Diffusion Coefficients Calculated from the Mediterranean Salinity Anomaly in the North Atlantic Ocean

Abstract

Vertical and horizontal austauch coefficients have been obtained from standard station data on the Mediterranean high-salinity tongue by use of a simple model including advection by a constant velocity and three-dimensional diffusion. It is shown that background effects can be reduced by applying the model to the salinity anomaly relative to a linear ?-S relationship. The analysis gives typical values for KH of 1.5 to 3?107 cm2 s?1 and for Kv of 0.3 to 0.7 cm2 s?1. It is argued that such values indicate the diffusion of potential density is not important in the main pycnocline of the North Atlantic anticyclonic gyre.