Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Dynamics of Atmospheres and Oceans 47-60 [+ 1 p.] ATLANTIQUE 2016 fdi:010069228 ENG Dynamics of Atmospheres and Oceans 0377-0265 ISI:000374368600004 10.1016/j.dynatmoce.2015.12.001 https://www.documentation.ird.fr/hor/fdi:010069228 https://www.documentation.ird.fr/intranet/publi/depot/2017-03-16/010069228.pdf 73 Horizon (IRD) The variability of sea surface Total Alkalinity (TA) and sea surface Total Inorganic Carbon (C-T) is examined using all available data in the western tropical Atlantic (WTA: 20 degrees S -20 degrees N, 60 degrees W -20 degrees W). Lowest TA and C-T are observed for the region located between 0 degrees N-15 degrees N/60 degrees W-50 degrees W and are explained by the influence of the Amazon plume during boreal summer. In the southern part of the area, 20 degrees S-10 degrees S/40 degrees W-60 degrees W, the highest values of TA and C-T are linked to the CO2-rich waters due to the equatorial upwelling, which are transported by the South Equatorial Current (SEC) flowing from the African coast to the Brazilian shore. An increase of C-T of 0.9 +/- 1 0.3 mu mol kg(-1) yr(-1) has been observed in the SEC region and is consistent with previous published estimates. A revised C-T-Sea Surface Salinity (SSS) relationship is proposed for the WTA to take into account the variability of C-T at low salinities. This new C-T-SSS relationship together with a published TA-SSS relationship allow to calculate pCO(2) values that compare well with observed pCO(2) (R-2 = 0.90). 032