Geophysical Union |
publishDate |
2024 |
url |
http://nora.nerc.ac.uk/id/eprint/535837/ https://nora.nerc.ac.uk/id/eprint/535837/1/JGR%20Oceans%20-%202024%20-%20Auckland%20-%20Wind%20Forcing%20Controls%20on%20Antarctic%20Bottom%20Water%20Export%20From%20the%20Weddell%20Sea%20via%20Bottom.pdf https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024JC021089 |
long_lat |
ENVELOPE(-63.071,-63.071,-70.797,-70.797) ENVELOPE(-46.500,-46.500,-60.000,-60.000) |
geographic |
Antarctic Curl South Scotia Ridge The Antarctic Weddell Weddell Sea |
geographic_facet |
Antarctic Curl South Scotia Ridge The Antarctic Weddell Weddell Sea |
genre |
Antarc* Antarctic Weddell Sea |
genre_facet |
Antarc* Antarctic Weddell Sea |
op_relation |
https://nora.nerc.ac.uk/id/eprint/535837/1/JGR%20Oceans%20-%202024%20-%20Auckland%20-%20Wind%20Forcing%20Controls%20on%20Antarctic%20Bottom%20Water%20Export%20From%20the%20Weddell%20Sea%20via%20Bottom.pdf Auckland, C.D.J. orcid:0000-0001-7613-6789 Abrahamsen, E.P. orcid:0000-0001-5924-5350 Meredith, M. orcid:0000-0002-7342-7756 Naveira Garabato, A.C.; Spingys, C.P.; Frajka-Williams, E.; Gordon, A.L. 2024 Wind Forcing Controls on Antarctic Bottom Water Export from the Weddell Sea via Bottom Boundary Layer Processes. Journal of Geophysical Research: Oceans, 129 (8), e2024JC021089. 21, pp. https://doi.org/10.1029/2024JC021089 <https://doi.org/10.1029/2024JC021089> |
op_rights |
cc_by_4 |
op_doi |
https://doi.org/10.1029/2024JC021089 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
129 |
container_issue |
8 |
_version_ |
1809824486441091072 |