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

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

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

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

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

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

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

RETRIEVAL OF TROPOSPHERIC NO2 FROM GOME (errors e in 1015 molecules cm-2) GOME SPECTRUM (423-451 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 = 0.5-3.2

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)

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

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

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