AN INVESTIGATION ON DIFFUSION CHARACTERISTICS IN THE PBL BY A NUMERICAL METHOD

Using the newly observed results of variation of mean wind, the turbulent statistics and Lagrangian time scales with height in the PBL, the stationarity three-dimensional equation of mass continuity which is gained by the secondorder closure assumption is solved by a numerical method. The influences of vertical shear of wind speed and the turbulent statistics, and of the roughness length on pollution concentrations in the PBL are analysed. The results are useful both in understanding the turbulent diffusion essence in the PBL and in establishing pollution models.