From the Great Plains to the Sierras: Stable Boundary Layer Flow Over Complex Terrain
Environmental Engineering Seminar Series
From the Great Plains to the Sierras:
Stable Boundary Layer Flow Over Complex Terrain
Predictions of the stable boundary layer (SBL) are challenging for air quality modeling, weather forecasting, and wind energy resource assessment purposes, because the length scale of turbulent eddies is much smaller than under convective or neutral conditions, thus making it difficult to resolve and characterize the turbulence. The SBL is further complicated by low-level jets, inertial oscillations, and gravity waves. Variations in surface topography, from shallow depressions to steep mountains, also greatly affect flow development. In this work, we perform large-eddy simulations (LES) of the SBL using a nested mesoscale atmospheric model to resolve flow features at very fine resolution. Simulations over the Great Plains and over the Sierras identify new intermittency mechanisms which lead to turbulent bursting events under stably stratified conditions. The role of turbulence closure models is also discussed.