The Coupled Ocean–Atmosphere Hydrothermohaline Circulation

AbstractThe thermohaline circulationof the ocean is compared to the hydrothermal circulationof the atmosphere. The oceanic thermohaline circulationis expressed in potential temperature–absolute salinity space and comprises a tropical cell, a conveyor beltcell, and a polar cell, whereas the atmospheric hydrothermal circulationis expressed in potential temperature–specific humidity space and unifies the tropical Hadley and Walker cells as well as the midlatitude eddies into a single, global circulation. The oceanic thermohaline streamfunction makes it possible to analyze and quantify the entire World Ocean conversion rate between cold–warm and fresh– saline watersin one single representation. Its atmospheric analog, the hydrothermal streamfunction, instead captures the conversion rate between cold–warm and dry–humid air in one single representation. It is shown that the ocean thermohaline and the atmospheric hydrothermal cells are connected by the exchange of heat and freshwater through the sea surface...