Air Quality Forecasting for Mexico City Metropolitan Area

1
Air Quality Forecasting for Mexico City
Metropolitan Area
Benjamin de Foy, MIT Luisa Molina, Mario Molina,
MIT First Air Quality Forecasting Workshop for
the GURME Latin American Project 13-16 October,
2003, Santiago, Chile Faculty of Physical and
Mathematical Sciences, University of Chile

• Operational Forecasts for MCMA2003 Field
  Campaign
• Meteorology
• Trajectories
• Photochemistry
• Comparisons Analysis

2
Requirements

• What Cloud and Rain Events do we Expect?
• Where will the Ozone Plume be?
• Periods Of Interest (POI)
• Areas of Influence for Emissions Mapping
• 3 Day Forecast Including Same Day Prediction

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System Description
Global Model - AVN
SMN National Forecast Global Models Satellite
Imagery Raob Soundings Surface Observations
Regional Model - MM5
Pre-Processor - CALMET
Photochemistry CIT
Trajectories
RAMA Forecast
Campaign Briefing
4
System Implementation

• Modular Architecture
• Platform Independent / Model Independent
• Perl Scripts for Execution, Matlab Scripts for
  Post-Processing
• NARSTO DES Format for Time Series Data,
  converted to NetCDF
• NetCDF Format for 2D 3D Data ( COARDS
  Conventions)

forecast2003.pl
Setup MM5
Run MM5
proc2003.pl
MM5 to CIT
Post-Process MM5
Trajectories
Run CIT
Post-Process CIT
Create Web Page
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MM5 Domains 1, 2 3
Domain Sizes D1 60 x 60, 27km D2 34 x 34,
9km D3 61 x 52, 3km 23 Vertical Levels
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Real-Time Internet Forecast
72 Hour Forecast Initialised with 00Z AVN at 00
CST Automatic Posting of Forecasts
to http//neza.mit.edu Same Day Forecast ready
at 530am, Local Time 2nd and 3rd Forecasts ready
at 730 and 900am Example 14th April 2003
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Mexico City Plume6am-6pm emissions, colored by
emission time
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MM5 Domain 3 Surface Wind Vectors
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MM5 Domain 3 Surface Wind Vectors
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MM5 Domain 3 Total Column Cloud Water
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MM5 Domain 3 Total Column Cloud Water
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CENICA Back Trajectories by Time of Day
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Maximum Forecasted Ozone
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3 Day Forecast Summary O3 Backtrajectories
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MM5 Evaluation
MM5 Bias vs. 5 SMN Met Stations in
Basin Bias Mean Obs Wind Speed -0.39
m/s 2.4 m/s Temperature -3.32 20 Relative
Humidity 20 42
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Mixing Heights Radiosonde/MM5
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CENICA April 2003 Obs vs. Model Wind Roses
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CENICA April 2003 Wind Speed by Time
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CENICA April 2003 Model Wind Speed by Time
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RAMA vs. CIT Maximum O3 Contours
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Ozone Forecasts at La Merced RAMA measurements
vs. CIT model CAM-MIT Field Campaign 8-24th
February 2002
(Model runs did not account for rain/clouds,
hence the large discrepancies on Feb
8,12,13,22,23)
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Conclusions

• Meteorological Forecasts on the Urban Scale
• Daily 3 day forecasts of Ozone
• Simple / Portable System Model Independent
• Trajectories show Areas of Influence Residence
  Times
• Good Qualitative Behaviour
• Needs Human Forecaster for Interpretation!