Fig. 1. Schematic diagram of Raman-Mie Lidar

Fig. 2. Comparing results of Sounding observations and Raman-Mie Aerosol Lidar observations in Hefei
(a): The vertical profile of water vapor mixing ratio on October 20, 2019; (b): The vertical profile of Rayleigh scattering, Raman extinction and Mie scattering extinction signals on October 16, 2019

Fig. 3. Vertical profile diagram of diurnal variation of 532nm extinction coefficient from October 27 to 31, 2019

Fig. 4. The observation results of RMAL and conventional air quality monitoring station from October 27 to 31, 2019

Fig. 5. The observation results of conventional meteorological element monitoring station from October 27 to 31, 2019

Fig. 6. Cluster analysis results of the 24-hour backward trajectory of the 500 m altitude air mass and the backward trajectory corresponding to the high value of PM_2.5 (blue trajectory) from December 2019 to February 2020