Large-eddy simulation of stable atmospheric boundary layers with a revised stochastic subgrid model

Abstract

Simulations of stable atmospheric boundary layers have been conducted at various stabilities with a revised, stochastic backscatter model based on Mason and Thomson's theoretical and numerical results. Compared to the previous results of Mason and Derbyshire, there is more turbulence and a deeper boundary layer, as was expected from the tendency of the parametrization change to increase the surface stress. Scatterplots of various local non-dimensional quantities against the gradient Richardson number are presented which indicate a high degree of collapse to a single local scaling curve. Agreement of the non-dimensional gradients with the surface-layer observations is greatly improved by the inclusion of backscatter.