◆ Observational data analysis indicates that cold water brought up by coastal upwelling south of Java can trigger the onset of Indian Ocean Dipole (IOD).
◆ A method to accurately determine coastal upwelling signal based on satellite chlorophyll-a data was developed and used for analysis in areas with limited observations.
◆ As IOD affects the global climate, including summer weather in Japan, the findings of this study are expected to help improve the predictability of both the global climate and IOD.