PARTPUFF - A LAGRANGIAN PARTICLE PUFF APPROACH FOR PLUME DISPERSION MODELING APPLICATIONS

Lagrangian particle models have been used successfully in dispersion s tudies for over a decade. With the ever-increasing speed of computers, the technique has increased in use due to its good performance in com plex meteorological conditions. However, the method needs significant computer resources, usually a supercomputer, to obtain statistically m eaningful solutions of pollutant dispersion and mean concentration for sources in typical air sheds. The particle-puff (PARTPUFF) method pro posed here uses a Gaussian puff solution in the horizontal directions and a particle solution for the vertical coordinate. This method allow s a particle/puff to influence more than one horizontal grid point and so the total number of particles needed for a model run is reduced. T he dispersion simulation still accounts for height-varying values of w inds and turbulence in the same way as conventional particle models. T he approach developed here has been verified by comparing results with a full particle model for the skewed convective boundary layer, and i n complex terrain including a land-sea interface and a sinusoidal hill . The results from the PARTPUFF approach agree well with those from th e full particle model. Particle numbers, memory, and computer time req uirements are reduced by two orders of magnitude, making it feasible t o use the model in a regulatory framework.