Application of Atmospheric Transport Models for Complex Terrain

Abstract

Numerical modeling techniques are applied to several diverse situations to study mesoscale transport of effluents in the earth's atmosphere. Simulations of a tracer release in complex terrain are compared with experiments carried out in the Northern California Geysers area during a period when nighttime drainage flow was the dominant feature. In addition, we study two situations, the Idaho National Engineering Laboratory and the Savannah River Laboratory, for which the terrain is assumed to not be a factor. These involve larger modeling areas and in one case, time periods extending over more than two diurnal cycles. These model simulations indicate that a diagnostic wind model utilizing terrain-following coordinates gives reasonable agreement with observations obtained over simple as well as complex terrain. In order to increase the accuracy in simulations of pollutant concentration distribution, much more refinement in wind measurements in space and time is needed since small differences in wind direction, for example, can produce a large difference in computed and measured concentration sufficiently downwind of a source.