An estimate of spatial uncertainty of mean concentrations predicted by Gaussian dispersion models.

摘要

Atmospheric dispersion models based on statistical theory predict the stochastic mean concentration at fixed points downwind. The uncertainty in the computed concentration, often expressed as a peak-to-mean ratio, is known to vary between two and five for Gaussian dispersion models. This paper shows that this can be correlated to uncertainty in the predicted location of a fixed concentration, and that in the centerline of the plume it is related to sigma(theta), the standard deviation of the observed horizontal wind direction. Practical formulae and methods are given that may be applied in the post-dispersion calculation phase of the risk assessment to ascertain the likely hazard zones.