The state of the Atlantic meridional overturning circulation

The Meridional Overturning Circulation (MOC) is a simplified representation of the complex three-dimensional ocean currents, which transport volume, heat, freshwater, carbon, and nutrients around the ocean. The uniqueness of the Atlantic MOC is that its associated Meridional Heat Transport (MHT) is northward in both hemispheres. The Atlantic MOC has been monitored at several trans-basin and western boundary moored arrays (e.g., Frajka-Williams et al., 2019; Berx et al., 2021; Hummels et al., 2022), as well as by synthesizing in situ and satellite altimetry measurements at several latitudes (Hobbs and Willis, 2012; Sanchez-Franks et al., 2021; Dong et al., 2021; Kersalé et al., 2021) (Figure 1). In this report, we are providing updates on the MOC and MHT estimates from the RAPID-Meridional Overturning Circulation and Heat-flux Array - Western Boundary Time Series (RAPID) moored array at 26.5°N and at 41°N and at several latitudes in the South Atlantic based on the synthetic approach. In addition, we are reporting on recent advances in monitoring and understanding the variability of flows comprising the lower limb of the Atlantic MOC. The updates for the Overturning in the Subpolar North Atlantic Program (OSNAP) and the South Atlantic MOC Basin-wide Array at 34.5°S (SAMBA) are pending; the most up to date time series for these arrays were published in the State of the Climate in 2021 report (Volkov et al., 2022).