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| Titel |
Analysis of aircraft and satellite measurements from the Intercontinental Chemical Transport Experiment (INTEX-B) to quantify long-range transport of East Asian sulfur to Canada |
| VerfasserIn |
A. Donkelaar, R. V. Martin, W. R. Leaitch, A. M. Macdonald, T. W. Walker, D. G. Streets, Q. Zhang, E. J. Dunlea, J. L. Jimenez, J. E. Dibb, L. G. Huey, R. Weber, M. O. Andreae |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 8, no. 11 ; Nr. 8, no. 11 (2008-06-17), S.2999-3014 |
| Datensatznummer |
250006188
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| Publikation (Nr.) |
 copernicus.org/acp-8-2999-2008.pdf |
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| Zusammenfassung |
| We interpret a suite of satellite, aircraft, and ground-based measurements
over the North Pacific Ocean and western North America during April–May 2006
as part of the Intercontinental Chemical Transport Experiment Phase B
(INTEX-B) campaign to understand the implications of long-range transport of
East Asian emissions to North America. The Canadian component of INTEX-B
included 33 vertical profiles from a Cessna 207 aircraft equipped with an
aerosol mass spectrometer. Long-range transport of organic aerosols was
insignificant, contrary to expectations. Measured sulfate plumes in the free
troposphere over British Columbia exceeded 2 μg/m3. We update the
global anthropogenic emission inventory in a chemical transport model
(GEOS-Chem) and use it to interpret the observations. Aerosol Optical Depth
(AOD) retrieved from two satellite instruments (MISR and MODIS) for
2000–2006 are analyzed with GEOS-Chem to estimate an annual growth in
Chinese sulfur emissions of 6.2% and 9.6%, respectively. Analysis of
aircraft sulfate measurements from the NASA DC-8 over the central Pacific,
the NSF C-130 over the east Pacific and the Cessna over British Columbia
indicates most Asian sulfate over the ocean is in the lower free troposphere
(800–600 hPa), with a decrease in pressure toward land due to orographic
effects. We calculate that 56% of the measured sulfate between 500–900 hPa over British Columbia is due to East Asian sources. We find evidence of
a 72–85% increase in the relative contribution of East Asian sulfate to
the total burden in spring off the northwest coast of the United States
since 1985. Campaign-average simulations indicate anthropogenic East Asian
sulfur emissions increase mean springtime sulfate in Western Canada at the
surface by 0.31 μg/m3 (~30%) and account for 50% of
the overall regional sulfate burden between 1 and 5 km. Mean measured daily
surface sulfate concentrations taken in the Vancouver area increase by 0.32 μg/m3 per 10% increase in the simulated fraction of Asian
sulfate, and suggest current East Asian emissions episodically degrade local
air quality by more than 1.5 μg/m3. |
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