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Author: Tesche, M. × End date: 2013 × Start date: 2013 × Subject: lidar ×

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    Four-dimensional distribution of the 2010 Eyjafjallajökull volcanic cloud over Europe observed by EARLINET
    (München : European Geopyhsical Union, 2013) Pappalardo, G.; Mona, L.; D'Amico, G.; Wandinger, U.; Adam, M.; Amodeo, A.; Ansmann, A.; Apituley, A.; Alados Arboledas, L.; Balis, D.; Boselli, A.; Bravo-Aranda, J.A.; Chaikovsky, A.; Comeron, A.; Cuesta, J.; De Tomasi, F.; Freudenthaler, V.; Gausa, M.; Giannakaki, E.; Giehl, H.; Giunta, A.; Grigorov, I.; Groß, S.; Haeffelin, M.; Hiebsch, A.; Iarlori, M.; Lange, D.; Linné, H.; Madonna, F.; Mattis, I.; Mamouri, R.-E.; McAuliffe, M.A.P.; Mitev, V.; Molero, F.; Navas-Guzman, F.; Nicolae, D.; Papayannis, A.; Perrone, M.R.; Pietras, C.; Pietruczuk, A.; Pisani, G.; Preißler, J.; Pujadas, M.; Rizi, V.; Ruth, A.A.; Schmidt, J.; Schnell, F.; Seifert, P.; Serikov, I.; Sicard, M.; Simeonov, V.; Spinelli, N.; Stebel, K.; Tesche, M.; Trickl, T.; Wang, X.; Wagner, F.; Wiegner, M.; Wilson, K.M.
    The eruption of the Icelandic volcano Eyjafjallajökull in April–May 2010 represents a "natural experiment" to study the impact of volcanic emissions on a continental scale. For the first time, quantitative data about the presence, altitude, and layering of the volcanic cloud, in conjunction with optical information, are available for most parts of Europe derived from the observations by the European Aerosol Research Lidar NETwork (EARLINET). Based on multi-wavelength Raman lidar systems, EARLINET is the only instrument worldwide that is able to provide dense time series of high-quality optical data to be used for aerosol typing and for the retrieval of particle microphysical properties as a function of altitude. In this work we show the four-dimensional (4-D) distribution of the Eyjafjallajökull volcanic cloud in the troposphere over Europe as observed by EARLINET during the entire volcanic event (15 April–26 May 2010). All optical properties directly measured (backscatter, extinction, and particle linear depolarization ratio) are stored in the EARLINET database available at http://www.earlinet.org. A specific relational database providing the volcanic mask over Europe, realized ad hoc for this specific event, has been developed and is available on request at http://www.earlinet.org. During the first days after the eruption, volcanic particles were detected over Central Europe within a wide range of altitudes, from the upper troposphere down to the local planetary boundary layer (PBL). After 19 April 2010, volcanic particles were detected over southern and south-eastern Europe. During the first half of May (5–15 May), material emitted by the Eyjafjallajökull volcano was detected over Spain and Portugal and then over the Mediterranean and the Balkans. The last observations of the event were recorded until 25 May in Central Europe and in the Eastern Mediterranean area. The 4-D distribution of volcanic aerosol layering and optical properties on European scale reported here provides an unprecedented data set for evaluating satellite data and aerosol dispersion models for this kind of volcanic events.
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    Evaluation of the Lidar/Radiometer Inversion Code (LIRIC) to determine microphysical properties of volcanic and desert dust
    (München : European Geopyhsical Union, 2013) Wagner, J.; Ansmann, A.; Wandinger, U.; Seifert, P.; Schwarz, A.; Tesche, M.; Chaikovsky, A.; Dubovik, O.
    The Lidar/Radiometer Inversion Code (LIRIC) combines the multiwavelength lidar technique with sun/sky photometry and allows us to retrieve vertical profiles of particle optical and microphysical properties separately for fine-mode and coarse-mode particles. After a brief presentation of the theoretical background, we evaluate the potential of LIRIC to retrieve the optical and microphysical properties of irregularly shaped dust particles. The method is applied to two very different aerosol scenarios: a strong Saharan dust outbreak towards central Europe and an Eyjafjallajökull volcanic dust event. LIRIC profiles of particle mass concentrations for the coarse-mode as well as for the non-spherical particle fraction are compared with results for the non-spherical particle fraction as obtained with the polarization-lidar-based POLIPHON method. Similar comparisons for fine-mode and spherical particle fractions are presented also. Acceptable agreement between the different dust mass concentration profiles is obtained. LIRIC profiles of optical properties such as particle backscatter coefficient, lidar ratio, Ångström exponent, and particle depolarization ratio are compared with direct Raman lidar observations. Systematic deviations between the LIRIC retrieval products and the Raman lidar measurements of the desert dust lidar ratio, depolarization ratio, and spectral dependencies of particle backscatter and lidar ratio point to the applied spheroidal-particle model as main source for these uncertainties in the LIRIC results.