THE DEVELOPMENT AND APPLICATION OF A SIMPLIFIED OZONE MODELING SYSTEM(SOMS)

This paper describes the development and evaluation of a computational ly efficient semiempirical photochemical model that can be used as a s creening tool to obtain quick estimates of the effect of a large numbe r of VOC and NOx emission control strategies on ozone concentrations. Selected control strategies can subsequently be examined with a more c omplex model. The model is one component of an ozone management system , the regional ozone decision model (RODM), designed to examine the co sts and environmental consequences of alternate ozone abatement strate gies. The model was developed by systematic simplification of a detail ed photochemical model, At each step of the simplification, the simpli fied model was tested against observations and against results from th e detailed model. The first major simplification was the introduction of a highly parameterized chemistry mechanism, originally developed by Azzi et al. (1992 Proc. 11th Int. Clean Air Conf., 4th Regional IUAPP A Conf:). This modification resulted in a factor of 5 improvement in t he computational efficiency of the model. The model with the simplifie d chemistry was then tested by applying it to a photochemical oxidant episode in the San Joaquin Valley of California. Further improvements in computational speed and efficiency were obtained by uncoupling the chemistry from the transport of VOC and NOx.