Interaction between the earth's atmosphere and the ground is primarily confined to a relatively thin atmospheric layer (about 1 km deep, the planetary boundary layer. There are observations available, primarily in the lowest few hundred meters of the atmosphere, that depict the distribution of wind, temperature and humidity that accompany the passage of a front. Fronts are often accompanied by severe weather: there is a need to diagnose the physical processes that are associated with fronts, and to predict their movement and severity. Yet there are few if any models, that can provide a fundamental conceptual framework upon which to analyze low-level observations taken during frontal passages. The proposed research is designed to develop a planetary boundary layer model that may be used for the analysis of meteorological variables that accompany the passage of an atmospheric front. Available data will be used to evaluate the relative importance of different physical processes, and to reduce the model to a form that is amenable to analysis. Independent data are expected to be available from instrumented meteorological tower measurements in the People's Republic of China, and from the U.S. National Weather Experiment (STORM) observational array in the mid-west (during the winter of 1992). These data may be used to verify model predictions, and to refine the model for use as a diagnostic tool in planetary boundary studies. This work is particularly relevant to STORM related activities during the 1990's and to work presently being carried out in the Severe Meso-Scale Laboratory of Nanjing University.
