Coastal and interfacial mixing. Laboratory experiments and satellite observations

Studies of mixing in coastal waters have been made using different paramete rs like the Rossby Deformation radius, the Rossby number and the flux and g radient Richardson numbers. In order to describe the structure of density i nterfaces and fronts and their hydrodynamic behavior, we have analyzed in l aboratory conditions different mixing processes near density interfaces to investigate experimentally the structure of these interfaces. The behaviour of both horizontal and vertical mixing fronts is studied and compared. We use a video analysis technique where mixing processes are recorded and anal yzed by means of the DigImage software. We present in our analysis the evol ution of the fronts and the local velocity fields, in term of the local gra dient Richardson number in both vertical and horizontal mixing events. The horizontal structures are also compared with satellite observations of coas tal induced eddies (Platonov and Redondo, 1999). (C) 2001 Elsevier Science Ltd. All rights reserved.