1. THE MODELS-3 COMMUNITY MULTI- SCALE AIR QUALITY (CMAQ) MODEL: 2002 RELEASE – NEW FEATURES Jonathan Pleim, Francis Binkowski, Robin Dennis, Brian Eder, Shaocai Yu, Gerald Gipson, James Godowitch, Tanya Otte, Thomas Pierce, Shawn Roselle, Kenneth Schere, and Jeffrey Young Atmospheric Modeling Division, NERL/USEPA Models-3/CMAS Workshop RTP, NC October 21, 2002

3. CMAQ Chemical Transport Model June 2002 Release Advection –Piecewise parabolic method (PPM) –Bott scheme Vertical Diffusion –Eddy-diffusivity (K z ) –Asymmetric Convective Model (ACM) Horizontal Diffusion –Eddy-diffusivity with K h grid size dependent

4. Cloud Processes –Aqueous chemistry and sub-grid clouds adapted from RADM –Simple grid-resolved cloud scheme at all grid resolutions Plume in Grid –Embedded Lagrangian plume with gas-phase photochemistry (aerosols will be added after June 2002) Dry deposition –RADM dry deposition model –M3dry: Adjunct to the PX Land Surface Model

5. Gas-phase Chemical Mechanisms –RADM2 –CB4 –SAPRC99 –All mechanisms linked to aerosol module and aqueous chemistry Gas-phase Chemistry Solvers –Quasi-steady state approximation (QSSA) –SMVGEAR –Modified Euler Backward Iterative method for all mechanisms

6. Updated Aerosol Model (Aero3) Lognormal size distribution (  g and D g) –Aitken mode (0-0.1 µm) –Accumulation mode (0.1-2.5 µm) –Coarse (PM10 - PM2.5) Aerosol processes: –Nucleation (revised) –Coagulation –ISORROPIA semivolatile equilibrium model –Clouds - CCN, aqueous chemistry, wet deposition PM2.5 }

7. Aerosol chemistry –Inorganic: Sulfate,Nitrate, Ammonium –Secondary anthropogenic and biogenic organic (updated yields and added semivolatile partitioning) –Speciated primary emissions Elemental carbon, organic carbon, sulfate, nitrate Future: soil dust, sea salt –Heterogeneous reaction of N 2 O 5 -> HNO 3 Regional haze –Visibility estimates in deciviews deciView = 10 ln (  ext / 0.01) Explicit hour-averaging of CMAQ output species Dynamic memory allocation / windowing

8. New Meteorology Chemistry Interface Processor (MCIP2) –MM5v3 compatible –Surface and PBL parameters passed through –Compatible w/ PX LSM and M3dry Emissions –Sparse Matrix Operator Kernel Emissions (SMOKE) System –Biogenic Emissions Inventory System (BEIS3)

9. Plume rise modifications (SMOKE) –Corrected stable plume rise: Greatly reduces low level emissions –Updated Neutral and Unstable algorithms –Added option for updated initial vertical plume spread algorithm: generally much narrower initial spread –Effects of these changes are still being evaluated

10. Model Domains 32 km 8 km 2 km

11. Evaluation Nashville 1999 Atlanta 1999 Houston 2000 Annual speciated PM 2001 Tampa Bay 2002 } 6/11 - 8/25