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CRC NARSTO-Northeast Modeling Study

CRC NARSTO-Northeast Modeling Study. Ralph E. Morris, Edward Tai, and Greg Yarwood ENVIRON International Corporation 101 Rowland Way Novato, California 94945 Models-3 User’s Workshop hosted by CMAS October 21-23, 2002 Research Triangle Park, North Carolina. Acknowledgements.

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CRC NARSTO-Northeast Modeling Study

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  1. CRC NARSTO-Northeast Modeling Study Ralph E. Morris, Edward Tai, and Greg Yarwood ENVIRON International Corporation 101 Rowland Way Novato, California 94945 Models-3 User’s Workshop hosted by CMAS October 21-23, 2002 Research Triangle Park, North Carolina G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  2. Acknowledgements • Coordinating Research Council (CRC) Atmospheric Impacts Committee (Brent Bailey, Coordinator) • Work performed with Alpine Geophysics, STI, and PSU • NARSTO acknowledged for data collection and analysis activities and comments • MM5 data provided by Nelson Seaman at PSU • NARSTO Data Analysis Study directed by Till Stoekenius at ENVIRON G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  3. Purpose • Investigate sensitivity of photochemical grid models to inputs and options using the extensive July 1995 NARSTO-Northeast database: • Photochemical Grid Model (CMAQ vs CAMx) • Meteorological Model (MM5 vs RAMS) • Level of FDDA in MM5 • VOC and/or NOx Emission Reductions • Grid Resolution (12-km vs 4-km) • Chemical Mechanism (CB-IV vs SAPRC97) • Advection Solver (Bott vs PPM vs Smolarkiewicz) G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  4. Overview of Approach • Minimize any interpolation of met data • LCP grid for MM5 met; PSP grid for RAMS met • MM5 run with 3 levels of FDDA • Analysis Nudging (AN) only • AN and Observation Nudging (ON) • AN, ON, and VAD nudging (FOBS) • CMAQ and CAMx sensitivity runs • 36-km, 12-km, and 4-km nests G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  5. G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  6. Emissions Processed by EMS95 G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  7. Difficulties Encountered/Lessons Learned • Emissions: Numerous delays were encountered waiting for the latest emissions that were not substantially different from the draft values. • CMAQ QSSA Chemistry Solver: QSSA chemistry solver is slow, inaccurate, and may go unstable so should not be used. • MAQSIP Modeling System: STI had difficulties getting MAQSIP to work which was believed to be due to not using the MAQSIP version of MM5. • Layer 1 Vertical Diffusivities: Both CMAQ (MCIP) and CAMx (MM5CAMx) modeling systems were updated during then study with a minimum layer 1 KV. G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  8. Ozone Hourly Time Series in NYC SubdomainCAMx/MM5, CAMx/RAMS, CMAQ/MM5 G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  9. Daily Maximum Ozone -- July 14, 1995CAMx/MM5 CMAQ/MM5 CAMx/RAMS G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  10. Daily Maximum Ozone -- July 15, 1995CAMx/MM5 CAMx/RAMS CMAQ/MM5 G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  11. 12-km vs 4-km Grids-- CMAQ July 14, 1995 G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  12. 12-km vs 4-km Grids -- CAMx July 14, 1995 G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  13. 12-km vs 4-km Grids -- CMAQ July 15, 1995 G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  14. 12-km vs 4-km -- CAMx July 15, 1995 G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  15. Comments on Grid Resolution Sensitivity • July 12-14 CMAQ and CAMx 4-km ozone estimates more like each other than their 12-km parent • 4-km ozone estimates generally lower than 12-km • CMAQ 4-km ozone smoother due to KH inversely proportional to grid spacing • July 15, 1995 very different response to 4-km grid: • MM5 4-km grid explicitly resolves convective activity with downdrafts etc. • Many other desirable features in MM5 4-km fields G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  16. MM5 12-km vs 4-km Wind Field 07/15/95 G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  17. Emission Reduction Sensitivity Tests • Investigate sensitivity of ozone responses to 50% NOx and/or 50% VOC anthropogenic emission reductions: • Photochemical model: CMAQ vs. CAMx • Grid resolution: 12-km vs. 4-km (NOx only) • Chemical mechanism: CB-IV vs SAPRC97 • Advection Solver: Bott vs Smolarkiewicz • Low-level vs Elevated NOx • Design Value Scaling for Four NE Sites G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  18. 50% Anthropogenic VOC Reduction G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  19. 50% Anthropogenic NOx Reduction G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  20. Emission Reduction Sensitivity Conclusions • NOx reductions result in wide-spread decreases in ozone except in urban cores where increases sometimes occur • VOC reductions result in ozone reductions in urban cores but little change elsewhere • CAMx/MM5 is more VOC sensitive than either CMAQ/MM5 or CAMx/RAMS • SPARC97 chemistry is more VOC sensitive than CB-IV • Use of a 4-km grid increases the NOx disbenefits in CAMx/MM5 but has less effects in CMAQ/MM5 G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

  21. Overall Conclusions • QSSA chemistry solver is slow and inaccurate and should not be used • Smolarkiewicz advection solver is overly diffusive and should not be used • CMAQ horizontal diffusion coefficient parameterization that is inversely proportional to grid resolution negates many of the benefits of high resolution grids • Meteorological modeling of convective activity should be studied for air pollution modeling • Ozone Design Value scaling can be very different using different models G:\crca24\CMAS_workshop\CMAS_CRC_NARSTO.ppt

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