1. Space-based Diagnosis of Surface Ozone Sensitivity to Anthropogenic Emissions
Randall Martin Aaron Van Donkelaar
Arlene Fiore

2. Ozone Control Strategies Require Independent Information on Effectiveness of Reducing NOx or VOCs
HCHO/NOy Ratio Used as Indicator
Would like to Observe from Space…
(ppbv)
NOx-Saturated
NOx-Sensitive
Sillman and He, 2002

3. Conduct Three Simulations With GEOS-CHEM CTM to Diagnose Quality of HCHO/NO2 Column Indicator
Base Case
Reduce Anthropogenic NOx Emissions by 50%
Reduce Anthropogenic VOC Emissions by 50%

4. Tropospheric HCHO/NO2 Column Ratio Is an Indicator of the Sensitivity of Afternoon Surface Ozone to NOx and VOC Emissions in a Well-mixed Environment GEOS-CHEM Model Calculation For Polluted Regions, Mar-Nov
NOx Saturated
NOx Sensitive

5. Tropospheric NO2 and HCHO Columns Largely Confined Near the Surface Also Closely Related to Surface NOx and VOC Emissions
Tropospheric NO2 column ~ ENOx
Tropospheric HCHO column ~ EVOC
Boundary
Layer CO
NO2
NO/NO2  
W ALTITUDE NO
hours
HCHO OH
HO2
hours
VOC
hours
HNO3
Emission
Emission
Nitrogen Oxides (NOx)
Volatile Organic Compounds (VOC)

6. Retrieve Tropospheric NO2 and HCHO Columns from GOME Largest Errors (from AMF) Cancel in the Ratio
Solar Io
Backscattered
intensity IB
Spectral Fit (UV/Vis)
Total HCHO & NO2 Slant Column
Remove Stratosphere
Tropospheric NO2 Slant Column
Scattering by
Earth surface
and by atmosphere
Calculate AMF
Tropospheric NO2 & HCHO Column

7. GOME Observations Show NOx-Sensitive Conditions Over Most Polluted Regions During August Major Industrial Areas are Clear Exceptions
White areas indicate clouds or data below the GOME detection limit
August

8. Biomass Burning Emissions are Clearly NOx-Sensitive, In Contrast with NOx-Saturated Conditions Over the Industrial Highveld
Also observe plume evolution
August

9. Seasonal Evolution from NOx-Sensitive to NOx-Saturated Conditions in Fall

10. GOME Observations Provide Confidence in a Recent Model Prediction NOx-Sensitive in the South and NOx-Saturated in the North in Fall
Seasonal Maximum in Surface Ozone in Urban China Occurs in Fall (More High-Pressure Systems)
GOME
Model
Luo et al., JGR, 2000

11. Conclusions
Satellite Observations of the Tropospheric HCHO/NO2 Column Indicate Ozone-NOx-VOC Sensitivity
Errors in Ratio Less Than for Individual Species
Sensitive Tool for Ozone Model Evaluation
SCIAMACHY/OMI Will Provide
Higher Spatial Resolution
Less sub-grid scale variation