Meteorological Transport of Particulate Material to the South Polar Plateau

Abstract

A series of aerosol measurements were made over the Antarctic Continent, during the austral spring of 1977. Vertical profiles indicate that the highest aerosol concentrations are present in the mixing layer, around the edges of the continent where some open water is present, and in a moist layer just above the surface over the South Polar Plateau. Aerosol concentrations, with respect to both mass and volume of air, decrease continuously with increasing altitude above these layers, and this smooth decrease continues without discontinuity when the local tropopause is crossed. Aerosol concentrations were distributed uniformly at all latitudes between 75 and 90°S in the 500?450 mb layer. A small systematic decrease in aerosol concentration with increasing latitude was detected above 400 mb. This decrease is attributed to the relatively calm and very cold conditions present above 400 mb, which allow small ice crystals to form by homogeneous nucleation which scavenge particles from the air by Brownian coagulation during their slow fall. These measurements indicate that the lower troposphere, especially those layers below 450 mb, is the most probable level at which particulate material is transported to the South Polar Plateau.