Intensification of Decadal Variability in Sea Surface Salinity in the Western Tropical Pacific

The decadal variability of sea surface salinity (SSS) is crucial for the global water cycle and the climate system. Previous studies have indicated that the SSS in the western tropical Pacific (WTP) Ocean exhibits significant decadal variability, which plays an important role in shaping tropical climate. Here we find that the amplitude of SSS decadal variability in the WTP has been intensified significantly since the early 1950s. A comprehensive analysis of the salinity budget indicates that the amplifying of SSS decadal variability in the WTP is primarily attributed to changes in both the freshwater flux and ocean dynamics. During the past decades, surface currents in the WTP get stronger and result in enhanced salinity advection. In addition, the amplitude of decadal variability of freshwater flux is increased as well due to anomalous atmospheric circulation associated with the Victoria mode.