Seasonally Different Response of the Indian Ocean to the Remote Forcing of El Nino: Linking the Dynamics and Thermodynamics

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Physical processes involved in basin-wide warming (BW) in the Indian Ocean (IO) and the IO “Dipole” mode (IOD) are investigated, using solutions to an air-sea coupled general circulation model (CGCM). In this study, we pay attention to the seasonal difference of the IO SST in response to the ENSO. A suite of time-slice CGCM experiments, by imposing the El Nino-related SST anomalies in the Pacific for the boreal summer and fall, are conducted to study the El Nino impact on the IO SST anomalies. The impacts of El Nino largely depend on the monsoon seasonality, and significantly contribute to the IOD and IO BW. Additional experiments demonstrate the salient seasonal difference in the SST sensitivity to the ocean dynamics.