Atlantic Heat Conveyor - (n.)
The considerable heat transfer from south to north by near-surface waters moving across the equator in the Atlantic. This movement is required to balance a southward flow of water in the ocean depths. This deep water, called the "North Atlantic Deep Water," moves sluggishly but the flow is considerable - some 20 Sverdrup - and is rather cold (between about 2°C and 4°C). So since the North Atlantic trades cold water for warm, it gains lots of heat in the process. This is the reason regions well north of 60°N, such as in Scandinavia, have comparably mild climates. The graph below shows the flow of heat (in units of 1013 Watts) across the present Atlantic (“+” symbol), across the Atlantic during glacial times (“o” symbol), and the world ocean average (thick solid line bordered by thin lines that represent the upper and lower limits ). The general trend to take from the graph is that heat is transported from southern to northern latitudes.