On a model for pollutant dispersion in the atmosphere with partially reflective boundary conditions

Abstract

The present work is an attempt to simulate stochastic effects in a deterministic model for pollutant dispersion in the atmospheric boundary layer by the use of a probability weighted boundary condition. More specifically, the escape of pollutant substances across the boundary layer horizon on the one side and the surface boundary on the other side are modelled by probabilities to quantify the fraction of pollutant that returns into the boundary layer from above and the process of adsorption or deposition on the ground layer. These effects are represented by partially reflective boundary conditions that together with advection-diffusion dispersion define the model in consideration. The consequences of the reflections are analysed using the meteorological conditions and data of the Hanford and Copenhagen experiments. A variety of trials have shown that partial reflection on the boundary layer horizon and the ground, respectively, obtain the most significant correlations between model and data suggesting that effects on the boundary are essential to model dispersion processes in the atmospheric boundary layer.