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| Titel |
Gaseous mercury distribution in the upper troposphere and lower stratosphere observed onboard the CARIBIC passenger aircraft |
| VerfasserIn |
F. Slemr, R. Ebinghaus, C. A. M. Brenninkmeijer, M. Hermann, H. H. Kock, B. G. Martinsson, T. Schuck, D. Sprung, P. Velthoven, A. Zahn, H. Ziereis |
| 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 ; 9, no. 6 ; Nr. 9, no. 6 (2009-03-19), S.1957-1969 |
| Datensatznummer |
250007087
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| Publikation (Nr.) |
 copernicus.org/acp-9-1957-2009.pdf |
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| Zusammenfassung |
| Total gaseous mercury (TGM) was measured onboard a passenger aircraft during
monthly CARIBIC flights (Civil Aircraft for Regular Investigation of the
Atmosphere Based on an Instrumented Container) made between May 2005 and March
2007 on the routes Frankfurt–São Paulo–Santiago de Chile and back
and Frankfurt–Guangzhou–Manila and back. The data provide for the
first time an insight into the seasonal distributions of TGM in the upper
troposphere and lower stratosphere (UT/LS) of both hemispheres and
demonstrate the importance of mercury emissions from biomass burning in the
Southern Hemisphere. Numerous plumes were observed in the upper troposphere,
the larger of which could be characterized in terms of Hg/CO emission ratios
and their probable origins. During the flights to China TGM correlated with
CO in the upper troposphere with a seasonally dependent slope reflecting the
longer lifetime of elemental mercury when compared to that of CO. A
pronounced depletion of TGM was always observed in the extratropical
lowermost stratosphere. TGM concentrations there were found to decrease with
the increasing concentrations of particles. Combined with the large
concentrations of particle bond mercury in the stratosphere observed by
others, this finding suggests either a direct conversion of TGM to particle
bound mercury or an indirect conversion via a semivolatile bivalent mercury
compound. Based on concurrent measurements of SF6 during two flights,
the rate of this conversion is estimated to 0.4 ng m−3 yr−1. A
zero TGM concentration was not observed during some 200 flight hours in the
lowermost stratosphere suggesting an equilibrium between the gaseous and
particulate mercury. |
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