Indian Ocean heat transport and its role in developing SST pattern in the post-monsoon season in CMIP6 models

The cross-equatorial oceanic heat transport (OHT) in the Indian Ocean during boreal summer is an integral component of the Indian summer monsoon (ISM). This OHT is believed to be a crucial factor in the interannual variability of ISM. Thus, a deeper understanding of OHT in climate model simulations is needed for the understanding of the simulated interannual variability of monsoon. Here we examine the Indian Ocean meridional OHT and how the OHT in the summer monsoon season impacts the development of SST patterns in the post-monsoon season. Our results show that the post-monsoon SST positively correlates with OHT during the summer monsoon in western IO and negatively correlates in the southeastern Indian Ocean. Further, it reveals that the OHT during summer monsoon explains the dipole pattern of SST in the post-monsoon over the equatorial Indian Ocean. This study also investigates how anomalous OHT during monsoon months contributes to the persistence of marine heat waves (MHW) in the post-monsoon season. Both CMIP6 models and observations suggest enhanced and persistent MHWs in the post-monsoon season are linked to stronger OHT during the summer season.