1. TESTING GLOBAL MODELS OF INTERCONTINENTAL POLLUTION TRANSPORT USING AIRCRAFT AND SATELLITE OBSERVATIONS
Daniel J. Jacob
with Mathew J. Evans, T. Duncan Fairlie, Rynda C. Hudman, Colette L. Heald,
Qinbin Li, Randall V. Martin, Paul I. Palmer, Rokjin J. Park, Yaping Xiao

2. INTERCONTINENTAL TRANSPORT, HEMISPHERIC POLLUTION
Tropopause
HEMISPHERIC POLLUTION BACKGROUND
Mixing
Free troposphere
“Direct”
intercontinental
transport
PBL
boundary layer advection
WCB
subsidence
Asia
N. America
Europe

3. Present-day ozone background at northern midlatitudes
HEMISPHERIC OZONE POLLUTION: IMPLICATIONS OF ENHANCED BACKGROUND FOR MEETING AIR QUALITY STANDARDS (AQS)
Europe AQS
(8-h avg.)
Europe AQS
(seasonal)
U.S. AQS
(8-h avg.)
U.S. AQS
(1-h avg.)
ppbv
Preindustrial
ozone
background
Present-day ozone background at northern midlatitudes

4. FOR OZONE, HEMISPHERIC ENHANCEMENT OF BACKGROUND IS A GREATER ISSUE THAN INTERCONTINENTAL TRANSPORT EVENTS
Model vs. observed
stats,
Ozone at Mace Head (Ireland), Mar-Aug 1997
Observed
[Simmonds]
GEOS-CHEM
model
N.America pollution
events in model
Li et al. [2002]

5. Asian dust in western U.S. Asian dust in southeastern U.S.
…FOR AEROSOLS IT IS PROBABLY THE OPPOSITE Dust observations from U.S. IMPROVE network
April 16, 2001
Asian dust in western U.S.
April 22, 2001
Asian dust in southeastern U.S.
mg m-3
Glen
Canyon, AZ
April 16, 2001: Asian dust!
Clear day

6. TRANSPACIFIC TRANSPORT OF ASIAN DUST PLUMES
GEOS-CHEM Longitude cross-section at 40N, 16 April, 2001
LONGITUDE
ALTITUDE (km)
100E
150E
150W
100W
Source region
(inner Asia)
Subsidence
over western U.S.
Asian plumes over Pacific 10 5
ASIA
UNITED STATES
T.D. Fairlie, Harvard

7. CONTRIBUTION OF ASIAN SOURCES TO CARBONACEOUS AEROSOLS IN NORTH AMERICA IS NEGLIGIBLE
Annual means, GEOS-CHEM simulation (1998)
Standard (OC+EC)
Asian sources only
Model simulation of 1998 observations from U.S. IMPROVE network OC EC
model
R.J. Park, Harvard
observations
observations

8. TRACE-P AIRCRAFT MISSION (March-April 2001)
CO observations from G.W. Sachse
Daily CO biomass burning emissions from AVHRR (C.L. Heald, Harvard)
CO fossil and
biofuel emissions
(D.R. Streets, ANL)

9. USING TRACE-P DATA TO CONSTRAIN ASIAN CO EMISSIONS
Bottom-up (a priori):
Asian anthropogenic emissions from D.R. Streets
Daily biomass burning emissions from AVHRR (C.L. Heald, Harvard)
Other sources from J.A. Logan
TRACE-P observations
GEOS-CHEM with a priori emissions
Inverse model analysis indicates that Chinese anthropogenic emissions are 30% too low (P.I. Palmer, Harvard)

10. NOy:CO RELATIONSHIP IN ASIAN OUTFLOW IN TRACE-P: Quantifying anthropogenic and biomass burning NOx emissions
Conclusion: bottom-up Asian NOx emission is correct within 50%
Fossil
Biomass
> 30oN
Fossil fuel
dominates
< 30oN
Biomass burning
dominates
M.J. Evans,
Harvard

11. NOy SPECIATION IN ASIAN OUTFLOW DURING TRACE-P
M. J. Evans, Harvard
NOx/NOy
PAN/NOy
(HNO3 + NO3-)/NOy
Observed
Model

12. GEOS-CHEM vs. observed CH4: a priori Asian CH4 source too high by 25%
TESTING a priori ASIAN METHANE SOURCE ESTIMATES WITH TRACE-P CORRELATIONS FOR CH4-C2H6-CO
Y. Xiao, Harvard
GEOS-CHEM vs. observed CH4:
a priori Asian CH4 source too high by 25%
GEOS-CHEM vs. observed C2H6/CH4:
Coal mining CH4source likely too high

13. TRANSPACIFIC TRANSPORT OF ASIAN CO AND OZONE IN TRACE-P: Feb 26-27, 2001 PLUME
MOPITT 500 hPa CO, Feb 26 2 1 3 2 3 4 5 CO
Ozone 4 5
TRACE-P profiles,
Feb 26-27
C.L. Heald, Harvard

14. MODEL ANALYSIS OF TRACE-P TRANSPACIFIC POLLUTION PLUME (GEOS-CHEM CO SIMULATION)
Feb 23, 0 GMT:
warm conveyor belt lifts CO over China
6-8 km
Feb 26, 0 GMT:
Plume encounters blocking H over central Pacific, splits
6-8 km
Feb 26, 12 GMT:
N branch of plume transported to N America, sampled by TRACE-P
6-8 km
Feb 27, 21 GMT:
S branch of plume transported to tropics to die, sampled by TRACE-P
3-4 km
C.L. Heald, Harvard

15. OZONE:CO RELATIONSHIPS IN TRANSPACIFIC POLLUTION PLUMES
Data from MOPITT underpass profiles
TRACE-P aircraft
GEOS-CHEM
High ozone production efficiency in low-latitude Asian plume, but U.S.-bound plume has little ozone production
N plume (40 N)
S plume (18 N)
C.L. Heald, Harvard

16. SURFACE OZONE ENHANCEMENT FROM ASIAN EMISSIONS DURING TRACE-P PERIOD (GEOS-CHEM)
Anthropogenic
Biomass burning
The Asian anthropogenic source contributes significantly to surface ozone in the western U.S. (mean 2-4 ppbv), while the influence from Asian biomass burning source emissions is negligible.
M.J. Evans, Harvard

17. Surface data at Trinidad Head, Apr-May 2002
ASIAN POLLUTION ENHANCEMENTS OF OZONE AND CO AT CALIFORNIA COASTAL SITE DURING ITCT-2K2
Surface data at Trinidad Head, Apr-May 2002
Apr 17
May 17
Observations (A.H. Goldstein)
GEOS-CHEM
Asian pollution enhancement in GEOS-CHEM
Ozone CO
R.C.Hudman,
Harvard
Maximum observed ozone correlates with Asian influence in model

18. GEOS-CHEM Tropospheric NO2
GOME Tropospheric NO2
GEOS-CHEM Tropospheric NO2
r = 0.75 bias=5%
DJF
MAM
JJA
R.V. Martin,
Harvard
SON
1015 molecules cm-2

19. CAN WE USE SATELLITES FOR GLOBAL MAPPING OF EMISSIONS
CAN WE USE SATELLITES FOR GLOBAL MAPPING OF EMISSIONS? NO2 TROPOSPHERIC COLUMNS FROM GOME
R.V. Martin,
Harvard
GOME NO2
GEOS-CHEM
JUN 96
JUL 96
AUG 96
r = 0.79
bias = -19%
1015 molec cm-2

20. TAKING THE LEAP: GLOBAL NOx EMISSIONS FROM GOME
ENOx, GOME = ENOx, GEOS-CHEM (WNO2, GOME/WNO2, GEOS-CHEM)
Tg N yr-1
36.6
37.3
R.V. Martin,
Harvard

21. INTERCONTINENTAL TRANSPORT EXPERIMENT – NORTH AMERICA (INTEX)
A NASA Global Tropospheric Chemistry Program aircraft mission
OBJECTIVES:
(1) To quantify the outflow of climatically important trace gases and aerosols (CIGAs) from North America to the Atlantic, and relate this outflow to our understanding of North American sources and sinks;
(2) To understand the chemical evolution of the North American outflow over the Atlantic, and assess the implications for global influence and intercontinental transport of pollution;
(3) To quantify the transpacific transport of Asian pollution to North America.and its implications for surface air quality.
TWO AIRCRAFT: NASA DC-8 and P-3B
TWO PHASES: A (Jun-Jul 2004) and B (Mar-Apr 2006)