Atlantic ocean heat transport enabled by Indo-Pacific heat uptake and mixing

The ocean transports vast amounts of heat around the planet, helping to regulate regional climate. One important component of this heat transport is the movement of warm water from equatorial regions toward the poles, with colder water flowing in return. Here, based on water-mass transformation techniques, we introduce a closed budget for heat transport in the temperature-latitude plane. This framework relates the ocean's meridional heat transport to the diabatic processes of surface forcing and turbulent mixing that move heat across temperature classes. Applied to a 1/4-degree global ocean model the framework highlights the role of the tropical Indo-Pacific in the global ocean heat transport. A large fraction of the northward heat transport in the Atlantic is ultimately sourced from heat uptake in the eastern tropical Pacific. Turbulent mixing moves heat from the warm, shallow Indo-Pacific circulation to the cold deeper-reaching Atlantic circulation. Our results underscore a renewed focus on the tropical oceans and their role in global circulation pathways.