Intercomparison of On-Orbit Calibration Consistency Between Terra and Aqua MODIS Reflective Solar Bands Using the Moon
Intercomparison of On-Orbit Calibration Consistency Between Terra and Aqua MODIS Reflective Solar Bands Using the Moon
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DOI：
10.1109/lgrs.2008.2005591
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发表时间：
2008-10
影响因子：
4.8
通讯作者：
X. Xiong;Junqiang Sun;W. Barnes
中科院分区：
文献类型：
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作者：
X. Xiong;Junqiang Sun;W. Barnes
两个几乎相同的中分辨率成像光谱仪传感器，一个在Terra上，另一个在Aqua卫星上，目前正在空间运行，在36个光谱波段进行连续的全球观测：20个反射太阳波段和16个热发射波段。对于波长为0.41至2.1微米的MODIS RSB，传感器指定的校准精度要求为反射率为plusmn2%，辐射率为plusmn5%。它们在轨道上由太阳漫射器（SD）和SD稳定性监测器进行校准。此外，还定期安排对月球的观测，以监测RSB辐射校准的稳定性。这封信描述了一种相互比较的方法，用于评估Terra和Aqua MODIS遥感卫星之间的校准一致性和每个光谱波段探测器之间的校准差异。它介绍了来自Terra和Aqua的中分辨率成像光谱仪在其重叠的使命操作的月球观测相互比较的结果。该方法使用来自月球模型的预测月球辐照度，以消除每个传感器进行的不同观测之间的月球观察几何差异。结果表明，Terra和Aqua的MODIS遥感卫星在月球观测过程中，除了具有电子串扰或饱和的波段外，都被一致地校准到± 1%以内。对于任何一个光谱带内的探测器，校准误差小于± 0.5%。这里开发的方法可以应用到其他传感器的相互比较研究。
Two nearly identical Moderate Resolution Imaging Spectroradiometer (MODIS) sensors, one on the Terra and the other on the Aqua satellite, are currently operating in space, making continuous global observations in 36 spectral bands: 20 reflective solar bands (RSBs) and 16 thermal emissive bands. For MODIS RSB with wavelengths from 0.41 to 2.1 mum, the sensor-specified calibration-accuracy requirements are plusmn2% for reflectance and plusmn5% for radiance products. They are calibrated on-orbit by a solar diffuser (SD) and an SD stability monitor. In addition, lunar observations are scheduled regularly to monitor the RSB radiometric calibration stability. This letter describes an intercomparison method developed for evaluating the calibration consistency between Terra and Aqua MODIS RSBs and calibration differences among detectors in each spectral band. It presents intercomparison results derived from Terra and Aqua MODIS lunar observations made over their overlapped mission operation. This method uses predicted lunar irradiances derived from a lunar model to remove lunar-viewing-geometry differences among different observations made by each sensor. The results, excluding the bands which either have electronic crosstalk or saturate during lunar observations, show that the Terra and Aqua MODIS RSBs have been consistently calibrated to within plusmn1%. For the detectors within any one spectral band, the calibration differences are less than plusmn0.5%. The methodology developed here can be applied to other sensors for intercomparison studies.