Interactions between the Tropical Atlantic, the Indian Ocean, and the Pacific on Decadal Time Scales

Previous studies revealed atmospheric bridges between the tropical Pacific, Atlantic, and Indian Ocean. In particular, several recent works indicate that the Atlantic sea surface temperature (SST) may contribute to the climate variability over the equatorial Pacific. Inspired by these studies, our work aims at investigating the impact of the tropical Atlantic on the entire tropical climate system, and uncovering the feedback of the Pacific on the Atlantic and Indian Ocean.

In this study, we performed ‘pacemaker’ simulations by restoring the satellite era tropical SST changes over the Atlantic, the Indian Ocean, and the Pacific, respectively, in a fully coupled model – the CESM1. Results reveal that the Atlantic warming heats the Indo-Western Pacific and cools the Eastern Pacific, enhances the Walker circulation and drives the subsurface Pacific to a La Niña mode, On the other hand, The Indian Ocean warming also contribute to the La Nina type changes over the Pacific, while the Pacific changes cools the Indian Ocean and the north tropical Atlantic slightly. The east Pacific cooling and the west Pacific warming play different roles in changing the status over the Indian Ocean and the Atlantic, which requests further investigation.