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Weimin Jiang, Helmut Roth, Steven C. Smyth

Comparison of MAQM and CMAQ model science, input/output files, and modelling results of a test case. Weimin Jiang, Helmut Roth, Steven C. Smyth. Outline. Why do air quality models need full and flexible process-level (PL) modularity ?

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Weimin Jiang, Helmut Roth, Steven C. Smyth

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  1. Comparison of MAQM and CMAQ model science, input/output files, and modelling results of a test case Weimin Jiang, Helmut Roth, Steven C. Smyth

  2. Outline • Why do air quality models need full and flexible process-level (PL) modularity ? • Brief review of the Modular Air Quality Model (MAQM) architecture and software components • MAQM v1 science vs. CMAQ v4.5 • MAQM v1 I/O files vs. CMAQ v4.5 • Preliminary performance evaluation of MAQM v1 vs. CMAQ v4.6 • Future work • Acknowledgements 2008 CMAS Conference

  3. Why AQM with PL modularity ? • Challenging tasks facing all serious air quality modellers: • Implement, revise, and/or update complicated model science correctly, efficiently, and in a timely manner; • Understand linkages between model behaviour & model science; • Compare and exchange model science and algorithms between models. • Process-level modularity is crucial to fulfilling these challenging tasks. 2008 CMAS Conference

  4. Why AQM with PL modularity ? (cont’d) • Desirable/dreamed outcomes of PL modularity in air quality models • Simple & transparent structure • Transferable code • Well structured model science & algorithms • Localised errors & bugs • Flexible process analysis capability • Potential feedbacks among meteorology, emissions, and air quality • Broad participation of the community in model development and improvement • Robust model science and policy applications 2008 CMAS Conference

  5. Emission Meteorology Gas_chem Advection ...... ... ... ... ...

  6. Emission Meteorology Gas_chem Advection ...... ... ... ... ...

  7. MAQM v1:software components • 1 simple MAQM driver: MAQM • 5 global data modules: • Grid_Data, Gas_Data, Aero_Data, Met_Data, Const_Data • 20 process modules: all optional and replaceable • Grid Init_met Init_gas Init_aero • BConc_gas BConc_aero Emission Gas_chem • Nucleation Condensation Inor_aero SOA • Coagulation Advection Diffusion Cloud • Ddep_gas Ddep_part Meteorology Output 2008 CMAS Conference

  8. MAQM v1:software components (cont’d) • 3 new pre-processors: optional depending on process modules used • PROCCHEM, ICON_CONVERSION, BCON_CONVERSION • 6 utility subroutines: • find_name, int2str, real2str, DgSgM2, valid_conc, PMx • 3 CMAQ pre-processors are used directly • MCIP, SMOKE, JPROC 2008 CMAS Conference

  9. MAQM v1: science • Mostly adopted/adapted from CMAQ v4.5 for now • New additions to and major differences from CMAQ • Units: SI-emphasis in code; flexible in output • Aerosol species and modes: all species in all models; flexible • PMx; size-resolved particle quantities • SOA and saprc99_ae4_aq_SVOC gas mechanism: • 10 lumped SVOCs recorded and tracked in both gas and aerosol phases • Mode-merging: not included in current version • Emissions: an independent process • Advection: optional CMAQ/PPM or simple upstream scheme • Cloud: resolved cloud with total convective & non-convective precipitations • Sea salt: not included in current version

  10. MAQM v1: input files • Grid, meteorology, emissions, photolysis rates: • fully compatible with CMAQ: • GRIDCRO2D, GRIDDOT2D, GRIDCRO3D; • METCRO3D, METDOT3D, METBDY3D, METCRO2D; • EMIS; • Jvalue. • Initial and boundary conditions: • ASCII files allowing flexible cell-range-specific concentration setting; • from ICONC_CONVERSION, BCONC_CONVERSION or other sources. 2008 CMAS Conference

  11. MAQM v1: output files • Gaseous species concentrations: GasConc_[yyyyddd]; • Modal aerosol quantities: Aero_Conc_[yyyyddd]; • total and speciated mass, number, and surface area concentrations; • Dg, sg. • Size-specific aerosol quantities: PMx_[yyyyddd]: • total and speciated mass, number, and surface area concentrations; • default size cut-offs: PM0.01, PM0.1, PM1, PM2.5, PM5, PM10; • size cut-offs can be changed by users. • I/O API format; user-selectable conventional or SI units. 2008 CMAS Conference

  12. Preliminary MAQM vs. CMAQ evaluation • 139 x 99 42 km cells; • 0:00 July 1 • – 5:00 July 30, 2002; • MAQM v1; • CMAQ v4.6 + PMx; • Same emissions; • Same GEM • meteorology; • Slightly different IC & BC. 2008 CMAS Conference

  13. MAQM vs. CMAQ:O3 statistics

  14. MAQM vs. CMAQ:temporal O3 patterns

  15. MAQM vs. CMAQ:spatial O3 distributions Average hourly O3 Maximum hourly O3

  16. MAQM vs. CMAQ:PM2.5 statistics

  17. MAQM vs. CMAQ:temporal PM2.5 patterns

  18. MAQM vs. CMAQ:spatial distribution ofaverage hourly PM2.5 2008 CMAS Conference

  19. MAQM vs. CMAQ:spatial distribution ofmaximum hourly PM2.5 2008 CMAS Conference

  20. Possible future work • Almost endless possibilities, e.g. • Module-by-module science investigation and improvement • New and alternative process modules • Revised meteorology and emission modules to use input files from alternative sources • On-line meteorology and/or emission modules: • Possibilities: air quality meteorology • emission • Time- and location-varying boundary conditions • Process impact/sensitivity analysis • Upstream and downstream modules: e.g., climate input, health impact, etc. • ...... 2008 CMAS Conference

  21. Acknowledgements • US EPA: • The CMAQ model; • Early ideas of AQM modularity; • Community modelling concept. • All the organizations that contributed to the CMAQ code that we adapted/adopted. • Environment Canada • Emissions, GEM meteorology, and measurement data • CMAS: CMAQ distribution and support; • Dr. John Li: contribution to MAQM code development 2008 CMAS Conference

  22. 2008 CMAS Conference

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