Abstract
In this paper a simple model of the planetary boundary layer (PBL) is proposed. The surface layer is modeled according to established similarity theory. Above the surface layer a prognostic equation for the mixing length is introduced. The time-dependent mixing length is a function of the PBL characteristics, including the height of the capping inversion, the local friction velocity and the surface heat flux. In a preliminary experiment, the behavior of the PBL is compared with observations from the Great Plains Experiment.
