VALIDATION STUDY OF WINDTRAX BACKWARD LAGRANGIAN MODEL

In last years, atmospheric dispersion models have reached considerable popularity in environmental research field. In this regard, given the difficulties associated to the estimation of emission rate for some kind of sources, and due to the importance of this parameter for the reliability of the results, backward dispersion models may represent very promising tools. This paper discusses a critical validation of the Windtrax backward Lagrangian model: the investigation does not only deal with the strict reliability of the model but also assesses under which conditions (i.e. stability class, number, and location of the sensors) the model shows the greatest accuracy. For this purpose, Windtrax results have been compared to observed values obtained from available experimental datasets. From this study, it turns out a general tendency of the model to predict the observed values with a good level of accuracy, especially under neutral atmospheric conditions. In addition, it seems that Windtrax underestimates the emission during unstable stratification and overestimates during stable conditions. Finally, by the definition of scenarios in which only a portion of the concentration sensors was considered, Windtrax performance appears better than acceptable even with a small number of sensors, as long as the positioning is not in the strict vicinity of the source.