大气气溶胶多角度偏振探测仪在轨辐射精度与真实性验证研究

In Flight Radiation evaluation and validation of Directional Polarimetric Camera

大气气溶胶多角度偏振探测仪(DPC)是由中国科学院安徽光电精密机械研究所光学遥感中心研制的国内首台(业务化运行的)多角度偏振对地观测卫星载荷,具有偏振谱段(490,670,865nm)和5个非偏谱段(443,565,763,765,910nm),对同一目标观测角度数可达9个。观测数据可用于大气气溶胶、地表植被分布、海水叶绿素浓度以及云分布等多项科学研究。然而,这些数据的可靠性依赖于DPC在轨辐射检测的精度与真实性。在总结多种光学遥感器绝对辐射定标测试方法的基础上,将敦煌外场定标测试验证,沙漠场景辐射精度验证与海洋场景耀光区测试相结合,相互对比验证了DPC在轨辐射探测精度,所观测的辐射数据为大气和地表产品的生产提供了必要基础。

The directional polarimetric camera(DPC)is the first(operational running)directional polarimetric instrument of Earth Observation Satellite designed by the optic remote sensing center of Anhui institute of optics and fine mechanics,Chinese Academy of Sciences,which has 3polarized bands(490,670,865nm)and 5unpolarized bands(443,565,763,765,910nm)and can provide as much as 9viewing directions for an observing object,which is capable of providing reliable measurements on directional characteristic of reflectance of earth-atmosphere system and polarized solar radiation.The science datasets can be used to the researches of atmospheric aerosols,the distribution of surface vegetation,the chlorophyll concentration of ocean and the distribution of cloud.However,the reliability of measurements depends on the accuracy of onboard calibration of the DPC.Because there is no onboard calibrator,utilizing natural scene for a substitution becomes the main method of onboard calibration.Thus,the comparison of the statistics of the calibration coefficients of different natural scenes is the only way to validate the calibrating accuracy of DPC.This paper introduces several common methods of absolute calibration of sensors and validates the accuracy of onboard calibration by respectively comparing the calibrating results from Dun Huang sites、desert sites and sun glint area over ocean sites,which constructed a necessary base for the successful use of the generation of atmosphere and surface products.