SUMMER 2004 FIELD STUDIES Modeling support by Harvard University A. MISSION PLANNING GEOS-CHEM hindcast simulations for 1997, 2000, 2001 Investigate main N American outflow mechanisms and pathways Examine chemical and aerosol characteristics of the outflow Make recommendations for ITCT/2K4 and INTEX flight patterns Paper to be completed in fall 2003 (Qinbin Li and Rynda Hudman)

B. MISSION EXECUTION GEOS-CHEM chemical forecasts (Duncan Fairlie, Rynda Hudman, Bob Yantosca): GEOS-4 met. forecasts from NASA/GMAO (1ox1o horiz. res.) 6 tracers: North American FF CO and BB CO, rest of world FF CO and BB CO, soot (water-soluble), stratospheric ozone continuous presence of Harvard team in the field Near-real-time satellite data from GOME, SCIAMACHY (Kelly Chance, Randall Martin) CO, NO2, HCHO column imagery Also possibly early data from Aura (TES) Design of satellite validation flights

Bottom-up inventories Chemical/aerosol processing C. POST-MISSION ANALYSES Central theme: inverse model analyses of North American sources of ozone precursors, aerosol precursors, and long-lived GGs A PRIORI KNOWLEDGE Bottom-up inventories Chemical/aerosol processing TOP-DOWN CONSTRAINTS FORWARD MODEL satellite GEOS-CHEM CTM Ozone-aerosols-GG coupled simulation validation in situ (aircraft and other) INVERSE MODEL ANALYSIS IMPROVED KNOWLEDGE

INTEGRATION OF AIRCRAFT, SATELLITES, MODELS, AND a priori EMISSION INVENTORIES IN TRACE-P Chinese anthrop ECO 50% too low biomass burning ECO 70% too high CO aircraft observations (G.W. Sachse) Inversion (P. Palmer) MOPITT CO observations Top-down constraints CTMs validation Chemical forecasts Daily CO biomass burning emissions from AVHRR (C.L. Heald) CO fossil and biofuel bottom-up emission inventory (D.R. Streets, ANL)

MOPITT VALIDATION PROFILES DURING TRACE-P Aircraft w/ av. kernels Aircraft MOPITT (v3, Dx = ±100 km) Averaging kernels

TRACE-P VALIDATION PROFILES: MOPITT vs. DC-8 CO columns 1018 molecules cm-2 MOPITT 2.25 ± 0.19 DC-8 w/avKer 2.12 ± 0.23 950-300 hPa 1.58 ± 0.19 DC-8 w/avKer r2 > 0.99 DC-8 950-300 hPa r2 =0.98

MEAN CO COLUMNS DURING TRACE-P (Mar-Apr 2001) MOPITT GEOS-CHEM w/ adjusted anthrop source, original biomass burning source Top-down constraints from MOPITT on Asian CO sources are consistent with aircraft observations Difference Heald et al. [2003]

NOy export efficiency out of the North American boundary layer: NOy-CO correlations along the NARE’97 flight tracks Export efficiency of NOy (mixing model of Parrish et al. ). Estimate export efficiency from NOy-CO: background concentrations of NOy, CO, emission ratio CO/NOy Parrish et al. [2003] GEOS-CHEM NOy export efficiency 9±5% (→ 17±13%) 11.5±3% (→ 17±7%) as NOx 8% 6±4% as PAN 34% 36±13% as HNO3 57% 52±14% Li et al. [2003]

Ozone production from exported North American anthropogenic NOy GEOS-CHEM, September 1997 Half the ozone production from exported anthopogenic NOy takes place in the very near-field from exported NOx; the other half is driven by PAN decomposition and is dispersed over the NH This eventual ozone production due to exported NOy is comparable to direct export of ozone pollution in terms of contribution to the global tropospheric ozone reservoir. Most ozone production has been realized in near-field, consistent with the low NOx/NOy ratio over the NARE’97 region. Parrish et al. [2003] forgot the export of PAN in contributing to ozone production. Li et al. [2003]