Overturning cells in the Southern Ocean and subtropical gyres
The circulation of the subtropical gyres can be decomposed into a horizontal recirculation along contours of constant Bernoulli potential and an overturning circulation across these contours. While the geometry and topology of Bernoulli contours is more complicated in the subtropical gyres than in t...
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ftcopernicus:oai:publications.copernicus.org:os6879 2023-05-15T18:24:13+02:00 Overturning cells in the Southern Ocean and subtropical gyres Polton, J. A. Marshall, D. P. 2018-01-15 application/pdf https://doi.org/10.5194/os-3-17-2007 https://os.copernicus.org/articles/3/17/2007/ eng eng doi:10.5194/os-3-17-2007 https://os.copernicus.org/articles/3/17/2007/ eISSN: 1812-0792 Text 2018 ftcopernicus https://doi.org/10.5194/os-3-17-2007 2020-07-20T16:27:08Z The circulation of the subtropical gyres can be decomposed into a horizontal recirculation along contours of constant Bernoulli potential and an overturning circulation across these contours. While the geometry and topology of Bernoulli contours is more complicated in the subtropical gyres than in the Southern Ocean, these subtropical overturning circulations are very much analogous to the overturning cell found in the Southern Ocean. This analogy is formalised through an exact integral constraint, including the rectified effects of transient eddies. The constraint can be interpreted either in terms of vertical fluxes of potential vorticity, or equivalently as an integral buoyancy budget for an imaginary fluid parcel recirculating around a closed Bernoulli contour. Under conditions of vanishing buoyancy and mechanical forcing, the constraint reduces to a generalised non-acceleration condition, under which the Eulerian-mean and eddy-induced overturning circulations exactly compensate. The terms in the integral constraint are diagnosed in an eddy-permitting ocean model in both the North Pacific subtropical gyre and the Southern Ocean. The extent to which the Eulerian-mean and eddy-induced overturning circulations compensate is discussed in each case. Text Southern Ocean Copernicus Publications: E-Journals Pacific Southern Ocean Ocean Science 3 1 17 30 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
The circulation of the subtropical gyres can be decomposed into a horizontal recirculation along contours of constant Bernoulli potential and an overturning circulation across these contours. While the geometry and topology of Bernoulli contours is more complicated in the subtropical gyres than in the Southern Ocean, these subtropical overturning circulations are very much analogous to the overturning cell found in the Southern Ocean. This analogy is formalised through an exact integral constraint, including the rectified effects of transient eddies. The constraint can be interpreted either in terms of vertical fluxes of potential vorticity, or equivalently as an integral buoyancy budget for an imaginary fluid parcel recirculating around a closed Bernoulli contour. Under conditions of vanishing buoyancy and mechanical forcing, the constraint reduces to a generalised non-acceleration condition, under which the Eulerian-mean and eddy-induced overturning circulations exactly compensate. The terms in the integral constraint are diagnosed in an eddy-permitting ocean model in both the North Pacific subtropical gyre and the Southern Ocean. The extent to which the Eulerian-mean and eddy-induced overturning circulations compensate is discussed in each case. |
format |
Text |
author |
Polton, J. A. Marshall, D. P. |
spellingShingle |
Polton, J. A. Marshall, D. P. Overturning cells in the Southern Ocean and subtropical gyres |
author_facet |
Polton, J. A. Marshall, D. P. |
author_sort |
Polton, J. A. |
title |
Overturning cells in the Southern Ocean and subtropical gyres |
title_short |
Overturning cells in the Southern Ocean and subtropical gyres |
title_full |
Overturning cells in the Southern Ocean and subtropical gyres |
title_fullStr |
Overturning cells in the Southern Ocean and subtropical gyres |
title_full_unstemmed |
Overturning cells in the Southern Ocean and subtropical gyres |
title_sort |
overturning cells in the southern ocean and subtropical gyres |
publishDate |
2018 |
url |
https://doi.org/10.5194/os-3-17-2007 https://os.copernicus.org/articles/3/17/2007/ |
geographic |
Pacific Southern Ocean |
geographic_facet |
Pacific Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
eISSN: 1812-0792 |
op_relation |
doi:10.5194/os-3-17-2007 https://os.copernicus.org/articles/3/17/2007/ |
op_doi |
https://doi.org/10.5194/os-3-17-2007 |
container_title |
Ocean Science |
container_volume |
3 |
container_issue |
1 |
container_start_page |
17 |
op_container_end_page |
30 |
_version_ |
1766204582706282496 |