HOW SHOULD THE PHOTOCHEMICAL MODELING SYSTEMS BE USED EM GUIDING EMISSIONS MANAGEMENT DECISIONS?

摘要

This study demonstrated that several state-of-science photochemical modeling systems display significant model-to-model differences when applied to only episodic days, making their use in traditional ozone attainment demonstrations highly uncertain. It was shown that atmospheric processes operating on time scales ranging from several days to several weeks are essential contributors to the days of high ozone concentrations at both urban and rural locations. In addition, the results from two seasonal simulations with two different modeling systems showed that the highest model-to-observation as well as model-to-model correlations are present on the synoptic and baseline time scales. This strongly suggests that the current generation modeling systems should be applied to simulation periods longer than a single episode in the regulatory setting. This notion is further emphasized by the finding that the model-predicted efficacies of a particular emission control strategy are highly variable for short simulation periods. Moreover, the shift from 1-hr to the 8-hr ozone standard requires that we move away from modeling over small domains for shorter time periods to modeling over larger domains for longer time periods.