Optical Thickness Inversion Of Fine Aerosol Particles Based On DPC Multi-angle Polarization Data

Aerosols are an important part of the earth-atmosphere system,which can have an important impact on the climate environment through indirect radiation/direct radiation,and also have an impact on human health.At present,there are two main methods to study the optical properties of aerosols: ground-based remote sensing and satellite remote sensing.Polarization detection in satellite remote sensing is a research hotspot in recent years.In order to meet the application requirements of the optical thickness of aerosol fine particles in the field of atmospheric environment,the high-precision inversion of the optical thickness of aerosol fine particles can be achieved by using the atmospheric multi-angle polarization detector（DPC）independently developed in China.Aiming at the problem that the semi-empirical model in the aerosol fine particle inversion algorithm on the DPC platform is not suitable for the estimation of urban surface polarization reflectance.In this study,based on DPC multi-angle polarization data,a research on optical thickness inversion of aerosol fine particles was carried out,including the following three parts:First,the analysis and calculation of the parameters of the vector radiation transfer equation.Based on the MIE scattering principle,the scattering/polarization phase function of a single spherical particle is calculated,and the aerosol spectral distribution function and parameters are introduced to obtain the aerosol polarized reflectance;the atmospheric molecular polarized reflectance is calculated by the empirical formula;through the vector radiation transfer software（6SV）Calculate atmospheric molecular transmittance and atmospheric total scattering transmittance.Second,an inversion algorithm for the optical thickness of aerosol fine particles based on the empirical orthogonal function is proposed,and the method for deriving the empirical orthogonal function on the polarization data is analyzed,and its application on the DPC platform is analyzed,and the surface polarization inversion rate is calculated and combined with In the first part,complete the optical thickness inversion process of aerosol fine particles.Thirdly,in order to fully verify the optical thickness inversion results of aerosol fine particles in this study,an intuitive comparison was made with the aerosol products of the MODIS satellite,and a quantitative comparison with the AERONET groundbased observation results,all of which were in good agreement.: The correlation coefficients of the comparison and verification results of the three sites are: 0.97,0.96,0.9;the mean absolute error: 0.08,0.07,0.12;The monthly average data of particle optical thickness was analyzed,and the change of the optical thickness of aerosol fine particles in Shandong in 2019 was analyzed.