Research On Aerosol Components Retrieval Based On Polarization Multi-angle Satellite

Satellite remote sensing observations of atmospheric aerosol components are of great significance to the study of global climate change,human health and air pollution,which is because the complex components can not only affect the radiation balance as cloud condensation nuclei and ice nuclei,but also cause a variety of human diseases.Satellite remote sensing,due to its advantages of wide monitoring range and real-time performance,has been used in remote sensing of aerosol components in recent years.At present,there are still few studies on satellite remote sensing of aerosol components,and the inversion algorithms are mainly constructed for absorptive components,which are difficult to compare and verify with chemical transmission models.Following aims of this paper:(1)Research on the aerosol composition inversion algorithm based on polarized multi-angle satellites:Addressing the problem that the aerosol components obtained by the existing methods lack organic matter,a hygroscopic aerosol composition estimation method based onκ-K(?)hler theory is proposed,which jointly retrieves water-soluble and water-insoluble organic components.The problem of the refractive index of a single solution measured in the laboratory can be used to calculate the birefringence index of a multi-solution system based on the Lorentz-Lorenz theory;the spectral difference identification method is used to distinguish the absorbing and non-absorbing aerosol components,and the absorbing aerosol components are combined.Black carbon and brown carbon components are distinguished by the spectral changes of the satellite;using the complex refractive index conversion model of the Maxwell-Garnett theory approximated by the effective medium to solve the problem of refractive index calculation of mixed aerosols,and the forward modeling of the satellite aerosol composition inversion algorithm is realized,which is to establish a unique conversion model between the satellite radiation value and the volume ratio of aerosol components.(2)Sensitivity test of the aerosol composition inversion algorithm to different inversion parameters:In order to analyze the sensitivity of the aerosol composition inversion algorithm proposed in this study to different inversion parameters,a series of sensitivity numerical experiments were designed based on the fixed variable method for the observation wavelength of multi-angle polarized satellites,and the vector radiation transfer model was used to calculate the polarization information of the satellite,quantize each channel quantifies the sensitivity of the observations to the inversion accuracy of aerosol optics,microphysics,and composition parameters.The results show that the multi-angle observation significantly increases the amount of applicable data,has better constraints on the inversion of microphysical parameters,and is more suitable for aerosol composition inversion research.The sensitivity of the satellite aerosol composition inversion algorithm to the fine mode of the complex refractive index of the aerosol microphysical parameters is generally high,the correlation coefficient R is 0.92,and the relative error is 0.01.The correlation coefficient R of the volume fraction of black carbon aerosol components is as high as0.92,and brown carbon is second only to black carbon with a correlation coefficient of0.88.(3)Joint verification of aerosol composition inversion algorithm based on ground-based and reanalysis data.Based on the satellite aerosol composition inversion algorithm proposed in this paper,the observation results of aerosol composition in China are comprehensively verified.The verification results show that the mass ratios of black carbon,inorganic salts and organic aerosols(8%,49%,43%)and the mass ratios of ground chemical sampling analysis results(11%,49%,40%)had high consistency.In this study,the daily atmospheric column aerosol composition products from the MERRA2 reanalysis data were compared with the spatial distribution of aerosol composition retrieved in this study.The results show that the two have similar spatial distribution,and the component content of MERRA2 is underestimated to some extent.(4)Analysis of the spatiotemporal evolution characteristics of aerosol components based on multi-angle polarization satellite inversion.In this study,the spatial and temporal distributions of optical,microphysical and chemical composition parameters of regional aerosols in China in January 2012 were retrieved based on POLDER.The results show that black carbon is mainly distributed in areas dominated by anthropogenic activities such as the Beijing-Tianjin-Hebei and Fenwei Plains,while the overall content of dust is higher in northern China.The concentration of black carbon and inorganic salts in the Beijing-Tianjin-Hebei region is higher than other regions,with an average of 1.5 mg/m~2 and 356 mg/m~2,respectively;the Yangtze River Delta has higher brown carbon(16.1 mg/m~2),sea salt(129.9 mg/m~2)and the mass concentration of inorganic salts(400 mg/m~2).The organic carbon mass concentration(232.7 mg/m~2)in the Fenwei Plain is higher than that in other regions.The black carbon content in this region is second only to the Beijing-Tianjin-Hebei region,and the atmospheric column content reaches 0.8 mg/m~2.In winter,the dust concentration in northern my country is generally higher,and the concentrations in northeast China and Xinjiang are as high as 862.2 mg/m~2 and 831.8 mg/m~2.The polarization multi-angle satellite aerosol composition inversion algorithm proposed in this study effectively improves the aerosol composition inversion accuracy,provides a favorable tool for studying the spatiotemporal distribution characteristics of different aerosol compositions,and promotes the development of satellite aerosol composition inversion methods.