gem-mach global the canadian global air quality modeling/forecasting system dr. sunling gong science...
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GEM-MACH Global The Canadian Global Air Quality
Modeling/Forecasting System
Dr. Sunling Gong
Science and Technology Branch
January 16-17, 2012
Page 2 – April 21, 2023
Outline
Introduction to Canadian AQ forecasting system: GEM-MACH;
System structure; Three major components;
emissions, gases and aerosols; Summary of applications.
Page 3 – April 21, 2023
"Multiscale" Examples:Three GEM Grid Configurations
globalregional
limited area
Page 4 – April 21, 2023
GEM-MACH - Structure
SMOKERegional DataCanada & US
SMOKERegional DataCanada & US
Gas PhaseChemistry
Gas PhaseChemistry
CAMCanadian Aerosol Module
CAMCanadian Aerosol Module
ISORROPIAEquilibrium Scheme
ISORROPIAEquilibrium Scheme
GEM
Mete
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Global Emissions
Global Emissions
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Global Emissions
Page 6 – April 21, 2023
NA anthropogenic42 km, hourly
CAN wildfires0.4 deg, hourly
EU anthropogenic
SA/EA anthropogenic0.4 deg, hourly/monthly
Implementation of Regional Gridded Emissions
Page 7 – April 21, 2023
GEM-MACH emission pre-processor
Combination of: - global emission inventories from EDGAR/MOZART (“background”) - continental/regional emissions from different sources (“AQ study domains”)
- Current global emission maps:- biomass burning, industrial, biogenic [EDGAR] (1)- fossil fuel [Cooke, 1999] (2)- biomass burning [Liousse, 1996] (2)
• Current regional emission maps:- Canadian wildfires (1)+(2)- boreal and temperate vegetation fires (1)+(2)- Canada and United States [AURAMS] (1)+(2)- Asian anthropogenic, biomass burning [ACE-Asia & INTEX B] (1)+(2)
(1) Gases, SO4, NO3; (2) BC, OC
Page 8 – April 21, 2023
North American Emissions
AREA (gridded emissions)
Inventories - CAN 2006- US 2005 - MEX 1999
Area emissions files contains - on road (cars, trucks, motorcycles, ...)
- off road (boat, train, construction vehicles, aircraft ...) - other types (agriculture, industries, ...)
Major points sources (none gridded emissions)
- more than 10 000 major points sources - stack height > 30 m for Canada - stack height > 35 m for US
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INTEX-B Area - Asia
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Global BC/OM emissions
Boreal and temperatewildland fires Fossil fuel use
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[Gong 2004, Monahan et al. 1986]
Emissions of Pollutants and Precursors – sea-salt
Page 12 – April 21, 2023Marticorena and Bergametti [1995]
Emissions of Pollutants and Precursors – soil dust
Ideal Threshold Friction Velocity
10Re 10Re0617.0exp0858.01129.0
10Re0.03
1Re928.1
129.0
)(5.0092.0
*
K
K
ru stS
1.56 0.38 cm 1331 )2(Re -X Xbabra Xs
5.0
4.2
5.0
)2(
006.01
2
spa
sp
rg
grK
Page 13 – April 21, 2023
• Roughness Roughness Marticorena and Bergametti [1995]
• Soil Moisture Soil Moisture Fécan et al. [1999]
Emissions of Pollutants and Precursors – soil dust
Threshold Friction Velocity
8.00
00**
/1035.0ln
/ln1)(
S
StSstR
z
zZuru
for 68.021.11
for 15.0*
*
wwww
ww
u
u
tR
t
Page 14 – April 21, 2023
r < 20 m
** uuR t
Marticorena and Bergametti [1995]
Emissions of Pollutants and Precursors – soil dust
Horizontal and Vertical Fluxes
Sr
SSrela
tot drrdSRRug
EG )(11 23*
6)(%134.010 claytotSD GF
Page 15 – April 21, 2023
Gas Phase Chemistry
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Gas-Phase Chemistry,
SOA formation
(ADOM-II Mechanism,Odum or Jiang SOA
approach,Vectorized Young&Boris
Algorithm)
Inorganic gas-phase processes usually included (Troposphere):
NO2 - NO - O3 cycle.
NO3 - N2O5 - HNO3 reactions (NOx Termination)
OH - HO2 - H2O2 cycle (including H2O path!)
HONO, HNO3, HNO4 formation and cycling
SO2, CO oxidation by OH
A look at some of these reactions:
Gas-phase chemistry mechanisms
Page 17 – April 21, 2023
Aerosols Dynamics
Page 18 – April 21, 2023
Aerosol Size Representations
•Flexible model structure•Multi-components Simulations•Physically based size distribution•Numeric diffusion for particle growth•Computational intensive (large bin no.)
•Flexible model structure•Computationally fast•Accuracy dependent on the form of the mode distribution functions•Pre-defined size distributions
Page 19 – April 21, 2023
Clear Sky Dynamics
Dry Deposition
O H , N O 3, O 3, H N O 3
G as C hem istry M odule
Sulphur Chem istry Nucleation Condensation Coagulation
Aerosol Dynam icsClear Sky
Aerosols CloudsAmbient size
rc
k[5,7]
Condensation
NucleationCoagulation
Gas H2SO4
Page 20 – April 21, 2023
Dry Deposition
•Land Use Category[EDC DAAC, 11 km]
•15 Surface Types
•ADOM Scheme
•SO2[Padro et al 1991]
Gases
•Two-layer Scheme•Dry dep. for surface layer•Sedimentation for all layers [Zhang et al., 2000]
Particles
Dry Deposition and Sedimentation
Page 21 – April 21, 2023
Wet Processes
Page 22 – April 21, 2023
Key Features
• Major smog components:CO, O3, SO2, NOx, NOy, PAN
• PM (aerosol) components:Sulphate, Black carbon, Organic Carbon,
Soil dust, Sea-salt and Nitrate PM2.5 and PM10
AOD – aerosol optical depth
Page 24 – April 21, 2023
• GEM Version– DM v 3.3.0
– PHY v 4.5
• Vertical 58 layers up to 0.1 hPa
• Horizontal resolution 2 2 • Time step – 30 min
• Year: 2010
GEM Configurations
Page 25 – April 21, 2023
CUACE/Dust
Data Assimilation
SDS Observations
拟建区域本底站
已建本底站
沙尘暴一期站点
中韩合作沙尘暴站点
拟建区域本底站
已建本底站
沙尘暴一期站点
中韩合作沙尘暴站点
lidar
Ground Obs.
SatelliteFY-2c
Gong and Zhang 2007, ACP
Dust Aerosol Assimilation
Page 26 – April 21, 2023
Comparisons of CUACE/Dust forecasting results for 10 April 2006 with and without data assimilation. The symbols of “S”, “$”, “§”, “&” indicate floating dust, blowing dust, SDS, severe SDS, respectively, obtained from surface meteorological stations of CMA
SDS Assimilation Results
Page 27 – April 21, 2023
Five Day Forecasts•Results Online to be downloaded:
–Gases:
CO, O3, SO2
–Aerosol Species
PM10, PM2.5
Sulphate PM10 & PM2.5
Soil Dust PM10 & PM2.5
•More offline results available
Page 28 – April 21, 2023
Types of Results online
•Surface and 850 hPa concentrations;
•Cross section at three longitudes to track the vertical transports along the Pacific;
•Point vertical profiles to compare with station observations.
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Data Fusion on O3 SimulationsJoshua Tree [34.08oN, 116.39oW]
Ozone Concentrations (ppbv)
0 200 400 600 800 1000 1200 1400 1600 1800
Alt
itu
de
(km
)
0
5
10
15
20
OzonesondeGEM-MACH GlobalMonthly Haloe MeanGMG-Rerun1 GMG-Rerun2 New Strato O3 D. Tarasick
Page 34 – April 21, 2023
Data Fusion on O3 Simulations
Point Sur [36.30oN, 121.89oW]
Ozone Concentrations (ppbv)
0 500 1000 1500 2000
Alt
itu
de
(km
)
0
5
10
15
20
OzonesondeGEM-MACH GlobalMonthly Haloe MeanGMG-Rerun1GMG-Rerun2New Strato O3 D. Tarasick
Page 35 – April 21, 2023
O3 Reduction due to 20% Cuts in NOx and VOC in Asia (annual average)
Page 36 – April 21, 2023
Future Work
Page 37 – April 21, 2023
GEM-MACH Global Futures
• Evaluations against observations: surface, satellites;
• Interfaced with regional GEM-MACH to provide boundary and initial conditions;
• Data assimilation capacity for a better forecast;
• More ......
Page 38 – April 21, 2023
Thanks!