APPLICABILITY OF GAUSSIAN DISPERSION MODELS FOR ACCIDENTAL RELEASES IN URBAN ENVIRONMENT - RESULTS OF THE "MICHELSTADT" TEST CASE IN COST ACTION ES1006

Dispersion modelling of accidental release cases in urban environment is presently developed to great detail using CFD and LES models. Comprehensive data sets are developed during the recent years for evaluation of such models. Still, the first practical issue at accidental releases is to run fast a model and to get fast idea of the area under danger. Using Gaussian models is fast, but not precise. The application of Gaussian models strongly depends on the complexity of the meteorological input they require and the parametrization of the effects of a built-up area. Within a COST ACTION ES 1006, a number of Gaussian models were evaluated on wind-tunnel data along with CFD and LES models. In this paper, some of the results obtained with ALOHA, TRACE and AERMOD are presented and discussed.