Keywords: annual mean surface concentrations, Lagrangian particle dispersion model, non-, hydrostatic wind field model, atmospheric dispersion models, environmental impact assessment, air pollution, environmental pollution, modelling, Germany
Comparisons of dispersion calculations between TA Luft and a method based on a more complex model combination (FITNAH/LPDM)
Dispersion calculations for regulatory purposes in Germany have been based on a Gaussian-type model for more than 20 years. Within this procedure nearly 88 000 hourly consecutive meteorological situations are evaluated statistically and put into 1944 classes. For each of these classes surface concentrations are calculated and combined to a one-year mean surface concentration field. Another procedure, consisting of the combination of a non-hydrostatic model for the wind field and a Lagrangian dispersion model, is used for 150 different meteorological input datasets. These datasets represent classes of meteorological situations, which are compiled from about 8000 consecutive twice-daily situations by cluster analysis. The two different methods have been applied to a source in the Rhine river valley. The results show differences, in both the value and the location, of the maximum of the mean surface concentration; the difference in location seems to be more significant than that in the maximum value.