Vertical Profiles of the Saltating Particle Concentration on a Desertified Area

Abstract

Vertical profiles of the total saltating particle concentration have been constructed for a range of wind speed changes in the surface layer of the atmosphere from 5.5 to 10.5 m/s, and the profiles of the concentration of aleurite (silt) and sandy particles according to measurements in a desertified area in the Astrakhan Region under conditions of quasi-continuous saltation have been found. In the saltation layer from 0 to 15 cm, the concentration of silty particles with a size of 47 μm decreases two times more slowly than the concentration of sand particles with a size of 156 μm. In the lower saltation layer about 9 cm thick, the logarithmic gradient of the total concentration does not depend on the wind speed, and in the upper saltation layer it changes from –0.40 to –0.21 cm–1 with an increase in the wind speed in the atmospheric surface layer from 5.5 to 10.5 m/s. It is shown that, in contrast to the lower saltation layer at heights of 11 and 15 cm, the dependences of the particle concentration on the wind speed turned out to be nonlinear. For the lower and upper layers of saltation, approximations of the concentration of saltation particles are obtained as a function of height, wind speed, and the threshold speed of saltation.