A DISPERSION MODEL EVALUATION STUDY FOR REAL-TIME APPLICATION IN COMPLEX TERRAIN

A few tracer experiments were carried out in autumn 1984 and summer 1985 at the Lago Brasimone site, on the Appennini Mountains approximately 50 km south of Bologna, with the purpose of assessing the atmospheric dispersion of pollutants under drainage flow conditions. The three-dimensional transport and diffusion model MATHEW/ADPIC (M/A) has been applied to selected tracer and meteorological data with the aim of assessing the model performance under complex terrain and meteorological conditions, and its sensitivity to input data available in real-time applications. Boundary layer input parameters were derived through standard algorithms based on tethersonde and pilot balloon measurements. Model simulations of the most significant tracer experiments have been assessed by means of several evaluation criteria, and the sensitivity to some input data has been investigated. The results show that if a limited spatial uncertainty in the computed concentration pattern is taken into account, M/A provides a good agreement with observed concentrations. The quality of the results is very sensitive to the presence of wind measurements where the deviation of the flow due to the shape of the valley is observed.