Simultaneous Prediction of Weather and Air Quality During Neaqs2004 Using The Wrf-chemistry Model

Abstract

The 2004 New England Air Quality Study (NEAQS) was an intensive effort to investigate the chemical and meteorological factors that contribute to poor air quality in the 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 several research aircraft. Although many of the ground stations routinely collect data year-round, the period of most intensive measurements was from July 1 through August 16, 2004. Real-time numerical weather and air quality forecasts during NEAQS 2004 were provided by several university and government institutions including the NOAA Forecast Systems Laboratory (FSL). The numerical model used to produce weather and air quality forecasts at FSL is the Weather Research and Forecast model (WRF) with chemistry (Grell et al., 2004). The WRF-Chem model is designed to integrate the meteorology and atmospheric chemistry simultaneously (online) as opposed to previous air quality models (e.g., CMAQ; Byun and Ching, 1999) that integrate the meteorology and atmospheric chemistry separately (“offline”). The WRF-Chem model incorporates an air chemistry mechanism package based on RADM2 (Stockwell et al., 1990), biogenic emissions, surface deposition, tracer transport by convection, turbulence, photolysis, and advective transport. In addition, atmospheric aerosols have been incorporated using the Modal Aerosol Dynamics Model for Europe (MADE) (Ackermann et al., 1998) which itself is a modification of the Regional Particulate Model (Binkowski and Shankar, 1995). Secondary organic aerosols (SOA) have been incorporated into MADE by Schell et al. (2001), by means of the Secondary Organic Aerosol Model (SORGAM). Real-time forecasts are being made with the WRF-Chem model for the eastern half of the U. S. This model configuration is one of several real-time simulations being conducted at NOAA/FSL (Koch et al., 2004). Select fields from the forecasts (00 and 12 UTC) are available online (http://www.wrf-model.org/WG11). For the purpose of diagnostic evaluation, retrospective simulations of the 2004 NEAQS forecasts were conducted using the WRF-Chem model. Comparisons are made between the meteorological and chemical species observations and the numerical simulation results in order to evaluate the WRF-Chem simulations. The presentation will briefly discuss the model configuration used in real-time forecasts. In addition, several high-pollution events will be compared in order to evaluate the overall performance of the WRF-Chem numerical model.