1994/04/01 by Chin-Hoh Moeng, Chin‐Hoh Moeng, Peter P. Sullivan · 757 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astro and Planetary Science #Atmospheric chemistry and aerosols #Boundary layer #Buoyancy #Classical mechanics #Convection #Geology #Mechanics #Meteorological Phenomena and Simulations #Meteorology #Physics #Planetary boundary layer #Shear (geology) #Shear flow #Shear velocity #Turbulence #Wind shear #Wind speed
paper · doi:10.1175/1520-0469(1994)051<0999:acosab>2.0.co;2
published in Journal of the Atmospheric Sciences 51(7), 999-1022 (American Meteorological Society)
openalex publication_date 1994/04/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Planetary boundary layer (PBL) flows are known to exhibit fundamental differences depending on the relative combination of wind shear and buoyancy forces. These differences are not unexpected in that shear instabilities occur locally, while buoyancy force sets up vigorous thermals, which result in nonlocal transport of heat and momentum. At the same time, these two forces can act together to modify the flow field. In this study, four large-eddy simulations (LESs) spanning the shear and buoyancy flow regimes were generated; two correspond to the extreme cases of shear and buoyancy-driven PBLs, while the other two represent intermediate PBLs where both forces are important. The extreme cases are used to highlight and quantify the basic differences between shear and convective PBLs in 1) flow structures, 2) overall statistics, and 3) turbulent kinetic energy (TKE) budget distributions. Results from the two intermediate LES cases are used to develop and verify a velocity scaling and a TKE budget model, which are proposed for the intermediate PBL. The velocity variances and the variance fluxes (i.e., third moments) normalized by this velocity scaling are shown to become quantities on the order of one, and to lie mostly between those of the two extreme PBL cases. The proposed TKE budget model is shown to adequately reproduce the profiles of the TKE budget terms and the TKE.