11th World Congress on Computational Mechanics (WCCM XI) 5th European Conference on Computational Mechanics (ECCM V) 6th European Conference on Computational Fluid Dynamics (ECFD VI) E. Oñate, J. Oliver and A. Huerta (Eds) FRACTAL AND KINEMATIC SIMULATION TURBULENCE METHODS IN COASTAL DIFFUSION MODELS J OSE M. REDONDO * , MARGARITA DIEZ †,* AND PHILIPPE FRAUNIE ϒ * Departament Fisica Aplicada , Universidad Politécnica de Cataluña (UPC) Campus Norte UPC, 08034 Barcelona, Spain e-mail: redondo@fa.upc.edu , www.upc.com † Ports de la Generalitatat (GenCat) Vilanova i la Geltru, 08800 Barcelona, Spain e-mail: margarita.diez@gencat.cat , www.gencat.org ϒ Mediterranean Institut of Oceanography (MIO) Univ. Sud Toulon Var, La Garde CEDEX, France e-mail: fraunie@univ-tln.fr , http://mio.pytheas.univ-amu.fr Key Words: Turbulent Diffusion, Coastal Flows, Pollution, Fractal Computing Methods. Abstract. The satellite-borne SAR and ASAR is an excellent system not only to detect man- made oil spills and slicks but it also detects dynamic features and the ocean eddies of different sizes. The study of the topology of the regions of different rugosity of the ocean surface can map the eddy shaped elliptic regions as well as the hyperbolic or shear dominated areas, is also a convenient tool to investigate the eddy structures, the scale to scale energy and enstrophy transfer of a certain area, and to calculate the eddy diffusivity values (Atale et al. 1997). The effect of bathymetry and local currents are important in describing the ocean surface behavior, and specially the non-homogeneous transition between the coastline and open sea. In the NW Mediterranean the maximum eddy size agrees with the limit imposed by the local Rossby deformation radius, Redondo and Platonov (2001, 2009). This is attained when buoyancy and Coriolis forces are in equilibrium, it is defined as Rd = (N/f)h, (where N is the Brunt-Vaisalla frequency, f is the local Coriolis parameter, function of the rotation of the earth and the latitude, with h the local thermocline depth), measured Rd is about 6-20 Km, which agrees with the numerical simulations in the area, where fractal aspects and measures are useful in order to determine local surface diffusion. Numerical models of the role of coastal eddy structures on dispersion of surface pollution are discussed and compared with remote sensing observations of the area highlighting the relationships between intermittency, fractal measurements and diffusivity.