基于嫦娥二号亮温数据与温度相关的月壤介电常数反演研究

发布时间：2018-01-15 19:12

本文关键词：基于嫦娥二号亮温数据与温度相关的月壤介电常数反演研究　出处：《华中科技大学》2016年硕士论文　论文类型：学位论文

【摘要】：介电常数是月壤基础物理参数,准确的月壤介电常数参数模型对月球主被动微波遥感和遥感参数的定量提取具有重要意义。现有的介电常数模型均没有考虑到物理温度的影响,然而研究表明,月壤介电常数与物理温度有关。本文基于月壤辐射亮温模型,并改进温度剖面的计算,利用嫦娥二号微波辐射亮温数据以及Diviner月球辐射测量仪(DLRE)红外亮温数据,反演出了与温度相关的月壤介电常数参数,并提出了考虑温度影响的微波波段月壤介电常数参数模型。本文首先介绍了月表多层辐射亮温模型,并分析了地形、物理温度剖面和介电常数等参数对辐射亮温的影响。利用嫦娥二号实测亮温数据进行时空归一化处理,得到时空归一化亮温差τ。由美国月球轨道勘测飞行器(LRO)上搭载的月球辐射测量仪(DLRE)读取月球表面物理温度数据。根据不同的温度段选取时空归一化亮温差τ,计算并分析在不同的温度段下τ与铁钛含量的相关系数。结果表明,在不同的温度段下τ与铁钛的相关性是不一样的,温度越高,相关系数越大。由此得出温度会影响月壤介电常数的结论。利用嫦娥二号亮温数据反演介电常数时,首先需要求解一维热传导方程得到月壤温度剖面,通过对比求解一维热传导方程得到的表面温度与实测表面温度,发现二者在某些地区存在较大差异。为了得到更准确的温度剖面,提出了根据实测表面温度查找对应温度剖面的改进方法。然后利用不同温度段下的嫦娥二号亮温数据,运用非线性多变量约束最优化方法,基于月表多层微波辐射亮温模型,对月壤介电常数进行反演,得到了温度范围在300~390K内考虑了温度影响的月壤介电常数模型。最后利用此介电常数模型计算了月海、月陆以及撞击坑等典型地貌区域的沿轨亮温,计算的亮温值与嫦娥二号实测亮温值之间的均方根误差在7K之内,较现有的介电常数模型的亮温计算值有较大改进。这也在一定程度上验证了本文所提介电常数参数模型的的准确性。
[Abstract]:Dielectric constant is the basic physical parameter of lunar soil. Accurate model of permittivity parameters of lunar soil is of great significance to the quantitative extraction of lunar active and passive microwave remote sensing and remote sensing parameters. The existing models of dielectric constant do not take into account the influence of physical temperature, however, the research shows that. The dielectric constant of lunar soil is related to physical temperature. Based on the radiant bright temperature model of lunar soil, the calculation of temperature profile is improved. Based on the light temperature data of Chang 'e-2 microwave radiation and the infrared bright temperature data of Diviner lunar radiometer, the permittivity parameters of lunar soil related to temperature are obtained. A microwave wave band permittivity model of lunar soil considering the influence of temperature is proposed. Firstly, the multi-layer radiant bright temperature model of lunar surface is introduced, and the topography is analyzed. The effect of physical temperature profile and dielectric constant on the radiation brightness temperature is studied. The Chang 'e-2 measured brightness temperature data are used to normalize the temperature in time and space. The space-time normalized bright temperature difference 蟿. The lunar radiometer DLREE carried by the US Lunar Orbital Reconnaissance vehicle (LRO) is obtained. The physical temperature data of the lunar surface are read. According to the different temperature bands, the space-time normalized brightness temperature difference 蟿 is selected. The correlation coefficient between 蟿 and Fe-Ti content at different temperatures is calculated and analyzed. The results show that the correlation between 蟿 and iron-titanium is different at different temperatures, and the higher the temperature is, the higher the temperature is. The larger the correlation coefficient is, the more the conclusion is that the temperature will affect the permittivity of lunar soil. When using the light temperature data of Chang 'e-2 to retrieve the dielectric constant, it is necessary to solve the one-dimensional heat conduction equation to get the temperature profile of lunar soil. By comparing the surface temperature obtained by solving one-dimensional heat conduction equation with the measured surface temperature, it is found that there is a great difference between them in some areas, in order to obtain a more accurate temperature profile. An improved method to find the corresponding temperature profile according to the measured surface temperature is proposed, and then the nonlinear multivariable constrained optimization method is applied to the Chang 'e-2 bright temperature data at different temperatures. Based on the bright temperature model of multi-layer microwave radiation, the permittivity of lunar soil was retrieved. The dielectric constant model of lunar soil considering the influence of temperature in the temperature range of 300 ~ 390K is obtained. Finally, the lunar sea is calculated by using this dielectric constant model. The root-mean-square error between the calculated brightness temperature and the measured light temperature of Chang 'e-2 is within 7K in the typical geomorphologic regions such as lunar land and impact crater. Compared with the existing dielectric constant model, the calculation value of brightness temperature is improved greatly, which verifies to some extent the veracity of the dielectric constant parameter model proposed in this paper.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P184.5

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