1. R C Hudman, D J Jacob, S Turquety, L Murray, S Wu, Q Liang,A Gilliland, M Avery, T H Bertram, E Browell, W Brune, R C Cohen, J E Dibb, F M Flocke, J Holloway, A Newman, X Ren, T B Ryerson, G W Sachse, H B Singh, P J Wooldridge A multi-platform analysis of the North American reactive nitrogen budget during the ICARTT summer intensive Friday, December 9, 2005 AGU 2005 *This work funded is by NOAA Office of Global Programs and NASA Tropospheric Chemistry Program

2. Assimilated Meteorological Data from GEOS: GEOS-4, 30  -levels 2 o x2.5 o GEOS-CHEM Model May-August 2004 NA Fire Inventory [Turquety et. al, 2005] EPA National Emissions Inventory 1999 v.1 (w/ modifications to VOCs) GEOS-CHEM 3D Model of Tropospheric (Ox-NOx-VOC coupled to aerosol) Chemistry NOx Lightning Emissions [Price and Rind, 1992]

3. GEOS-CHEM VS. ICARTT Mean comparison along the flight tracks DC-8 (top) Large UT NO 2 bias BL bias in CO and NO 2 Ozone FT bias 5-10 ppbv Observed Simulated WP-3 (bottom) CONO 2 PANHNO 3 O3O3

4. Large overestimate powerplant/industry dominated Midwest and in the South Observed Simulated Improved Simulation DC-8 Midwest 50% reduction in power and industry source as determined by Frost et al., [2005] improves boundary layer NOx simulation ICARTT OBSERVATIONS CONFIRM LARGE DECREASE SINCE 1999 IN INDUSTRY/POWER SOURCE 0 1 2 3 > 4 MEAN(Model NOx/ Observed NOx): All DC-8 & WP-3 flts 0-2 km

5. PAN BIAS: BACKGROUND or N. AMER. ENHANCEMENT? CO – PAN correlations at 8-10 km Modeled Observed PAN discrepancy in enhancement CO vs. PAN Asian Fossil Fuel CO tracer vs. PAN PAN (ppbv) North American Fossil Fuel tracer vs. PAN PAN ( ppbv ) PAN correlation dominated by NA tracer

6. INSUFFICIENT CONVECTIVE INJECTION OF BL POLLUTION? …not likely NOx concentrations are higher in the UT than in the BL DC-8 NOx

7. Observed DC-8 NOx > 8km National Lightning Detection Network [Gtons N July 1 –August 15, 2004] [ppbv NOx] HIGH UPPER TROP NOx CO-LOCATED WITH LIGHTNING ACTIVITY DURING ICARTT

8. GEOS-CHEM UPDATED LIGHTNING EMISSIONS vs. NATIONAL LIGHTNING DETECTION NETWORK GEOS- Chem Standard Ltng Simulation X 4 over U.S. National Lightning Detection Network [Gtons N July 1 –August 15, 2004]

9. New OZONE COMPARISON INTEX-NA SOUTHEAST U.S. Lightning increase over the U.S. corrects ozone bias Improved ozone at surface reflects NOx emission reduction NO 2 O3O3

10. New Old Obs HOx COMPARISON INTEX-NA SOUTHEAST U.S. 2-3 X bias in upper tropospheric OH HO 2 OH

11. DECREASING OH WOULD PUT MANY THINGS INTO PLACE… ….but how do you decrease OH by X2-3? - Reducing OH would allow us to increase lightning emissions by less, thus reducing HNO 3 - NO x lifetime would increase, thus fixing underestimate of NO x in upper tropospheric outflow