USE OF METEOROLOGICAL MODELS AS INPUT TO REGIONAL AND MESOSCALE AIR-QUALITY MODELS - LIMITATIONS AND STRENGTHS

The importance of meteorological variability and uncertainty is descri bed and discussed in the context of dispersion and chemistry of air po llution. Synoptic, mesoscale, and turbulent scales are defined in rela tion to pollution dilution. Spatial variability effects due, for examp le, to synoptic baroclinicity, propagating synoptic and mesoscale feat ures, and surface-forced atmospheric circulations are described. Tempo ral variability resulting from diurnal and seasonal effects are discus sed and examples presented. Among the questions addressed is the impor tance of differential advection relative to horizontal diffusion at di fferent space and time scales. The concept of delayed diffusion is pre sented. Among the conclusions is that regulating agencies such as the EPA and NPS have generally not taken sufficient advantage of regional and mesoscale meteorological model-generated wind and turbulence field s, nor used the limits on the accuracy of these models to provide an u pper limit to the skill of air quality models. Part of this failure is due to the poor communication by scientific researchers, of model cap abilities and limits to the agencies and other users of meteorological model output as part of air quality assessments. (C) 1998 Elsevier Sc ience Ltd. All rights reserved.