Keywords: air pollutants, dispersion, sigma parameterisation
Different parameterisation of a Gaussian scheme: intercomparison study
The aim of this work is to define the most efficient parameterisation of the PBL (planetary boundary layer) by using the simulation with a simple Gaussian dispersion model of the plume type and comparing it with the improved OML model. A different type of σy and σz parameterisation in a Gaussian dispersion scheme was introduced. The old Pasquill–Gifford scheme and the new boundary layer parameterization based on Monin–Obukhov length and other convective scaling parameters were compared, using a classical Gaussian model. For this comparison, the hourly average concentration and the long-term concentrations generated by these models, using same input data, were computed. These computed values and the field observations clearly show the importance of the parameterisations used by the models and the necessity of improving them. With this new parameterisation we can easily add in new phenomena, such as dry and wet deposition, building effects and stack tip downwash penetration.