基于循环采样统计的敦煌辐射校正场表面反射比空间变异特征研究

Research on viogram feature of surface reflectance of Dunhuang radiation calibration site based on recycling sampling method

利用地学统计中的变差函数,采用循环采样法对敦煌辐射校正场表面反射比的空间分布特征进行了测量和分析,结果表明,其可见光光谱区表面反射比的空间变程约为20～50 m。目前使用的同步测量采样范围(<5 m)明显小于光谱数据的空间变程,使得测量数据的随机性误差较大,不能准确地代表大尺度的平均反射比。为了减少测量尺度差异造成的偏差,地表同步反射比测量的空间采样范围应该不小于卫星光谱测量数据的空间变程。

Viogram in geostatistics and the recycling sampling method were used to study the space variation feature of surface reflectance of Dunhuang radiometric calibration site（DRCS）.The statistic results show that the range of spatial dependence of DRCS surface reflectance in visual spectral range are between 20 m to 50 m which are much larger than the sampling range（ 5 m） used in the operational calibrating methods.Therefore,the ground reflectance sampling space should be larger than its spatial dependence range so as to avoid the bias due to the size difference between satellite and ground measurements.