Abstract:Compared with the situation on clear days, the vertical distribution of aerosol and meteorological conditions during haze and heavy haze events in central part of Shandong Province from 2007 to 2017 are analyzed by utilizing the data of CALIPSO (The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) and NCEP FNL （Final Operational Global Analysis） 1°×1° reanalysis data. The results show that aerosol particles in haze and heavy haze weather mainly concentrate below 2.7 km and 1.5 km in the lower troposphere. With 0.9, 1.66 and 1.34 km as the critical heights, the extinction coefficient (EC) of clear days, haze days and heavy haze days decreases exponentially above the critical height and logarithmically below the height. The average annual paraticulate deploarization ratio (PDR) and color ratio (CR) range of haze days and severe haze days are 0.1-0.3 and 0.5-0.9, respectively. In heavy haze days, aerosol particles below 2 km are relatively regular and small in size, and their irregularity and size increase sharply within 2-4 km. PDR increases gradually with height in and below 7 km but decreases gradually above 7 km. Different from clear days, CR basically increases with the height on haze days. The contribution of polluted dust aerosol to near-ground EC on heavy haze days and haze days is 0.58 km-1 and 0.36 km-1, respectively. The second is 〖JP2〗the polluted continental type, contributing 0.27 km-1 and 0.20 km-1〖JP〗 respectively. On the heavy haze days, the low average wind speed and high relative humidity in and below 1.5 km are conducive to the increase of EC. On haze days, low average wind speed and high relative humidity are maintained at a higher height, making the height of aerosol high concentration layer up to 2.7 km. During haze days, the sources of near-surface pollutants are long-distance transmission from Mongolia, Inner Mongolia and the neighboring provinces. In heavy haze days, the transport of pollutants in the direction of Mongolia and Henan accounts for more, reaching to 25.26% and 31.58% respectively. The proportion of multi-layer inversion corresponding to heavy haze is close to 50%, and the proportion of ground+low-suspended type and ground+high-suspended type are the largest. Since these two types of inversion correspond to smaller outflow below the inversion layer, the atmosphere is more stable,and aerosol particles are concentrated in the lower layer when it is heavy haze weather.