| As one of the more serious areas of atmospheric pollution in China,the Jiangsu,Anhui,Shandong,and Henan border area has received widespread attention in recent years,and it is important to carry out accurate atmospheric environmental monitoring to improve the atmospheric environmental quality in border area.Aerosols are an important factor contributing to changes in the atmospheric environment,and the study of aerosol optical properties can scientifically evaluate the atmospheric pollution status and analyse the sources of atmospheric particulate pollution.Based on the ground and satellite observation data in the past 10 years,this study analyses the time-series variation characteristics,spatial distribution and changes of aerosol optical properties in the junction area and uses ground and satellite data to synthesize and analyse two pollution events in 2021.The results of the study are as follows:（1）Study of the optical properties and types of ground-observed aerosols.AOD showed an overall decreasing trend year by year from 2014 to 2021,with a 47.5%decrease in 2021 compared to 2014,with annual average SSA values greater than 0.92and annual average AE values greater than 1.The cumulative annual seasonal averages of AOD showed summer>spring>autumn>winter,with the smallest AE in spring in the seasonal variation.AOD and SSA showed an inverted"U"shape,and the cumulative annual daily variation of AOD showed an increasing trend of SSA with a"U"shape.The aerosols in the study area are dominated by mixed type and biomass burning/urban industry type,and the proportion of dust type aerosols increases in spring.2022 AOD,AE changes in the two sites have high consistency,with finer aerosols in summer at Panan Lake site and more clean periods overhead.（2）Study of the optical properties of aerosols observed by satellite All four satellite products and ground-based AOD products reached significant correlation levels,and overall,GOCI AOD data had the best effect.2011-2020 annual change of AOD in the junction area of Jiangsu,Shandong,Henan and Anhui showed a decreasing trend year by year.During the“12th Five-Year Plan”period,the spatial distribution was high in the west and low in the east,and high in the north and low in the south.during the“13th Five-Year Plan”period,the high value areas continued to decrease and the low value areas expanded.Significant distribution of cumulative yearly average monthly AOD in the junction area.In November,December,January and February,The spatial distribution is mainly low in the south-east,high values in June,July and August,and high values in September and October in Shangqiu,northeastern Jining,eastern Zaozhuang and southern Suqian.PCA modal analysis shows that the pattern of AOD change in the junction area in mode 1 shows a high consistency,while the change in AOD in mode 2 has obvious regional variability.The Sen+MK trend analysis shows a clear downward trend in AOD over the last 10 years in the majority of regions,with a slight downward trend in a few regions.（3）Integrated ground-based satellite observation applications.AOD and particulate matter both show positive correlation,with the correlation coefficient R varying from 0.39 to 0.71 in all seasons,and the correlation between AOD and PM2.5is 0.28 and 0.42 on pollution days and non-pollution days,respectively.From 2014 to2020 only some of the star areas in the junction area show median AOD when non-polluted,and overall higher AOD in southwest Shandong Province and in Shangqiu City when polluted.The two pollution events show that the average PM2.5,AOD and AE values at the first pollution were 133μg/m3,0.94 and 0.89 respectively,and this pollution event was caused by an increase in fine particles in particulate matter.The second pollution was two dust transfers,the second dust transfer lasted longer but the pollution level was reduced compared to the first.This thesis has 45 figures,7 tables,and 115 references. |
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