利用SARA结合高分一号数据反演气溶胶光学厚度

Inversion of Aerosol Optical Depth from GF-1 Data Using SARA

简化的气溶胶反演算法(simplified aerosol retrieval algorithm,SARA)摆脱了传统气溶胶光学厚度(aerosol optical depth,AOD)反演算法对查找表的依赖,在暗地表区域和亮地表区域均有较好的反演效果。由于中分辨率成像光谱仪(moderate resolution imaging spectroradiometer,MODIS)数据得到的AOD空间分辨率不足,因此在SARA的基础上结合更高空间分辨率的高分一号(GF-1)宽视场(wide field of view,WFV)数据开展了AOD反演研究。精度验证结果表明,反演结果与地基观测值具有较高的一致性,相关系数为0.962,均方根误差为0.073,平均绝对误差为0.051,预期误差为88.6%;反演结果与同期的MODIS气溶胶产品相比,空间上分布较为一致,且具有较高的空间覆盖度、分辨率和精度。针对高分数据的算法适用性研究表明,GF-1 WFV相机的观测几何和辐射定标误差引起的反演误差较小,绝对误差均在0.04以内,相对误差均在10%以内。

The simplified aerosol retrieval algorithm(SARA)gets rid of the dependence of traditional aerosol optical depth(AOD)inversion algorithm on the lookup table,and it can get great inversion effect in both dark surface area and bright surface area.Due to the spatial resolution of AOD obtained from the data of moderate resolution imaging spectroradiometer(MODIS)is insufficient,the AOD inversion is carried out with GF-1 wide field of view(WFV)data based on SARA.The retrieved AODs show a high consistency with ground-based AOD measurements,with average correlation coefficient 0.962,root mean square error0.073,mean absolute error 0.051 and expected error 88.6%.Compared with the MODIS aerosol products in the same period,the inversion results are more consistent in space and have higher spatial coverage,resolution and accuracy.Algorithm suitability study shows that the inversion error caused by the observation geometry and radiometric calibration error of GF-1 WFV camera is small,the absolute error is within0.04,and the relative error is within 10%.