Abstract
Abstract. This paper presents a comparison of the operational performances of two Community Multiscale Air Quality (CMAQ) model v4.7 simulations that utilize input data from the 5th-generation Mesoscale Model (MM5) and the Weather Research and Forecasting (WRF) meteorological models. Two sets of CMAQ model simulations were performed for January and August 2006. One set utilized MM5 meteorology (MM5-CMAQ) and the other utilized WRF meteorology (WRF-CMAQ), while all other model inputs and options were kept the same. For January, predicted ozone (O3) mixing ratios were higher in the Southeast and lower Mid-west regions in the WRF-CMAQ simulation, resulting in slightly higher bias and error as compared to the MM5-CMAQ simulations. The higher predicted O3 mixing ratios are attributed to less dry deposition of O3 in the WRF-CMAQ simulation due to differences in the calculation of the vegetation fraction between the MM5 and WRF models. The WRF-CMAQ results showed better performance for particulate sulfate (SO42−), similar performance for nitrate (NO3−), and slightly worse performance for nitric acid (HNO3), total carbon (TC) and total fine particulate (PM2.5) mass than the corresponding MM5-CMAQ results. For August, predictions of O3 were notably higher in the WRF-CMAQ simulation, particularly in the southern United States, resulting in increased model bias. Concentrations of predicted particulate SO42− were lower in the region surrounding the Ohio Valley and higher along the Gulf of Mexico in the WRF-CMAQ simulation, contributing to poorer model performance. The primary causes of the differences in the MM5-CMAQ and WRF-CMAQ simulations appear to be due to differences in the calculation of wind speed, planetary boundary layer height, cloud cover and the friction velocity (u∗) in the MM5 and WRF model simulations, while differences in the calculation of vegetation fraction and several other parameters result in smaller differences in the predicted CMAQ model concentrations. The performance for SO42−, NO3− and NH4+ wet deposition was similar for both simulations for January and August.
Highlights
Air quality models, such as the Community Multiscale Air Quality (CMAQ) modeling system (Byun and Schere, 2006) and the Comprehensive Air Quality Model with extensions (CAMx) (ENVIRON, 2009), require gridded, high resolution meteorological data in order to accurately predict the transformation, transport and fate of pollutants in the atmosphere
This study examines the operational performance of two sets of January and August 2006 CMAQ simulations, with one set using meteorological data provided by MM5 (MM5-CMAQ) and the other using data provided by the Weather Research and Forecasting model (WRF) model
Two sets of CMAQv4.7 simulations were performed for January and August 2006, with one set using the MM5 meteorology and the other set using WRF model meteorology
Summary
Air quality models, such as the Community Multiscale Air Quality (CMAQ) modeling system (Byun and Schere, 2006) and the Comprehensive Air Quality Model with extensions (CAMx) (ENVIRON, 2009), require gridded, high resolution (both temporally and spatially) meteorological data in order to accurately predict the transformation, transport and fate of pollutants in the atmosphere. Gridded Eulerian meteorological models, such as the 5th Generation Mesoscale Model (MM5; Grell et al, 1994) and the Weather Research and Forecasting model (WRF; Skamarock et al, 2008), are used to provide the meteorological data required by air quality models. For the past 15 years, MM5 has been used to provide meteorological data for air quality simulations. Releases of new versions of MM5 by the community have ceased since the WRF model has taken its place.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
