Modelling Dispersion Parameters in a Planetary Boundary Layer Dominated by Convection
The Gaussian plume model concept is still important for estimating ground-level concentrations due to tall stack emissions and is usually suitable for regulatory use in air quality models. Improved dispersion algorithms in updated Gaussian models calculate the dispersion parameters σy and σz in terms of distinct scaling parameters for turbulence. In this work, we use the convective similarity theory and Taylor’s statistical diffusion theory to derive a general expression for the dispersion parameters in a planetary boundary layer dominated by convection. The novelty is use Taylor’s theory to construct a relation for the dispersion parameters that is described only in terms of the universal characteristics of the turbulent field in a convective boundary layer (CBL), eliminating in this manner, the necessity of dispersion parameters fitting from diffusion experiments.