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| Titel |
Fluorescence from atmospheric aerosol detected by a lidar indicates biogenic particles in the lowermost stratosphere |
| VerfasserIn |
F. Immler, D. Engelbart, O. Schrems |
| 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 ; 5, no. 2 ; Nr. 5, no. 2 (2005-02-08), S.345-355 |
| Datensatznummer |
250002346
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| Publikation (Nr.) |
 copernicus.org/acp-5-345-2005.pdf |
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| Zusammenfassung |
| With a lidar system that was installed in Lindenberg/Germany, we observed in
June 2003 an extended aerosol layer at 13km altitude in the lowermost
stratosphere. This layer created an inelastic backscatter signal that we
detected with a water vapour Raman channel, but that was not produced by Raman
scattering. Also, we find evidence for inelastic scattering from a smoke plume
from a forest fire that we observed in the troposphere. We interpret the
unexpected properties of these aerosols as fluorescence induced by the laser
beam at organic components of the aerosol particles. Fluorescence from ambient
aerosol had not yet been considered detectable by lidar systems. However,
organic compounds such as polycyclic aromatic hydrocarbons sticking to the
aerosol particles, or bioaerosol such as bacteria, spores or pollen fluoresce
when excited with UV-radiation in a way that is detectable by our lidar system.
Therefore, we conclude that fluorescence from organic material released by
biomass burning creates, inelastic backscatter signals that we measured with our
instrument and thus demonstrate a new and powerful way to characterize aerosols
by a remote sensing technique. The stratospheric aerosol layer that we have
observed in Lindenberg for three consecutive days is likely to be a remnant from
Siberian forest fire plumes lifted across the tropopause and transported around
the globe. |
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