||The mass circulation of the oceans that carries cold polar surface water to depth,
sinking due to higher density and wind forcing. The mass transport also carries salt,
oxygen, and other properties. Deep circulation is wind driven, with a tidal mixing
component. It cools the surface and evaporates water, which determines where deep
convection occurs. Wind-driven turbulence in the deep ocean mixes cold water upward
at lower latitudes. Deep circulation has relative slow current movements but transport
of water is comparable to surface transport and is responsible for closing the Earth's
heat budget and determining climate.