Analysis Of The Spatial-temporal Variation Of Aerosol Optical Properties In Coastal Region

Aerosols can directly and indirectly affect atmospheric radiation.This paper provides theoretical basis and data support for further research on the impact of atmospheric aerosols on climate change and atmospheric environmental governance by studying the spatiotemporal variation of optical properties of atmospheric aerosols.Using CALIPSO data,the paper analyzes the variation characteristics of aerosol types and optical properties of various types of aerosols in coastal areas.Two typical regions(Beijing-Tianjin and Pearl River Delta)are compared and analyzed.The results show that:The optical properties of aerosols in coastal areas vary greatly from north to south.High AOD values are mainly distributed in the North China Plain,northern central China and northeastern China,while low AOD values are mainly concentrated in the South China Sea.The aerosol particle depolarization ratio and color ratio are higher in spring and lower in summer.The depolarization ratio in the north is larger than that in the south,and the color ratio in the South China Sea is relatively higher all year round.The AOD value,extinction coefficient and particle depolarization ratio in the Beijing-Tianjin region were generally higher than those in the Pearl River Delta region,while the color ratio was lower than that in the Pearl River Delta region in summer,autumn and winter.The polluted dust and dust in Beijing-Tianjin region are relatively high and their interannual variation is large.In the Pearl River Delta region,smoke and clean marine are dominant and their proportions have little interannual fluctuation.The proportion of dust and polluted dust in coastal area is the highest,followed by smoke and polluted continental type.The extinction coefficients of polluted continental and smoke aerosols are relatively high throughout the year,followed by polluted dust aerosols.The proportion of the three types of aerosols increases with the increase of AOD value.The extinction coefficients of clean marine,clean continent,dust and dusty marine are small and decrease gradually with the increase of AOD value.The clean continental,polluted continental and smoke are mainly spherical small particles.The dust is dominated by large non-spherical particles.The polluted dust and dusty marine have the characteristics of spherical particles and non-spherical particles.The clean marine is dominated by large spherical particles.The clean marine and polluted continent mainly appear below 2km.The clean continent,polluted dust and dust mainly distribute below 6km,and the smoke can reach6-8km altitude layer.