Modeling of the vertical transport of polydispersed aerosol particles in the atmospheric surface layer

The integral model equations for determining the dry deposition and resuspension of polydispersed aerosol particles in the atmospheric surface layer to and from aerodynamic smooth and rough surfaces are derived and discussed. These model equations are based on micrometeorological ideas of heightinvariant vertical transfer of momentum, sensible heat and matter as well as a representative terminal settling velocity for the entire particle size distribution. The fluxes in the turbulent region of the atmospheric surface layer are parameterized by flux-gradient relationships. The calculation of molecular-turbulent fluxes in the underlying sublayer is based on flux-gradient relationships for aerodynamic smooth surfaces (where a representative Brownian diffusion coefficient for the entire particle size distribution is taken into account), and the sublayer Stanton number as well as Reynolds' analogy between concentration, temperature and wind velocity distributions for rough surfaces. Model re sults which were derived from observation data of wind velocity, dry- and wet-bulb temperatures and NH4+ -concentrations collected in the GREIV I experiment are presented and discussed.