Strengthening Connections in Observing the North Atlantic Meridional Overturning Circulation: Outcomes from a Joint RAPID-OSNAP Workshop

The Atlantic Meridional Overturning Circulation (AMOC) redistributes heat, salt, oxygen, carbon, and nutrients in the Atlantic Ocean, providing warmth and moisture to the climate of northern Europe (Rhines and Häkkinen, 2003), displacing the Intertropical Convergence Zone northward of the equator (Ben-Yami et al., 2024), sequestering anthropogenic carbon in the deep ocean (Brown et al., 2021), and seeding the subpolar North Atlantic with sufficient nutrients to support the annual spring phytoplankton bloom (Williams et al., 2026). While models and proxies of the AMOC have been instrumental in understanding its past and future variability, large inter-model differences necessitate direct observations to provide a baseline from which to compare the models, as well as an unambiguous time series of recent AMOC variability. However, measuring a system as large and complex as the AMOC presents many challenges: spanning thousands of kilometers horizontally and covering full ocean depths, the AMOC is composed of currents that vary on daily to millennial time scales. Recirculating flows that can be an order of magnitude stronger than the AMOC itself further complicate observations.