粗糙月面微波辐射亮温计算方法研究

发布时间：2018-07-12 15:35

本文选题：大尺度粗糙度 + 小尺度粗糙度　；参考：《华中科技大学》2012年硕士论文

【摘要】：探测月壤厚度对月球资源的开发和利用有重要的研究价值，建立完善准确的亮温辐射传输模型是反演的关键。月壤表面粗糙度是研究的难点之一，考虑粗糙度对辐射亮温的影响也是待研究解决的问题，也是本文的研究对象。本文以国家863高科技项目重大研究课题探月工程为依托，研究月表粗糙度与月表微波辐射亮度温度之间的关系模型，并以嫦娥二号卫星携带的微波辐射计探测的亮温数据作为检验模型正确性的依据。本文首先结合嫦娥一号激光高度计7km分辨率的高程数据解析Apollo着陆点地区56k m×56km范围内的地形粗糙度信息。接着将大尺度的粗糙度对有效太阳辐照度的修正运用到热传导方程的边界条件中，建立大尺度粗糙面分层模型求解月壤温度剖面。月表即使大范围内平坦（例如月海），也会有微小的起伏，这种起伏通常在厘米甚至毫米级，与高频（如19.35GHz）入射波的波长可比拟。根据辐射传输理论和粗糙面随机散射理论，运用二阶微扰法，建立上界面为粗糙面的分层微波辐射传输亮温模型。这样将大尺度的温度剖面计算模型和小尺度的亮温辐射传输模型结合起来建模，使模型对不同的月表地形特征更具有通用性。计算结果表明，月球表面的大尺度粗糙度使太阳辐照减小，从而使月壤剖面的温度降低，月表辐射亮温也随着粗糙度的增加而降低。微波辐射计四个通道中，3GHz频段的波长最长，对月壤的穿透深度最大，因此这个频段的模拟亮温对反演月壤厚度具有很大的价值。小尺度粗糙度的引入使月表辐射亮温增加，，在3GHz、7.8GHz和更高频率19.35GHz，模拟亮温值与嫦娥二号实测亮温值相比差距更小。
[Abstract]:The exploration of lunar soil thickness is of great value to the development and utilization of lunar resources. The key to inversion is to establish a perfect and accurate radiative transfer model of bright temperature. The surface roughness of lunar soil is one of the difficulties in the study. It is also a problem to be solved to consider the influence of roughness on the radiant brightness temperature, which is also the research object of this paper. In this paper, based on the lunar exploration project of the national 863 high-tech project, the relationship between the surface roughness and the temperature of microwave radiation is studied. The bright temperature data detected by the microwave radiometer carried by Chang 'e-2 satellite are taken as the basis for checking the correctness of the model. In this paper, the height data of the 7km resolution of the Chang 'e-1 laser altimeter are firstly used to analyze the terrain roughness information in the area of the Apollo landing site in the range of 56km 脳 56km. Then the large scale roughness correction to the effective solar irradiance is applied to the boundary condition of the heat conduction equation, and a large scale rough surface stratification model is established to solve the lunar soil temperature profile. Even if the moon surface is flat in a wide range (for example, the moon sea), there will be small fluctuations, usually in centimeters or millimeters, comparable to the wavelength of high frequency (such as 19.35 GHz) incident waves. According to the radiation transfer theory and the rough surface random scattering theory, using the second-order perturbation method, a laminar microwave radiation transmission bright temperature model with the upper interface as a rough surface is established. In this way, the large scale temperature profile calculation model and the small scale bright temperature radiation transfer model are combined to model the model, which makes the model more general for different monthly surface topographic features. The calculated results show that the large scale roughness of the lunar surface decreases the solar irradiation, thus reducing the temperature of the lunar soil profile, and the radiant brightness temperature of the lunar surface decreases with the increase of the roughness. The wavelength of 3 GHz band is the longest and the penetration depth of the lunar soil is the largest among the four channels of microwave radiometer, so the simulated bright temperature in this frequency band is of great value in retrieving the thickness of lunar soil. With the introduction of small scale roughness, the radiant brightness temperature of the monthly surface is increased, and the difference between the simulated brightness temperature and the measured light temperature of Chang 'e-2 is smaller at the frequency of 7.8GHz and higher frequency of 19.35GHz.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：P184.5

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