Study On Aerosol Optical Thickness And Particle Concentration In Xi'an Based On MODIS Inversion

In recent years,with the rapid development of China's economic Society and the advancement of urbanization,environmental pollution effect accumulate continuously,and the fine particulate matter(PM_2.5)and inhalable particles matter(PM₁₀)have become the most important pollutants in air pollution,however,Aerosol pollution has received extensive attention from domestic and foreign scholars due to its important impact on human health and environmental quality.Satellite remote sensing technology is widely used in atmospheric aerosol monitoring,because its characteristics of macroscopic,economy and high efficiency,the successful application of this technology is of great significance to monitor and evaluate air quality accurately.Xi'an is a typical city for air pollution monitoring and prevention in the west of China.So this paper select Xi'an as a research area,based on the inversion of aerosol optical depth by medium resolution imaging spectrometer MODIS,Combine with the particle concentration data and establish the relationship model of AOD,PM_2.5 and PM₁₀ concentration to achieve the goal of dynamic monitoring of air quality.The research contents are as follows:Firstly,the principle of aerosol inversion is expounded,confirm the method of aerosol inversion,and discuss the specific steps in the aerosol inversion process.Secondly,The Dark Dense Vegetation?DDV?method is used to retrieve the Aerosol Optical Depth in Xi'an by MODIS data to obtain the annual and seasonal aerosol distribution in this research.It is concluded that the distribution characteristics of aerosol in Xi'an tend to be higher in the north and lower in the south,the seasonal characteristics are the largest in summer,the second in spring,and smaller in autumn and winter.The MODIS AOD inversed in this study and MOD04 aerosol products agrees well,the comparing result shows that their distribution trend is consistent,and the correlation coefficient is 0.88,the MODIS data can monitor the aerosol well.And analyze the spatiotemporal distribution characteristics,dynamic transportation and diffusion of aerosols in Xi'an.Then,the mass concentrations of PM_2.5 and PM₁₀ in Xi'an from June 2014 to December2018 were calculated and analyzed,the key research in this part is spatial and temporal variation of particle concentration in Xi'an and analyze the correlation between the two,it is find that the correlation coefficient reached 0.834,the correlation is significant.Finally,the correlation between AOD,PM_2.5 and PM₁₀ mass concentration was improved by using vertical correction and humidity correction to amend AOD.Establish the relationship model of AOD to estimate mass concentration of PM_2.5 and PM₁₀ by regression analysis.Then,the optimal fitting model of annual and seasonal AOD estimation of PM_2.5 and PM₁₀ was obtained.