Atlantic Meridional Overturning Circulation Influence on the Annual Mean Intertropical Convergence Zone Location in the Miocene.

The Intertropical Convergence Zone (ITCZ) has an annual mean location north of the equator today. The factors determining this location and the evolution to its modern state are actively debated. Here we investigate how the Atlantic Meridional Overturning Circulation (AMOC) influences the ITCZ during the early‐to‐middle Miocene. By conducting a sensitivity study with an open Canadian Arctic Archipelago gateway, we show that North Atlantic Deep‐Water formation strengthens the AMOC, in alignment with Miocene North Atlantic ventilation proxies. A vigorous AMOC increases northward Atlantic Ocean heat transport and cross‐equatorial atmospheric energy transport shifts southwards to compensate, pushing the ITCZ northwards. Our study supports AMOC development as a strong contributor to the ITCZ's northern location today. Existing proxy‐based interpretations of ITCZ history are too sparse to strongly confirm these results. We predict a strong in‐phase relationship between AMOC strength and ITCZ's northward location, which should be testable in high resolution paleoclimate records. Plain Language Summary: The Intertropical Convergence Zone (ITCZ) is a narrow tropical region where tropical rainfall is concentrated. Its annual mean position is predominantly north of the equator in the modern climate, especially in the Atlantic and eastern Pacific oceans. The position of the ITCZ varies seasonally and over long‐time scales. One hypothesis is that Atlantic Meridional Overturning Circulation (AMOC) energy transport displaces the ITCZ north of the Equator. We test this hypothesis in a paleoclimate simulation with realistic early‐to‐middle Miocene (20–11.6 million years ago) configurations. By opening the Canadian Arctic Archipelago gateway, a crucial connection between the Arctic Ocean and North Atlantic, we find that a strong AMOC transports more heat northward in the ocean, and in compensation, the flow of atmospheric energy across the equator shifts southward, consequently pushing the ITCZ north of the equator. More Miocene proxy records are required to empirically support this model result. Key Points: Opening an Arctic Ocean gateway in Miocene climate simulations generates a strong Atlantic Meridional Overturning Circulation (AMOC) and increases northward ocean heat transportTo compensate, atmospheric energy transport across the equator shifts southward, pushing the Intertropical Convergence Zone (ITCZ) north of the equatorAMOC strengthening is a mechanism in past warm climates for northward ITCZ shifts [ABSTRACT FROM AUTHOR]