Modeling Postconvective Submesoscale Coherent Vortices in the Northwestern Mediterranean Sea

Type Article
Date 2017-12
Language English
Author(s) Damien P.1, 2, Bosse A3, Testor P.3, Marsaleix P.2, Estournel C.2
Affiliation(s) 1 : CICESE, Dept Oceanog Fis, Ensenada, Baja California, Mexico.
2 : Univ Toulouse, CNRS, UPS, Lab Aerol, Toulouse, France.
3 : MNHN, CNRS IRD UPMC, UMR 7159, LOCEAN, Paris, France.
Source Journal Of Geophysical Research-oceans (2169-9275) (Amer Geophysical Union), 2017-12 , Vol. 122 , N. 12 , P. 9937-9961
DOI 10.1002/2016JC012114
WOS© Times Cited 27
Note This article also appears in: Dense water formations in the North Western Mediterranean: from the physical forcings to the biogeochemical consequences
Keyword(s) submesoscale coherent vortices, dense waters spreading, western Mediterranean Sea, deep basin ventilation
Abstract

For the first time, the formation of submesoscale coherent vortices (SCVs) during intermediate and deep convection events is documented in a realistic high-resolution (1 km) numerical simulation of the oceanic circulation in the northwestern Mediterranean Sea. Winter intermediate and deep convection leads to the formation of anticyclonic and cyclonic eddies with lifetimes exceeding 1 year. By focusing on three typical eddies, the main characteristics of such vortices are discussed. The anticyclonic eddies are typical of SCVs observed in deep convection areas so far. They are characterized by a small radius (similar to 6.5 km) and orbital peak velocities of about 7 cm/s located at great depth (similar to 1500 m) or intermediate depth (similar to 500 m). The cyclonic vortices show very similar characteristics, such as a high Rossby number (similar to 0.4), but with surface-intensified structures. The long lifetimes of both anticyclonic and cyclonic eddies reflect very slow diffusive processes between their core and their surroundings and a strong resistance to external perturbations. These long-lived eddies are found to participate in the spreading of a significant portion (from 15 to 35%) of the convected waters in the Gulf of Lions and contribute to the ventilation of the deep basin.

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