Stable Boundary Layers and Subfilter-Scale Motions

• Published in: Atmosphere 2023-07, Vol.14 (7), p.1107
• Main Authors: McWilliams, James C., Meneveau, Charles, Patton, Edward G., Sullivan, Peter P.
• Format: Article
• Language: English
• Subjects: Atmospheric boundary layer; Atmospheric research; Boundary conditions; Boundary layer; Boundary layers; Eddies; Energy spectra; Finite element method; Fluctuations; Fluid dynamics; Friction; gray zone; Large eddy simulation; Large eddy simulations; Low-level jets; Mean winds; Oceanic eddies; Oceanic turbulence; Outerwear; Physics; Reynolds averaged Navier-Stokes method; Reynolds number; Simulation; Stochasticity; stratified turbulence; subfilter-scale motions; surface layer observations; Tensors; Turbulence; Velocity; Vertical profiles; Vertical velocities; Viscosity; Wind; Winds
• ISSN: 2073-4433; 2073-4433
• DOI: 10.3390/atmos14071107

Recent high-resolution large-eddy simulations (LES) of a stable atmospheric boundary layer (SBL) with mesh sizes N=(5123,10243,20483) or mesh spacings ▵=(0.78,0.39,0.2) m are analyzed. The LES solutions are judged to be converged based on the good collapse of vertical profiles of mean winds, temperature, and low-order turbulence moments, i.e., fluxes and variances, with increasing N. The largest discrepancy is in the stably stratified region above the low-level jet. Subfilter-scale (SFS) motions are extracted from the LES with N=20483 and are compared to sonic anemometer fields from the horizontal array turbulence study (HATS) and its sequel over the ocean (OHATS). The results from the simulation and observations are compared using the dimensionless resolution ratio Λw/▵f where ▵f is the filter width and Λw is a characteristic scale of the energy-containing eddies in vertical velocity. The SFS motions from the observations and LES span the ranges 0.1