地基月球反射光谱观测模拟研究

发布时间：2018-04-04 05:25

本文选题：地基观测　切入点：月球反射光谱　出处：《吉林大学》2016年硕士论文

【摘要】：月球是距离地球最近的天体,针对月球辐射的相关研究从未停止过。目前,针对该领域的研究主要体现在对月观测卫星的数据获取及分析,已经具备相对成熟的算法及研究成果,但地基观测方面国内还有所欠缺。地基观测可为获取月球辐照度提供长期的、稳定的手段,在数据质量和稳定性上有较高的准确度,并且可建立长期的、可供今后对月观测领域研究的天体数据库;同时,由于月球是一个稳定的辐射源,地基月球反射光谱的模拟也为今后地球卫星的辐射定标提供定量化参考,对于我国在对月观测领域的研究具有重要意义。地基月球反射光谱的模拟涉及到月球辐射在地球大气中的传输过程模拟计算。大气是影响辐射传输的关键性因素,各种大气组分的存在会对辐射传输产生包括吸收、散射及折射等作用,在一定程度上会改变到达地表的月球辐照度量值。因此,有必要模拟大气中的辐射传输过程。本文选取大气辐射传输模型MODTRAN为研究工具,模拟地基观测条件下大气对于月球辐射传输的影响。输入参数包括大气计算模式、大气典型组分(H2O、CO2、CH4、N2O、CO等)及气溶胶的吸收和散射作用、观测几何、传感器参数等,计算出400nm-2500nm范围内不同波长大气对于辐射的衰减系数。当月球入射辐射及已有反射率已知时,可根据计算出的月球反射辐射及大气衰减系数,计算出地球表面接收的月球辐射量,从而得到地基月球反射率。然而,不同的大气参数组合会模拟不同的大气辐射传输过程。因此,根据观测条件的要求,建立了不同月球天顶角及相关几何参数的组合,分别对不同大气辐射传输过程进行模拟计算,为最终大气衰减系数的确定提供保障。选择观测波段为400nm-2500nm的高光谱成像光谱仪,开展地基月球观测试验。通过光纤与计算机相连,选择晴空夜晚对月球的辐照度数据进行连续观测和数据处理,得到月球反射光谱数据。与模拟计算结果对比分析,找到了实测数据与模拟数据间的差异。根据观测结果对MODTRAN中输入参数做了相关的调整和完善,得到了较为准确的模拟反射光谱数据,完成了地基月球反射光谱的模拟计算。美国的对月地基观测系统ROLO处于该领域研究的前沿地带。地基观测月球反射率的模拟研究,可为我国相关研究提供定量化的参考和借鉴,为今后对月观测仪器的定标及研制提供重要的指示性意义。
[Abstract]:The moon is the closest celestial body to Earth, and the study of lunar radiation has never stopped.At present, the research in this field is mainly reflected in the data acquisition and analysis of the lunar observation satellite, and has been relatively mature algorithms and research results, but there are still some deficiencies in the field of ground-based observation.Ground-based observations can provide a long-term, stable means of obtaining lunar irradiance, have higher accuracy in terms of data quality and stability, and establish a long-term database of celestial bodies for future research in the field of lunar observations; at the same time,As the moon is a stable source of radiation, the simulation of the ground-based reflection spectrum also provides a quantitative reference for the future radiometric calibration of Earth satellites, which is of great significance for the study of the field of lunar observation in China.The simulation of the reflection spectrum of the ground-based moon is related to the simulation calculation of the transmission process of the lunar radiation in the earth's atmosphere.The atmosphere is the key factor affecting the radiation transfer. The presence of various atmospheric components will produce the effects of absorption, scattering and refraction on the radiation transfer, and to some extent will change the lunar irradiance to the surface.Therefore, it is necessary to simulate the radiation transfer process in the atmosphere.In this paper, the atmospheric radiation transfer model (MODTRAN) is chosen as the research tool to simulate the influence of the atmosphere on the lunar radiation transfer under the condition of ground-based observation.The input parameters include the atmospheric calculation model, the atmospheric typical component H _ 2O _ 2CO _ 2H _ 2CO _ (4) H _ 4N _ 2O _ (CO), the absorption and scattering of aerosol, the observed geometry and sensor parameters, etc. The attenuation coefficients of atmospheric radiation at different wavelengths in 400nm-2500nm range are calculated.When the incident radiation and reflectivity of the moon are known, the amount of lunar radiation received on the surface of the earth can be calculated according to the calculated reflection radiation and attenuation coefficient of the atmosphere, and the reflectivity of the ground-based moon can be obtained.However, different combinations of atmospheric parameters simulate different atmospheric radiation transfer processes.Therefore, according to the requirements of the observation conditions, the combinations of different lunar zenith angles and related geometric parameters are established, respectively, to simulate the different atmospheric radiation transfer processes, which provides a guarantee for the determination of the final atmospheric attenuation coefficient.A hyperspectral imaging spectrometer with 400nm-2500nm was selected to carry out the ground-based lunar observation experiment.By connecting the optical fiber to the computer, the lunar irradiance data are continuously observed and processed in the clear sky at night, and the reflection spectrum data of the moon are obtained.The difference between the measured data and the simulated data is found by comparing with the simulation results.According to the observation results, the input parameters in MODTRAN are adjusted and perfected, and more accurate simulated reflection spectrum data are obtained, and the simulation calculation of the lunar reflection spectrum on the ground is completed.The American lunar-ground observation system (ROLO) is at the forefront of this field.The simulation study of the lunar reflectivity of ground-based observation can provide a quantitative reference for the related research in China and provide important indicative significance for the calibration and development of the lunar observation instrument in the future.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P184

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