【摘要】 测量地表反射率对研究地物光谱特征以及卫星地表产品检验具有重要意义。利用地物光谱仪获得青藏高原阿里地区的沙地地表反射率，并研究分析其典型光谱特征。针对Terra和Aqua卫星的中分辨率成像光谱仪(MODIS)的地表反射率产品(MOD09/MYD09)和地表反照率产品(MCD43 A4)开展真实性检验和误差影响分析。结果表明，阿里地区戈壁具有典型沙地光谱特征，各波段的地表反射率数值在0.08～0.35之间，在300～700 nm光谱范围的地表反射率随波长增大而增加，而在750～1 750 nm光谱范围的地表反射率变化较小。与我国敦煌辐射校正场的沙地反射率相比，光谱曲线相似度很高，光谱夹角为2.18°。星地对比的结果受观测几何和大气光照条件的影响，下午星Aqua产品验证效果优于上午星Terra,平均误差约为5%,这与MODIS官方标称的精度相一致。研究表明，阿里地区沙地的光谱特征稳定且有代表性，是我国光学卫星在轨辐射定标和检验的理想场地。更多还原

【Abstract】 Measuring surface reflectance is crucial for studying the spectral characteristics of ground objects and inspecting satellite surface products. This paper uses a ground spectrometer to measure the sand surface reflectance in the Ali region of the Qinghai-Tibet Plateau, and studies and analyzes its typical spectral characteristics. Conduct authenticity testing and error impact analysis on the surface reflectance products(MOD09/MYD09) and surface albedo products(MCD43 A4) generated by the Moderate Resolution Imaging Spectroradiometer(MODIS) aboard the Terra and Aqua satellites. The results indicate that the Gobi in the Ngari region exhibits typical sand spectral characteristics. The surface reflectance values in each band range from 0.08 to 0.35. The surface reflectance in the 300～700 nm spectral range increases with the wavelength, while in the 750～1 750 nm spectral range, the surface reflectance also increases with the wavelength. The surface reflectance changes less in the nm spectral range. Compared to my country’s sand reflectance of the Dunhuang radiation correction field, the spectral curve is very similar, and the spectral angle is 2.18°. The observation geometry and atmospheric lighting conditions influence the results of the star-ground comparison. The validation accuracy of the afternoon star Aqua product is superior to that of the morning star Terra, with an average error of approximately 5%, aligning with the official nominal accuracy of MODIS. Research shows that the spectral characteristics of the sandy land in the Ngari area are stable and representative, making it an ideal site for on-orbit radiation calibration and inspection of our country’s optical satellites.更多还原