© Eugene S. Takle, 2002
In discussions of climate and climate change, ocean circulation invariably is discussed. The term "thermohaline circulation" frequently is used, but there seems to be considerable disagreement about what this term means. The word "thermohaline" suggests heat (thermo-) and salt ( - haline), but does this suggest motion that is created and sustained by gradients of temperature (hence heat flow) and salinity (hence salt flow) or some other mechanism, such as buoyancy in polar areas? Wunsch (2002) clarifies this issue by explaining that the fundamental driving force in ocean circulation is the wind field (not buoyancy or thermal or salt gradients). He concludes that "the term 'thermohaline circulation' should be reserved for the separate circulations of heat and salt, and not conflated into one vague circulation with unknown or impossible energetics." Buoyancy of surface water determines vertical transport of heat and salt, but does not drive the circulation.
Reference
Wunsch, C., 2002: What is the thermohaline circulation? Science, 298, 1179-1181.