On the conversion of Pasquill categories for use over sea

Pasquill stability categories or similar classifications can be used to estimate dispersion of airborne material. Such categories are defined in terms of synoptic surface-layer variables. In order to transpose experience gained over land to sea, the different boundary conditions over land and sea must be considered. Using the assumption that the turbulence intensity and hence diffusion will be the same over land and sea if the boundary conditions expressed by sensible heat flux and shear stress are equal, a conversion is derived. With a reasonable degree of accuracy, synoptic parameters, mean wind speed and air sea temperature difference can be used at sea to specify stability categories.During the course of this research, it was found that Golder's relation between stability categories and Monin-Obukhov length can not be used at sea, since this relationship must depend on the Bowen ratio and albedo.