Meridional Overturning Circulation
D1. Physical and chemical oceanography and marine meteorologyDefinition
Zonally integrated north-south circulation in an ocean basin.
The meridional overturning circulation (MOC) is the zonally integrated, north-south plus vertical circulation of an ocean basin, expressed as an overturning streamfunction in latitude-depth space. It combines wind-driven and density-driven cells and quantifies how much water sinks, spreads, and upwells. The Atlantic MOC (AMOC) and the global conveyor are its best-known forms; the overturning sets meridional heat and carbon transport.