Numerical models with a horizontal resolution of several tens of meter are developed to study atmospheric diffusion over complex terrain. They consist of two sub- models: the one is for wind and turbulence simulation and the other is for advection and turbulent diffusion. Governing equations employed in the former model are Boussinesq, non - hydrostatic equations of motion while for the latter we use a Lagrangian particle diffusion model proposed by Thomson. One of the important factors for the simulation is a choice of turbulence models that are still under active investigations. In this respect, our approach is application - oriented so that a well - documented standard k - ε models is employed in a generalized curvilinear coordinates system. Here we focus upon the models' performance for topographic effect with neutral stability. For flat and bell — shaped lower boundaries, computed wind, turbulence and diffusion fields are checked against wind tunnel experiments. Comparisons are also made between diffusion fields over real topography.
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