Equatorial Pacific Warming Attenuated by SST Warming Patterns in the Tropical Atlantic and Indian Oceans

Most climate models project an enhanced mean sea surface temperature (SST) warming in the equatorial Pacific and Atlantic, and a zonal SST dipole in the Indian Ocean. The remote influences of these SST change patterns remain uncertain. To examine the extent to which the patterns of SST changes in the tropical Indian and Atlantic Oceans modulate the warming in the tropical Pacific Ocean, we compare nudging experiments with prescribed structured and uniform SST changes in the tropics outside the Pacific. We find that the warming patterns in the tropical Indian and Atlantic Oceans, respectively, drive a canonical La Niña-like and elongated equatorial cooling through the Bjerknes feedback, acting to attenuate the warming in the equatorial Pacific substantially. The different SST cooling responses emanate from subtle differences between the initial wind forcing driven by the two basins' SST change patterns. These results have significant implications for future climate change projections.