View
214
Download
0
Category
Preview:
Citation preview
Chemical transport modeling in support of NPS-CIRA activities
Mike Barna1
Marco Rodriguez2
Kristi Gebhart1
Bret Schichtel1
Bill Malm1
Jenny Hand2
1 ARD-NPS, Fort Collins, CO2 CIRA, Fort Collins, CO
June 16, 2011National Park ServiceU.S. Department of the Interior Cooperative Institute
for Research in the Atmosphere
Air quality models, generally speaking
• Air quality models are ‘transfer functions’ that convert emissions to impacts (concentration & deposition) at downwind receptors
• They are useful for…• Filling in gaps of unmonitored species• Developing source apportionments• Evaluating ‘what if’ scenarios• A component in a weight-of-evidence evaluation
• Want to employ current ‘state-of-the-science’ models in our work
Models used for regulatory work
puff models
near-fieldmodels
oneatmosphere
models
e.g., AERMOD
What are the peak exposure levels very
near a source?
e.g., Calpuff
What are the impacts from this powerplant
plume?
e.g., CAMx
What is the chemical state of the
atmosphere, and which sources influenced it?
complexity
How CAMx works
• CAMx treats the atmosphere as a big box (the ‘model domain’) which is then chopped-up into a bunch of little boxes.
• In each little box, the chemical evolution over time is evaluated, and once per hour the concentration and deposition of species is reported.
Things that CAMx can do (or try to do)
• Sulfate• Ozone• Oxidized nitrogen• Reduced nitrogen• Organics• Deposition• Wind blown dust• Toxics/mercury
easier
harder
Current modeling efforts
• Simulating oxidized and reduced nitrogen impacts at Rocky Mountain NP (RoMANS2)
• Examining the ‘carrying capacity’ of western US airsheds in terms of nitrogen deposition and ozone
• Air quality impacts from oil and gas development
• Fire impacts on regional ozone (DEASCO3)
Need a large-scale perspective
• Pollutants and precursors can travel 100’s – 1000’s kms before reaching a receptor
• Lots of things can happen en route:• Chemical transformation• Deposition
(Tong & Mauzerall, 2008)
The NPS – CIRA modelers
• Kristi Gebhart (NPS), Marco Rodriguez (CIRA), Mike Barna (NPS)
• Modeling hardware:• 30 Xeon cores• 60 GB memory• 50 TB storage
Two examples of current modeling
• Nitrogen deposition
• Ozone
Nitrogen deposition
11
• NH3: rapid deposition, NH3 NH4+, no gas-phase oxidation
• NOx: complicated photochemistry, HNO3 NO3-, some species rapidly deposit (HNO3, NO.)
NH3 NOx
Where does the nitrogen go?
12
CASTNet species:
example ‘missing N’ species:
Simulated nitrogen
13
NH4+
NO3
SO4=
NH3
HNO3
SO2
Beaver Meadows (RMNP) Grant, Nebraska
RoMANS CAMx results, April 2006
spring: summer:
Example CAMx apportionment (w/PSAT)
CAMx tracer runs
• Another apportionment tool is to treat emissions as conserved tracers, and then apply statistical models to indicate largest contributors
Estimated NH3 emissions in Brush, CO
Ozone
18(Jaffe & Ray, 2007)
Western ozone trends
Simulated 8hr ozone (2005)
Observed peak 8hr ozone (2004 – 2006)
(WRAP, 2010)
21
NOx emissions from O&G
22
Ozone impacts from oil & gas emissions
Ozone impacts from NGS NOx
National Park Peak hourly ozone impactfrom NGS (ppb)
Grand Canyon (Marble Canyon) 15Grand Canyon (Grand Canyon Village) 6Canyonlands 3Capitol Reef 7Bryce Canyon 5Zion 3Mesa Verde 2
Should we focus on VOCs or NOx?
HCHO
NO2
HCHO/NO2
HCHO and NO2 can be detected from the OMI satellite, and provide
‘indicator species’ to help assess whether a region is
VOC or NOx limited.
HCHO/NO2 > 1Suggests NOx limited
(Duncan et al., 2010)
Summary
• Established modeling group working on issues important to NPS, including nitrogen deposition and ozone
• It’s notable that several of our projects are linked to nitrogen emissions
• Future projects:• Climate change influence on regional air quality• Fire impacts
Recommended