WRFChem-GOCART

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WRFChem-GOCART

• Qian Tan, Mian Chin
• UMBC, GSFC

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Our Goal

• Impacts of emissions and long-range transport on
  regional air quality
• Dust, aerosol, and other pollutants.
• Using global-regional atmospheric modeling system
• Impacts of aerosols on climate
• Aerosol and radiation
• Aerosol and cloud
• Aerosol and water cycle

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GOCART WRF-Chem
Temporal resolution 20 minutes Daily, monthly, seasonally, yearly, interannual Few minutes Short-term, episode
Spatial resolution Global 2x2.5 or 1x1.25 degree Finer in next generation Regional Flexible Few kilometers and up
Processes Emission, transport, deposition, and chemistry/evolution. Emission, transport, deposition, and chemistry/evolution.
Species Sulfate, black carbon, organic carbon, dust, sea salt. More detailed speciation and size distribution
Required Met fields Prescribed Chem fields Emission inventory Met Chem BC Full chemistry Emission inventory
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Working Plan

• Setup WRF, WRF-Chem
• Model validation
• Update WRF-Chems aerosol module based on GOCART,
  and using it as the initial and boundary
  conditions.
• Addressing scientific questions.
• Provide aerosol distributions (various
  resolutions) to this community

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WRF Chem

• Model set up
• Default settings
• RADM with MADE/SORGAM
• Eastern United States
• Reliable detailed emission inventory
• Observations
• Meteorological and chemical species
• Ground based and space based
• Summer 2004
• An intensive aircraft observation campaign.

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Model Domain
Surface Elevation
Rough elevation at boundary
Domain 3600km x 3000km, Grid 30 km x 30 km,
Lambert projection.
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Snapshots of WRFChem Simulation
SO2
CO
NO2
0.1 0.2 0.4 0.6 0.8 1 1.5 2 ppm
0.002 0.005 0.01 0.015 0.02 0.03 0.04 0.05
ppm
O3
0.002 0.005 0.01 0.015 0.02 0.03 0.04 0.05
ppm
0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 ppm
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PM 2.5
SO4_Aitken
SO4 _Accum
EC_Aitken
EC_Accum
0.05 0.1 0.5 1 2 3 5 10 ug/g
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Chemical Observations

• EPA (ground based observations)
• Good spatial and temporal coverage
• 200 sites for CO, 400 sites for SO2.
• Continuously hourly data for gas species and
  daily for aerosols.
• Concerns
• Detection limit/noise is comparable to real data.
• Most primary air pollutants are well controlled.
• Different instruments and networks
• Different precision

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EPA Sites
CO
SO2
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EPA Data
Data with less accuracy
Hourly CO (2004)
Data oscillation due to instrument calibration
(CO)
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What we want to get from this workshop

• Advice on model setup/validation
• WRF
• Using it as default?
• Bias/uncertainties?
• Wind, precipitation, convection, etc.
• WRFChem
• Initialization using a global CTM
• Spin up for chemical fields
• Days, weeks, or longer?
• Nudging with chemical observations
• Experience of using global models to drive
  WRF/WRFChem.
• Physical parameterizations
• Coordinates

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Backup Slides

• SO2 Emissions at different layers (esp. for point
  sources)
• Ozone evolution during daytime.

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SO2 Emissions (EPA 1999 NEI) at difference layers
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Ozone evolution during daytime.
EST 7Am
EST 8Am
EST 9Am
EST 10Am
EST 11Am
EST 12Pm
EST 1Pm
EST 2Pm
EST 3Pm
EST 4Pm
EST 5Pm
EST 6Pm