Spring-to-summer observations of the aerosol load over Sofia-city using near-horizontal lidar sensing

Abstract

Using lidar and contact facilities, the relation is investigated experimentally between the extinction coefficient and the mass concentration of near-ground aerosol pollution over some districts in Sofia City. The extinction coefficient profiles of the aerosol ensembles along the lidar line of sight (LOS) are measured at the lidar wavelengths of 510.6 nm (CuBr-vapor laser source) and 1064 nm and 532 nm (Nd:YAG laser source). The particulate mass concentration is determined using data obtained concurrently by air-quality measuring sensors close to the LOS. Thus, the results obtained of the aerosol mass concentration-to-extinction calibration constant of the lidar concern mainly the sites around the nearest stations. To help the interpretation of the results, the accompanying weather conditions are also described. The experiments are conducted in the spring and the summer and the results obtained reflect the ecological peculiarities of the corresponding city regions of interest. The values found of the calibration constant are consistent with those obtained earlier in the same seasons.