Barotropic vorticity balance of the North Atlantic subpolar gyre in an eddy-resolving model
The circulation in the North Atlantic Subpolar gyre is complex and strongly influenced by the topography. The gyre dynamics is traditionally understood as the result of a topographic Sverdrup balance, which corresponds to a first order balance between the planetary vorticity advection, the bottom pr...
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ftcopernicus:oai:publications.copernicus.org:osd80945 2023-05-15T17:28:14+02:00 Barotropic vorticity balance of the North Atlantic subpolar gyre in an eddy-resolving model Corre, Mathieu Gula, Jonathan Tréguier, Anne-Marie 2019-10-28 application/pdf https://doi.org/10.5194/os-2019-114 https://www.ocean-sci-discuss.net/os-2019-114/ eng eng doi:10.5194/os-2019-114 https://www.ocean-sci-discuss.net/os-2019-114/ eISSN: 1812-0792 Text 2019 ftcopernicus https://doi.org/10.5194/os-2019-114 2019-12-24T09:48:17Z The circulation in the North Atlantic Subpolar gyre is complex and strongly influenced by the topography. The gyre dynamics is traditionally understood as the result of a topographic Sverdrup balance, which corresponds to a first order balance between the planetary vorticity advection, the bottom pressure torque and the wind stress curl. However, this dynamics has been studied mostly with non-eddy-resolving models and a crude representation of the bottom topography. Here we revisit the barotropic vorticity balance of the North Atlantic Subpolar gyre using a high resolution simulation (≈ 2-km) with topography-following vertical coordinates to better represent the mesoscale turbulence and flow-topography interactions. Our findings highlight that, locally, there is a first order balance between the bottom pressure torque and the nonlinear terms, albeit with a high degree of cancellation between each other. However, balances integrated over different regions of the gyre – shelf, slope and interior – still highlight the important role played by nonlinearities and the bottom drag curls. In particular the topographic Sverdrup balance cannot describe the dynamics in the interior of the gyre. The main sources of cyclonic vorticity are the nonlinear terms due to eddies generated along eastern boundary currents and the time-mean nonlinear terms from the Northwest Corner. Our results suggest that a good representation of the mesoscale activity along with a good positioning of the Northwest corner are two important conditions for a better representation of the circulation in the North Atlantic Subpolar Gyre. Text North Atlantic Copernicus Publications: E-Journals Curl ENVELOPE(-63.071,-63.071,-70.797,-70.797) |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
The circulation in the North Atlantic Subpolar gyre is complex and strongly influenced by the topography. The gyre dynamics is traditionally understood as the result of a topographic Sverdrup balance, which corresponds to a first order balance between the planetary vorticity advection, the bottom pressure torque and the wind stress curl. However, this dynamics has been studied mostly with non-eddy-resolving models and a crude representation of the bottom topography. Here we revisit the barotropic vorticity balance of the North Atlantic Subpolar gyre using a high resolution simulation (≈ 2-km) with topography-following vertical coordinates to better represent the mesoscale turbulence and flow-topography interactions. Our findings highlight that, locally, there is a first order balance between the bottom pressure torque and the nonlinear terms, albeit with a high degree of cancellation between each other. However, balances integrated over different regions of the gyre – shelf, slope and interior – still highlight the important role played by nonlinearities and the bottom drag curls. In particular the topographic Sverdrup balance cannot describe the dynamics in the interior of the gyre. The main sources of cyclonic vorticity are the nonlinear terms due to eddies generated along eastern boundary currents and the time-mean nonlinear terms from the Northwest Corner. Our results suggest that a good representation of the mesoscale activity along with a good positioning of the Northwest corner are two important conditions for a better representation of the circulation in the North Atlantic Subpolar Gyre. |
format |
Text |
author |
Corre, Mathieu Gula, Jonathan Tréguier, Anne-Marie |
spellingShingle |
Corre, Mathieu Gula, Jonathan Tréguier, Anne-Marie Barotropic vorticity balance of the North Atlantic subpolar gyre in an eddy-resolving model |
author_facet |
Corre, Mathieu Gula, Jonathan Tréguier, Anne-Marie |
author_sort |
Corre, Mathieu |
title |
Barotropic vorticity balance of the North Atlantic subpolar gyre in an eddy-resolving model |
title_short |
Barotropic vorticity balance of the North Atlantic subpolar gyre in an eddy-resolving model |
title_full |
Barotropic vorticity balance of the North Atlantic subpolar gyre in an eddy-resolving model |
title_fullStr |
Barotropic vorticity balance of the North Atlantic subpolar gyre in an eddy-resolving model |
title_full_unstemmed |
Barotropic vorticity balance of the North Atlantic subpolar gyre in an eddy-resolving model |
title_sort |
barotropic vorticity balance of the north atlantic subpolar gyre in an eddy-resolving model |
publishDate |
2019 |
url |
https://doi.org/10.5194/os-2019-114 https://www.ocean-sci-discuss.net/os-2019-114/ |
long_lat |
ENVELOPE(-63.071,-63.071,-70.797,-70.797) |
geographic |
Curl |
geographic_facet |
Curl |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
eISSN: 1812-0792 |
op_relation |
doi:10.5194/os-2019-114 https://www.ocean-sci-discuss.net/os-2019-114/ |
op_doi |
https://doi.org/10.5194/os-2019-114 |
_version_ |
1766120789548990464 |