French airborne lidar measurements for Eyjafjallajökull ash plume survey

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Chazette, P., Dabas, A., Sanak, J., Lardier, M., Royer, P.
• Other Authors: Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Chimie Atmosphérique Expérimentale (CAE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), LEOSPHERE France, LEOSPHERE
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2012
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Eyjafjallajökull
• Online Access: https://hal.archives-ouvertes.fr/hal-02902895; https://hal.archives-ouvertes.fr/hal-02902895/document; https://hal.archives-ouvertes.fr/hal-02902895/file/acp-12-7059-2012.pdf; https://doi.org/10.5194/acp-12-7059-2012

International audience An UltraViolet 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 li-dar 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 m 2 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.