Study On The Spatiotemporal Variation Characteristics Of Aerosols In Eastern China Based On Multi-source Dat

In order to gain a deeper understanding of the large-scale and long-term aerosol physicochemical properties in different regions of eastern China,this article used AERONET,MODIS,CHAP,MERRA-2,and CALIPSO data to study the aerosol optical,microphysical properties,and mass concentration in eastern China,and conducted a comprehensive analysis of the aerosol characteristics in Xuzhou.The results show that the AOD of Beijing and the Taihu is higher in summer and lower in winter,with an average of 0.40～0.87;The AOD in Hong Kong is high in spring and low in winter（0.32-0.51）.The maximum AE in Beijing and the Taihu occurs in summer;The AE in Hong Kong is the smallest in summer（1.27）and the largest in spring（1.36）.SSA in Beijing and the Taihu is larger in summer and smaller in winter,and SSA in Hong Kong station is larger in autumn（0.93）and smaller in summer（0.91）.From the spatial distribution of MODIS AOD and CHAP PM_2.5,it can be seen that the overall AOD in eastern China is larger in spring and summer,smaller in autumn and winter.The AOD in the Beijing Tianjin Hebei region,the Yangtze River Delta region,and the Two Lakes region is higher,while the annual average AOD in most eastern regions shows a downward trend.The PM_2.5 mass concentration in eastern China shows a characteristic of high in autumn and winter,and low in spring and summer.The high values are mainly distributed in the Beijing Tianjin Hebei and its surrounding areas,and the annual average PM_2.5 mass concentration in most areas shows a downward trend.From the spatiotemporal distribution of different component mass concentrations of MERRA-2,it can be seen that the ground mass concentration of dust aerosols is higher in spring and lower in summer,with a decreasing trend from inland to coastal areas.The ground mass concentrations of black carbon and organic carbon aerosols are higher in autumn and winter,lower in spring and summer,and higher in areas with heating and densely populated areas.The ground mass concentration of sulfate aerosols is high in summer and low in spring.The high values in summer and autumn are concentrated in the surrounding areas of Beijing Tianjin Hebei region,while the high values in winter and spring appear in the two lakes region.Sea salt aerosols are high in summer and autumn,and low in winter and spring,mainly distributed along the coast.From an annual change perspective,except for sea salt,all other aerosols show a downward trend.Aerosol extinction coefficient from CALIPSO（δ）From a vertical distribution perspective,the total aerosols in the Pearl River Delta regionδHigh values occur in summer,ranging from approximately 0.1 to 0.2 km^-1 at 0.5-2 km,near the ground level in the Yangtze River Delta and Pearl River Delta regionsδThe biggest characteristics of winter are approximately 0.38 km^-1 and 0.45 km^-1,respectively.Dust aerosols in three regionsδHigh values all occur in spring,polluting sand and dustδThe high values all occur in winter.Summer Elevated Smoke and Dust in the Beijing Tianjin Hebei and Yangtze River Delta Regionsδis Large,rising smoke and dust in the Pearl River Delta regionδHigh values occur in spring.The AOD in Xuzhou region is high in summer and low in winter,with opposite AE.The particle spectrum presents a bimodal distribution,and the dominant particles in spring and summer are coarse and fine particles respectively.The effective radius of particles is larger in spring and smaller in summer.The SSA is the smallest and AAOD is the largest in winter,while the opposite is true in summer.There is a significant negative correlation between radiative forcing（ARF）and AOD,and a strong negative correlation between radiative forcing efficiency（ARFE（BOA））at the atmospheric bottom and SSA.Atmospheric radiative forcing（ARF（ATM））is greater in winter and spring.Winter aerosolsδThe fastest decrease with height and the slowest in summer.AOD shows a distribution characteristic of high in the urban area and low in the surrounding areas,with an average annual decrease in AOD.The PM_2.5 in the northwest of Xuzhou is the highest,while in the south it is the lowest,showing an overall downward trend.The proportion of sand and dust in the mass concentration of various particulate matter columns in Xuzhou is the highest,followed by sulfate.The column mass concentration shows a downward trend,with the most significant decrease in sand and dust.