1. TOP-DOWN CONSTRAINTS ON EMISSION INVENTORIES OF OZONE PRECURSORS
Daniel Jacob Dorian Abbot Paul Palmer
Kelly Chance Thomas Kurosu
Randall Martin

2. HOW DO WE EVALUATE AND IMPROVE BOTTOM-UP INVENTORIES?
Surface NOX
Global NOx Emissions (Tg N yr-1)
Fossil Fuel (20-33)
Biomass Burning (3-13) Soils (4-21)
Here in Tg N yr-1 (based on)
Fossil Fuel 24 (GEIA)
Biomass Burning 6 (Logan/Duncan)
Soils 5 (Yienger and Levy)

3. TOP-DOWN INFORMATION FROM THE GOME SATELLITE INSTRUMENT
Operational since 1995
Nadir-viewing solar backscatter instrument ( nm)
Low-elevation polar sun-synchronous orbit, 10:30 a.m. observation time
Spatial resolution 320x40 km2, three cross-track scenes
Complete global coverage in 3 days

4. USE GOME MEASUREMENTS TO RETRIEVE NO2 COLUMNS TO MAP NOx EMISSIONS
Retrieval Summary
Spectral Fit ( nm)
GOME
Total Slant Column
Remove Stratosphere
Tropospheric Slant Column
Tropospheric NO2 column ~ ENOx
Calculate AMF
Tropospheric Column
BOUNDARY
LAYER
Martin et al., 2002
NO2
NO/NO2  
W ALTITUDE NO
lifetime ~hours
HNO3
Emission
NITROGEN OXIDES (NOx)

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

6. STRATEGY: OPTIMIZE SURFACE INVENTORY 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
Martin et al., 2003

7. TOP-DOWN INFORMATION FROM GOME REDUCES ERROR IN NOX EMISSION INVENTORY
Bottom-up error a Mean=2.0
Top-down error t Mean=2.0
Mean=1.6
Martin et al., 2003

8. OPTIMIZED SURFACE NOX EMISSIONS
36.4 Tg N yr-1
37.7 Tg N yr-1
Martin et al., 2003

9. A POSTERIORI MINUS A PRIORI EMISSIONS
Martin et al., 2003

10. GEOS-CHEM isoprene emissions (in progress using GBEIS)
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 (in progress using GBEIS)
Abbot et al., 2003