Integration of Satellite and In-situ Observations for Asian Combustion Sources and Transpacific Transport

1. Asian combustion sources and transpacific transport: An integration of satellite and in situ observations Colette L. Heald ACCESS Yellowstone, Wyoming September 2, 2005 ACKNOWLEDGEMENTS • Daniel Jacob and the Atmospheric Chemistry Modeling Group at Harvard • The TRACE-P, MOPITT and MODIS Science Teams • NASA Earth System Science Fellowship • Natural Science and Engineering Research Council of Canada

2. GROWTH IN EAST ASIA IS THE MAJOR DRIVER FOR GLOBAL ATMOSPHERIC CHANGE Asian CO ↑ 60% But there is considerable uncertainty in East Asian emission forecasts

3. INTEGRATION OF AIRCRAFT AND SATELLITE OBSERVATIONS TRACE-P Satellite validation MOPITT Inverse Model Model Error Quantification Chemical Forecast BOTTOM-UP EMISSIONS • Asian export fluxes • Transpacific pollution • transport • Global Asian influence GEOS-CHEM CTM

4. A B C D E TRACE-P PLUME: Feb. 22-27, 2001 • Aircraft observations during outbound trans-Pacific TRACE-P flights observed elevated levels of CO (and O3) O3 CO

5. H TRANSPORT AND CHEMICAL EVOLUTION OF THE PLUME Origin: Warm Conveyor Belt over Asia Northern plume (observed at A) sees no O3 enhancement. Southern plume (observed at D and E) subsides, leads to PAN decomposition and O3 production ECMWF Evolution: Split by blocking high pressure

6. MOPITT OBSERVATIONS OF A TRANSPACIFIC PLUME Total column CO GEOS-CHEM x Avgker GEOS-CHEM (12 GMT) MOPITT Asian pollution exported via cold front Feb 23 Feb 24 Plume encounters a blocking H Pressure System and splits Feb 25 Feb 26 Elevated CO reaches North America Southern branch at low latitudes produces O3 Feb 27

7. TRANSPACIFIC TRANSPORT DURING TRACE-P MOPITT: solid Model: dotted 4 trans-Pacific events reached North America during Spring 2001 Satellites can be used to track pollution transport! [Heald et al., JGR, 2003b]

8. MOPITT AND GEOS-CHEM DURING TRACE-P(Feb 20-Apr 10, 2001) MOPITT – GEOS-CHEM MOPITT CO Column Model is high (avg=18%) over SE Asia BB too high R2: 0.9679 Slope: 0.9678 GEOS-CHEM (w/ Avgker) CO Column Comparison indicates that emission inventories may be inaccurate

9. Inverse Model Sare error covariance matrices, K is the Jacobian matrix of the forward model APPROACH: INVERSE MODEL(February-April 2001) Forward Model (GEOS-CHEM) 2°x2.5° resolution Anthropogenic CO [Streets et al., 2003] and Logan & Yevich TRACE-P Aircraft CO OBSERVATIONS EMISSIONS MOPITT CO (daily v.3 column) Biomass Burning CO [Heald et al., 2003a]

10. a priori (grey bar = uncertainty) “best case” inversion Ia posteriori error on “best case” I range of inverse solutions MOPITT INVERSION: RANGE OF SOLUTIONS Regions dominated by anthropogenic emissions are underestimated, Regions dominated by biomass burning emissions are overestimated. The range of solutions provides a better estimate of uncertainty than a posteriori error.

11. COMPARING AIRCRAFT AND SATELLITE RESULTS Aircraft not well-suited to sampling all of SE Asian outflow Aircraft and MOPITT generally consistent, but differ on quantitative partitioning [Heald et al., JGR, 2004]

12. Visibility reduction at Glen Canyon, Arizona due to transpacific transport of Asian dust April 16, 2001 Clear Day TRANSPACIFIC TRANSPORT OF ASIAN AEROSOLS Despite their short lifetimes, aerosols can be transported across the Pacific and can affect North American air quality standards and visibility. Most documented cases consist of transport of dust: BUT Model simulations suggest that anthropogenic aerosols from Asia can ALSO be transported to the United States [Park et al., 2004] Asian contribution is comparable to “natural” standard set by EPA Haze Rule for W. U.S. (0.12 µg m-3)

13. TRANSPACIFIC TRANSPORT DURING THE SPRING MODIS = MODerate resolution Imaging Spectroradiometer (launched EOS-Terra Dec 1999) peak Asian dust ALSO substantial anthropogenic aerosol transport GEOS-CHEM underestimates MODIS observations by factor of ~2 in Spring AERONET sites indicate a MODIS retrieval bias at low AOD

14. AN EXAMPLE OF TRANSPACIFIC TRANSPORT OF ASIAN AEROSOL POLLUTION AS SEEN BY MODIS April 25, 2001 April 26, 2001 April 27, 2001

15. IMPACT OF ASIAN SULFATE ON U.S. AIR QUALITY NW US: Observed during Asian events 1.04 μgm-3 NW US: Observed 0.72 μgm-3 NW US: Asian events 0.60 μgm-3 NW US: Simulated Asian 0.18 μgm-3 Asian aerosols preferentially impact ground sites in the NW US. Observations at IMPROVE sites are elevated from mean when simulated Asian influence is high [Heald et al., in preparation]

16. PROJECTED SOx EMISSIONS IN ASIA • One projection suggests that • emissions of SOx will more than • double in China between • 1995-2020 • [Streets & Waldhoff, 2000] courtesy: David Streets Increasing SOx emissions from Asia will degrade North American air quality and present a further barrier to attainment of domestic air quality regulations in the United States (eg. EPA Haze Rule)

17. ACE-Asia Aircraft Observations GRC POSTER: ONGOING WORK What is the source of this FT organic carbon aerosol?

18. CONCLUSIONS • MOPITT and MODIS satellite instruments can be used to track transpacific transport of pollution • BUT comparisons between remote and in situ observations or models must be interpreted with an understanding of the properties and assumptions in satellite products • Satellite and aircraft observations provide consistent constraints on emission sources, but satellites can provide additional geographical disaggregation due to their spatial coverage • Biomass burning emissions in Asia are much less than previously thought and inverse modeling of emissions has led to identification of underestimated emissions from small industrial coal facilities in China • Transpacific transport of sulfate is driven by spring events (> 1 μg/m3) and primarily affects the northwestern United States. • Increasing SOx emissions from Asia will represent a further barrier to attainment of air quality objectives in the United States