Meridional Overturning Circulation

THE MERIDIONAL OVERTURNING circulation is an oceanic system driven by physical forces related to temperature, salinity, and momentum. The circulation is a generally closed system with an important role in redistributing heat on a global scale. Regions of intense heat loss at high latitudes produce cold (dense) water that sinks to the oceans' depths. This abyssal water spreads toward the equator, while the sinking water is replenished by warmer water flowing poleward near to the ocean surface. The upper level waters link the circulation, fed in regions of upwelling from the oceans' depths. Although other areas of subduction exist, especially in the Waddell Sea in Antarctic waters, a key source of the cold abyssal water is in the North Atlantic Ocean. It is the Atlantic ...