Abstract |
The Complex Terrain Dispersion (CTDMPLUS), a point-source, steady-state, dispersion model for complex terrain applications, is described and its performance summarized. The model is unique in the manner in which it simulates the flow and plume distortion near the terrain. Emphasis is given to windward side impacts. Simplicity is maintained by applying flow distortion corrections to flat-terrain, Gaussian and bi-Gaussian pollutant distributions. The performance of CTDMPLUS contrasts with that of a currently-recommended, complex-terrain, regulatory model. In stable or neutral conditions, CTDMPLUS shows relatively small average bias compared to field observations. The root-mean-square differences between CTDMPLUS and the observations are consistently lower and the percent of predictions within a factor of two are significantly higher than those of the regulatory model. In convective conditions, with comparisons unpaired in time or space, CTDMPLUS performs very well. |