A routine for the calculation of the time-dependent height of the atmospheric boundary layer from surface-layer parameters

Abstract

A simple routine has been implemented to deduce the 24-hour evolution of the height of the atmospheric boundary layer. This uses a reduced data set of surface-layer parameters, as obtained for example from surface automatic stations. The routine is based on the combination and fitting of the three already existent models for the evolution of the convective boundary layer, the stable boundary layer, and the surface inversion layer. Hourly values of temperature, friction velocity and potential temperature scale (or sensible heat flux) in the surface layer need only to be supplied as input data. The lapse rate at the top of the daytime mixed layer is derived from the calculated surface inversion profile at sunrise, so that only a rough evaluation of the lapse rate in the free atmosphere remains to be given. The sensitivity of the mixed-layer height is expected to be not very strong with respect to this last parameter (final part of the growth). The routine has shown satisfactory performances when compared with sodar measurements, working with only a rough average estimate of the free atmosphere lapse rate. © 1997 Kluwer Academic Publishers.