Evolution of mean wind and turbulence fields in a quasi-baroclinic convective boundary layer with strong wind shears

摘要

The growth of the atmospheric convective boundary layer (CBL) is forced mostly by buoyancy production at the surface. However, wind shear has a significant impact on the turbulence structure within the CBL and can contribute significantly to CBL growth when mean winds or wind shear in the lower atmosphere are strong and buoyancy flux from the surface and stratification in the free atmosphere above are both weak. Regimes of CBL growth in calm (shear-free), windy, and strong wind shear cases were studied using large eddy simulation (LES). The study evaluated the effects of shear on the CBL growth rate, the evolution of mean wind profiles within the CBL, and semi-organized and turbulent flow structures.