Reshaping the Antarctic Circumpolar Current via Antarctic Bottom Water export
Zonal momentum input into the Antarctic Circumpolar Current (ACC) by westerly winds is ultimately removed via topographic form stress induced by large bathymetric features that obstruct the path of the current. These bathymetric features also support the export of Antarctic Bottom Water (AABW) acros...
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Online Access: | http://hdl.handle.net/1885/218368 https://doi.org/10.1175/JPO-D-17-0007.1 |
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ftanucanberra:oai:openresearch-repository.anu.edu.au:1885/218368 2024-01-14T10:01:30+01:00 Reshaping the Antarctic Circumpolar Current via Antarctic Bottom Water export Hogg, Andrew Stewart, Andrew D application/pdf http://hdl.handle.net/1885/218368 https://doi.org/10.1175/JPO-D-17-0007.1 en_AU eng American Meteorological Society 0022-3670 http://hdl.handle.net/1885/218368 doi:10.1175/JPO-D-17-0007.1 Journal of Physical Oceanography Journal article ftanucanberra https://doi.org/10.1175/JPO-D-17-0007.1 2023-12-15T09:34:36Z Zonal momentum input into the Antarctic Circumpolar Current (ACC) by westerly winds is ultimately removed via topographic form stress induced by large bathymetric features that obstruct the path of the current. These bathymetric features also support the export of Antarctic Bottom Water (AABW) across the ACC via deep, geostrophically balanced, northward flows. These deep geostrophic currents modify the topographic form stress, implying that changes in AABW export will alter the ocean bottom pressure and require a rearrangement of the ACC in order to preserve its zonal momentum balance. A conceptual model of the ACC momentum balance is used to derive a relationship between the volume export of AABW and the shape of the sea surface across the ACC’s standing meanders. This prediction is tested using an idealized eddy-resolving ACC/Antarctic shelf channel model that includes both the upper and lower cells of the Southern Ocean meridional overturning circulation, using two different topographic configurations to obstruct the flow of the ACC. Eliminating AABW production leads to a shallowing of the sea surface elevation within the standing meander. To quantify this response, the authors introduce the “surface-induced topographic form stress,” the topographic form stress that would result from the shape of the sea surface if the ocean were barotropic. Eliminating AABW production also reduces the magnitude of the eddy kinetic energy generated downstream of the meander and the surface speed of the ACC within the meander. These findings raise the possibility that ongoing changes in AABW export may be detectable via satellite altimetry. Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Australian National University: ANU Digital Collections Antarctic Southern Ocean The Antarctic Journal of Physical Oceanography 47 10 2577 2601 |
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Open Polar |
collection |
Australian National University: ANU Digital Collections |
op_collection_id |
ftanucanberra |
language |
English |
description |
Zonal momentum input into the Antarctic Circumpolar Current (ACC) by westerly winds is ultimately removed via topographic form stress induced by large bathymetric features that obstruct the path of the current. These bathymetric features also support the export of Antarctic Bottom Water (AABW) across the ACC via deep, geostrophically balanced, northward flows. These deep geostrophic currents modify the topographic form stress, implying that changes in AABW export will alter the ocean bottom pressure and require a rearrangement of the ACC in order to preserve its zonal momentum balance. A conceptual model of the ACC momentum balance is used to derive a relationship between the volume export of AABW and the shape of the sea surface across the ACC’s standing meanders. This prediction is tested using an idealized eddy-resolving ACC/Antarctic shelf channel model that includes both the upper and lower cells of the Southern Ocean meridional overturning circulation, using two different topographic configurations to obstruct the flow of the ACC. Eliminating AABW production leads to a shallowing of the sea surface elevation within the standing meander. To quantify this response, the authors introduce the “surface-induced topographic form stress,” the topographic form stress that would result from the shape of the sea surface if the ocean were barotropic. Eliminating AABW production also reduces the magnitude of the eddy kinetic energy generated downstream of the meander and the surface speed of the ACC within the meander. These findings raise the possibility that ongoing changes in AABW export may be detectable via satellite altimetry. |
format |
Article in Journal/Newspaper |
author |
Hogg, Andrew Stewart, Andrew D |
spellingShingle |
Hogg, Andrew Stewart, Andrew D Reshaping the Antarctic Circumpolar Current via Antarctic Bottom Water export |
author_facet |
Hogg, Andrew Stewart, Andrew D |
author_sort |
Hogg, Andrew |
title |
Reshaping the Antarctic Circumpolar Current via Antarctic Bottom Water export |
title_short |
Reshaping the Antarctic Circumpolar Current via Antarctic Bottom Water export |
title_full |
Reshaping the Antarctic Circumpolar Current via Antarctic Bottom Water export |
title_fullStr |
Reshaping the Antarctic Circumpolar Current via Antarctic Bottom Water export |
title_full_unstemmed |
Reshaping the Antarctic Circumpolar Current via Antarctic Bottom Water export |
title_sort |
reshaping the antarctic circumpolar current via antarctic bottom water export |
publisher |
American Meteorological Society |
url |
http://hdl.handle.net/1885/218368 https://doi.org/10.1175/JPO-D-17-0007.1 |
geographic |
Antarctic Southern Ocean The Antarctic |
geographic_facet |
Antarctic Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_source |
Journal of Physical Oceanography |
op_relation |
0022-3670 http://hdl.handle.net/1885/218368 doi:10.1175/JPO-D-17-0007.1 |
op_doi |
https://doi.org/10.1175/JPO-D-17-0007.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
47 |
container_issue |
10 |
container_start_page |
2577 |
op_container_end_page |
2601 |
_version_ |
1788067265102479360 |