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R. C. Hudman, D. J. Jacob, S. Turquety, Lee Murray, ITCT-2K4 science team, INTEX-NA science team

A multi-platform analysis of the North American reactive nitrogen budget during the ICARTT summer intensive. R. C. Hudman, D. J. Jacob, S. Turquety, Lee Murray, ITCT-2K4 science team, INTEX-NA science team. Measurements: M. Avery, R. Cohen, J. Dibb, F. Flocke, J. Holloway, A. Neuman,.

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R. C. Hudman, D. J. Jacob, S. Turquety, Lee Murray, ITCT-2K4 science team, INTEX-NA science team

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  1. A multi-platform analysis of the North American reactive nitrogen budget during the ICARTT summer intensive R. C. Hudman, D. J. Jacob, S. Turquety, Lee Murray, ITCT-2K4 science team, INTEX-NA science team Measurements: M. Avery, R. Cohen, J. Dibb, F. Flocke, J. Holloway, A. Neuman, T. Ryerson, G. Sachse, H. Singh, P. Wennberg • GEOS-CHEM • NEI-99 emissions (VOC modifications) • 2x2.5 resolution NEAQS/ITCT2k4 ICARTT science meeting

  2. ICARTT 0-2 km NOy* partitioning: Rapid Oxidation of NOx downwind of continent Merged Observations GEOS-CHEM NOx/NOy NE/MW: 25% South: 18% OffShore: 15% Large NOx sources PAN/NOy NE/MW: 19% South: 20% OffShore: 10% HNO3/NOy NE/MW: 56% South: 62% OffShore: 74% Rapid NOx oxidation *“NOy”=NOx + HNO3 + PAN

  3. ICARTT 4-8 km NOy partitioning: Role of PAN increases Observed Modeled NOx/NOy PAN/NOy PAN in outflow HNO3/NOy

  4. ICARTT 8+ km NOy partitioning: Large Lightning Presence Observed Modeled NOx/NOy PAN/NOy PAN dominates outflow HNO3/NOy

  5. GEOS-CHEM vs. INTEX-NA and ITCT2k4: Comparison along the flight tracks* NO2 underestimate above 6 km Overestimate of CO & NOx anthro. source Similar PAN underestimate O3 FT bias • local, strat, • BB filtered • Gridded tp 2x25

  6. Top: PAN bias: Background or NA Enhancement? Modeled Observed PAN - CO correlations in free tropopshere PAN discrepency in enhancement Bottom: Modeled Tagged tracer correlations 6-8 km PAN correlation dominated by NA tracer [Q. Liang, UW]

  7. Relative Importance of Upper trop NOx sources: July Lightning and Aircraft Totals IPCC Aviation and Global Atm (1999) 1992 ~.5 2015(proj) ~1.0 Most we can increase aviation srce x2 NOT ENOUGH! July Total (Tg N) Global Aircraft Source July (Tg N): .05, Yearly ~ .5 Lightning Source July (Tg N): .5, Yearly ~ 5 U.S. Aircraft Source July (Tg N): .012 Lightning Source July (Tg N): .067 LI ~ 5 x Aircraft

  8. Insufficient Convection? …not likely Propane – NO2 correlations in BL and 8-10 km

  9. OTD/LIS Climatology and GEOS-CHEM 2004 Mean July flash rate GEOS-CHEM OTD/LIS [Flashes/km2/day] Factor of two underestimate above 35 N over U.S.

  10. Convective Mass Flux GEOS-4 vs. GEOS-3: Vertical Placement of NOx emissions greatly influences mean [NOx] Different assumptions in the vertical placement of lightning NOx  50% increase in mean [NOx]

  11. O3 vs. CO correlation 0-2 km: All INTEX and ITCT-2K2 data All Data Northeast RMA slope = .47 R^2 = .5 Lower O3/CO correlation in South South RMA slope = .35 R^2 = .3 RMA slope = .47 R^2 = .49 [Lee Murray]

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