Accession Number : ADP002660

Title :   Observational Evidence for an Eddy-Driven Deep Circulation in the North Atlantic,


Personal Author(s) : Hogg,N. G.

Report Date : 1983

Pagination or Media Count : 24

Abstract : Evidence from long-term moorings and water properties in the North West Atlantic is presented which suggests that there are two components to the deep, subthermocline circulation. Inshore of the 4000-m isobath is the Deep Western Boundary Current, relatively rich in anthropogenically derived material while offshore is a deep recirculating flow composed of one or more gyres transporting perhaps 4 times as much water as the Deep Western Boundary Current. The recirculating flows are similar in scale to those described from numerical models by Holland and Rhines (1980) although the flow under the Gulf Stream is in the opposite direction. The thermocline heat flux in the Gulf Stream recirculation is southward and down the mean temperature gradient. This causes a thickness flux also toward the south which is of comparable magnitude to the relative vorticity flux and, therefore, possibly the driving force for the deep mean circulation. It appears that this thickness flux is driven by spontaneous baroclinic instability of the mean flow.

Descriptors :   *Ocean currents, North Atlantic Ocean, Deep oceans, Circulation, Eddies(Fluid mechanics), Heat flux, Gulf Stream, Symposia

Distribution Statement : APPROVED FOR PUBLIC RELEASE