%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Hasson, A. E. A.
%A Delcroix, Thierry
%A Dussin, R.
%T An assessment of the mixed layer salinity budget in the tropical Pacific Ocean. Observations and modelling (1990-2009)
%D 2013
%L fdi:010060687
%G ENG
%J Ocean Dynamics
%@ 1616-7341
%K Sea surface salinity ; Mixed-layer budget ; Seasonal variability ; Interannual variability
%K OCEAN PACIFIQUE ; ZONE TROPICAL
%M ISI:000315337200004
%N 2-3
%P 179-194
%R 10.1007/s10236-013-0596-2
%U https://www.documentation.ird.fr/hor/fdi:010060687
%> https://www.documentation.ird.fr/intranet/publi/2013/03/010060687.pdf
%V 63
%W Horizon (IRD)
%X This paper investigates mechanisms controlling the mixed-layer salinity (MLS) in the tropical Pacific during 1990-2009. We use monthly 1A degrees aEuro parts per thousand x 1A degrees gridded observations of salinity, horizontal current and fresh water flux, and a validated ocean general circulation model with no direct MLS relaxation in both its full resolution (0.25A degrees and 5 days) and re-sampled as the observation time/space grid resolution. The present study shows that the mean spatial distribution of MLS results from a subtle balance between surface forcing (E -aEuro parts per thousand P, evaporation minus precipitation), horizontal advection (at low and high frequencies) and subsurface forcing (entrainment and mixing), all terms being of analogous importance. Large-scale seasonal MLS variability is found mainly in the Intertropical and South Pacific Convergence Zones due to changes in their meridional location (and related heavy P), in the North Equatorial Counter Currents, and partly in the subsurface forcing. Maximum interannual variability is found in the western Pacific warm pool and in both convergence zones, in relation to El Nio Southern Oscillation (ENSO) events. In the equatorial band, this later variability is due chiefly to the horizontal advection of low salinity waters from the western to the central-eastern basin during El Nio (and vice versa during La Nia), with contrasted evolution for the Eastern and Central Pacific ENSO types. Our findings reveal that all terms of the MLS equation, including high-frequency (< 1 month) salinity advection, have to be considered to close the salinity budget, ruling out the use of MLS (or sea surface salinity) only to directly infer the mean, seasonal and/or interannual fresh water fluxes.
%$ 032