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

Assimilated Meteorological Data from GEOS:

GEOS-4, 30 -levels 2ox2.5o

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-CHEM3D Model of Tropospheric

(Ox-NOx-VOC coupled to aerosol) Chemistry

NOx Lightning Emissions [Price and Rind, 1992]

GEOS-CHEM VS. ICARTTMean comparison along the flight tracks

DC-8 (top)

Large UT NO2 bias

BL bias in CO and NO2

Ozone FT bias 5-10 ppbv

Observed Simulated

WP-3 (bottom)

CO NO2 PAN HNO3 O3

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

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

INSUFFICIENT CONVECTIVE INJECTION OF BL POLLUTION? …not likely NOx concentrations

are higher in the UT than in the BL

DC-8 NOx

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

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]

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

NO2O3

New

Old

Obs

HOx COMPARISON INTEX-NA SOUTHEAST U.S. 2-3 X bias in upper tropospheric OH

HO2 OH

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 HNO3

- NOx lifetime would increase, thus fixing underestimate of NOx in upper tropospheric outflow