Parameterization of the Atmospheric Boundary Layer for Air Pollution Dispersion Models

摘要

The characteristic features of the turbulent atmospheric boundary layer (ABL) are reviewed by means of scaling arguments. The goal was to characterize the meteorological conditions affecting diffusion for transport on the order of 10 km or less. The idealized ABL is divided into a number of regions, each characterized by distinct scaling parameters for the turbulence. With these scaling parameters wind and vertical dispersion are parameterized. The lateral dispersion is treated separately. Methods are suggested for estimating the surface fluxes of heat and momentum, and the mixing height. These are needed for the characterization of diffusion within each of the regions of the ABL. The diffusion is often found to be other than Gaussian in the vertical direction. Several of the models characterize directly the crosswind integrated concentration at the surface, thus avoiding whenever justified the assumption of a Gaussian distribution of material in the vertical. Comparisons are presented for the surface releases conducted during Project Prairie and the nonbuoyant elevated releases conducted at Copenhagen.