通道式辐射计自动观测数据的反射率光谱拓展方法

A Method for Hyperspectral Reflectance Reconstruction from Automatic Observation with Multispectral Radiometer

为了适应光谱特性、观测角度不同的卫星载荷定标需求,提出了一种考虑地表双向反射分布函数特性(BRDF)的通道式辐射计光谱反射率拓展方法。利用国家高分辨遥感综合定标场的星地观测数据,对提出的自动观测数据光谱拓展方法进行验证。结果表明,通道反射率光谱拓展结果与地物光谱仪实测值相比平均相对差异为2.67%;而与Sentinel-2A/B卫星实际观测结果相比,各波段差异均在10%以内。进一步开展了不确定性分析,利用提出的光谱拓展方法获得的地表光谱反射率不确定度为3.34%,基于该方法的Sentinel-2A/B蓝、绿、红、近红外波段辐射定标总不确定度分别为3.35%,3.77%,4.10%,4.29%。

A method for hyperspectral reflectance reconstruction from observed data with an automatic multispectral radiometer is presented. The surface bidirectional reflectance distribution function effect is considered in our method in order to meet the on-orbit calibration requirement of sensors with different spectral characteristics and viewing angles. The satellite-ground synchronous observation data from the National Calibration and Validation Site for High Resolution Remote Sensors are used to validate the proposed method. The results show that the average relative difference between the reconstructed hyperspectral reflectance and the measured reflectance by a field spectrometer is about 2.67%. Compared with observation values of Sentinel-2 A/B, the difference is less than 10% for each band. Furthermore, the results of uncertainty analysis show that uncertainty of hyperspectral reflectance obtained by the proposed method is about 3.34%. The overall uncertainty of radiometric calibration at blue, green, red, and near-infrared bands of Sentinel-2 A/B is about 3.35%, 3.77%, 4.10%, and 4.29%, respectively.