Observed Variability of Near-Surface Salinity Field on Seasonal and Interannual Time Scales and Its Impact on the Evolution of Sea Surface Temperature of the Tropical Indian Ocean

Abstract

A subset of the newly published salinity and temperature climatologies of the global ocean is assembled to examine the observed seasonal variability of the near-surface salinity field of the tropical Indian Ocean. The role of vertical haline stratification in the near-surface layers on the manifestation of the barrier layer thickness in the new climatology is addressed. The warm pool of the tropical Indian Ocean is characterized to identify the geographic regions where the near-surface haline stratification and the warm pool core co-exist. Among the three regions within the warm pool of the tropical Indian Ocean, viz., southeastern Arabian Sea, southwestern Bay of Bengal and eastern equatorial Indian Ocean, a strong coupling between the near-surface haline stratification and the subsequent evolution of the warm pool core is most prominently seen only in the southeastern Arabian Sea. The observed year to year co-variability of the near-surface low salinity pool and the warm pool core in the southeastern Arabian Sea is examined.