建立了基于星上定标光谱仪(SCS)太阳漫反射板的绝对辐射定标模型。通过对2018年12月12日星上漫反射板定标数据进行处理,得到SCS绝对辐射定标系数。以TERRA MODIS为参考载荷,对SCS辐射定标系数进行三次交叉验证。为了提高光谱匹配精度,消除光谱设置的差异,对SCS各通道实测等效辐亮度进行插值迭代,得到光谱辐亮度,并将该结果与TERRA MODIS光谱响应函数进行积分,得到预测等效辐亮度。通过比较发现,MODIS各通道预测与实测等效辐亮度具有非常好的一致性,相对偏差均值最大为2.78%,表明SCS辐射定标系数真实可靠,具有较高的定标精度。同时也验证了双向反射分布函数(BRDF)、透过率等参数具有较高的测试精度。

Based on the solar diffuser of the satellite calibration spectrometer (SCS), we establish an absolute radiometric calibration model. We can obtain the absolute radiometric calibration coefficient of SCS by processing the on-board diffuser calibration data obtained on December 12, 2018. The radiometric calibration coefficient of SCS is cross-validated thrice using TERRA MODIS, which is used as the reference load. In order to improve the accuracy of spectral matching and to eliminate the difference in spectra setting , the measured equivalent radiance of SCS is interpolated to obtain the spectral radiance, and subsequently the obtained results are integrated with the spectral response function of TERRA MODIS to obtain the predicted equivalent radiance. The comparison results show that the predicted equivalent radiance of each band of MODIS is in consistency with the measured equivalent radiance and the maximum relative deviation is 2.78%, which indicates that the SCS radiometric calibration coefficient is reliable and has a high calibration accuracy. It is verified that the parameters such as bidirectional reflection distribution function (BRDF) and transmittance have relatively high test precision.