The Structure of Turbulence in the Near-neutral Atmospheric Boundary Layer

Abstract

Abstract In this paper, the idea of local similarity, previously used to study turbulence in the stably stratified boundary layer, is used to investigate the structure of turbulence in the neutral atmospheric boundary layer and to relate this structure to the turbulent kinetic energy balance. It is found that in the lower half of the boundary layer, the turbulence exhibits local similarity and that the turbulence kinetic energy budget is essentially a balance between shear production and dissipation. In the upper half of the boundary layer, where turbulent transport is a significant term in the turbulence kinetic energy balance, local similarity breaks down. This is consistent with the second-order moment equations, which suggest that local similarity arises in situations where the turbulent and pressure transport terms are small. Results from a large-eddy simulation of the neutral boundary layer are also investigated using local similarity. The simulated turbulence agrees well with the observations for t...