1. VALIDATION OF OMI TROPOSPHERIC NO 2 DURING INTEX-B AND APPLICATION TO CONSTRAIN NO x EMISSIONS IN THE EASTERN UNITED STATES AND MEXICO K. F. Boersma, D. J. Jacob, E.J. Bucsela, A.E. Perring, R. Dirksen, R.J. van der A, R.M. Yantosca, R.J. Park, M.O. Wening, T.H, Bertram, R.C. Cohen

2. OMI NO 2 VALIDATION DURING INTEX-B AIRCRAFT CAMPAIGN 21 DC-8 validation spirals (open circles) Mean OMI tropospheric NO 2 (March 2006 - KNMI near-real-time product v0.8)

3. Spiral 2 (up) OMI VALIDATION SPIRAL IN INTEX-B NO 2 (ppbv) Spiral 1 (down) DC-8 floor is 1000 ft. over land, 500 ft. over ocean: must extrapolate to surface for comparison to OMI tropospheric column Pressure (hPa) 1000 200 02 In situ data from U.C.Berkeley (Ron Cohen)

4. OMI VALIDATION STATISTICS IN INTEX-B Mexico City points: large extrapolation to the ground Is required Subset with extrapolated fraction < 30% yields slope = 0.99 ± 0.17 (r 2 = 0.67, n = 12) Ocean subset indicates OMI negative bias = - 0.6x10 15 molecules cm -2, fitting error 0.5x10 15 molecules cm -2

5. CONTINUITY FROM SCIAMACHY TO OMI Differences between OMI (13:30) and SCIAMACHY (10:00) can be explained by diurnal variation in NOx emissions and chemistry [Boersma et al., 2007] Mean August 2006 data

6. CONSTRAINING NO x EMISSIONS IN EASTERN U.S. FOR MARCH 2006 Bottom-up: EPA NEI99 for March OMI with  NO2  /E NOx from GEOS-Chem Adjust NEI 99 data to match OMI for different NO x emission categories: Power plants, industry  25% On-road vehicles  30% Off-road vehicles  9% TOTAL ANTHROPOGENIC  3% Resulting fit r 2 = 0.87 Error ± 25% Could rising vehicular emissions counter benefit of power plant reductions?

7. CONSTRAINING NO x EMISSIONS IN MEXICO Bottom-up: BRAVO in N. Mexico, GEIA elsewhere, 20% soil contribution OMI with  NO2  /E NOx from GEOS-Chem Bottom-up inventory too low by factor of 2.0 Mexico City: likely due to fires Elsewhere: likely due to soil emissions

8. TOWARD BETTER UNDERSTANDING OF THE MIDDLE EAST OZONE MAXIMUM Zhang et al. [2006] averaging kernels (July 2005) TES observations for July 2005 reprocessed with uniform a priori

9. OMI TROPOSPHERIC NO 2 DATA OVER MIDDLE EAST Comparison with bottom-up estimate (GEIA) indicates large underestimates of NO x emissions in Iran and Saudi Arabia

10. OMI EVALUATION WITH URBAN NO 2 DATA IN ISRAEL Tropospheric NO 2 column, 10 15 cm -2 Carmiel Beer Sheva OMI in situ Seasonal variation for 2006; in situ surface data extrapolated through local boundary layer depth with Y. Rudich and M. Trainic (Weizmann)

11. COMPARISON OF OMI AND SCIAMACHY WITH NO 2 DATA AT ALL ISRAEL STATIONS SCIAMACHY (10:00 local)OMI (13:30 local) r = 0.55 (n=136) RMA: y = 0.19 + 0.97x r = 0.61 (n=396) RMA: y = -1.28 + 0.90x