Aerosol optical depth determined by lidar and spectrometer

Four campaigns of investigation of the atmosphere over the urban area of the Sofia city were carried out. An EARLINET scanning aerosol lidar, a spectrometer and a ground meteorological station were used during the observations. Multiple aerosol layers of variable thickness (200 600 m) were systematically observed in the planetary boundary layer over the area. A study of various optical characteristics of the atmospheric aerosol such as extinction coefficient, aerosol optical depth, Angstrom parameters (&agr; and &bgr;), etc. is performed and their variations are followed during the convective boundary layer formation.