VALIDATION OF OMI TROPOSPHERIC NO 2 DURING INTEX-B AND APPLICATION TO CONSTRAIN NOx 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
OMI NO 2 VALIDATION DURING INTEX-B AIRCRAFT CAMPAIGN Mean OMI tropospheric NO 2 (March 2006 - KNMI near-real-time product v 0. 8) 21 DC-8 validation spirals (open circles)
OMI VALIDATION SPIRAL IN INTEX-B 200 Pressure (h. Pa) Spiral 1 (down) In situ data from U. C. Berkeley (Ron Cohen) Spiral 2 (up) 1000 0 NO 2 (ppbv) 2 DC-8 floor is 1000 ft. over land, 500 ft. over ocean: must extrapolate to surface for comparison to OMI tropospheric column
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. 6 x 1015 molecules cm-2, fitting error 0. 5 x 1015 molecules cm-2
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
CONSTRAINING NOx EMISSIONS IN EASTERN U. S. FOR MARCH 2006 Bottom-up: EPA NEI 99 for March OMI with WNO 2 /ENOx from GEOS-Chem Error ± 25% Adjust NEI 99 data to match OMI for different NOx emission categories: • Power plants, industry. 25% • On-road vehicles k 30% • Off-road vehicles k 9% • TOTAL ANTHROPOGENIC k 3% Resulting fit r 2 = 0. 87 Could rising vehicular emissions counter benefit of power plant reductions?
CONSTRAINING NOx EMISSIONS IN MEXICO Bottom-up: BRAVO in N. Mexico, GEIA elsewhere, 20% soil contribution OMI with WNO 2 /ENOx 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
TOWARD BETTER UNDERSTANDING OF THE MIDDLE EAST OZONE MAXIMUM TES observations for July 2005 reprocessed with uniform a priori (July 2005) averaging kernels Zhang et al. [2006]
OMI TROPOSPHERIC NO 2 DATA OVER MIDDLE EAST Comparison with bottom-up estimate (GEIA) indicates large underestimates of NOx emissions in Iran and Saudi Arabia
OMI EVALUATION WITH URBAN NO 2 DATA IN ISRAEL Tropospheric NO 2 column, 1015 cm-2 Seasonal variation for 2006; in situ surface data extrapolated through local boundary layer depth Carmiel OMI in situ Beer Sheva with Y. Rudich and M. Trainic (Weizmann)
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) r = 0. 61 (n=396) RMA: y = 0. 19 + 0. 97 x RMA: y = -1. 28 + 0. 90 x
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