# Presentation: 546614

## Development of a New Canadian Operational Air Quality Forecast ModelGEM-MACH

- Sylvain Ménard
- Air Quality Models Applications Section
- and the GEM-MACH team

- www.ec.gc.ca

- 2007 National Air Quality Conferences: Air Quality Forecasting,
- Mapping, and Monitoring and Communicating Air Quality and Communities in Motion
- February 11-14, 2007. Royal Plaza Hotel, Orlando, Florida

## PLAN

**PLAN**
**GEM-MACH project objective**
**History of the National Air Quality Forecast Program in Canada**
**GEM-MACH grid/configuration **
**GEM-MACH emissions package**
**GEM-MACH chemistry package **
**Model evaluation**

- Air Quality Modelling Applications GroupCanadian Meteorological CentreMeteorological Service of Canada

## GEM-MACH

**G****lobal ****E****nvironnemental ****M****ulti-échelle modèle –**
**M****odélisation de la qualité de l'****A****ir et de la ****CH****imie**
_**And**_
**G****lobal ****E****nvironmental ****M****ultiscale model – **
**M****odelling ****A****ir quality and ****CH****emistry**

***“******GEM-MACH” stands for***

## GEM-MACH project 

**Project objective**
- 	“Late 2007, to **replace** the current Canadian operational air quality forecast model CHRONOS (Ozone, PM2.5, PM10.0, AQHI) by GEM-MACH. The chemistry library in GEM-MACH will be superior to the one in CHRONOS with a _**better representation of fine particles**_**.**
**Project approach**
- Chemistry and emissions packages will be _embedded in the GEM meteorological model. _
- 	         -_**on-line chemistry**_
- Chemistry package will benefit from GEM infrastructure
- 	- Message Passing Interface (_**MPI**_) capable”
- 	- GEM-MACH will be able to use the full power of the supercomputer architecture.
**Note: **
- 	- CHRONOS is an _**off-line chemistry**_ model.
- 	- The code is _**not using MPI**_ technology (can’t run with more than 16 CPU)

## National AQ forecast program in Canada

**History of the National Air Quality Forecast Program in Canada**** **
**Summer 1999****: **_**Pilot**__ Air Quality Forecasting Program_ for eastern Canada
- 	 Limited to ground-level ozone (21 km spatial resolution)
**Summer 2001****: **_**Operational **__Air Quality Prediction Program_ extended to all subarctic Canada (public)
**Summer 2002:**** **
** **Introduction of _bulk aerosol scheme in __**experimental**__ CHRONOS_ version
** **

## National AQ forecast program in Canada

**History of the National Air Quality Forecast Program in Canada**
**Summer 2003:**
- Implementation of _bulk aerosol scheme in __**operational**_ CHRONOS version (public)
_**Experimental**__ Objective Analysis of ground-level ozone_
-  **Summer 2004 - 2005:**
-  Continuation of ozone and PM operational AQ forecasts
**February 2006:**
- Beginning of the development of GEM-MACH project
**Late 2007:**
_**GEM-MACH to replace CHRONOS**_** for operational AQ forecast**.

## GEM-MACH grid

- GEM-MACH vs CHRONOS modeling domain

**CHRONOS**

**GEM-MACH**

- GEM-MACH
- 465x400
- dx=15km
- CHRONOS
- 350x250
- dx=21km

## GEM-MACH vs CHRONOS config

|  | CHRONOS | GEM-MACH | Better AQ forecasts with GEM-MACH? |
| --- | --- | --- | --- |
| 
Grid projection | 
Polar stereographic | 
Rotated (lat,lon) |  |
| 
Grid configuration | 
Limited area (LU) | Global uniform (GU)
Limited area (LU) | Address regional and global scale  |
| 
Model  horizontal resolution | 
21 km  | 
15 km | Better representation of dyn. and phy. HI-RES topography will lead to better (UU,VV,WW) |
| 
Model time step | 
3600 s | 
450 s | Better representation of winds (eg: frontal system) and clouds lifetime, etc. |
| 
Model top  | 
6 km | 
10 mb (~30 km)
 | Better resolution of vertical process (convection, diffusion,..) |

## GEM-MACH vs CHRONOS config

|  | CHRONOS | GEM-MACH | Better AQ forecasts with GEM-MACH? |
| --- | --- | --- | --- |
| 
Vertical coordinate
(terrain following) | 
Gal-chen (24 levels) | 
Hybrid (58 levels)
 |  |
| 
Statistical tool | 
Updateable Model 
Output Statistics (UMOS)
(in testing mode) | 
Updateable Model 
Output Statistics (UMOS) 
 | 
Better O3 and PM2.5 forecasts at specific locations |

- New Supercomputing Facilities
- (more than 1000 CPU units)

## GEM-MACH emissions

| Anthropogenic Emissions 
Processing System | Tools / database |
| --- | --- |
| Emissions inventories | US 2001, CAN 2000, MEX 1999
(Canadian NPRI and US-EPA) |
| Emissions processing system | SMOKE v2.2 (run off-line)
   - Major points sources (non-gridded)
   - Area emissions (gridded) |
| Surrogate processing | UNC spatial surrogate tools v1.1
   - Vectorial data (shapefile)
   - E-Grid (GEM-MACH rotated lat,lon)  |
| GIS  | QGIS, SPI  |

## GEM-MACH emissions

| Biogenic Emissions 
Processing System | Tools |
| --- | --- |
| Biogenic Emission Inventory System | BEIS v3.0.9 (emissions factors from v3.1.2)
Species (NO, VOC, isoprene, monoterpene) |
| Biogenic Emission Landuse database | BELD3+2000 Canadian National Forest Inventory
Note: Biogenic emissions are generated on-line in GEM-MACH at each model timestep (air temperature, radiation, cloud cover ...) |

- Biogenic
- Isoprenes (g/s)
- 15 km resolution
- on GEM-MACH grid
- (but using USGS categories)

## GEM-MACH chemistry

| CHARACTERISTIC / MODEL  | CHRONOS  | GEM-MACH  |
| --- | --- | --- |
| Meteorological Driver  | GEM (off-line)  | GEM (on-line)  |
| PM Size Distribution Representation  | Sectional method (2 bins:  PM2.5 and PMc)  | Sectional method (flexibility to allow different number of size bins (2-12) based on Canadian Aerosol Module (Gong et al., 1997a,b, 2000)  |
| PM Composition Representation  | 4 species: sSO4, sOC, H2O, primary PM  | 9 species: SO4, NO3, NH4, EC, pOC, sOC, CM, SS, H2O  |
| Emissions  | PM2.5 and PMc emission are assumed to be bulk emissions (no speciation, no further size disaggregation); 17 gas-phase species emitted  | PM2.5 and PMc emissions speciated to 7 species and size disaggregated to 2-12 bins by primary source type (major and minor point, area, mobile); 17 gas-phase species emitted  |
| Advection  | Positive-definite, nonoscillatory, semi-Lagrangian method (Smolarkiewicz and Pudykiewicz, 1991)  | Semi-Lagrangian method (Côté et al, 1993...) |
| Vertical  Diffusion  | Based on prognostic equation for TKE with the values of the vertical diffusion coeff. derived from GEM  | Based on prognostic equation for TKE  |
| Subgrid Convective Mixing  | Not included  | Not included  |

## GEM-MACH chemistry

| CHARACTERISTIC / MODEL  | CHRONOS  | GEM-MACH  |
| --- | --- | --- |
| Gas-Phase Chemistry Mechanism

Chemical Solver

Photolysis  | ADOM-2 mechanism (Stockwell and
Lurmann, 1989); 47 advected species

Vectorized version of Young and Boris (1977): Makar (1995)
Table lookup  | ADOM-2 mechanism (Stockwell and
Lurmann, 1989) with
1) p-SO4 replaced by H2SO4, 
2) N2O5 + H2O “heterogeneous nitrate
formation” rate enhancement switch=off.

Vectorized version of Young and Boris
 (1977): Makar (1995)
Table lookup  |
| Aqueous-Phase Chemistry Mechanism

Solver  | None  | Based on ADOM mechanism (Young
and Lurmann, 1984); nucleation scavenging reactions replaced by explicit particle activation; 20 reactions, 7 gas and 13 aqueous species (Gong2001)

Vectorized Young & Boris (based on Makar, 1995)  |
| Aerosol Dynamics  | Sedimentation  | Nucleation, Condensation
Coagulation, Sedimentation  |
| Heterogeneous Chemistry  | HETV (vectorized inorganic heterogeneous chemistry based on the [Halogens excluded] ISORROPIA metastable option). | HETV (vectorized inorganic heterogeneous chemistry based on the [Halogens excluded] ISORROPIA). |

## GEM-MACH chemistry

| CHARACTERISTIC / MODEL  | CHRONOS  | GEM-MACH  |
| --- | --- | --- |
| Secondary Organic (SOA) Yields  | Based on Pandis et al. (1992)  | IAY scheme Based on Jiang (2004)  |
| Cloud (Physical) Processes  | Cloud attenuation and enhancement photolysis rates, based on ADOM algorithm.  | Cloud attenuation and enhancement photolysis rates, based on ADOM algorithm. 
1) Aerosol activation (based on Jones et al., 1994)
2) Droplet scavenging of interstitial aerosol  |
| Dry Deposition  | New resistance-based methods for gases (Zhang et al., 2002)) and size-segregated model for particles (Zhang et al., 2001); 15 land-use categories.  | New resistance-based methods for gases (Zhang et al., 2002)) and size-segregated model for particles (Zhang et al., 2001); 15 land-use categories  |
| 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 particles size dependant and soluble.  |
| Initialization  | Fixed initial conditions (cold start)
From previous run (warm start)  | Fixed initial conditions (cold start)
From previous run (warm start)  |
| Chemical boundary conditions  | zero gradient inflow, open boundary out-flow  | climatological profiles  |

## Model evaluation and validation

**Model evaluation/validation**
**Goal:**  	_GEM-MACH to replace the current operational AQ forecast model CHRONOS_ after a formal 	evaluation/validation procedure through CPOP (**C**omité des **P**asses **O**pérationnelles et **P**arallèles, “CMC 	operational and parallel runs committee”)
**Risk:** 	GEM-MACH must give better AQ forecasts than CHRONOS and/or _must show gains or advantages _	_over the older system_
***a) ******	******Preliminary model evaluation***
- -	Build an independent quality assurance team separate from the development team to evaluate the model and to test different model configurations.
- -	Evaluate GEM-MACH model against intensive AQ measurement campaigns
- 	(e.g., ICARTT 2004, Pacific 2001, ...).
- Run GEM-MACH in real-time on a daily basis to produce a 48-hour forecast of O3/PM2.5.
- Compare model output against hourly observations for ozone and PM2.5 coming from
-        AIRNOW (US EPA database of Canadian and U.S. measurements ).
- -	Compare GEM-MACH vs CHRONOS performance.

## Model evaluation and validation

**Model evaluation/validation**
***b) Formal model evaluation/validation***
- - Preparation of a GEM-MACH operational model configuration setup.
- - CPOP proposal preparation and presentation to CMC Operations
-    (based on preliminary model evaluation results)
- - Preparation of a GEM-MACH parallel run by CMC Operations
- - _Both GEM-MACH and CHRONOS will be run by A&P (Analysis and Prognosis Division)_
-   _on a daily_ _basis over a long period of time (months)._
- - Obtain subjective and objective verifications to justify the replacement of CHRONOS by
-   GEM-MACH. GEM-MACH _must show gains or advantages over the older system_.

## www.ec.gc.ca