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

<p>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) influenced the ITCZ during the early-to-middle Miocene. By conducting a paleoclimate modeling sensitivity study to northern high-latitude gateway opening, 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 the cross-equatorial atmospheric energy transport shifts southwards to compensate. This results in a northward shift of the ITCZ, particularly over the Pacific and Atlantic oceans. Our study supports the development of the AMOC as a strong contributor to the ITCZ's northern location today. Existing proxy-based interpretations of the ITCZ history are broadly consistent with our results but too sparse to strongly confirm or refute them. We predict a strong in-phase relationship between AMOC strength and northward location of the ITCZ, which should be testable in high resolution paleoclimate records.</p>

<p>The datasets found in "Atlantic Meridional Overturning Circulation Influence on the Annual Mean Intertropical Convergence Zone Location in the Miocene" were generated using the Purdue Supercomputing systems and are simulations from the NCAR Community Climate System Model version 4 (CCSM4), which is an open-source community model and available at: https://www2.cesm.ucar.edu/models/ccsm4.0/. </p>