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Eddy-topography interactions and the fate of the Persian Gulf Outflow

Eddy-topography interactions and the fate of the Persian Gulf Outflow
Eddy-topography interactions and the fate of the Persian Gulf Outflow

The Persian Gulf feeds a warm and salty outflow in the Gulf of Oman (northern Arabian Sea). The salt climatological distribution is relatively smooth in the Gulf of Oman, and the signature of a slope current carrying salty waters is difficult to distinguish hundreds of kilometers past the Strait of Hormuz, in contrast to other outflows of the world ocean. This study focuses on the mechanisms involved in the spreading of Persian Gulf Water (PGW) in the Gulf of Oman, using a regional primitive equation numerical simulation. The authors show that the dispersion of PGW occurs through a regime that is distinct from, for example, the one responsible for the Mediterranean outflow dispersion. The background mesoscale eddy field is energetic and participates actively to the spreading of PGW. Remotely formed eddies propagate into the Gulf of Oman and interact with the topography, leading to submesoscales formation and PGW shedding. Eddy-topography interactions are isolated in idealized simulations and reveal the formation of intense frictional boundary layers, generating submesoscale coherent vortices (SCVs). Interactions take place at depths encompassing the PGW depth, thus SCVs trap PGW and contribute to its redistribution from the boundaries to the interior of the Gulf of Oman. The overall efficiency of these processes is confirmed by a strong contribution of eddy salt fluxes in the interior of the basin, and is quantified using particle statistics. It is found to be a highly dispersive regime, with an approximated eddy diffusivity of inline image.
outflow, mesoscale, submesoscale, Persian Gulf, Gulf of Oman
2169-9275
6700-6717
Vic, Clement
408e7f4a-468f-4139-90a6-3a95228ad758
Roullet, G.
12977456-4652-46bc-8d39-1e93f45c666d
Capet, X.
3c8624e7-e770-414a-9ecc-c04db4eea706
Carton, X.
0d9a7d00-b23c-4b3b-b45a-430f29f58684
Molemaker, M. J.
b9794526-4b24-480b-8e68-a871ce8c0e9e
Gula, J.
ff09d520-0745-45fb-9e04-bc4063818977
Vic, Clement
408e7f4a-468f-4139-90a6-3a95228ad758
Roullet, G.
12977456-4652-46bc-8d39-1e93f45c666d
Capet, X.
3c8624e7-e770-414a-9ecc-c04db4eea706
Carton, X.
0d9a7d00-b23c-4b3b-b45a-430f29f58684
Molemaker, M. J.
b9794526-4b24-480b-8e68-a871ce8c0e9e
Gula, J.
ff09d520-0745-45fb-9e04-bc4063818977

Vic, Clement, Roullet, G., Capet, X., Carton, X., Molemaker, M. J. and Gula, J. (2015) Eddy-topography interactions and the fate of the Persian Gulf Outflow. Journal of Geophysical Research: Oceans, 120 (10), 6700-6717. (doi:10.1002/2015JC011033).

Record type: Article

Abstract


The Persian Gulf feeds a warm and salty outflow in the Gulf of Oman (northern Arabian Sea). The salt climatological distribution is relatively smooth in the Gulf of Oman, and the signature of a slope current carrying salty waters is difficult to distinguish hundreds of kilometers past the Strait of Hormuz, in contrast to other outflows of the world ocean. This study focuses on the mechanisms involved in the spreading of Persian Gulf Water (PGW) in the Gulf of Oman, using a regional primitive equation numerical simulation. The authors show that the dispersion of PGW occurs through a regime that is distinct from, for example, the one responsible for the Mediterranean outflow dispersion. The background mesoscale eddy field is energetic and participates actively to the spreading of PGW. Remotely formed eddies propagate into the Gulf of Oman and interact with the topography, leading to submesoscales formation and PGW shedding. Eddy-topography interactions are isolated in idealized simulations and reveal the formation of intense frictional boundary layers, generating submesoscale coherent vortices (SCVs). Interactions take place at depths encompassing the PGW depth, thus SCVs trap PGW and contribute to its redistribution from the boundaries to the interior of the Gulf of Oman. The overall efficiency of these processes is confirmed by a strong contribution of eddy salt fluxes in the interior of the basin, and is quantified using particle statistics. It is found to be a highly dispersive regime, with an approximated eddy diffusivity of inline image.

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Accepted/In Press date: 15 September 2015
Published date: 15 October 2015
Keywords: outflow, mesoscale, submesoscale, Persian Gulf, Gulf of Oman
Organisations: Physical Oceanography

Identifiers

Local EPrints ID: 398062
URI: http://eprints.soton.ac.uk/id/eprint/398062
ISSN: 2169-9275
PURE UUID: 135c9dc9-882a-4c6e-aadf-8a0514076128

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Date deposited: 13 Sep 2016 13:28
Last modified: 15 Mar 2024 01:28

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Contributors

Author: Clement Vic
Author: G. Roullet
Author: X. Capet
Author: X. Carton
Author: M. J. Molemaker
Author: J. Gula

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