Incremental Testing of the Community Multiscale Air Quality (CMAQ) Modeling System Version 4.7

1. Incremental Testing of the Community Multiscale Air Quality (CMAQ) Modeling System Version 4.7 Shawn J. Roselle, K. Wyat Appel, Kristen M. Foley, Prakash V. Bhave, Jonathan E. Pleim, Rohit Mathur, Tanya L. Otte, Robert C. Gilliam, Golam Sarwar, Christopher G. Nolte, Alice B. Gilliland, Robert W. Pinder, and Jenise L. Swall

2. Model Developers contributing to CMAQv4.7: Jesse Bash Prakash Bhave Arastoo Pour Biazar (UAH) Frank Binkowski (UNC) Russ Bullock Ann Marie Carlton Ellen Cooter Bill Hutzell Jim Kelly (now with CARB) Rohit Mathur Sergey Napelenok Chris Nolte Tanya Otte Jon Pleim George Pouliot Shawn Roselle Golam Sarwar Donna Schwede Uma Shankar (UNC) David Wong Aijun Xiu (UNC) Jeff Young WRF simulations: Rob Gilliam Tanya Otte Jon Pleim Support: model simulations, emissions processing, data extractions, IC/BCs Lucille Bender (CSC) Charles Chang (CSC) Ryan Cleary (CSC) Steve Howard Allan Huffman (CSC) Nancy Hwang (CSC) Lara Reynolds (CSC) Acknowledgements

3. Science Improvements for CMAQv4.7 • Aerosols • Heterogeneous reaction probability (N2O5) • Re-derived parameterization based on Davis et al. (2008) • SOA Model Enhancements (presentation by S. Napelenok) • Updates: isoprene SOA, sesquiterpene SOA, polymerization, acid-catalyzed SOA, NOx-dependent SOA yields, and enthalpy of vaporization (Edney et al., 2007) • In-cloud SOA formation pathways (glyoxal, methylglyoxal) (Carlton et al., 2008) • Changes in gas-phase chemistry mechanism, emissions speciation, and biogenic emissions model, to represent SOA precursors • Coarse PM (poster by J. Kelly and P. Bhave) • Semi-volatile inorganic components (NO3-, Cl-, and NH4+) can condense and evaporate from the coarse mode, via dynamic mass transfer • Nonvolatile sulfate can condense on the coarse mode • Variable standard deviation of coarse mode size distribution • Emissions of sea salt from the surf zone

4. Science Improvements for CMAQv4.7 (cont.) • Chemistry • HONO enhancements (Sarwar et al., 2008) • Heterogeneous reaction on aerosol and ground surfaces • Emissions from mobile sources • Photolysis Options (beta versions) • In-line photolysis rate module, with aerosol feedback (Binkowski et al., 2008) (poster by C. Nolte) • Photolysis rates adjusted using satellite-derived cloud information (currently table-approach only) (Pour Biazar et al., 2008) • Aqueous Chemistry • Added two organic oxidation reactions (glyoxal, methylglyoxal) (Carlton et al., 2008) • Updates to Henry's Law constants based on literature review • Base CB05 mechanism with Cl2 chemistry (Yarwood et al., 2005) • Multi-pollutant Capability • Include HAPs and Hg in single modeling platform (presentation by W. Hutzell)

5. Science Improvements for CMAQv4.7 (cont.) • In-line options • Dry Deposition • Moved calculation into CCTM • Emissions (poster by J. Young) • Integrated BEIS into CCTM • Incorporated Plume-rise into CCTM • Bi-directional NH3 and Hg surface flux (optional) • For NH3, fertilizer emissions will be applied through the flux model (under development) • Emissions • Biogenic emissions: added sesquiterpene emissions • Speciation changes for HONO and benzene • Sea-salt emissions • Updated flux parameterizations & surf zone emissions • Used Spatial Allocator to produce ocean file

6. Science Improvements for CMAQv4.7 (cont.) • Clouds • Convective cloud model • Revised to reduce layer configuration differences • Changed the integration timestep • Resolved cloud model • Correction in precipitation flux calculation

7. Incremental Testing • This release was incrementally tested for extended time periods • January & August 2006 • 12 km eastern U.S. domain (nested from 36 km continental U.S. domain) • 34 vertical layers (no layer collapsing) • Operational evaluation performed for each major science increment • Transition from MM5 to WRF (poster by W. Appel) • All simulations presented here used WRF2.2 • Benefits • Diagnostic evaluation: • Documents the impact of each model change on performance • Provides more detailed information regarding differences in results between model release versions • Provided QA/QC for model simulations, input data, and implementation

8. Incremental Simulations BASE: Modified version of CMAQv4.6 that included chlorine chemistry GAMMA N2O5: New parameterization for N2O5 SOA: New SOA module HONO: Surface HONO reactions and HONO emissions COARSE MODE: Addition of Dynamic coarse mode CLOUDS: Revised convective and resolved cloud models CMAQv4.7: Final release version

9. BASE BASE GAMMA N2O5 GAMMA N2O5 SOA SOA HONO HONO COARSE MODE COARSE MODE CLOUDS CLOUDS CMAQ4.7 CMAQ4.7 Model Bias in SO4 --- CASTNET Weekly Observations August 2006 January 2006 Sulfate model performance improved with cloud model revisions

10. BASE BASE GAMMA N2O5 GAMMA N2O5 SOA SOA HONO HONO COARSE MODE COARSE MODE CLOUDS CLOUDS CMAQ4.7 CMAQ4.7 Model Bias in NO3 --- CASTNET Weekly Observations August 2006 January 2006 Base model used Evans and Jacob (2005) parameterization, that included a sign error

11. BASE BASE GAMMA N2O5 GAMMA N2O5 SOA SOA HONO HONO COARSE MODE COARSE MODE CLOUDS CLOUDS CMAQ4.7 CMAQ4.7 Model Bias in TNO3 --- CASTNET Weekly Observations August 2006 January 2006 Again, base model used Evans and Jacob (2005) parameterization, that included a sign error

12. BASE BASE GAMMA N2O5 GAMMA N2O5 SOA SOA HONO HONO COARSE MODE COARSE MODE CLOUDS CLOUDS CMAQ4.7 CMAQ4.7 Model Bias in NH4 --- CASTNET Weekly Observations August 2006 January 2006

13. BASE BASE GAMMA N2O5 GAMMA N2O5 SOA SOA HONO HONO COARSE MODE COARSE MODE CLOUDS CLOUDS CMAQ4.7 CMAQ4.7 Model Bias in OC --- IMPROVE Daily Observations August 2006 January 2006 Model value – Observed value (μg/m3) Model value – Observed value (μg/m3) Note: primary reason for decrease in OC is change in enthalpy of vaporization

14. BASE BASE GAMMA N2O5 GAMMA N2O5 SOA SOA HONO HONO COARSE MODE COARSE MODE CLOUDS CLOUDS CMAQ4.7 CMAQ4.7 Model Bias in TC --- STN Daily Observations August 2006 January 2006

15. BASE BASE GAMMA N2O5 GAMMA N2O5 SOA SOA HONO HONO COARSE MODE COARSE MODE CLOUDS CLOUDS CMAQ4.7 CMAQ4.7 Model Bias in SO4 Wet Deposition --- NADP Weekly Observations August 2006 January 2006 Model value – Observed value (kg/ha) Model value – Observed value (kg/ha)

16. Model value – Observed value (kg/ha) Model value – Observed value (kg/ha) BASE BASE GAMMA N2O5 GAMMA N2O5 SOA SOA HONO HONO COARSE MODE COARSE MODE CLOUDS CLOUDS CMAQ4.7 CMAQ4.7 Model Bias in NO3 Wet Deposition --- NADP Weekly Observations August 2006 January 2006

17. Model value – Observed value (kg/ha) Model value – Observed value (kg/ha) BASE BASE GAMMA N2O5 GAMMA N2O5 SOA SOA HONO HONO COARSE MODE COARSE MODE CLOUDS CLOUDS CMAQ4.7 CMAQ4.7 Model Bias in Cl Wet Deposition --- NADP Weekly Observations August 2006 January 2006 Model Bias improved with the addition of dynamic coarse mode

18. SOA BASE HONO CLOUDS COARSE MODE GAMMA N2O5 Model Bias in 8-hr. Max. O3 --- AQS Daily Observations Model value – Observed value (ppb)

19. Other Changes for CMAQv4.7 • MCIPv3.4 required (soon to be released) • Diagnostic Tools (will be released later this year) • Direct Decoupled Method (DDM) • Primary carbon source apportionment model • Sulfate tracking model • Model options removed • Plume-in-grid • CB4 mechanisms • Aero3 module and AE3 mechanisms • RADM cloud module • Stand-alone mercury version of CMAQ (capability is included in the multipollutant version)

20. Model Development for Future CMAQ Releases • Two-way Coupled WRF/CMAQ (presentations by J. Pleim and D. Wong) • Chemistry • Alternative gas-phase chemical mechanisms (SAPRC-2007, RACM2) • Continued development of the inline photolysis module • Aerosols • Speciation of fine soil, non-carbon organic matter • Source Apportionment of PMother • Influence of organics on γN2O5 • Thermodynamics of crustal/soil species • Clouds • Rosenbrock solver for aqueous chemistry • Grell convective cloud module • Dry Deposition • Mosaic land-use approach • National Land Cover Data (NLCD)