1. SATELLITE OBSERVATIONS OF TROPOSPHERIC CHEMISTRY from TOMS and GOME: Implications for AURA
Randall Martin, Daniel Jacob,
Jennifer Logan, Paul Palmer
Harvard University
Kelly Chance, Thomas Kurosu
Harvard-Smithsonian Center for Astrophysics

2. TROPOSPHERIC OZONE COLUMNS (Sep’96-Aug’97)
GEOS-CHEM MODEL
TOMS (CCD)
DJF
MAM
JJA
SON
R = 0.66, BIAS = -0.5 DU

3. OZONE ENHANCEMENT FROM LIGHTNING (GEOS-CHEM) largely explains observed wave-1 pattern in TOMS ozone

4. SIMULATED OZONE CONCENTRATIONS AND FLUXES AT 300 hPa IN JAN 97
Incursion of northern hemispheric ozone over the South Atlantic
through the “westerly duct” contributes to the wave-1 pattern

5. OZONE VERTICAL PROFILES OVER ABIDJAN
North African Dec-Feb ozone enhancement from biomass burning
seen by aircraft observations but not by TOMS
GEOS-
CHEM
TOMS
(distributed w/assumed standard profile)
MOZAIC
aircraft
data

6. RAYLEIGH SCATTERING LIMITS SENSITIVITY OF TOMS TO SEASONAL VARIATION IN LOWER TROPOSPHERE
TOMS sensitivity to ozone
(LIDORT radiative
transfer model)
TOMS standard profiles
S. Atlantic
profile
Abidjan profile

7. CORRECTION FOR TOMS RETRIEVAL EFFICIENCY CANNOT EXPLAIN DISCREPANCY OVER ABIDJAN What will OMI and TES Observe?
TOMS (CCD)
Corrected CCD
Tropopause
GEOS-CHEM
200 hPa
MOZAIC
(200 hPa)
Month

8. RETRIEVAL OF TROPOSPHERIC NO2 FROM GOME (errors e in 1015 molecules cm-2)
GOME SPECTRUM ( nm)
SLANT NO2 COLUMN
TROPOSPHERIC SLANT NO2 COLUMN
TROPOSPHERIC NO2 COLUMN
Fit spectrum
e1 = 0.8
O3, O4, H2O, Ring, Undersampling,
Common Mode
Use Central Pacific GOME data with:
HALOE to test strat zonal invariance
PEM-Tropics, GEOS-CHEM 3-D model to treat tropospheric residual
Remove stratospheric contribution, diffuser plate artifact
e2 = 0.4
Use radiative transfer model with:
local surface albedos from GOME
local vertical shape factors from GEOS-CHEM
local cloud info from GOMECAT
Apply AMF to convert slant column to vertical column
Quantitative retrieval for partly cloudy scenes
e3 =

9. CAN WE USE OMI TO ESTIMATE NOx EMISSIONS. TEST IN U. S
CAN WE USE OMI TO ESTIMATE NOx EMISSIONS? TEST IN U.S. WHERE GOOD A PRIORI EXISTS
Comparison of GOME retrieval (July 1996) to GEOS-CHEM model fields
using EPA emission inventory for NOx
GOME
BIAS = +18%
R = 0.78
NO/NO2  
WITH ALTITUDE
NOx lifetime
~1day
GEOS-CHEM
(EPA emissions)

10. GOME RETRIEVAL OF TROPOSPHERIC NO2 vs. GEOS-CHEM SIMULATION (July 1996)
GEIA & Logan
emissions
scaled to 1996

11. NO2 COLUMN FROM LIGHTNING SMALL COMPARED TO RETRIEVAL ERROR
Tropospheric NO2 Column Enhancement from Lightning (6 Tg N yr-1) for July (GEOS-CHEM)
Error in Tropospheric NO2 Column Retrieval 7-33x1014 molecules cm-2

12. CONCLUSIONS WAVE-1 from Lightning Surface NOx from GOME
Correction not enough