Acceleration and overturning of the Antarctic Slope Current by winds, eddies, and tides
All exchanges between the open ocean and the Antarctic continental shelf must cross the Antarctic Slope Current (ASC). Previous studies indicate that these exchanges are strongly influenced by mesoscale and tidal variability, yet the mechanisms responsible for setting the ASCs transport and structur...
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Online Access: | https://doi.org/10.1175/JPO-D-18-0221.1 http://ecite.utas.edu.au/134357 |
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ftunivtasecite:oai:ecite.utas.edu.au:134357 2023-05-15T13:55:18+02:00 Acceleration and overturning of the Antarctic Slope Current by winds, eddies, and tides Stewart, AL Klocker, A Menemenlis, D 2019 https://doi.org/10.1175/JPO-D-18-0221.1 http://ecite.utas.edu.au/134357 en eng Amer Meteorological Soc http://dx.doi.org/10.1175/JPO-D-18-0221.1 Stewart, AL and Klocker, A and Menemenlis, D, Acceleration and overturning of the Antarctic Slope Current by winds, eddies, and tides, Journal of Physical Oceanography, 49, (8) pp. 2043-2074. ISSN 0022-3670 (2019) [Refereed Article] http://ecite.utas.edu.au/134357 Earth Sciences Oceanography Physical Oceanography Refereed Article PeerReviewed 2019 ftunivtasecite https://doi.org/10.1175/JPO-D-18-0221.1 2020-01-06T23:16:22Z All exchanges between the open ocean and the Antarctic continental shelf must cross the Antarctic Slope Current (ASC). Previous studies indicate that these exchanges are strongly influenced by mesoscale and tidal variability, yet the mechanisms responsible for setting the ASCs transport and structure have received relatively little attention. In this study the roles of winds, eddies, and tides in accelerating the ASC are investigated using a global oceansea ice simulation with very high resolution (1/48 grid spacing). It is found that the circulation along the continental slope is accelerated both by surface stresses, ultimately sourced from the easterly winds, and by mesoscale eddy vorticity fluxes. At the continental shelf break, the ASC exhibits a narrow (~3050 km), swift (>0.2 m s −1 ) jet, consistent with in situ observations. In this jet the surface stress is substantially reduced, and may even vanish or be directed eastward, because the ocean surface speed matches or exceeds that of the sea ice. The shelfbreak jet is shown to be accelerated by tidal momentum advection, consistent with the phenomenon of tidal rectification. Consequently, the shoreward Ekman transport vanishes and thus the mean overturning circulation that steepens the Antarctic Slope Front (ASF) is primarily due to tidal acceleration. These findings imply that the circulation and mean overturning of the ASC are not only determined by near-Antarctic winds, but also depend crucially on sea ice cover, regionally-dependent mesoscale eddy activity over the continental slope, and the amplitude of tidal flows across the continental shelf break. Article in Journal/Newspaper Antarc* Antarctic Sea ice eCite UTAS (University of Tasmania) Antarctic The Antarctic Journal of Physical Oceanography 49 8 2043 2074 |
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Open Polar |
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eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Earth Sciences Oceanography Physical Oceanography |
spellingShingle |
Earth Sciences Oceanography Physical Oceanography Stewart, AL Klocker, A Menemenlis, D Acceleration and overturning of the Antarctic Slope Current by winds, eddies, and tides |
topic_facet |
Earth Sciences Oceanography Physical Oceanography |
description |
All exchanges between the open ocean and the Antarctic continental shelf must cross the Antarctic Slope Current (ASC). Previous studies indicate that these exchanges are strongly influenced by mesoscale and tidal variability, yet the mechanisms responsible for setting the ASCs transport and structure have received relatively little attention. In this study the roles of winds, eddies, and tides in accelerating the ASC are investigated using a global oceansea ice simulation with very high resolution (1/48 grid spacing). It is found that the circulation along the continental slope is accelerated both by surface stresses, ultimately sourced from the easterly winds, and by mesoscale eddy vorticity fluxes. At the continental shelf break, the ASC exhibits a narrow (~3050 km), swift (>0.2 m s −1 ) jet, consistent with in situ observations. In this jet the surface stress is substantially reduced, and may even vanish or be directed eastward, because the ocean surface speed matches or exceeds that of the sea ice. The shelfbreak jet is shown to be accelerated by tidal momentum advection, consistent with the phenomenon of tidal rectification. Consequently, the shoreward Ekman transport vanishes and thus the mean overturning circulation that steepens the Antarctic Slope Front (ASF) is primarily due to tidal acceleration. These findings imply that the circulation and mean overturning of the ASC are not only determined by near-Antarctic winds, but also depend crucially on sea ice cover, regionally-dependent mesoscale eddy activity over the continental slope, and the amplitude of tidal flows across the continental shelf break. |
format |
Article in Journal/Newspaper |
author |
Stewart, AL Klocker, A Menemenlis, D |
author_facet |
Stewart, AL Klocker, A Menemenlis, D |
author_sort |
Stewart, AL |
title |
Acceleration and overturning of the Antarctic Slope Current by winds, eddies, and tides |
title_short |
Acceleration and overturning of the Antarctic Slope Current by winds, eddies, and tides |
title_full |
Acceleration and overturning of the Antarctic Slope Current by winds, eddies, and tides |
title_fullStr |
Acceleration and overturning of the Antarctic Slope Current by winds, eddies, and tides |
title_full_unstemmed |
Acceleration and overturning of the Antarctic Slope Current by winds, eddies, and tides |
title_sort |
acceleration and overturning of the antarctic slope current by winds, eddies, and tides |
publisher |
Amer Meteorological Soc |
publishDate |
2019 |
url |
https://doi.org/10.1175/JPO-D-18-0221.1 http://ecite.utas.edu.au/134357 |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic Sea ice |
genre_facet |
Antarc* Antarctic Sea ice |
op_relation |
http://dx.doi.org/10.1175/JPO-D-18-0221.1 Stewart, AL and Klocker, A and Menemenlis, D, Acceleration and overturning of the Antarctic Slope Current by winds, eddies, and tides, Journal of Physical Oceanography, 49, (8) pp. 2043-2074. ISSN 0022-3670 (2019) [Refereed Article] http://ecite.utas.edu.au/134357 |
op_doi |
https://doi.org/10.1175/JPO-D-18-0221.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
49 |
container_issue |
8 |
container_start_page |
2043 |
op_container_end_page |
2074 |
_version_ |
1766261711575187456 |