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| Titel |
French airborne lidar measurements for Eyjafjallajökull ash plume survey |
| VerfasserIn |
P. Chazette, A. Dabas, J. Sanak, M. Lardier, P. Royer |
| 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 ; 12, no. 15 ; Nr. 12, no. 15 (2012-08-06), S.7059-7072 |
| Datensatznummer |
250011370
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| Publikation (Nr.) |
 copernicus.org/acp-12-7059-2012.pdf |
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| Zusammenfassung |
| An Ultra-Violet Rayleigh-Mie lidar has been integrated aboard the French
research aircraft Falcon20 in order to monitor the ash plume emitted by the
Eyjafjallajökul volcano in April–May 2010. Three operational flights
were carried out on 21 April, 12 and 16 May 2010 inside French, Spanish and
British air spaces, respectively. The original purpose of the flights was to
provide the French civil aviation authorities with objective information on
the presence and location of the ash plume. The present paper presents the
results of detailed analyses elaborated after the volcano crisis. They bear
on the structure of the ash clouds and their optical properties such as the
extinction coefficient and the lidar ratio. Lidar ratios were measured in
the range of 43 to 50 sr, in good agreement with the ratios derived from
ground-based lidar near Paris (France) in April 2010 (~48 sr).
The ash signature in terms of particulate depolarization was consistent
during all flights (between 34 ± 3 % and 38 ± 3%). Such a value
seems to be a good identification parameter for volcanic ash. Using specific
cross-sections between 0.19 and 1.1 m2 g−1, the minimum
(maximal) mass concentrations in the ash plumes derived for the flights on
12 and 16 May were 140 (2300) and 250 (1500) μg m−3,
respectively. It may be rather less than, or of the order of the critical
level of damage (2 mg m−3) for the aircraft engines, but well above
the 200 μg m−3 warning level. |
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