Deposition of Atmospheric Aerosol Particles to Beech- and Spruce Forest

Abstract

Trace constituents are removed from the atmosphere either by incorporation into rain or by deposition onto surfaces like soil, vegetation, waters. Dry deposition onto natural surfaces can hardly be represented by mathematical models or by artificial surfaces, for realistic approximations of the complex boundary (e.g. vegetation/ atmosphere) is not yet possible. Therefore, it was attempted to determine the deposition of atmospheric trace constituents to a natural surface in a direct way. A beech- und a spruce forest were used as a natural surface. The amount of matter dry deposited on the vegetation surface is derived by means of the difference of concentrations in precipitation above and beneath the canopy area. Leaching and absorption of certain substances by leaves and twigs are taken into consideration. Dry deposition velocities are determined from the transfer rates (atmosphere to vegetation) of the aerosol compounds and their simultaneously measured air concentration. They will be discussed with results of other investigations.