Variations of SST and Thermocline Depth in the Tropical Indian Ocean During Indian Ocean Dipole Events

Interannual variations in the surface and subsurface tropical Indian Ocean were studied using HadISST and SODA data-sets.Wind and heat flux datasets were used to discuss the mechanisms for these variations.Our results indicate that the surface andsubsurface variations of the tropical Indian Ocean during Indian Ocean Dipole(IOD)events are significantly different.A prominentcharacteristic of the eastern pole is the SSTA rebound after a cooling process,which does not take place at the subsurface layer.Inthe western pole,the surface anomalies last longer than the subsurface anomalies.The subsurface anomalies are strongly correlatedwith ENSO,while the relationship between the surface anomalies and ENSO is much weaker.And the subsurface anomalies of thetwo poles are negatively correlated while they are positively correlated at the surface layer.The wind and surface heat flux analysissuggests that the thermocline depth variations are mainly determined by wind stress fields,while the heat flux effect is important onSST.