Carey Jang, Pat Dolwick, Norm Possiel, Brian Timin, Joe Tikvart U.S. EPA Office of Air Quality Planning and Standards (OAQPS) Research Triangle Park, North Carolina Applications and Evaluation of Applications and Evaluation of USEPA’s Models-3/CMAQ System: From USEPA’s Models-3/CMAQ System: From Regional and Urban Air Pollution to Regional and Urban Air Pollution to Global Climate Change Global Climate Change
Transcript
Slide 1
Carey Jang, Pat Dolwick, Norm Possiel, Brian Timin, Joe Tikvart
U.S. EPA Office of Air Quality Planning and Standards (OAQPS)
Research Triangle Park, North Carolina Applications and Evaluation
of USEPAs Models-3/CMAQ System: From Regional and Urban Air
Pollution to Global Climate Change
Slide 2
OUTLINE b Overview of USEPAs One-Atmosphere Models-3/CMAQ
Modeling System b Applications and Evaluation of Models-3 /CMAQ
System b OAQPS Modeling Initiative on Intercontinental Transport
and Climatic Effects of Pollutants
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Third-Generation Air Quality Models: U.S.EPAs Models-3/CMAQ
System Open-Access Community-Based Models : User-friendly, Modular,
Common modeling framework for scientists and
policy-makers.User-friendly, Modular, Common modeling framework for
scientists and policy-makers. b Advanced Computer Technologies :
High performance hardware and software technologies
(Cross-platform, GUI, distributed computing, visualization tools,
etc.).High performance hardware and software technologies
(Cross-platform, GUI, distributed computing, visualization tools,
etc.). b One-Atmosphere Modeling : Multi-pollutant (Ozone, PM,
visibility, acid deposition, air toxics, etc.),
Multi-scale.Multi-pollutant (Ozone, PM, visibility, acid
deposition, air toxics, etc.), Multi-scale.
Acid Rain (NO 3 - deposition) Water Quality (Nitrogen
deposition, Lake Acidification) NO x Visibility (Fine PM) (NOx +
VOC + hv) --> Ozone (NO 3 -, NH 4 + ) PM NO x -Related Air
Quality Issues
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Acid Rain ( SO 4 2- deposition) SO x (Fine PM) Visibility (SO 4
2-, NH 4 + ) PM SO x -Related Air Quality Issues Water Quality
(Lake acidification, Toxics deposition)
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Air Toxics Ozone Acid Rain Visibility PM 2.5 WaterQuality. OH.
OH role in pollutants formation : One-Atmosphere NOx + VOC + OH +
hv ---> O 3 SOx [or NOx] + NH 3 + OH ---> (NH 4 ) 2 SO 4 [or
NH 4 NO 3 ] SO 2 + OH ---> H 2 SO 4 NO 2 + OH ---> HNO 3 VOC
+ OH ---> Orgainic PM OH Air Toxics (POM, PAH, Hg (II), etc.)
Fine PM (Nitrate, Sulfate, Organic PM) NOx + SOx + OH (Lake
Acidification, Eutrophication)
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Example of One-Atmosphere Modeling Impact of 50 % NOx Emission
Reduction on PM 2.5
Impact of 50% NOx emission reduction O 3 decrease HOx
decrease
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Formation of Secondary PM : Sulfate PM formation: H 2 SO 4 + 2
NH 3 ---> (NH 4 ) 2 SO 4 (s) Gas Phase: O 2,H 2 O SO 2 + OH
---> H 2 SO 4 Aqueous Phase: H 2 O SO 2 + H 2 O 2 ---> H 2 SO
4 (Dominate over low pH) SO 2 + O 3 ---> H 2 SO 4 Nitrate PM
formation: HNO 3 + NH 3 NH 4 NO 3 (aq,s) Gas Phase : (daytime) NO 2
+ OH ---> HNO 3 Gas &Aq Phase : (nighttime) N 2 O 5 + H 2 O
---> HNO 3 Oraginc PM formation: Gas Phase : VOC + OH --->
Organic PM (semi- volatile) (Long-chain VOCs, Aromatics, Biogenic
VOCs)
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Impact of 50% NOx emission reduction O 3 decrease HOx
decrease
O 3 Episode in the Northeast U.S. (7/12-15, 1995) Nested 4 km
grid domain (144 x 147 cells)
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Measurement Sites and Terrain Features (Courtesy of USEPA/ORD,
Daewon Byun)
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Model Predictions vs. Observations
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Models-3/CMAQ Applications at EPA/OAQPS b Western U.S.
Application Episodic O 3, July 96, 36/12 km, Evaluation completed b
Annual Nationwide U.S. Application 1-atmosphere, annual 1996,
36-km, evaluation & diagnostics, on-going annual 2000 b Eastern
U.S. Application 1-atmosphere, July 95, urban applications,
36/12/4-km, emissions control & growth b Intercontinental
Transport/Air Quality & Climate Change Intercontinental
transport and climatic effects of air pollutants
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12 km western US ozone domain 36 km western US ozone domain 36
km eastern US domain Models-3/CMAQ Modeling: Domain Maps 36 km
Annual National US domain 12 km domain 4 km domain
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Western U.S. Application b Objectives : New M3/CMAQ Domain New
Episode (July 1996) b Model Setup : Episodic O 3 modeling
Meteorology : MM5 Emissions : Tier-2 regridded 36km/12km, 12 layers
Compared against UAM-V 177 153
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ModeledObserved
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Chem Diffusion O 3 Conc. dO 3 /dt Process Contribution to O 3
(ppm / hr) O 3 Conc. and Trend ( ppm & ppm / hr) Time Step
(7/19 - 7/31/96) Process Analysis : (Los Angeles grid)
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Western U.S. CMAQ Ozone Modeling
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BEIS3 Sensitivity Testing -- Western U.S.
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Annual Nationwide U.S. Application b Features : Annual CMAQ Run
Nationwide CMAQ Domain b Model Setup : Annual PM and O 3 (1996)
36-km, 8 vertical layers Meteorology : MM5 Emissions Processing:
SMOKE Model Evaluation: Compared against observed data (IMPROVE
& CASTNET) & REMSAD
National 1996 CMAQ Modeling: CB4 vs. RADM2 Nitrate PM (Jan.
1996)
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Formation of Secondary PM : Sulfate PM formation: H 2 SO 4 + 2
NH 3 ---> (NH 4 ) 2 SO 4 (s) Gas Phase: O 2,H 2 O SO 2 + OH
---> H 2 SO 4 Aqueous Phase: H 2 O SO 2 + H 2 O 2 ---> H 2 SO
4 (Dominate over low pH) SO 2 + O 3 ---> H 2 SO 4 Nitrate PM
formation: HNO 3 + NH 3 NH 4 NO 3 (aq,s) Gas Phase : (daytime) NO 2
+ OH ---> HNO 3 Gas &Aq Phase : (nighttime) N 2 O 5 + H 2 O
---> HNO 3 Oraginc PM formation: Gas Phase : VOC + OH --->
Organic PM (semi- volatile) (Long-chain VOCs, Aromatics, Biogenic
VOCs)
OAQPS Modeling Initiative on Intercontinental Transport and
Climatic Effects of Air Pollution
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Background : b O 3 and PM are not only key air pollutants, but
also major climate- forcing substances; b Reduction of non-CO 2
substances (e.g., O 3 and PM, especially black carbon) could be a
viable alternative to CO 2 reduction to curb global warming. A key
strategy suggested was to focus on air pollution to benefit
regional and local air quality and global climate simultaneously
(Hansen et al., PNAS, 2000); b Black carbon could be the second
largest heating component after CO 2 contributing to global
warming; Control of fossil-fuel black carbon could be the most
effective method of slowing glabal warming (Jacobson, Nature,
2001); Air Pollution/Climate Change Modeling Initiative
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(Hansen et al., PNAS, 2001) Climatic Effects of Air Pollution O
3 (0.3+0.1) Black (0.8) Carbon
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Background (continued): b There is also mounting evidence that
criteria pollutants originating from some developing countries,
especially those in Asia such as China and India, could impact U.S.
domestic air quality as well as contribute to the global background
of climate-forcing substances. This intercontinental transport
issue is expected to worsen with the rapid growth in emissions in
these regions. b For example, recent modeling studies showed that
by 2020 Asian emissions could contribute as much as 2 ~ 6 ppb of O
3 in the western U.S., offsetting the Clean Air Act efforts up to
25% in that region (Jacob et al., Geophys. Res. Letts., 1999) and
increase global mean O 3 level up to 10% (Collins et al., Atmos.
Env., 2000); Asian and Sahara dust could contribute a significant
amount of PM in the western and southeastern U.S. (Husar,
http://capita.wustl.edu/CAPITA/).http://capita.wustl.edu/CAPITA/ !
Air Pollution/Climate Change Modeling Initiative
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(4/7) Asian Dust Storm Event: April 2001 (NASA/TOMS) (4/9)
(4/11)(4/12) (4/13)(4/14)
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(Byun and Uno, 2000) Transport of CO : March 2000 (NASA/MOPITT)
(3/10) (3/12) (3/13) (3/15)
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Objectives : b To assess available approaches for evaluating
the linkage of air pollution to climate change and enhancing
modeling capacity within EPA to address these linkage issues. b To
explore the impacts of intercontinental transport of O 3 and PM as
well as their implications for US domestic and regional air quality
and global climate change b To design integrated emissions control
strategies to benefit global climate and regional and local air
quality simultaneously Air Pollution/Climate Change Modeling
Initiative
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Work Plan : Phase I : Short-Term (~6 months) b Establish a
better scientific foundation to address the issues related to
intercontinental transport and climatic effects of air pollutants
by leveraging current studies 1. Global Modeling of O 3 and PM 2.
Global Radiative Forcing of Aerosols 3. Emission Inventories for
Climate-Forcing Pollutants b Hold a Workshop on Air Quality and
Climate Change and establish an expert advisory panel to provide
guidance in developing a conceptual model and modeling protocol for
Phase II work. Air Pollution/Climate Change Modeling
Initiative
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Work Plan : Phase II - Long-Term (~2 years) Based on Phase I
effort, a series of activities will be conducted. These efforts may
include, but not limited to: 1. Support continued development of
global and regional modeling capabilities for studying
policy-relevant climatic effects of air pollution and the impacts
of intercontinental transport 2. Improve global and regional
emission inventories for global and regional modeling of O 3 and PM
3. Develop nesting capability between global chemistry/climate
models and regional air quality models 4. Simulate hemispheric or
regional air quality under a variety of current and future global
and regional emission scenarios 5. Evaluate global and regional air
quality models using a diverse set of observational data sets,
including data from satellites, surface networks, intensive field
studies, etc 6. Assessment of the potential radiative forcing and
climate benefits resulting from planned and alternative non-CO2
control strategies Air Pollution/Climate Change Modeling
Initiative
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(Byun and Uno, 2000) (MCNC, 2000) 3D Tracer from Gobi
DesertTrans-Pacific O 3 simulation Air Pollution/Climate Change
Modeling Initiative
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1. Support continued development of global and regional
modeling capabilities for studying policy-relevant climatic effects
of air pollution and the impacts of intercontinental transport Are
there existing global/regional models that can be practically used
for the assessment of these two issues simultaneously? If not,
which models are better for addressing the climatic effects of air
pollution (global climate/chemistry model)? Which are better for
addressing the impacts of intercontinental transport (global
chemistry/regional air quality models)? 2. Improve global and
regional emission inventories for global and regional modeling of O
3 and PM Are current global and regional EI sufficient for O 3 and
PM modeling? If not, what are the weaknesses of exising
regional/global EI? O 3 and PM precursors (NOx, SOx, VOC, NH 3,
etc.), black carbon? Geographic distribution (Asia, America,
Europe?) and resolution (global, regional, and urban)? Source
categories (biomass burning, biogenic emissions, domestic,
mobile/point/area sources, etc.)? EI modeling tools to convert EI
to data needed for modeling? Charge Questions
Slide 59
3. Develop nesting capability between global chemistry/climate
models and regional air quality models Are the chemical boundary
conditions sufficiently represented in regional air quality models?
Do global models have sufficient resolution to address regional
impacts? Is grid-nesting between global and regional models a good
approach to bridge these gaps? 4. Simulate hemispheric or regional
air quality under a variety of current and future global and
regional emission scenarios What current and future scenarios are
to be simulated? Emissions sensitivity scenarios (NOx, SOx, VOC,
BC, CH 4, etc.)? Source categories sensitivity scenarios (fossil
fuel, transportation, biomass burning, etc.)? IPCC & LRTAP
emission scenarios? Climate change scenarios? Energy use scenarios?
Charge Questions
Slide 60
5. Evaluate global and regional air quality models using a
diverse set of observational data sets What data sets are available
for evaluating the model results? Satellite and spacecraft? Surface
network? Remote/Sentinel monitoring stations? Special field
studies? How to effectively use the observed data to evaluate
against the model results? 6. Assessment of the potential radiative
forcing and climate benefits resulting from planned and alternative
non-CO2 control strategies Can global climate models be used to
estimate the climate-forcing effects of air pollutants? How to
account for the photochemistry of O 3 and PM? Can regional air
quality models be used to estimate the climate- forcing effects How
to translate changes in pollutant concentrations to climatic-
forcing? Can we assume changes in pollutant concentration is linear
to changes in radiative properties? How to extrapolate from
regional-/hemispheric-scale modeling results to global-scale
climate change? Charge Questions