Mesoscale Modeling and Four-Dimensional Data Assimilation in Areas of Highly Complex Terrain

Abstract

Abstract A multiscale four-dimensional data assimilation (FDDA) technique, based on Newtonian relaxation, is incorporated into a mesoscale model and evaluated using meteorological and tracer data collected during the Atmospheric Studies in Complex Terrain (ASCOT) field experiment in the winter of 1991. The mesoscale model is used to predict the synoptically driven flows and small-scale circulations influenced by terrain along the Front Range in Colorado in the vicinity of Rocky Flats Plant for four nocturnal periods during the ASCOT field experiment. Data assimilation is used to create dynamically consistent analysis fields based on the mesoscale forecasts and the special asynoptic data taken during this experiment. Observations from towers, minisodars, airsondes, tethersondes, rawinsondes, and profilers near the Rocky Flats Plant, as well as observations from surface stations throughout Colorado, are incorporated into the high-resolution analysis fields. The wind and turbulence quantities produced by the...