CRC NARSTONortheast Modeling Study Ralph E Morris Edward

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: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt

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 • MM 5 data provided by Nelson Seaman at PSU • NARSTO Data Analysis Study directed by Till Stoekenius at ENVIRON G: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt

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 (MM 5 vs RAMS) – Level of FDDA in MM 5 – VOC and/or NOx Emission Reductions – Grid Resolution (12 -km vs 4 -km) – Chemical Mechanism (CB-IV vs SAPRC 97) – Advection Solver (Bott vs PPM vs Smolarkiewicz) G: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt

Overview of Approach • Minimize any interpolation of met data – LCP grid for MM 5 met; PSP grid for RAMS met • MM 5 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: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt

G: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt

Emissions Processed by EMS 95 G: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt

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 MM 5. • Layer 1 Vertical Diffusivities: Both CMAQ (MCIP) and CAMx (MM 5 CAMx) modeling systems were updated during then study with a minimum layer 1 KV. G: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt

Ozone Hourly Time Series in NYC Subdomain CAMx/MM 5, CAMx/RAMS, CMAQ/MM 5 G: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt

Daily Maximum Ozone -- July 14, 1995 CAMx/MM 5 G: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt CMAQ/MM 5 CAMx/RAMS

Daily Maximum Ozone -- July 15, 1995 CAMx/MM 5 G: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt CAMx/RAMS CMAQ/MM 5

12 -km vs 4 -km Grids-- CMAQ July 14, 1995 G: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt

12 -km vs 4 -km Grids -- CAMx July 14, 1995 G: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt

12 -km vs 4 -km Grids -- CMAQ July 15, 1995 G: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt

12 -km vs 4 -km -- CAMx July 15, 1995 G: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt

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: – MM 5 4 -km grid explicitly resolves convective activity with downdrafts etc. – Many other desirable features in MM 5 4 -km fields G: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt

MM 5 12 -km vs 4 -km Wind Field 07/15/95 G: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt

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 SAPRC 97 – Advection Solver: Bott vs Smolarkiewicz – Low-level vs Elevated NOx • Design Value Scaling for Four NE Sites G: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt

50% Anthropogenic VOC Reduction G: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt

50% Anthropogenic NOx Reduction G: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt

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/MM 5 is more VOC sensitive than either CMAQ/MM 5 or CAMx/RAMS • SPARC 97 chemistry is more VOC sensitive than CB-IV • Use of a 4 -km grid increases the NOx disbenefits in CAMx/MM 5 but has less effects in CMAQ/MM 5 G: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt

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: crca 24CMAS_workshopCMAS_CRC_NARSTO. ppt