FN Archimer Export Format
PT J
TI Mixed Layer formation and restratification in presence of mesoscale and submesoscale turbulence
BT 
AF COUVELARD, Xavier
   DUMAS, Franck
   GARNIER, Valerie
   PONTE, Aurelien
   TALANDIER, Claude
   TREGUIER, Anne-Marie
AS 1:1,2;2:2;3:2;4:1;5:1;6:1;
FF 1:PDG-ODE-DYNECO-PHYSED;2:PDG-ODE-DYNECO-PHYSED;3:PDG-ODE-DYNECO-PHYSED;4:PDG-ODE-LPO;5:;6:;
C1 UMR 6523 CNRS Ifremer IRD UBO, Lab Phys Oceans, Ctr Ifremer Brest, Plouzane, France.
   Ctr Ifremer Brest, DYNECO PHYSED IFREMER, Plouzane, France.
C2 CNRS, FRANCE
   IFREMER, FRANCE
SI BREST
SE PDG-ODE-DYNECO-PHYSED
   PDG-ODE-LPO
UM LOPS
IN WOS Ifremer jusqu'en 2018
   copubli-france
IF 3.337
TC 14
UR https://archimer.ifremer.fr/doc/00286/39714/38169.pdf
LA English
DT Article
DE ;Barticlinic jet;Mixed layer instabilities;Restratification;Mixedlayer depth;Vertical mixing;NEMO
AB Recent realistic high resolution modeling studies show a net increase of submesoscale activity in fall and winter when the mixed layer depth is at its maximum. This submesoscale activity increase is associated with a reduced deepening of the mixed layer. Both phenomena can be related to the development of mixed layer instabilities, which convert available potential energy into submesoscale eddy kinetic energy and contribute to a fast restratification by slumping the horizontal density gradient in the mixed layer. In the present work, the mixed layer formation and restratification was studied by uniformly cooling a fully turbulent zonal jet in a periodic channel at different resolutions, from eddy resolving (10 km) to submesoscale permitting (2 km). The effect of the submesoscale activity, highlighted by these different horizontal resolutions, was quantified in terms of mixed layer depth, restratification rate and buoyancy fluxes. Contrary to many idealized studies focusing on the restratification phase only, this study addresses a continuous event of mixed layer formation followed by its complete restratification. The robustness of the present results was established by ensemble simulations. The results show that, at higher resolution, when submesoscale starts to be resolved, the mixed layer formed during the surface cooling is significantly shallower and the total restratification almost three times faster. Such differences between coarse and fine resolution models are consistent with the submesoscale upward buoyancy flux, which balances the convection during the formation phase and accelerates the restratification once the surface cooling is stopped. This submesoscale buoyancy flux is active even below the mixed layer. Our simulations show that mesoscale dynamics also cause restratification, but on longer time scales. Finally, the spatial distribution of the mixed layer depth is highly heterogeneous in the presence of submesoscale activity, prompting the question of whether it is possible to parameterize submesoscale effects and their effects on the marine biology as a function of a spatially-averaged mixed layer depth.
PY 2015
PD DEC
SO Ocean Modelling
SN 1463-5003
PU Elsevier Sci Ltd
VL 96
UT 000366058600006
BP 243
EP 253
DI 10.1016/j.ocemod.2015.10.004
ID 39714
ER

EF