1. Chris Sioris Kelly Chance
Space-Based Constraints on NOx Emissions and Aerosol Single Scattering Albedo
Chris Sioris Kelly Chance
Randall Martin
Aaron Van Donkelaar
Lyatt Jaeglé

2. Global Surface NOx Emissions Uncertain to Factor of 2 Implications for Tropospheric Ozone, Aerosols, and Indirect Effect
GEIA
Duncan et al.
Yienger and Levy
A priori
Bottom-up errors estimated by comparing surface NOx emission inventory used here with an independent inventory (EDGAR).
Top-down errors very conservative estimate based on processes. Top-down errors will be reduced in the future.
Relative Uncertainty

3. SCIAMACHY/GOME Spectral Measurement Regions
30 km x 60 km
40 km x 320 km

4. Spectral Fit of NO2 Nonlinear least-squares fitting
Distinct NO2 Spectrum
Solar Io
Ozone
Backscattered
intensity IB
NO2
Scattering by
Earth surface
and by atmosphere
Albedo A
O2-O2
Nonlinear least-squares fitting

5. Perform a Radiative Transfer Calculation to Account for Viewing Geometry and Scattering Cloud Screening: Remove Scenes with IB,c > 0.7*IB,o
IB,o
IB,c Io q
FRESCO Clouds Fields [Koelemeijer et al., 2002]
Surface Reflectivity [Koelemeijer et al., 2003]
LIDORT Radiative Transfer Model [Spurr et al., 2002] Rc Ro Pc dt Rs

6. Cloud-filtered Tropospheric NO2 Columns Observed from the SCIAMACHY Satellite Instrument (Data  ICARTT)
Lifetime ~ hours
NO/NO2  
W ALTITUDE
May-Sept 2004
detection
limit

7. Major Urban Centers Are Concentrated NOx Sources
May-Sept 2004
detection
limit

8. SPACE-BASED CONSTRAINTS ON NOx EMISSIONS
Tropospheric NO2 Columns
GOME
GEOS-CHEM model (GEIA)
JJA 1997
r = 0.75 bias=5%
1015 molecules cm-2
Martin et al. [2003]
Error
weighting
A priori emissions (GEIA)
A posteriori emissions
Difference

9. 43 Tg N
May-Sept 2004
Tg N
SCIAMACHY minus a priori

10. Satellite Observations of Soil NOx Emissions from Sahel 40% of African NOx Emissions from Soils
Results for the year 2000
Jaeglé, Martin, et al., JGR, 2004

11. Aerosol Single Scattering Albedo Major Source of Uncertainty in Global Radiative Forcing Estimates
IPCC [2001]

12. Maximum Sensitivity to Aerosol Optical Thickness Over Dark Surfaces More Sensitive to Single Scattering Albedo Over Bright Surfaces
Saharan Dust Plume
Staten Island Refinery Fire
King et al., BAMS, 1999

13. TOMS Aerosol Index Measures Absorbing Aerosols In Ultraviolet Where Rayleigh Scattering Acts as Bright Surface
July
TOA spectral albedo measured by GOME

14. MODIS Optical Depth Includes Both Scattering and Absorbing Aerosols
Requires
aerosol size distribution information (AERONET and GEM-AQ)
Aerosol relative vertical distribution (LIDAR, GEM-AQ)
Use radiative transfer model to calculate SSA that reproduces observed Aerosol Index
July 2000
MODIS AOD at 470 nm
July 2000

15. Funding
Canadian Foundation for Climate and Atmospheric Sciences (CFCAS)
Natural Sciences and Engineering Research Council of Canada (NSERC)
National Aeronautics and Space Administration (NASA)
Canadian Foundation for Innovation (CFI)
Nova Scotia Research and Innovation Trust (NSRIT)