[Characteristics of Aerosol Vertical Distribution over the Yangtze River Delta Region of China in 2018].

Based on the lidar data provided by cloud-aerosol lidar and infrared pathfinder satellite observations (CALIPSO) from December 2017 to November 2018, the temporal and spatial variation characteristics of 532 nm aerosol extinction coefficient, aerosol depolarization ratio, aerosol color ratio, and various types of aerosols in the troposphere over the Yangtze River Delta region of China were analyzed in detail. The altitude variation of aerosol optical parameters showed that the extinction ability of aerosols was generally stronger in the lower troposphere than that in the upper troposphere, the shape of particles was generally more regular in the lower troposphere than that in the upper troposphere, and the size of particles was generally smaller in the lower troposphere than that in the upper troposphere. The seasonal variation of aerosol optical parameters showed that the extinction ability of aerosols in the upper troposphere was generally stronger in summer and autumn than that in winter and spring, the shape of particles below 2 km was generally more regular in summer and autumn than that in winter and spring, and the size range of particles in the upper troposphere was generally larger in summer and autumn than that in winter and spring. The occurrence frequency of polluted dust aerosols over the Yangtze River Delta throughout the year was the highest (37.4816%). The occurrence frequency of smoke aerosols, polluted continental aerosols, and clean marine aerosols in the troposphere was higher in summer and autumn than that in winter and spring. However, the occurrence frequency of dust aerosols in summer and autumn was relatively low.