Study On The Retrieval Of Atmospheric Aerosol Optical Depth And Its Environmental Effects

Aerosol Optical Depth (AOD) is a basic parameter in total aerosol content, which can be used to represent the degree of atmospheric pollution. The AOD data from ground observation is difficult to reflect the spatial and temporal distribution. Some studies have demonstrated that the AOD retrieved using satellite remote sensing data can make up for this shortage. As the one of the most developed economic province of China, Jiangsu province has a high proportion of total GDP and total industrial output in China. Meanwhile, due to large amounts of toxic substances by industrial production and exhausts emissions, air pollution has become increasingly hazardous in Jiangsu province. The haze weather frequently occurred in recent years. These environmental issues have threatened seriously people’s health and environment quality. Aerosol is a key factor which contributes to haze weather. It will be useful to obtain the overall information of aerosol spatial and temporal distribution for atmospheric monitoring and air pollution controlling.Taking Jiangsu province as the study area, this paper obtained AOD distribution using Dark Dense Vegetation (DDV) and V5.2method respectively. And validated the two results of AOD distribution using AOD measured data from CE-318instrument on the ground. Then the spatial and temporal distribution of AOD and the possible affecting factors in the study area have been discussed based on AOD map from V5.2method, which has a higher accuracy than DDV method. Finally, using the MODIS aerosol optical depth product data to make correlation analysis with visibility data and PM2.5data respectively, and on this basis to establish the regression model. In addition, combined with meteorological data, empirical analysis was carried out basis on a haze pollution process in Nanjing City. The main research results of this paper are as follows:(1) Retrieved AOD distribution of spring and summer in Jiangsu province in2010by using Dark Dense Vegetation (DDV) and V5.2method based on MODIS LIB data. And validated the two results of AOD distribution using AOD measured data from CE-318instrument on the ground. The results showed that:the inversion outcomes of two algorithms remain consistent in the overall trend, showed the AOD in the southern was higher than northern, but the AOD from V5.2is more accurate than that from DDV in the study area. The absolute error and relative error of AOD from V5.2method is0.13and26.48%respectively.(2) Analyzed the result obtained using V5.2method from two sides of spatial distribution and seasonal variation. The results showed that:in the study area, there was a very difference of AOD distribution in both spatial and seasonal. In detail, AOD gradually decrease from southern area of Jiangsu province to the northern area. The mean AOD of southern Jiangsu, center Jiangsu and northern Jiangsu is0.77,0.65and0.58respectively. For seasonal changes, AOD mean value changed in a small range in spring and summer in2010. But variation tendency was distinct in different regions. In the south of Jiangsu, AOD in spring was significantly lower than that in summer. The mean value is reduced from0.81to0.70. In the north of Jiangsu, AOD was increased with the mean value rose from0.56to0.62. In the center Jiangsu, seasonal change is not obvious with AOD mean value were0.66and0.63.It can be found through analysis that AOD was significantly negative correlation with NDVI and has a good consistency with the scale of urbanization, besides, the distribution of AOD was also affected by the geographical environment, industrial distribution, local large construction and precipitation.(3) Established the regression model by using AOD to make correlation analysis with visibility data and PM2.5data respectively based on MODIS aerosol products(MOD04), obtained the distribution map of visibility and PM2.5in Nanjing in2013. The results showed that Nanjing has the lowest visibility and the highest PM2.5mass concentration in winter. In view of the serious haze pollution in Nanjing on December2rd to1lth,2013, combined with corresponding time meteorological data, carried on the empirical analysis results suggested that the cause of the severe haze was mainly due to the underlying transport of pollutants from Nanjing local and surrounding areas.