Variability in the Indian Ocean circulation and salinity and its impact on SST anomalies during dipole events

The GFDL Modular Ocean Model (MOM4) has been used to understand the variability of the Indian Ocean circulation and salinity during Indian Ocean Dipole events. The model simulations are compared with HadISST, SODA and ECCO data sets. During the positive dipole years, the climatological cyclonic circulation in the Bay of Bengal weakens or is replaced by an anticyclonic circulation. The interannual variability in the Wyrtki Jet and Bay of Bengal circulation has significant influence on fresh water transport between the equatorial Indian Ocean and Bay of Bengal. The salinity anomalies in the equatorial Indian Ocean are significant during the positive dipole years. The salinity anomalies are positive in the southeastern equatorial Indian Ocean and negative in the central equatorial Indian Ocean. The advection of low salinity water from the eastern equatorial Indian Ocean and Bay of Bengal is attributed to the salinity anomalies in the central equatorial Indian Ocean. The salinity variability in the equatorial Indian Ocean influences the surface and subsurface temperatures by forming or eroding the barrier layer