Two multiscale air pollution prediction numerical models are being used and maintained at NOAA/FSL. The first is based on the MM5 meteorological model (MM5-Chem) and the second on the nonhydrostatic, eulerian-mass coordinate version of the Weather Research and Forecast(WRF) meteorological model (WRF-Chem). Both models use a fully coupled "online" chemical mechanism package based on RADM2. In addition, biogenic emissions, deposition, tracer transport by convection and turbulence, photolysis, and advective transport are all treated simultaneously with the meteorology.

In 2002, real-time MM5-Chemistry forecasts were provided during the New England Air Quality Study (NEAQS-2002) field program. NEAQS-2002 was an intensive effort to investigate the chemical and meteorological factors that contribute to poor air quality in the coastal New England region. The campaign combined efforts of numerous educational institutions as well as federal, state, and local agencies. Observational data were collected from an extensive network of ground sites, from the NOAA research vessel Ronald H. Brown, and from the DOE G-1 aircraft. Since the completion of NEAQS-2002, retrospective simulations using the WRF-Chem model have been conducted on NOAA/FSL's massively parallel supercomputer.

The presentation will briefly discuss the structure of both numerical models and describe the numerical model configurations. Thereafter, comparisons will be made between the meterological and chemical species observations and the numerical simulation results. Preliminary examination of the model results show that the MM5-Chem model and the WRF-Chem model produce comparable results and have reasonable skill in forecasting periods of poor air quality.