AGU Fall MeetingDecember 4, 2005 - PowerPoint PPT Presentation
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AGU Fall MeetingDecember 4, 2005
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Title: PowerPoint Presentation Author: Randall Martin Last modified by: Vijay Natraj Created Date: 8/2/2001 5:09:44 PM Document presentation format – PowerPoint PPT presentation
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Title: AGU Fall MeetingDecember 4, 2005
1
Vijay Natraj (California Institute of
Technology) Hartmut Bösch (Jet Propulsion
Laboratory)Yuk Yung (California Institute of
Technology)
Quantifying Aerosol Types and Their Impact on
Trace Gas Retrievals From Satellite Measurements
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Major Source of Retrieval Uncertainty
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Global Aerosol Climatology
Courtesy Kahn et al, 2001
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Aerosol Optical Properties
- Each mixing group is a combination of 4 different
aerosol components from a basic set of 7 (Kahn et
al., 2001). - Sulfate (land/water), seasalt, carbonaceous,
black carbon spherical gt Mie code (de Rooij and
van der Stap, 1984) - Mineral dust (accumulated/coarse) mixture of
oblate and prolate spheroids gt T-matrix code
(Mishchenko and Travis, 1998) - Lognormal distribution
- Polarization fully considered
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Scattering Matrix (755 nm)
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Forward Model Details
- Park Falls, Wisconsin, July (SZA 31 degrees)
- Exponential drop-off in aerosol extinction (scale
height 1 km, optical depth 0.1) - OCO spectral regions
- Forward model RADIANT (Christi, CSU) single
scattering approximation for polarization - Lorentzian instrument lineshape function
(resolving powers O2 A band 17000, CO2 bands
20000)
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Weighting Functions (O2 A Band)
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Weighting Functions (Weak CO2 Band)
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Weighting Functions (Strong CO2 Band)
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Retrieval Groups Single Scattering Albedo
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Retrieval Groups Normalized Extinction
Coefficient
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Sensitivity Tests
- Measurement error 0.43 ppm
- Smoothing error 0.29 ppm
- Error due to incorrect assumption of aerosol type
within retrieval group - Group 1 0.27 ppm
- Group 2 0.02 ppm
- Group 3 0.03 ppm
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Conclusions
- Aerosol retrieval groups determined from basic
aerosol mixing groups - Choosing incorrect mixing group within retrieval
group leads to small errors - Need to test more scattering geometries to
validate retrieval types - More realistic aerosol profiles need to be
included
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Acknowledgments
- OCO L2 Team (JPL)
- Matt Christi (CSU)
- Michael Mishchenko (GISS)
- Olga Kalashnikova and Ralph Kahn (JPL)
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Related Talks/Posters
- Charles Miller (A14C-02)
- Hartmut Boesch (A12D-05)
- Gretchen Aleks (A33B-0883)
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Importance of Polarization
- Need to consider both atmospheric/surface and
instrumental polarization
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