Over the past decade comprehensive air quality modeling systems have emerged as useful tools for research and policy making in environmental risk assessment.A primary concern in the interpretation and use of predictions from such systems, however, relates to uncertainties in the model predictions. A major source of these uncertainties relates to the "offline" nature of calculations in the three basic components of such systems: meteorology, emissions, and chemistry and transport. The very nature of this existing "offline" chemistry calculation paradigm introduces room for errors and uncertainties in interpolation of meteorological variables in air quality models and precludes the inclusion of any feedback mechanism that can incorporate the effect of atmospheric loading of various pollutants on calculations of physics and dynamics of the atmosphere. Additional uncertainties in such calculations could also arise from the use of differing physical parameterizations and numerical schemes in the meteorological model and the chemistry transport model (CTM). In several applications, due to practical limitations such as diskspace, often redundant calculations need to be performed in the CTM to re-diagnose certain meteorological information, such as turbulence and cloud formation.
In this paper we describe the initial development and testing of a fully integrated, physically and numerically consistent, regional-scale coupled atmospheric dynamics and chemistry modeling system. A variety of test cases involving both tracer transport and detailed treatment of tropospheric chemical pathways will be presented. Preliminary evaluation of model performance will be discussed
Symposium on Interdisciplinary Issues in Atmospheric Chemistry