Characteristics Of Three-dimensional Aerosol Distribution In Eastern China Based On Satellite Data

Aerosols plays an important role in climate change,excessive concentrations of aerosols can cause air pollution,the spatial and temporal distribution of aerosols has become a hot research topic.Using statistical analysis of the multiple aerosol optical parameters?optical depth,extinction coefficient,color ratio and depolarization ratio?from MODIS₃k and CALIPSO Level2 data products,we yield the spatial and temporal distribution of aerosol in East China from 2007 to 2016 in this paper,compared the three-dimensional distribution of aerosols before and after the policy “Atmosphere Ten Articles”,the vertical distribution of aerosol particles during a pollution case on January 3,2014 was also analyzed in combination with the backward trajectory.The results show that the AOD in East China is characterized by high in north and low in south,high in plain and low in mountain.The main high value areas appeared at the junction of Jiangsu,Shandong and Anhui,the surrounding area of Taihu Lake and the central Hubei and central Jiangxi,the low value areas appeared in central Shandong and southern Zhejiang,and the seasonal variation of AOD is high in spring and summer and low in autumn and winter.Aerosol decreases with height,large size and irregular shape aerosol particle in spring is affected by sand dust,summer has more precipitation and high relative humidity,aerosol particle size is small,and sphericity is better.Aerosol below 2km in autumn and winter is more affected by artificial aerosols,with smaller particle size and better sphericity,and it is affected by sand dust above 2km,and the aerosol particle size is large and the shape is irregular.After the enactment of ‘Ten Atmosphere',the aerosol AOD in the East China was significantly decreased,the near-ground extinction coefficient and the aerosol particle size also decreased,and the sphericity became better,shows that the proportion of anthropogenic aerosols decreased.In the process of pollution on January 3,2014,the pollutants in the 1000-1500 m over Nanjing were from the sand-dust layer at 1000-1500 m over Anhui.The aerosol concentration was the highest at 500 m,and the extinction coefficient was greater than 1.5.The particle size of the aerosol particle is large,the color ratio is more than 0.8,the aerosol particle size is smaller at 500 m,the color ratio is less than 0.4,and the aerosol shape is irregular at a height of 500 m,and the depolarization ratio exceeds 0.14.