ON THE TRANSPORT AND DISTRIBUTION OF GIANT SEA-SALT PARTICLES OVER LAND [I] THEORETICAL MODEL

Abstract

The transport and distribution of giant sea-salt particles inland from the coast are studied on the basis of the diffusion theory. The wind speed and the eddy diffusivity are assumed as constant. It is presumed that sea-salt particles originate only on the sea surface, and that vertical distribution of the particles at the coast is given in an exponential form. On land, a ground sink caused by sedimentation plus the impaction by trees and other obstacles on the ground surface is considered. The outstanding result is that a maximum value in the vertical distribution of the number concentration of the giant sea-salt particles always appears at some height above the land, in agreement with the observational fact of the vertical distribution of the particles inland. Also, the number concentration on the ground surface inland decreases with the increasing magnitude of the impaction effect. The effect of the impaction by trees and other ground obstacles is expressed by the impaction-sedimentation ratio. A preliminary estimate of the ratio, obtained by an application of the present model to a few observational data, indicates a value of the order of magnitude of 10 to 100.