MODTRAN （moderate resolution atmospheric transmission）的夜间辐亮度模式能够模拟夜间月球辐射传输，但是该模式中的月球辐照度模型在月相函数、月球反照率、日月距离以及地月距离的获取或计算方法上相对简略，导致月球辐照度模拟精度较低。利用扰动分析方法评价MODTRAN月球辐照度模型对月球模型参数的敏感性，结果表明影响MODTRAN月球辐照度模型精度的主要参数为地月距离、月相函数、月球反照率。为了分析MODTRAN月球辐照度模型适用范围，利用月球辐照度模型MT2009（Miller-Turner 2009）和SeaWiFS （sea-viewing wide field-of-view sensor）星上对月观测数据作为基准，对MODTRAN月球辐照度模型进行比较分析。结果显示：1）当波长大于0.675μm时，该模型模拟结果与2种辐射基准结果更为接近；2）月相角绝对值小于30°时，地月距离为390000km处附近的相对差异小于10%；3）月相角绝对值大于30°时，远地点附近的相对差异更小，当月相角范围在-41°~-30°/30°~41°时，远地点处最大相对差异在10%左右。研究表明MODTRAN夜间辐亮度模式只有在有限几何条件下适宜开展微光遥感载荷定标工作，以此为基础，未来将对MODTRAN的月球辐照度模型进行改进以便将MODTRAN充分利用到微光遥感中。
The night radiance mode of MODTRAN (moderate resolution atmospheric transmission) can simulate the lunar irradiance transfer, but the lunar-source model of MODTRAN simplifies the calculation of the lunar phase function, lunar albedo, sun-moon distances, and earth-moon distances. This simplicity can lead to some errors in the result, which affects the calibration accuracy. So, the sensitivity of MODTRAN lunar-source model to lunar model parameters is evaluated by using perturbation analysis method in this paper. The results show that the most important parameters affecting the accuracy of lunar irradiance simulation from MODTRAN are earth-moon distances, lunar phase function, and lunar albedo. This paper used lunar irradiance model MT2009 (Miller-Turner 2009) and SeaWiFS (sea-viewing wide field-of-view sensor) satellite data as benchmarks to compare and analyze lunar-source function of MODTRAN. The results showed that:1) Lunar irradiance calculated by MODTRAN were in better agreement with the values from MT2009 and SeaWiFS when wavelength was greater than 0.675μm; 2) When the absolute value of lunar phase angle was less than 30° and earth-moon distance was 390000km, the relative differences between MODTRAN and benchmarks were less than 10%; 3) When the absolute value of lunar phase angle was greater than 30° and the moon was closed to apogee, the relative differences between lunar irradiance model of MODTRAN and benchmarks were light. While lunar phase angle was between -41° and -30° or between 30° and 41° and the moon was closed to apogee, maximum relative difference was about 10%. This paper indicates that MODTRAN lunar-source model is suitable for low-light remote sensing calibration under specific conditions. More research work on MODTRAN lunar-source model will be carried out in the future.
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