Diffusion Model for a Convective Layer. Part I: Numerical Simulation of Convective Boundary Layer

Abstract

A simple turbulence model is used to study the moist convective boundary layer, in which a prognostic equation is applied to calculate the turbulent kinetic energy E. An observational length scale of the vertical velocity component, l, is used in the mixed layer, while a length scale associated with gravity waves is applied in the stable layer. The eddy coefficient is proportional to El. This model simulates well the temperature, mixing ratio and mean wind observed in the Wangara experiments. The turbulent kinetic energy and eddy fluxes generated are also in good agreement with those observed, as well as with those obtained from other more complicated models. Furthermore, the parameterization and results generated are used in a pollution model, which will be presented in Part II of this study.