FN Archimer Export Format
PT J
TI From Mixing to the Large Scale Circulation: How the Inverse Cascade Is Involved in the Formation of the Subsurface Currents in the Gulf of Guinea
BT 
AF Assene, Fernand
   Morel, Yves
   Delpech, Audrey
   Aguedjou, Micael
   Jouanno, Julien
   Cravatte, Sophie
   Marin, Frederic
   Ménesguen, Claire
   Chaigneau, Alexis
   Dadou, Isabelle
   Alory, Gael
   Holmes, Ryan
   Bourlès, Bernard
   Koch-Larrouy, Ariane
AS 1:1,2;2:1;3:1;4:1,7;5:1;6:1;7:1;8:3;9:1,7,8;10:1;11:1;12:4;13:5;14:1,6;
FF 1:;2:;3:;4:;5:;6:;7:;8:PDG-ODE-LOPS-OH;9:;10:;11:;12:;13:;14:;
C1 LEGOS, Université de Toulouse, CNES, CNRS, IRD, 31400 Toulouse, France
   Department of Oceanography, Institute of Fisheries and Aquatic Sciences, University of Douala at Yabassi, BP 7236 Douala-Bassa, Cameroon
   LOPS, Université de Bretagne Occidentale, Ifremer, CNRS, IRD, 29280 Plouzané, France
   CCRC, ARC CLEX and the School of Mathematics and Statistics, University of New South Wales, NSW 2052 Sydney, Australia
   IMAGO, IRD, 29280 Plouzané, France
   Mercator Ocean, 31520 Ramonville-Saint-Agne, France
   International Chair in Mathematical Physics and Applications (ICMPA-UNESCO Chair), University of Abomey-Calavi, 072BP50 Cotonou, Rep. Benin
   Institut de Recherches Halieutiques et Océanologiques du Bénin (IRHOB), 03BP1665 Cotonou, Rep. Benin
C2 IRD, FRANCE
   UNIV DOUALA, CAMEROON
   IFREMER, FRANCE
   UNIV NEW SOUTH WALES, AUSTRALIA
   IRD, FRANCE
   MERCATOR OCEAN, FRANCE
   UNIV ABOMEY CALAVI, BENIN
   IRHOB, BENIN
SI BREST
SE PDG-ODE-LOPS-OH
UM LOPS
IN WOS Ifremer UMR
   DOAJ
   copubli-france
   copubli-p187
   copubli-int-hors-europe
   copubli-sud
TC 8
UR https://archimer.ifremer.fr/doc/00645/75697/76601.pdf
   https://archimer.ifremer.fr/doc/00645/75697/76602.zip
LA English
DT Article
CR PIRATA
DE ;equatorial atlantic;NEUC (North Equatorial Undercurrents);SEUC (South Equatorial Undercurrents);vortices;mixing;friction
AB In this paper, we analyse the results from a numerical model at high resolution. We focus on the formation and maintenance of subsurface equatorial currents in the Gulf of Guinea and we base our analysis on the evolution of potential vorticity (PV). We highlight the link between submesoscale processes (involving mixing, friction and filamentation), mesoscale vortices and the mean currents in the area. In the simulation, eastward currents, the South and North Equatorial Undercurrents (SEUC and NEUC respectively) and the Guinea Undercurrent (GUC), are shown to be linked to the westward currents located equatorward. We show that east of 20∘ W, both westward and eastward currents are associated with the spreading of PV tongues by mesoscale vortices. The Equatorial Undercurrent (EUC) brings salty waters into the Gulf of Guinea. Mixing diffuses the salty anomaly downward. Meridional advection, mixing and friction are involved in the formation of fluid parcels with PV anomalies in the lower part and below the pycnocline, north and south of the EUC, in the Gulf of Guinea. These parcels gradually merge and vertically align, forming nonlinear anticyclonic vortices that propagate westward, spreading and horizontally mixing their PV content by stirring filamentation and diffusion, up to 20∘ W. When averaged over time, this creates regions of nearly homogeneous PV within zonal bands between 1.5∘ and 5∘ S or N. This mean PV field is associated with westward and eastward zonal jets flanking the EUC with the homogeneous PV tongues corresponding to the westward currents, and the strong PV gradient regions at their edges corresponding to the eastward currents. Mesoscale vortices strongly modulate the mean fields explaining the high spatial and temporal variability of the jets. 
PY 2020
PD SEP
SO Fluids
SN 2311-5521
PU MDPI AG
VL 5
IS 3
UT 000580785200001
DI 10.3390/fluids5030147
ID 75697
ER

EF