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Comparison of Two Annual PM 2.5 Modeling Results for the South Coast Air Basin. 7 th Annual CMAS Conference October 8, 2008 Bong Mann Kim and Joe Cassmassi. Annual PM 2.5 Simulations. CAMx and CMAQ January 1, 2005 – December 31, 2005 Same input files Emissions Meteorological data
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Comparison of Two Annual PM2.5 Modeling Results for the South Coast Air Basin 7th Annual CMAS Conference October 8, 2008 Bong Mann Kim and Joe Cassmassi
Annual PM2.5 Simulations • CAMx and CMAQ • January 1, 2005 – December 31, 2005 • Same input files • Emissions • Meteorological data • Boundary and initial files • Compared with 2005 PM2.5 data measured for the Multiple Air Toxics Exposure Study (MATES III)
Input Files • Emissions • Monthly weekday, Saturday, Sunday • Monthly biogenic emissions • Meteorological data • MM5 initialized from NCEP w/ one-day “ramp up” period and run for 5-day w/o FDDA • Boundary and initial files • Generated from WRAP visibility global modeling results
Ambient Data • PM2.5 sampling conducted as part of MATES III program • PM2.5 data collected once every 3 days • Sampled from April 2004 to Mach 2006 at ten locations • PM2.5 mass, ions, carbon, metals • PM2.5 data from eight sites are used in the model performance evaluation
Comparison of Model Performance • PM2.5 mass, NH4, NO3, SO4, OC, EC, Others • Statistics • Mean bias (MB) • Mean error (ME) • Normalized mean bias (NMB) • Normalized mean error (NME) • Graphics • Error plots • Scatter plots • Time series plots
Error Plots CAMx CMAQ
Conclusions • CAMx and CMAQ produced similar results • Both models tend to over-predict NH4, NO3, OC, others, and PM2.5 mass • CAMx predicted better for OC, others and PM2.5 mass • CMAQ predicted better for NH4, NO3, and SO4 • CAMx is about 2 times faster than CMAQ • CAMx takes ~3 days with one CPU • CMAQ takes ~7 days with one CPU