Upslope Flow Systems

Thermally driven upslope winds typically occur during the day under sunny conditions. As closed systems or as part of larger-scale flow systems in complex terrain they are particularly important in air pollution dispersion at places like Los Angeles and Mexico City. It is often assumed that upslope flows vent air pollutants out of the convective boundary layer into the free atmosphere. It is demonstrated in this book that air pollution can be trapped or recirculated, raising many questions: What is the boundary-layer structure over a heated slope and its relation to the upslope system? Is there a continuous transition between the two extremes of recirculation and venting or are there two distinct regimes? What are the determining parameters? This book addresses these questions using field observations and water-tank experiments. Researchers and practitioners will gain insights into the kinematics of upslope flow systems and the structure of the boundary layer in complex terrain. This book can also serve as a course compendium in mountain or boundary-layer meteorology and physical scale modeling.