Heat budget of the North Atlantic Ocean. Contours are in cal cm^-2day^-1; contouring interval is 50 cal cm^-2day^-1, broken contours indicate intermediate 25 cal cm^-2day^-1 contours. Oceanic heat gain is indicated by blue contours, oceanic heat loss by gold contours; the zero contour is red.

Top left: Net heat gain from solar radiation

Top right: Evaporative heat loss

Bottom left: Sensible heat loss

In the absence of currents and continents, the contours in these panels would be zonal (running east-west). Deviations are caused by heat transported in meridional (north-south running) ocean currents caused by land barriers. (This type of heat transfer is called advective heat transport.) Notice that over most of the ocean, evaporative heat loss nearly matches the net heat input. Sensible heat loss is large in the Gulf Stream region where warm water is moved from the tropics to temperate regions and is significantly warmer then the air; this also increases the evaporative heat loss. Sensible heat gain occurs on the east coast where cold water upwells to the surface, making the water at the surface colder than the air.

The lower right panel gives the sum of the other three panels. It shows large imbalances of the local heat budget, which have to be accounted for by transport of heat through ocean currents. This oceanic heat transport is therefore the inverse of the lower right panel. It is dominated by the transport of warm water in the Gulf Stream, i.e. large heat gain in the Gulf Stream region from water advected from the tropics.

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