Atmospheric Motions and Turbulent Transport Phenomena under Stratified Conditions

Buoyancy force associated with density stratification plays a key role in environmental flows. It damps or enhances vertical motions directly in the stratified flows. Under stable stratification, it induces internal gravity waves and blocking, which cause drastic changes in the flow pattern. In addition to these direct effects, buoyancy force deforms the turbulence structure in the stratified flows, which, in turn, causes drastic changes in the turbulent transport mechanisms of momentum, heat and mass, and therefore in the flow pattern. In this paper, these direct and indirect effects of buoyancy forces are reviewed, with special attention focused on the stratified atmospheric motions.