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| Titel |
CARIBIC observations of gaseous mercury in the lowermost stratosphere |
| VerfasserIn |
Franz Slemr, Ralf Ebinghaus, Hans Kock, Carl Brenninkmeijer, Markus Hermann, Andreas Weigelt, Andreas Zahn, Peter van Velthoven, Bengt Martinsson |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250047962
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| Zusammenfassung |
| A unique set of gaseous mercury measurements in the upper troposphere and lower stratosphere
(UT/LS) has been obtained during the monthly CARIBIC (www.caribic-atmospheric.com)
flights since 2005. The passenger Airbus 340-600 of Lufthansa covered routes to the Far East,
North America, India, and the southern hemisphere. The accompanying measurements of
CO, O3, NOy, H2O, aerosols, SF6 and many other parameters as well as backward
trajectories enable a detailed analysis of these measurements. The CARIBIC measurements
represent a good approximation of total gaseous mercury (TGM) concentrations, thus
including gaseous elemental mercury and the majority of reactive gaseous mercury
(presumably Hg2+) compounds as speciation tests have shown. Tropospheric values are
variable, and often correlate with CO. Above the tropopause a strong decline of mercury
concentration with increasing PV and O3 is always observed. The systematic decrease of
TGM in the stratosphere with altitude implies its conversion to particle bound mercury. The
observation of lowest TGM concentrations at highest particle concentrations in the
stratosphere provides evidence for such conversion. We will show how a seasonally
dependent conversion rate could be derived using concomitantly measured SF6 mixing
ratios as a timer. We also will discuss the implications for the atmospheric mercury
budget. |
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