PM_2.5 Concentration Quantitative Estimation Analysis Based On MODIS Of Lanzhou In Winter

Particulate matter (PM_2.5) is one of the important factors that affect the quality ofatmospheric environment. It not only causes serious harm to human health, but alsoaffects the global climate, as well as regional urban visibility. The study of itsdistribution features of a wide range is conducive to control PM_2.5concentrationdensity, improve urban air quality and reduce the effect of environmental pollution onhuman health. At present, China PM_2.5concentration monitoring lacks a completesystem because relying solely on the ground observation stations can not reflect thespatial distribution features of respiratory particulate matter in a wide range. In recentyears, with the continuous development of remote sensing technology, MODIS datahas been applied widely in various research fields because of its free charge, highspatial and temporal resolution, such as inversion in the aerosol optical depth,pollutants monitoring, sudden atmospheric pollution event monitoring and pollutantsregional transport research.Remote sensing retrieval of atmospheric particulate matter is built on the basis ofaerosol optical depth, aiming to estimate the spatial distribution concentration ofPM_2.5by establishing an AOD-PM relational model. In this essay, Lanzhou city istaken as an example, MODIS L1B data between December,1st,2011and March,1st,2012under the sunny environment has been adopted, a lookup table has been built bycalling the atmospheric transport model6S mode in the ENVI environment, using theIDL language to determine the reflectance, retrieve the aerosol optical thickness andanalysis the AOD spatial distribution characteristics in winter in Lanzhou city,obtaining the conclusion that: The aerosol optical thickness distribution in winter inLanzhou presents two high-value areas, Xigu District and Chengguan districtrespectively, which is in line with the fact that the two area have heavy pollutioncaused by their industrial concentration, population density and their consistent flowof people traffic. It is on this basis that in this essay, the AOD-PM_2.5regression modelhas been established, using Lanzhou ground measured PM_2.5data, winter PM_2.5concentration has been estimated in Lanzhou, and PM_2.5data validation analysisestimates of other time has been used to show that AOD-PM regression model isapplicable in the inversion of PM_2.5in Lanzhou city. Ultimately, the influencing factors of PM_2.5spatial distribution have been analysed in Lanzhou city and humanactivities, climate, topography are considered major factors causing the highconcentration of PM_2.5in Lanzhou city.