Accurate weather forecasting in the vicinity of major mountain ranges is an extremely difficult meteorological problem. Interactions between large-scale weather systems and mountainous regions often spawn complex mesoscale weather patterns. Efforts to forecast the development of these weather patterns are limited by deficiencies in understanding of the physical processes governing mesoscale circulations in complex terrain. Additionally, mesoscale orographic effects also influence the global circulation through the action of "gravity wave drag". Errors in the parameterization of gravity-wave drag in global- scale models are believed to be a major source of error in extended range forecasts. Under previous support from the National Science Foundation, the Principal Investigator has studied airflow over mountains with the immediate goal of extending understanding of the dynamics of orographically generated mesoscale disturbances and the interaction between these disturbances and the large synoptic-scale flow. He proposes to use a combination of theory, numerical models and observations to continue this line of research. The ultimate goal is to increase fundamental understanding leading to improved weather forecasts and climate models by developing a more accurate parameterization of gravity- wave drag.//
