Monitoring Of Aerosol Diurnal Variation And Evaluation Of Direct Radiation Effects By Cooperative Geostationary Satellite And Ground-Based Remote Sensing

With the acceleration of urbanization and industrialization,a large number of energy resources have been consumed,which leads to the problem of air pollution becoming more and more serious.As an important part of the atmosphere,aerosols are not only closely related to the atmospheric environmental quality,and have a significant impact on human life,production and human health,but also play an important role in the ecological balance of the air system.Therefore,AOD inversion and aerosol direct radiation effects in Jiangsu,Zhejiang and Shanghai regions were studied by using eye-safe ultraviolet lidar data and GOCI data of geostationary satellite.The aerosol extinction coefficients of 0.2-5 km altitude were obtained by Fernald method from representative weather data of eye-safe ultraviolet lidar.It was found that the extinction coefficients of atmospheric aerosols varied greatly under different pollution levels.The extinction coefficients near the surface were very large in haze,and the extinction coefficients of aerosols in heavily polluted weather were more than five times higher than those in clear sky.Comparing the vertical distribution maps of extinction coefficients of aerosols in daytime and night,it was found that most aerosols were distributed at about 2 km in height,sometimes at 3km,reaching the peak at noon,while at night aerosols were basically distributed below 1 km,and in some time periods they were distributed below 0.5 km,with no obvious fluctuation.The AOD inversion results of Jiangsu,Zhejiang and Shanghai regions were obtained by using the dark blue algorithm and building a look-up table and cost function based on 188 clear sky GOCI data in 2017.The data of Beichen and Taihu stations were used to verify the accuracy:R~2 was 0.605 and 0.622,showing good fitting accuracy.The spatial and temporal distribution of AOD showed that the AOD values were generally higher in the north and lower in the south.The high value areas were concentrated in the lower and gentle areas of Shanghai and Jiangsu,and the low value areas were located in the higher elevation mountain areas of Zhejiang.On the time scale,the percentage of AOD>0.4 area increased with time from 9:00 to 12:00,and decreased to 41.4%,70.1%,93.8%,98.1%,82.9%at 13:00,7.5%,3.1%at 14:00 and 13.1%at15:00,respectively.At 16:00,the percentage of AOD>0.4 area increased slightly,accounting for 13.1%.On the time scale of seasonal average,the trend of intra-day variation of the whole season was similar,and the time of intra-day maximum was different.Based on the AOD data of 8 time phases per day,the diurnal variations of aerosol direct radiation effects in Jiangsu,Zhejiang and Shanghai were further analyzed.The mean values of atmospheric top and surface aerosol direct radiation effects were-6.7W/m~2 and-59.9W/m~2,respectively.The aerosol direct radiation effect tended to be low in the north and high in the south in space,and changed obviously in the day,reaching the lowest value(absolute maximum)at 12:00.