Horizontal mixing in the Southern Ocean from Argo float trajectories
We provide the first observational estimate of the circumpolar distribution of cross‐stream eddy diffusivity at 1000 m in the Southern Ocean using Argo float trajectories. We show that Argo float trajectories, from the float surfacing positions, can be used to estimate lateral eddy diffusivities in...
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Online Access: | https://doi.org/10.1002/2015JC011440 http://ecite.utas.edu.au/132285 |
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ftunivtasecite:oai:ecite.utas.edu.au:132285 2023-05-15T16:02:34+02:00 Horizontal mixing in the Southern Ocean from Argo float trajectories Roach, CJ Balwada, D Speer, K 2016 application/pdf https://doi.org/10.1002/2015JC011440 http://ecite.utas.edu.au/132285 en eng Wiley-Blackwell Publishing Ltd http://ecite.utas.edu.au/132285/2/132285 - Horizontal mixing in the Southern Ocean from Argo float trajectories.pdf http://dx.doi.org/10.1002/2015JC011440 Roach, CJ and Balwada, D and Speer, K, Horizontal mixing in the Southern Ocean from Argo float trajectories, Journal of Geophysical Research: Oceans, 121, (8) pp. 5570-5586. ISSN 2169-9275 (2016) [Refereed Article] http://ecite.utas.edu.au/132285 Earth Sciences Oceanography Physical Oceanography Refereed Article PeerReviewed 2016 ftunivtasecite https://doi.org/10.1002/2015JC011440 2019-12-13T22:30:13Z We provide the first observational estimate of the circumpolar distribution of cross‐stream eddy diffusivity at 1000 m in the Southern Ocean using Argo float trajectories. We show that Argo float trajectories, from the float surfacing positions, can be used to estimate lateral eddy diffusivities in the ocean and that these estimates are comparable to those obtained from RAFOS floats, where they overlap. Using the Southern Ocean State Estimate (SOSE) velocity fields to advect synthetic particles with imposed behavior that is Argo‐like and RAFOS‐like diffusivity estimates from both sets of synthetic particles agreed closely at the three dynamically very different test sites, the Kerguelen Island region, the Southeast Pacific Ocean, and the Scotia Sea, and support our approach. Observed cross‐stream diffusivities at 1000 m, calculated from Argo float trajectories, ranged between 300 and 2500 m 2 s −1 , with peaks corresponding to topographic features associated with the Scotia Sea, the Kerguelen Plateau, the Campbell Plateau, and the Southeast Pacific Ridge. These observational estimates agree with previous regional estimates from the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES) near the Drake Passage, and other estimates from natural tracers (helium), inverse modeling studies, and current meter measurements. These estimates are also compared to the suppressed eddy diffusivity in the presence of mean flows. The comparison suggests that away from regions of strong topographic steering suppression explains both the structure and magnitude of eddy diffusivity but that eddy diffusivities in the regions of topographic steering are greater than what would be theoretically expected and the ACC experiences localized enhanced cross‐stream mixing in these regions. Article in Journal/Newspaper Drake Passage Scotia Sea Southern Ocean eCite UTAS (University of Tasmania) Southern Ocean Kerguelen Drake Passage Scotia Sea Pacific Kerguelen Island ENVELOPE(69.500,69.500,-49.250,-49.250) Campbell Plateau ENVELOPE(171.000,171.000,-50.667,-50.667) Journal of Geophysical Research: Oceans 121 8 5570 5586 |
institution |
Open Polar |
collection |
eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Earth Sciences Oceanography Physical Oceanography |
spellingShingle |
Earth Sciences Oceanography Physical Oceanography Roach, CJ Balwada, D Speer, K Horizontal mixing in the Southern Ocean from Argo float trajectories |
topic_facet |
Earth Sciences Oceanography Physical Oceanography |
description |
We provide the first observational estimate of the circumpolar distribution of cross‐stream eddy diffusivity at 1000 m in the Southern Ocean using Argo float trajectories. We show that Argo float trajectories, from the float surfacing positions, can be used to estimate lateral eddy diffusivities in the ocean and that these estimates are comparable to those obtained from RAFOS floats, where they overlap. Using the Southern Ocean State Estimate (SOSE) velocity fields to advect synthetic particles with imposed behavior that is Argo‐like and RAFOS‐like diffusivity estimates from both sets of synthetic particles agreed closely at the three dynamically very different test sites, the Kerguelen Island region, the Southeast Pacific Ocean, and the Scotia Sea, and support our approach. Observed cross‐stream diffusivities at 1000 m, calculated from Argo float trajectories, ranged between 300 and 2500 m 2 s −1 , with peaks corresponding to topographic features associated with the Scotia Sea, the Kerguelen Plateau, the Campbell Plateau, and the Southeast Pacific Ridge. These observational estimates agree with previous regional estimates from the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES) near the Drake Passage, and other estimates from natural tracers (helium), inverse modeling studies, and current meter measurements. These estimates are also compared to the suppressed eddy diffusivity in the presence of mean flows. The comparison suggests that away from regions of strong topographic steering suppression explains both the structure and magnitude of eddy diffusivity but that eddy diffusivities in the regions of topographic steering are greater than what would be theoretically expected and the ACC experiences localized enhanced cross‐stream mixing in these regions. |
format |
Article in Journal/Newspaper |
author |
Roach, CJ Balwada, D Speer, K |
author_facet |
Roach, CJ Balwada, D Speer, K |
author_sort |
Roach, CJ |
title |
Horizontal mixing in the Southern Ocean from Argo float trajectories |
title_short |
Horizontal mixing in the Southern Ocean from Argo float trajectories |
title_full |
Horizontal mixing in the Southern Ocean from Argo float trajectories |
title_fullStr |
Horizontal mixing in the Southern Ocean from Argo float trajectories |
title_full_unstemmed |
Horizontal mixing in the Southern Ocean from Argo float trajectories |
title_sort |
horizontal mixing in the southern ocean from argo float trajectories |
publisher |
Wiley-Blackwell Publishing Ltd |
publishDate |
2016 |
url |
https://doi.org/10.1002/2015JC011440 http://ecite.utas.edu.au/132285 |
long_lat |
ENVELOPE(69.500,69.500,-49.250,-49.250) ENVELOPE(171.000,171.000,-50.667,-50.667) |
geographic |
Southern Ocean Kerguelen Drake Passage Scotia Sea Pacific Kerguelen Island Campbell Plateau |
geographic_facet |
Southern Ocean Kerguelen Drake Passage Scotia Sea Pacific Kerguelen Island Campbell Plateau |
genre |
Drake Passage Scotia Sea Southern Ocean |
genre_facet |
Drake Passage Scotia Sea Southern Ocean |
op_relation |
http://ecite.utas.edu.au/132285/2/132285 - Horizontal mixing in the Southern Ocean from Argo float trajectories.pdf http://dx.doi.org/10.1002/2015JC011440 Roach, CJ and Balwada, D and Speer, K, Horizontal mixing in the Southern Ocean from Argo float trajectories, Journal of Geophysical Research: Oceans, 121, (8) pp. 5570-5586. ISSN 2169-9275 (2016) [Refereed Article] http://ecite.utas.edu.au/132285 |
op_doi |
https://doi.org/10.1002/2015JC011440 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
121 |
container_issue |
8 |
container_start_page |
5570 |
op_container_end_page |
5586 |
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1766398234298679296 |