Presented at the 2013 Aquarius/SAC-D Science Team MeetingThis study investigates the sea surface salinity (SSS) and barrier layer variability in the equatorial Pacific using recently available Aquarius and Argo data. Comparison between the two datasets indicates that Aquarius able to capture most of the SSS features identified by Argo. Despite some discrepancies in the mean value, the SSS from the two datasets shows essentially the same seasonal cycle both in magnitude and phase. For the period of observation between August 2011 and July 2013 Aquarius nicely resolved the zonal displacement of the SSS front along the equator, showing its observing capacity of the western Pacific warm pool. Analysis of the Argo data provides further information on surface stratification. A thick barrier layer present on the western side of the SSS front during all the period of observation, moving back and forth along the equator with its correlation with the Southern Oscillation Index exceeding 0.80. Generally, the thick barrier layer moves eastward during El Niño and westward during La Niña. The mechanisms responsible for this zonal displacement are discussed.