Application of a Synergetic Lidar and Sunphotometer Algorithm for the Characterization of a Dust Event Over Athens, Greece.

ABSTRACT

Greece, on July 20, 2011. A full lidar data set in terms of backscatter signals at 355, 532 and 1064 nm, as well as depolarization at 532 nm was acquired from the European Aerosol Research Network (EARLINET) station of Athens and combined with Aerosol Robotic Network (AERONET) data, in order to retrieve the concentration and extinction coefficient profiles of dust. The lidar measurements showed a free tropospheric layer between 1-5 km above Athens, with low Ångström exponent of ~0.5 and high particle depolarization ratio, ~25-30%, both values characteristic of dust particles. The application of LIRIC revealed high concentration profiles of non-spherical coarse particles in the layer of 0.04-0.07 ppb and a smaller fine particle component with concentrations of ~0.01 ppb. The extinction coefficients at 532 nm ranged between 50 and 90 Mm-1 for coarse nonspherical particles and between 25 and 50 Mm-1 for fine particles. The retrievals were compared with modeled dust concentration and extinction coefficient profiles from the Dust Regional Atmospheric Modeling (BSC-DREAM8b) showing good agreement, especially for the coarse mode.