Development of a Nested Grid, Second Moment Turbulence Closure Model and Application to the 1982 ASCOT Brush Creek Data Simulation

Abstract An improved, second-moment turbulence-closure model and a random particle kernel diffusion model are described and tested with the 1982 ASCOT (Atmospheric Studies in Complex Terrain) data collected in Brush Creek, Colorado. Three improvements of the models are the nested grid capability, inclusion of terrain shadows and application of a kernel method for concentration estimation. The present models are unique in a sense that wind variances needed for the computation of transport and diffusion of airborne materials are obtained directly from the second-moment turbulence-closure model.