1. 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)

2. 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

3. 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

4. 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)

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

6. 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
hPa
1.58 ± 0.19
DC-8 w/avKer r2 > 0.99
DC hPa r2 =0.98

7. 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]

8. 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]

9. 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]