Method for Validation of Lagrangian Particle Air Pollution Dispersion Model Based on Experimental Field Data Set from Complex Terrain

Validation of air pollution dispersion model is very important process. It determines performances and efficiency of model in well defined conditions. Conditions consist of type of terrain orography (flat or complex), size of domain (local, regional, continental, global), number of grid cells in domain, meteorological conditions (strong or weak winds, etc.) and emission types (stacks, traffic, domestic heating). Results of validation give good guidelines how, where and when model can be successfully applied. Validation is especially important when model is used for regulatory purposes. FAIRMODE European guidelines for air pollution modelling explicitly require that modeling tool must be successfully validated in similar environment (FAIRMODE, 2010). Slovenian legislation (Ur.l. RS, st. 31/2007, 2007) that is following European Council Directive of 28th June 1984 on combating air pollution from industrial plants (EUR-Lex 84/360/EEC, 1984) requires that the modeling tool for reconstructions of air pollution around stationary industry sources meet the requirements of complex terrain because most of Slovenian industry is located in the bottom of basins, river canyons and valleys. Complex terrain defines a set of specific atmospheric conditions: low wind speeds, temperature inversions, flow over topography, presence of terrain obstacles or discontinuities (land-sea, urban-rural environment), etc. Lagrangian particle dispersion model is the only air pollution model at the moment that is successfully achieving these requirements (Wilson and Sawford, 1996, Schwere et al., 2002). It has significantly evolved in last years and moved from research usage to usage for operational regulatory purposes (Tinarelli et al., 2000, Graff, 2002). Validations over complex terrain are still very rare. They are very important for research community and governmental environment agencies. Research community use the results for further developments and improvements of modeling techniques and environment agencies for setting up and implementation of regulatory policies. A study has been made to improve traditional air pollution model validation methodology. It is upgraded to estimate inaccuracy in position and time of the Lagrangian particle air pollution dispersion model. New validation methodology has been demonstrated on a field from a very complex terrain from Saleska region (Slovenia). For validation Lagrangian