The Wind Meandering Phenomenon in an Eulerian Three-Dimensional Model to Simulate the Pollutants Dispersion

Usually in stable conditions in the Planetary Boundary Layer (PBL), during occurrence in which the horizontal wind velocity magnitude is low (u ¡ 2 m/s), are observed low frequency oscillations of the horizontal wind. These horizontal wind oscillations characterize the wind meandering phenomenon.Therefore, the aim of the present work is to develop a new model to simulate the atmospheric pollutant dispersion taking into account the meandering in low wind speed. To accomphish this aim will be presented a new analytical solution for the three-dimensional advection-diffusion equation. The advection-diffusion equation is solved combining the Laplace transform and GILTT (Generalized Integral Laplace Transform Technique) techniques. The importance of the present study to describe the pollutant dispersion in low wind conditions lies in the fact that such conditions occur frequently and are of crucial importance in air pollution evaluations. In such conditions, traditional models employed to calculate the contaminants concentration can be not utilized to predict the pollutants dispersion.A characteristic of the wind meandering is the presence of significant negative lobules observed in the autocorrelation functions, of the horizontal components of the vector wind in low wind conditions.In this study we employ a Eulerian dispersion model to investigate the transport phenomenon of contaminants caused by the wind meandering.