Sensitivity analysis of the Unified Danish Eulerian Model with respect to emission levels and chemical reaction rates.

A number of numerical experiments with a large-scale air pollution model (Unified Danish Eulerian Model, UNI-DEM) have been carried out to compute Sobol sensitivity measures. Sensitivity analysis of ozone concentrations according to variations of rates of chemical reactions is developed. The sensitivity study has been done for the areas of four European cities (Genova, Milan, Manchester, and Edinburgh) with different geographical locations. Sensitivity analysis of the output of UNI-DEM according to emission levels is also provided. The influence of emission levels on the concentrations of four important air pollutants (ammonia, ozone, ammonium sulphate and ammonium nitrate) over three European cities (Milan, Manchester, and Edinburgh) is considered. Variance-based methods are most often used for providing sensitivity analysis. Sobol variance-based approach for global sensitivity analysis has been applied to compute the corresponding sensitivity measures. Advanced stochastic methods based on modified Sobol sequences are used for computing the sensitivity measures. The numerical experiments show that the stochastic algorithms for the multidimensional integrals under consideration are one of the best stochastic techniques for computing the small in value sensitivity indices. [ABSTRACT FROM AUTHOR]