Atmospheric transport models for complex terrain

Two codes, ATMOS1 and ATMOS2, have been developed to model respectively, wind fields and pollutant transport in three dimensions with particular application to complex terrain. ATMOS1 models wind fields with the use of a mass conservation error minimization principle employing available observations. ATMOS2 employs these wind fields to model transport by advection and diffusion using a Crowley second-order flux extimation. Both codes employ terrain-following vertical coordinates which provide critical resolution of the boundary layer and simplify boundary conditions at the surface. A companion paper provides examples of models produced by the codes with comparison to observation