Measurements and estimates of tracer diffusion in the NW Mediterranean Sea

The eddy diffusivities in the ocean exhibit a large variation and show a marked anisotropy, not only horizontal values are much larger than vertical ones but there is a strong dependenee on the spatial extent of the tracer dye or pollutant. In the case of oil spilIs, these are strongly influenced by the buoyancy and horizontal diffusion depends on ambient factors such as wave activity, wind and currents.