Evaluation of horizontal diffusivity in the sea surface layer

In this paper the dispersion analysis of drifter campaigns realized in two different domains, the Gulf of Mexico and the Mar Grande Basin (Italy), was carried out using both relative and absolute approach. Relative dispersion, diffusivity and velocity variance were computed identifying different growth regimes. An exponential growth of the dispersion process was detected on the initial phase of deployment and empirical laws for horizontal diffusivity were inferred. Velocity variance and integral time scale were obtained using different techniques to evaluate short-term dispersion phenomena and submesoscale turbulence. A spectral analysis realized in accordance with the Taylor's theory was used to estimate the Lagrangian time scale in domains strongly affected by inertial oscillations. The turbulence parameters inferred can be used as input data in particle Lagrangian models of dispersion providing useful tools for surface dispersion prediction in marine environment