【摘要】 为解决目前城市上空气溶胶光学厚度反演中城市地表复杂与卫星分辨率较低的问题,提出一种改进的反演算法。首先利用波段修正后的MODIS(moderate resolution imaging spectroradiometer)地表反射率产品探究了城市区与非城市区在红、蓝波段地表反射率的比值统计关系,然后运用6S辐射传输模型构建查找表反演获得北京及其周边地区的AOD分布。通过AERONET(aerosolrobotic network)观测数据验证算法的反演精度,利用相对平均偏差RMB、平均绝对误差MAE、平均相对误差MRE、均方根误差RMSE和相关系数R共5个指标进行衡量,结果表明:反演结果与AERONET观测数据具有较高的一致性,5个观测站点的R都大于0.95,MAE范围为0.037～0.065,MRE范围为24.08%～39.54%,RMSE范围为0.047～0.083,RMB范围为0.86～1.452,且所有观测点对中有超过84%满足MODIS气溶胶产品的误差精度要求,说明算法对获取高分辨率城市地区的AOD具有较好的可行性。更多还原

【Abstract】 A modified retrieval algorithm was proposed to overcome low spatial resolutions and high reflectance during the process of aerosol optical depth(AOD) retrieval in urban areas. First, the ratio of reflectance between red and blue bands in urban and non-urban areas was studied using MODIS reflectance products following band correction. Then, the 6 S radiation transfer model was utilized to build lookup tables for the retrieval of AOD over Beijing and its surrounding areas. Ground-based AERONET observations from five sites(Beijing, Beijing_CAMS, Beijing_RADI, Beijing_PKU, and Xianghe) were used to validate the retrieved AOD. The results showed that the correlation coefficients were all above 0.95, the mean absolute error was from 0.037 to 0.065, the mean relative error was from 24.08% to 39.54%, the root mean square error was from 0.047 to 0.083, and the relative mean bias was from 0.86 to 1.452. In addition, more than 84% of the inversion results met the error accuracy requirements for MODIS aerosol products. The study concluded that the algorithm is effective at obtaining AOD in high-resolution urban areas更多还原