结合高分五号卫星DPC和EMI数据反演陆地气溶胶

搭载于高分五号卫星的DPC和EMI载荷是我国新型的多角度偏振和紫外观测载荷，如何结合这两个载荷数据改进陆地气溶胶的反演是迫切需要开展研究的科学问题。本项目研究了结合暗目标法、紫外算法、多角度偏振算法的优势，构建了从DPC和EMI数据联合反演陆地气溶胶的算法。.首先针对EMI载荷特征，模拟紫外波段卫星信号，选择用于气溶胶指数计算的波段，实现吸收型气溶胶的提取；接着，统计分析MODIS红光和蓝光波段地表反射率函数关系，利用地物光谱数据定量评估波段响应的影响，建立基于DPC的总气溶胶光学厚度的扩展暗目标法反演算法；然后，基于紫外算法和扩展暗目标法反演结果，约束多角度偏振数据的最优匹配算法，反演水溶型、黑炭型气溶胶比例信息，改进气溶胶反演结果；最后，以华北地区为实验区，利用太阳光度计等地基观测数据验证本项目气溶胶反演结果的精度，借助MODIS、VIIRS等传感器气溶胶产品评估对本项目模型的适用性。

The DPC and EMI sensors on GF-5 satellite are new Multi-angle Polarization and ultraviolet observation sensor in China. How to improve the inversion of terrestrial aerosols by combining these two sensor data is a scientific problem that needs to be studied urgently. This project studies the advantages of combining dark target, near-UV and multi-angle polarization algorithms, and improves a joint inversion algorithm of terrestrial aerosol from DPC and EMI data..Firstly, according to the EMI sensor characteristics, simulate the satellite signal in the ultraviolet bands, select the bands for aerosol index calculation, and extract absorbent aerosols. Secondly, statistical analysis of the surface reflectance function in red and blue bands of MODIS is carried out, and the influence of band response is quantitatively evaluated by using spectral data of typical land surfaces, and the extended dark target method of total aerosol optical depth based on DPC is established. Then, based on the inversion results of near-UV and extended dark target algorithms, the best fitting method of multi-angle polarization data is constrained to retrieve the proportion of water-soluble and black-carbon aerosols and improve the aerosol inversion results. Finally, taking North China as the experimental area, the accuracy of the aerosol inversion results of this project is validated by using ground-based observation data such as sun-photometer, and the applicability of our algorithm is evaluated by the aerosol product of sensors such as MODIS, VIIRS and so on.