神舟3号飞船中分辨率成像光谱仪场地替代定标新方法研究

New Method Study of Sites Vicarious Calibration for SZ-3/CMODIS

神舟3号飞船(SZ-3)搭载的中分辨率成像光谱仪(CMODIS)是我国下一代对地环境卫星遥感器的试验仪器,能获取地气系统30个可见光-近红外通道观测数据,这些高光谱数据应用,特别是定量遥感产品反演受到辐射定标的严重制约。文章在传统的在轨遥感器场地辐射校正基础上,提出了星地准同步观测场地辐射校正新方法,在缺少足够地面同步观测数据情况下,实现了CMODIS场地辐射校正,并达到了预期辐射校正精度要求。同时基于敦煌场地反射率光谱光滑的特点,利用EOS/MODIS大气订正后的通道反射比进行光谱内插,开展一种新的交叉定标方法试验。文章针对SZ-3/CMODIS数据,用此两种方法独立进行场地替代定标,试验结果能够相互验证,表明这两种定标方法切实可行,定标精度可靠,为我国下一代环境气象卫星传感器在轨辐射定标提供了新的定标方法和技术。

Chinese MODIS onboard ShenZhou-3 spacecraft （SZ-3/CMODIS） is the experiment instrument of next generation environmental and meteorological satellites. CMODIS can obtain the data of 30 bands in visible and near infrared region from the earth-atmosphere system. But the quantitative application of these data is limited by radiometric calibration. The present paper addresses a new concept of semi-synchronous measurements with satellite observation based on the traditional sites vicarious calibration. It can meet the expected calibration requirement under the condition of no enough ground measurements. In addition to this, the reflectance of Dunhuang Calibration site is very smooth on the Vis-NIR speetral region. A new cross-calibration was also condueted experimentally using the spectral interpolation of atmospheric correction reflectance from EOS/MODIS, The results of these two methods were compared and verified with each other and showed that they are effective and reliable. These new radiometric calibration methods provide good technique experiences for the next generation in-flight optical sensors.