1. Using Space-based Observations to Improve Model Calculations of Transboundary Pollution Transport
Randall Martin Aaron Van Donkelaar
Daniel Jacob Dorian Abbot
Kelly Chance Chris Sioris
Arlene Fiore

2. Transport Pattern on High-Ozone Days
90th percentile O3 concentrations for summers
and mean 850hPa winds on days when O3 > 90th percentile

3. Top-down Information from the GOME Satellite Instrument
Launched in 1995
Spatial resolution 320x40 km2
Complete global coverage in ~3 days
Spectral Fit (UV/Vis)
Total HCHO & NO2 Slant Column
Remove Stratosphere
Tropospheric NO2 Slant Column
Calculate AMF
Tropospheric HCHO & NO2 Column

4. Tropospheric NO2 and HCHO 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)

5. GEOS-CHEM isoprene emissions
GOME HCHO COLUMNS SHOW SEASONAL VOC EMISSIONS
GOME GEOS-CHEM (GEIA) GOME GEOS-CHEM (GEIA)
MAR
JUL
APR
AUG
MAY
SEP
JUN
OCT
molec cm
Agreement in general pattern, regional discrepancies point to need for improving
GEOS-CHEM isoprene emissions
Abbot et al., 2003

6. GEOS-CHEM Tropospheric NO2
GOME Tropospheric NO2
GEOS-CHEM Tropospheric NO2
r=0.75 bias 5%
Martin et al., 2003
1015 molecules cm-2

7. STRATEGY: OPTIMIZE INVENTORIES USING A PRIORI BOTTOM-UP AND GOME TOP-DOWN INFORMATION
Top-down emissions
A priori emissions
A posteriori emissions
A priori errors
Top-down errors
GOME
GEOS-CHEM

8. Investigate Discrepancies with Bottom-up Inventories
AUG 2002
Martin et al., 2003

9. Surface ozone concentrations are sensitive to the ratio of NOx emissions to VOC emissions
(ppbv)
NOx-Saturated
NOx-Sensitive
Sillman and He, 2002

10. 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
Martin et al., 2004

11. GOME Satellite Observations of Ozone-NOx-VOC Sensitivity
Martin et al., 2004

12. SCIAMACHY Provides Much Finer Spatial Resolution (30 km x 60 km)
OMI (13 km x 24 km) Will Be Launched in June
AUG 2002

13. MODIS Optical Depth for July 2002
Aaron Van Donkelaar