ON THE TOTAL GEOSTROPHIC CIRCULATION OF THE NORTH-ATLANTIC OCEAN - FLOW PATTERNS, TRACERS, AND TRANSPORTS

This is an attempt to provide patterns of how at all depths in the North Atlantic Ocean that balance the transport and are consistent with the patterns of characteristics. It identifies the paths of flow and the sources of the characteristics. In particular it attempts to account for the high heat and salt content of the deep North Atlantic in terms of an increment of very warm and saline Mediterranean water that partly circulates within the anticyclonic gyre of the North Atlantic and the cyclonic gyre to the south and east before passing southward into the South Atlantic. The direct effect of the Mediterranean outflow is to provide heat and salt to these gyres. The deeper water of these gyres has entered from the South Atlantic at depths below 1500 m and is colder and less saline than the waters to the north. The increment of heat and salt that pours into these waters as they pass northward along the eastern boundary is carried both northward to Iceland and westward across the Atlantic. Part of the northward how carries higher salinities to mix with Norwegian Sea waters and become denser, though still relatively warm and saline. The westward component provides the high heat and salt content of the deep Gulf Stream and of the southward flow along the western boundary. As a result the 0.7x10(6)m(3)s(-1) of very warm and saline water from the Mediterranean Sea is not immediately carried southward out of the North Atlantic but only after some excursions through these gyres. The residence time of the increments in the North Atlantic is therefore longer, and leads to an accumulation of heat and salt.