A Study On Characteristics Of Aerosol Inversion And Spatial And Temporal Distribution Over East China With MODIS Data

In this paper, firstly, modified DDV algorithm was used to retrieve the aerosol optical depth over east China. And then, the AOD retrieved from satellite was validated with AERONET solar direct radiance measurements. A certain error exists in the AOD obtained by modified DDV method, which mainly due to the uncertainty of the aerosol models and surface reflectance. Then, the suitable aerosol models was determined by using the method combining with ground-based observations and satellite remote sensing retrieval in the study area. And then, the paper attempts to retrieve aerosol and surface optical properties simultaneously from multi-angle data observed by the single satellite. Four perspectives were included in the paper as follows:(1) We used modified DDV algorithm to retrieve the aerosol optical depth, and got the spatial distribution of AOD over east China. A certain error was found in the AOD obtained by modified DDV method, when compared with AERONET solar direct radiance measurements, which reason was analyzed in the paper.(2) The suitable aerosol models was determined by using the method combining with ground-based observations and satellite remote sensing retrieval in the study area. In this paper, the urban and the city aerosol model defined by SRA in 6S model were optimized in east china: select aerosol model of dust particles 0.17, water-soluble 0.82 and soot 0.01 in summer and of dust 0.56, water-soluble 0.42 and soot 0.02 in winter. The results showed that: The retrieval aerosol optical depth correlation coefficient used the urban and the city aerosol model offered by SRA in 6S model and the optimized aerosol model are 0.36,0.42 and 0.75 in summer 0.41,0.44 and 0.64 in winter. It can be seen that if use appropriate aerosol model, the accuracy of aerosol optical depth retrieved can be greatly improved. Finally, NASA MODIS Level-3 production from 2001 to 2010 was utilized in order to analysis the characteristics of distribution of aerosol optical depth over East China area and surrounding areas.(3) This paper attempts to retrieve aerosol and surface optical properties simultaneously from multi-angle data observed by the single satellite. A case study was conducted using the MODIS 1B data of May4-8,2009. The resulting aerosol optical depth was compared with that of the aerosol product (MOD04), the correlation is 0.7914. The resulting land surface reflectance and that of the surface reflectance product (MOD09) appears good consistency. In this regard, the algorithm can obtain good accuracy of aerosol and surface reflectance result simultaneously, when the period of the aerosol is not change significantly.(4) NASA MODIS Level-3 production from 2001 to 2010 was utilized in order to analysis the characteristics of distribution and inter-annual,monthly,seasonal variation of aerosol optical depth over East China area and surrounding areas. The results showed that: the high value areas appeared in the Yangtze River Delta region. The AOD is higher in spring and summer than that in autumn and winter. In summer/autumn, fine-mode aerosol was the main component while in winter/spring, coarse-mode aerosol was the dominant component. The values of monthly AOD reached peak in June and dropped significantly in July and August in Henan, Anhui, Jiangsu and Shandong provinces.