Interannual Variability of Tropical Indian Ocean Associated with Indian Ocean Dipole Events Co-occurred with El Ni(n)over-tildeo

The feature and evolution mechanisms of the tropical Indian Ocean (TIO) SST anomalies during Indian Ocean Dipole (IOD) events that co-occurred with El Ni (n) over tildeo are studied using Simple Ocean Data Assimilation (SODA) data sets and an ocean general circulation model. The southeastern TIO SST anomalies are cooled by vertical heat advection, and then experience a warming process because of surface heat flux. The equatorial western TIO is warmed by surface heat flux, while horizontal and vertical heat advections are responsible for the off-equatorial warming. Then the negative surface heal flux anomalies and the negative vertical heat advection anomalies take over for the cooling of the western and eastern TIC, respectively.