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, and Louis-Philippe Crevier2

1Air Quality Research Division, Environment Canada, Toronto, Ontario2Air Quality Modelling Applications Section, Environment Canada, Montreal, QC3Air Quality Research Division, Environment Canada, Montreal, Quebec4Independent consultant, Toronto, Ontario

8th CMAS Conference Chapel Hill, NC 19 October 2009

DRAFT – Page 2 – April 21, 2023

Talk Outline

• Background

• GEM-MACH: General description

• GEM-MACH15: Configuration

• GEM-MACH15: Performance evaluation

• Current status

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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, ...)

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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)

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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

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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

GEM MACH with 15-km grid spacing

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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

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"Multiscale" Examples:Three GEM Grid Configurations

global regional

limited area

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GEM-MACH Data Flow(2005/6) CAN-USA-MEXEmission inventories

SMOKE

Area Major points

GEM-MACHEmissions pre-processor

GEM-MACHMain model

PM2.5, O3, NO2, ...Temperature, pressure …

GEMMeteorological pre-processor

GenPhysXBiogenic info

(Beld3, emis factor) Climatology Geophys MeteorologicalAnalysis

off-linesystem

on-linesystem

RPN standard file formatRPN standard file format

Emissions binary files for each CPU tile

Meteorological binary files for each CPU tile

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Chemical Process Representations in CHRONOS vs. GEM-MACH15

PROCESS CHRONOS GEM-MACH15

Emissions PM2.5 and PMc primary emissions are assumed to be bulk emissions; 17 gas-phase species emitted

PM2.5 and PMc emissions speciated to 7 species by primary source type (point, area, mobile); 17 gas-phase species emitted

Gas-Phase Chemistry Mechanism

ADOM-2 mechanism (Stockwell andLurmann, 1989); 47 advected species

ADOM-2 mechanism (Stockwell andLurmann, 1989) with1) p-SO4 replaced by H2SO4+p-SO4

2) N2O5 + H2O “heterogeneous nitrate formation” rate enhancement switch=off.

Aqueous-Phase Chemistry

None ADOM aqueous-phase chemistry

PM Composition and size distribution

2 size bins: PM2.5, PM10

4 chemical species: sSO4, sOC, H2O, primary PM

2 size bins: PM2.5, PM10

8 chemical species: SO4, NO3, NH4, EC, pOC, sOC, CM, SS

Aerosol Dynamics Sedimentation Sedimentation, Nucleation, Condensation, Coagulation

Secondary Organic (SOA) Yields

Based on Pandis et al. (1992) IAY scheme Based on Jiang (2004)

Wet Deposition Distribution of LWC is used to calculate the wet scavenging term by applying Sundqvist formulae for the rate of release of precipitation

Transfer of tracers from cloud to rain water based on precipitation production. In-cloud and below-cloud scavenging of soluble gases and particles (size-dependent) .

Chemical boundary conditions

Zero-gradient inflow, open-boundary out-flow

Climatological profiles with Davies lateral boundary conditions

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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 levels to 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)]

DRAFT – Page 12 – April 21, 2023

GEM15 and GEM-MACH15 Grids

GEM15 core grid (red) ; GEM-MACH15 grid (blue)

• 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

DRAFT – Page 13 – April 21, 2023

CHRONOS GEM-MACH15• 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

• 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

CHRONOS and GEM-MACH15 Setups

DRAFT – Page 14 – April 21, 2023

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

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Example of Day 2 Hourly O3 Comparison (Full Domain)

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Example of Day 1 Hourly NO2 Comparison (Full Domain)

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

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Summer 2008 O3 and NO2 Monitor Locations

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CHRONOS vs. GEM-MACH15:Discrete Statistics June-July-Aug. 2009

Metric North Am Cda E Cda W Cda US E US W US

O3 R 0.64/0.64 0.51/0.55 0.54/0.54 0.48/0.57 0.65/0.64 0.67/0.66 0.58/0.61

O3 MB -1.68/4.62 -2.71/1.92 -1.78/3.40 -4.48/-0.91 -1.36/5.26 -0.51/6.52 -8.21/-4.77

O3 RMSE unbiased 15.23/14.92 14.80/12.63 13.93/12.72 16.18/11.95 15.31/15.27 15.13/14.92 15.02/14.25

PM2.5 R 0.23/0.32 0.16/0.22 0.19/0.26 0.10/0.11 0.29/0.39 0.25/0.35 0.16/0.15

PM2.5 MB -0.70/2.08 -0.09/0.77 -0.18/2.35 0.05/-1.69 -1.02/2.52 -0.87/3.76 -1.41/-0.74

PM2.5 RMSE unbiased 12.94/13.63 15.94/15.78 15.40/15.57 16.75/15.14 11.39/12.74 12.39/13.65 8.19/9.17

NO2 R NA 0.52/0.51 0.54/0.49 0.51/0.52 NA NA NA

NO2 MB NA 2.54/1.53 2.95/2.08 2.17/1.03 NA NA NA

NO2 RMSE unbiased NA 9.23/8.86 8.69/9.10 9.68/8.61 NA NA NA

Region

Not statistically different 0 % yellow 

CHRONOS better 43 % blue 

GEM-MACH better 57 % red 

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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

Ozone catégorie 80-160 ppb Juin-Juillet 2009

0,000

0,200

0,400

0,600

0,800

1,000

POD FAR CSI

CHRONOS

GEM-MACH15

Ozone catégorie 40-80 ppb Juin-Juillet 2009

0,000

0,200

0,400

0,600

0,800

1,000

POD FAR CSI

CHRONOS

GEM-MACH15

PM2.5 catégorie 15-30 ug/m3 Juin-Juillet 2009

0,000

0,200

0,400

0,600

0,800

1,000

POD FAR CSI

CHRONOS

GEM-MACH15

PM2.5 catégorie >30 ug/m3 Juin-Juillet 2009

0,000

0,200

0,400

0,600

0,800

1,000

POD FAR CSI

CHRONOS

GEM-MACH15

DRAFT – Page 21 – April 21, 2023

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

Thank you for your attention!