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月亮辐照度是可见近红外波段一种稳定的辐射参考基准,对月观测已成为星载遥感仪器辐射定标和验证的一种新方法。风云三号03星(FY-3C)中分辨率光谱成像仪(Moderate Resolution Spectral Imager,MERSI)增加了对月观测功能,改进了太阳反射波段的在轨辐射定标。本文收集分析了MERSI在轨工作以来的全部11组对月观测数据,利用通道间辐照度比值方法移除月相角,日—月—星相对距离等因素对月亮辐照度观测值的影响,开展了可见光近红外波段的辐射定标工作,实现了MERSI太阳反射通道的辐射定标系数动态跟踪和评估。通过线性回归及统计发现,通道8辐射响应的年衰减率达到了14.55%,通道9达到了8.42%,通道1、6、10、11、16和19的年衰减率为1.15%—4.72%,其余通道未检测到衰减。研究结果可以用于订正MERSI数据的辐射定标系统性偏差,提高MERSI全寿命期的辐射定标精度。
The moon irradiance is a stable radiation reference in the visible near-infrared band. The moon observation has become a new method for radiation calibration and verification of spaceborne remote sensing instruments. FY-3C Moderate Resolution Spectral Imager (MERSI) adds on-the-moon observations and improves on-orbit radiation calibration in the solar reflection band. In this paper, we collected and analyzed all 11 pairs of monthly observation data since MERSI was in orbit, and used the method of irradiance ratio between channels to remove the effects of moon phase angle and relative distance of day-moon-moon on the moon irradiance observation , Carried out the visible near infrared band radiation calibration work to achieve the MERSI solar reflection channel radiation calibration coefficient of the dynamic tracking and evaluation. Through linear regression and statistics, the annual attenuation rate of channel 8 radiation reached 14.55%, channel 9 reached 8.42%, and the annual attenuation rates of channels 1, 6, 10, 11, 16 and 19 were 1.15% -4.72% The remaining channels did not detect any attenuation. The results of the study can be used to correct the systematic deviation of the radiation calibration of the MERSI data and improve the radiation calibration accuracy over the MERSI lifetime.