Climate-Relevant Ocean Transport Measurements in the Atlantic and Arctic Oceans

and nutrients all around the globe. Because of their importance in regulating climate, weather, extreme events, sea level, fisheries, and ecosystems, large-scale ocean currents should be monitored continuously. The Atlantic is unique as the only ocean basin where heat is, on average, transported northward in both hemispheres as part of the Atlantic Meridional Overturning Circulation (AMOC). The largely unrestricted connection with the Arctic and Southern Oceans allows ocean currents to exchange heat, freshwater, and other properties with polar latitudes. A number of observational arrays, shown in Figure 1, together with the main circulation features, have been established across the Atlantic and in the Arctic Oceans to improve our understanding of and to monitor changes in the AMOC, as well as large-scale changes in water mass properties (e.g., temperature, salinity) and ocean transports (how much heat or salt is transported by currents). The arrays incorporate multiple observing platforms such as ship-based hydrographic transects, submarine cable measurements, moored sensor arrays (see Figure 2) at a number of latitudes, surface drifters, satellite observations,