Experimental observations of the dependence of lateral and vertical dispersion characteristics on source height

The results of some recently analyzed diffusion experiments are examined to study the effects of source height on lateral and vertical dispersion characteristics, σ _θ, at elevated release heights is shown to be a poor predictor of the lateral plume spread near the surface; σ _θ near ground level is more useful at all downwind distances. For relatively short downwind distances, vertical dispersion for elevated releases is shown to be significantly larger than for surface releases.