Open AccessControl of salinity on the mixed layer depth in the world ocean: 2. Tropical areas
Author(s) -
Mignot Juliette,
de Boyer Montégut Clement,
Lazar Alban,
Cravatte Sophie
Publication year - 2007
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2006jc003954
Subject(s) - climatology , stratification (seeds) , subtropics , tropical atlantic , argo , salinity , tropics , mixed layer , geology , thermohaline circulation , walker circulation , environmental science , surface runoff , sea surface temperature , atmospheric sciences , oceanography , seed dormancy , ecology , botany , germination , dormancy , fishery , biology
A new global climatology of the barrier layer (BL) thickness based on the analysis of instantaneous temperature and salinity profiles was presented in the first part of this paper. It is used here to revisit the mean properties of the phenomenon in the tropics. Consistent with previous studies, thick and persistent BLs are detected in the deep tropics of each ocean. Their formation involves various mechanisms such as intense precipitations, oceanic circulation, wind seasonality, and river runoff, in relation with the specific geography and climatology of each basin. The weak seasonal cycle of the BL in the equatorial Pacific is analyzed in particular. Thick BLs are also detected in winter on the equatorial flank of each of the subtropical salinity maxima. They are due to the specific salinity stratification in this area and to the seasonal homogenization of temperature over the vertical under the action of atmospheric heat fluxes. Thick BLs in the western tropical Atlantic that are partly associated with important vertical temperature inversions are furthermore identified and described. More generally, agreement of the BLs mean properties in these areas with previous literature confirms the robustness of the features and validates this new product that uses most available data including the most recent ones issued from the ARGO floats.