"Theory of the airflow over mountains"

Abstract

It has long been realised that the local topography of the earth may have an important influence on the atmospheric circulation of a particular region and corresponding effects on weather and climate. Although considerable research has greatly clarified many aspects of airflow over mountains and the consequent interaction between the earth and the atmosphere, further work is required and in some areas obscure points still remain to be resolved. This study provides a survey of the most significant theoretical work relating to the flow of air over mountain-like obstacles and attempts to clarify some of the areas in which obscurities are found. It is basically concerned with the displacement undergone by an airstream when crossing mountains or hilly terrain. The resulting motion can vary from a mere mountain disturbance, giving rise to 'hill lift', to a more substantial disturbance in the form of a train of waves downstream - the so-called 'lee wave' phenomenon.