Impact of Mexico City on Regional Air Quality

1
Impact of Mexico City on Regional Air Quality

• Louisa Emmons
• Jean-François Lamarque
• NCAR/ACD

2
Chem-Climate WG White Paper

• Hemispheric pollution to regional air quality An
  issue of resolution
• Louisa Emmons, Lyatt Jaegle, Loretta Mickley
• Scientific advances to be accomplished within
  this project
• 1) Improved understanding of feedbacks between
  climate change and air pollution effects of
  changing temperatures/precipitation/water vapor
  on chemistry, effects of changing emissions
  (biogenic NOx and VOC, lightning NOx, biomass
  burning, anthropogenic emissions), effects of
  changing meteorology (synoptic and hemispheric
  scales, stratosphere-troposphere exchange).
• 2) Improved understanding of feedbacks between
  climate change and export of pollution to the
  global atmosphere will a warmer climate lead to
  more efficient export of pollution? How will it
  affect the long-range transport of pollution?
• 3) Improved understanding of the horizontal
  resolution needed to accurately predict the
  influences of future climate change on regional
  air quality and vice versa, through the use of
  the Weather Research and Forecasting (WRF) model
  in conjunction with CAM.
• 4) Exploration of the possibility of downscaling
  global simulations for analysis of regional air
  quality.

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MILAGRO

• March 2006
• Comprehensive set of measurements from city to
  regional scales

INTEX-B - NASA - DC-8 based in Houston MIRAGE-Mex
- NSF - C-130 based in Veracruz ground
measurements MAX-Mex - DOE - G1 MCMA - Molina
Center - surface and mobile lab
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Model Simulations

• Meteorology NCEP/GFS analyses (42 levels)
• Emissions
• anthropogenic POET-2000 and Mexico NEI (1999)
• biomass burning GFED-2 and C. Wiedinmyers
  N.America calculations (MODIS daily fire counts)
• MOZART-4
• T42 (2.8)
• T85 (1.4)
• T170 (0.7)
• CAM-Chem
• 0.47x0.63

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Model EvaluationComparison to C-130 measurements
- all flights binned by altitude
Mexico City points

• Finer resolution generally matches observations
  better

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Model Evaluation Comparison to surface
measurements (T1)
O3 ppbv
CO ppbv
Acetone ppbv
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Ozone from Mexico City - March 2006

• NO emissions from Mexico City are tagged to
  quantify O3 production
• Average over March 2006, surface to 400 hPa
• T85 has higher concentrations over Mexico City,
  but not larger regional impact

NO emissions
POET emissions inventory
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March 19 strong outflow event

• T85 - higher O3 throughout plume than T42
• CAM-Chem - higher O3 over city but weaker plume
• C-130 data will be used to evaluate

2.8
1.4
0.5
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Radiative forcing of Mexico City emissions

• CAM-Chem, 0.47x0.63 resolution, driven by
  NCEP-GFS winds

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CAM-Chem/DART in support of ARCTAS

• Arctic Research of the Composition of the
  Troposphere from Aircraft and Satellites (ARCTAS)
  
• NASA aircraft campaign coincident with NOAA and
  DOE experiments
• Part of POLARCAT/IPY
• April - Fairbanks - Arctic haze, surface halogen
  chemistry
• July - near Edmonton - Boreal wildfires

Chemical Forecasts EnKF Data Assimilation met
obs, MOPITT CO, MODIS AOD Then free-running
forecasts (5 days) for flight planning Post-campa
ign Analysis Evaluate and improve
CAM-Chem Interpret aircraft and satellite
observations