Coupled Mode of Net Heat Flux and Wind Explain the Formation of the Indian Ocean Dipole

Net heat flux, sea surface temperature (SST), and sea surface wind in the northern Indian Ocean were investigated using the TropFlux, ERA5, and J-OFURO3 datasets and correlation analysis, power spectrum analysis, and singular value decomposition (SVD) methods, respectively. The relationships between net heat flux, SST, and sea surface winds were determined. The coupled modes of net heat flux and wind have been found to explain the SST variations in the Indian Ocean basin and the generation mechanism of the Indian Ocean Dipole (IOD). The correlation between net heat flux and wind is strongly negative. The SST lags the net heat flux and wind by approximately one month and has strong positive and negative correlations, respectively. The correlation between net heat flux and wind in the northern Indian Ocean is not only seasonal but also regionally dependent on seasonal variations. Using the SVD method, the important role of net heat flux in local sea-air interactions is discussed and identified as the initial perturbation that triggers the SST anomalies in the Southeast Indian Ocean, and the areas with key sea-air interactions and the generation mechanisms of the local sea-air interactions that form the IOD are determined.