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| Titel |
The impact of monsoon outflow from India and Southeast Asia in the upper troposphere over the eastern Mediterranean |
| VerfasserIn |
H. A. Scheeren, J. Lelieveld  , G. J. Roelofs, J. Williams, H. Fischer, M. Reus, J. A. Gouw, C. Warneke, R. Holzinger, H. Schlager, T. Klüpfel, M. Bolder, C. Veen, M. Lawrence |
| 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 ; 3, no. 5 ; Nr. 3, no. 5 (2003-10-01), S.1589-1608 |
| Datensatznummer |
250001265
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| Publikation (Nr.) |
 copernicus.org/acp-3-1589-2003.pdf |
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| Zusammenfassung |
| A major objective of the Mediterranean INtensive Oxidant Study (MINOS) was to investigate
long-range transport of pollutants (notably ozone precursor species). Here we present trace
gas measurements from the DLR (German Aerospace Organization) Falcon aircraft in the
eastern Mediterranean troposphere. Ten day backward trajectories and a coupled
chemistry-climate model (ECHAM4) were used to study the nature and origin of pollution
observed in the upper troposphere between 6 and 13 km altitude. We focus on a large
pollution plume encountered over the eastern Mediterranean between 1 and 12 August
originating in South Asia (India and Southeast Asia), referred to as the Asian plume,
associated with the Asian Summer Monsoon. Vertical as well as longitudinal gradients of
methane, carbon monoxide, hydrocarbons including acetone, methanol, and
acetonitrile, halocarbons, ozone and total reactive nitrogen (NOy) are presented, showing the chemical
impact of the Asian plume compared to westerly air masses containing pollution from North
America. The Asian plume is characterized by enhanced concentrations of biomass burning
tracers (acetylene, methyl chloride, acetonitrile), notably from biofuel use. Concentrations of
the new automobile cooling agent HFC-134a were significantly lower in the Asian plume
than in air masses from North America. Relatively high levels of ozone precursors (CO,
hydrocarbons) were found in both air masses, whereas lower ozone concentrations in the
Asian plume suggest NOx-limited conditions. Consistently, ECHAM model simulations
indicate that the expected future increase of NOx-emissions in Asia enhances the
photochemical ozone production in the Asian plume. The size and location of the Asian
plume near the tropopause provides an important potential for pollution transport into the
lowermost stratosphere. We present observations indicative of Asian pollution transport into
the lower stratosphere. |
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