Wind-Forced Submesoscale Symmetric Instability around Deep Convection in the Northwestern Mediterranean Sea

Type Article
Date 2021-03
Language English
Author(s) Bosse Anthony1, Testor PierreORCID2, Damien PierreORCID3, Estournel ClaudeORCID4, Marsaleix PatrickORCID4, Mortier LaurentORCID2, 5, Prieur Louis6, Taillandier VincentORCID6
Affiliation(s) 1 : Mediterranean Institute of Oceanography, Aix Marseille University, Université de Toulon, CNRS, IRD, MIO UM 110, F-13288 Marseille, France
2 : Laboratoire d’Océanographie et du Climat: Expérimentations et Approches Numériques, Sorbonne Universités, UPMC Université Paris 06, IPSL, CNRS, IRD, MNHN, LOCEAN UMR 182, F-75252 Paris, France
3 : Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA 90025, USA
4 : Laboratoire d’Études en Géophysique et Océanographie Spatiales, CNRS, CNES, IRD, Université de Toulouse, LEGOS UMR 5566, F-31400 Toulouse, France
5 : ENSTA-Paristech, F-91120 Palaiseau, France
6 : Laboratoire d’Océanographie de Villefranche, Sorbonne Universités, CNRS, IMEV-LOV UMR 7093, F-06230 Villefranche-sur-Mer, France
Source Fluids (2311-5521) (MDPI AG), 2021-03 , Vol. 6 , N. 3 , P. 123 (26p.)
DOI 10.3390/fluids6030123
WOS© Times Cited 6
Note This article belongs to the Special Issue Submesoscale Processes in the Ocean
Keyword(s) deep convection, submesoscale dynamics, frontal instability, subduction

During the winter from 2009 to 2013, the mixed layer reached the seafloor at about 2500 m in the northwestern Mediterranean Sea. Intense fronts around the deep convection area were repeatedly sampled by autonomous gliders. Subduction down to 200–300 m, sometimes deeper, below the mixed layer was regularly observed testifying of important frontal vertical movements. Potential Vorticity dynamics was diagnosed using glider observations and a high resolution realistic model at 1-km resolution. During down-front wind events in winter, remarkable layers of negative PV were observed in the upper 100 m on the dense side of fronts surrounding the deep convection area and successfully reproduced by the numerical model. Under such conditions, symmetric instability can grow and overturn water along isopycnals within typically 1–5 km cross-frontal slanted cells. Two important hotpspots for the destruction of PV along the topographically-steered Northern Current undergoing frequent down-front winds have been identified in the western part of Gulf of Lion and Ligurian Sea. Fronts were there symmetrically unstable for up to 30 days per winter in the model, whereas localized instability events were found in the open sea, mostly influenced by mesoscale variability. The associated vertical circulations also had an important signature on oxygen and fluorescence, highlighting their under important role for the ventilation of intermediate layers, phytoplankton growth and carbon export.

Full Text
File Pages Size Access
Publisher's official version 26 10 MB Open access
Supplementary File 1 9 MB Open access
Top of the page

How to cite 

Bosse Anthony, Testor Pierre, Damien Pierre, Estournel Claude, Marsaleix Patrick, Mortier Laurent, Prieur Louis, Taillandier Vincent (2021). Wind-Forced Submesoscale Symmetric Instability around Deep Convection in the Northwestern Mediterranean Sea. Fluids, 6(3), 123 (26p.). Publisher's official version : , Open Access version :