Status of the New Canadian Air Quality Forecast Model: GEM-MACH15

1. Status of the New Canadian Air Quality Forecast Model: GEM-MACH15 Michael Moran1, Donald Talbot2, Sylvain Ménard2, Véronique Bouchet1, Paul Makar1, Wanmin Gong1, Alexander Kallaur3, Hugo Landry2, Ping Huang4, Sunling Gong1,andLouis-Philippe Crevier2 1Air Quality Research Division, Environment Canada, Toronto, Ontario 2Air Quality Modelling Applications Section, Environment Canada, Montreal, QC 3Air Quality Research Division, Environment Canada, Montreal, Quebec 4Independent consultant, Toronto, Ontario 8th CMAS Conference Chapel Hill, NC 19 October 2009

2. Talk Outline • Background • GEM-MACH: General description • GEM-MACH15: Configuration • GEM-MACH15: Performance evaluation • Current status

3. Environmental Forecasting at EC Daily weather forecasts plus • Ocean waves and storm surges • Sea ice • Air pollution potential • Volcanic ash • UVB index and total column O3 • Surface O3,PM2.5, and PM10 • AQ Health Index (AQHI: based on O3,PM2.5, and NO2) • Hazardous releases (e.g., Chernobyl, FMD, ...)

4. Chronology of EC Air-Quality Prediction Program • 1998: Experimental CTM-based forecasts of ground-level O3 begin for eastern Canada with CHRONOS (40-km grid spacing) • 2001: Operational CHRONOS ozone forecasts begin; new national domain, 21-km grid spacing • 2003: Bulk PM2.5/PM10 forecasts added to CHRONOS output suite (4 chemical components)

5. Objective for GEM-MACH15 Project (Autumn 2005)To replace CHRONOS, the current EC operational off-line regional AQ forecast model for O3, NO2, PM2.5, and PM10, with a new GEM-based on-line operational AQFM that includes a science package equivalent to the one in the AURAMS CTM

6. Terminology • What is GEM? • Environment Canada’s operational global/medium-range and regional/short-range weather forecast model • What is GEM-MACH? • GEM with on-line chemistry from AURAMS CTM • What is GEM-MACH15? • proposed operational limited-area configuration of GEM­MACH with 15-km grid spacing

7. Acronym “GEM-MACH” Stands For modèle Global Environnemental Multi-échelle –Modélisation de la qualité de l'Air et de la CHimie et / and Global Environmental Multiscale model – Modelling Air quality and CHemistry

8. "Multiscale" Examples:Three GEM Grid Configurations regional global limited area

9. GEM-MACH Data Flow (2005/6) CAN-USA-MEX Emission inventories SMOKE off-line system GenPhysX Biogenic info (Beld3, emis factor) Area Major points Climatology Geophys Meteorological Analysis RPN standard file format RPN standard file format GEM-MACH Emissions pre-processor GEM Meteorological pre-processor on-line system Emissions binary files for each CPU tile Meteorological binary files for each CPU tile GEM-MACH Main model PM2.5, O3, NO2, ... Temperature, pressure …

10. Chemical Process Representations in CHRONOS vs. GEM-MACH15

11. Simplifications to GEM-MACH15 for Operational Use • Perform meteorological calculations every time step (450 s) but AQ calculations every 2nd time step (900 s) • Used 58 vertical levels to 0.1 hPa rather than 80 levelsto 0.1 hPa used by GEM15 • Used metastable option in heterogeneous chemistry • Switched from 12-bin to 2-bin representation of PM size distribution [reduces number of advected tracer fields by 80 from 137 to 57, i.e., by ~60%, but had to implement new sub-bin calculations to account for size dependence in some PM processes (sea-salt emissions, dry deposition, intersectional transport)]

12. GEM15 and GEM-MACH15 Grids • GEM15 employs a variable grid, but uniform core has 15-km spacing • GEM-MACH15 employs a limited-area grid (LAM), also with 15-km spacing and co-located with GEM15 grid points • GEM15 supplies meteorological initial conditions and hourly lateral boundary conditions to LAM GEM15 core grid (red) ; GEM-MACH15 grid (blue)

13. CHRONOS and GEM-MACH15 Setups CHRONOS GEM-MACH15 • 348 x 465, rotated lat-long projection • horizontal grid spacing of 15 km • 58 eta hybrid levels to 0.1 hPa • Δt = 450 s for meteorology • Δt = 450 x 2 = 900 s for chemistry • Emissions: 2006 Cdn, 2005 US, 1999 Mx • 350 x 250, polar stereographic proj’n • horizontal grid spacing of 21 km • 24 Gal-Chen vertical levels to ~ 6 km • Δt = 3600 s • Emissions: 2000 Canadian & 2001 US with adjustments to 2007 EGU levels

14. Summer 2009 "Parallel Run" Evaluation • GEM-MACH15 was run “in parallel” alongside CHRONOS from May 27 to Aug. 17, 2009 • Subjective evaluation • CMC and regional AQ forecasters (6 offices) • comparison to GEM15, to local AQ measurements, and to CHRONOS • Objective evaluation • discrete statistics (with significance testing) • categorical statistics

15. Example of Day 2 Hourly O3 Comparison (Full Domain)

16. Example of Day 1 Hourly NO2 Comparison (Full Domain)

17. Example of Day 1 Hourly PM2.5 Comparison (Eastern North America)

18. Summer 2008 O3 and NO2 Monitor Locations

19. GEM-MACH better 57 % red CHRONOS better 43 % blue Not statistically different 0 % yellow CHRONOS vs. GEM-MACH15:Discrete Statistics June-July-Aug. 2009

20. CHRONOS vs. GEM-MACH15:Categorical Statistics– June-July 2009 • Percent Correct (PC) is in CHRONOS’s favour for this period: O3 = 0.77 (0.80); PM2.5 = 0.73 (0.77) • Probability of Detection (POD) is slightly in favour of GEM-MACH15 • False Alarm Rate (FAR) and Critical Success Index (CSI) are comparable for two models for this period

21. Outcome of "Parallel Run" Evaluation • Request at the Sept. 3, 2009 meeting of the Committee on Operational and Parallel Runs at the Canadian Meteorological Centre (CMC) for GEM-MACH15 to be elevated to operational status was accepted • Final modifications to GEM-MACH15 operational suite are now being completed’; the switch from CHRONOS to GEM-MACH15 is expected the week of Oct. 26th • GEM-MACH15 is a better platform for further development and improvements • Entire effort has taken about 4 years

22. Thank you for your attention!