Multispectral lidar to study the atmospheric aerosols chemical composition: measurements in Buenos Aires of ashes from volcano Calbuco eruption.

PAWELKO E, SALVADOR J, PALLOTTA J; QUEL E

Conferencia; The 13th International Conference on Atmospheric Sciences and Applications to Air Quality (ASAAQ13); 2015

The Lidar Division of CEILAP is developing a lidar (Light Detection and Ranging) to study thechemical composition of atmospheric aerosols in Argentinean Lidar Network. The instrument workswith fluorescence, elastic and inelastic scattering in order to characterize the atmospheric particles inreal time and with high spatial, temporal and spectral resolution. The transmission system isimplemented by a Nd:Yag laser which emits in its first three harmonics (1064, 532 and 355 nm) at10Hz. Reception is performed with three Newtonian telescopes. The main telescope has 50 cmdiameter area and it is used to collect the fluorescence and Raman backscatter in coaxial arrangementwith the laser beam. Two other telescopes with 20 cm diameter are used in biaxial setup for recover532 nm orthogonal polarization backscatter and Mie, Raman and Rayleigh Backscatter (355, 532,1064, 387, 408 and 607 nm), respectively. The Raman and fluorescence signals generated by laserinteraction (532 or 355 nm) with the molecules composing atmospheric aerosols are processed with amultispectral acquisition system. The multispectral device consists of a Crossed Czerny-Turnerspectrometer, a 32 channels hybrid photomultiplier and a photocount detection system which works at15 m spatial and 4.5 nm spectral resolutions. This method allows to recover Raman and fluorescencespectrum within the atmospheric boundary layer and the first kilometers of the free atmosphere. Theinstrumental setup and the measurements of ashes from volcano Calbuco eruption on April 2015 arepresented and discussed.