“嫦娥一号”卫星微波探测对月表参数反演的理论与应用

发布时间：2018-01-11 18:22

本文关键词：“嫦娥一号”卫星微波探测对月表参数反演的理论与应用　出处：《复旦大学》2013年博士论文　论文类型：学位论文

【摘要】：在长期的地质演化过程中,月球表面由于受到火山喷发等地质活动以及外来陨石小天体撞击的影响,逐渐形成了以撞击坑为主要地貌的地形结构,并形成了几乎覆盖整个月球表面的月壤层。由于月球表面缺少大气层,长期暴露在空间环境中的月壤层不断接受太阳风粒子以及宇宙射线的辐射,蕴含着丰富的具经济价值的化学元素,如可供人类可利用的清洁能源3He等,因此对月壤厚度的反演是估算月球能源的重要指标。月球的地质结构不仅会对月表的温度分布产生影响,也记录了月球形成与演化的历史,对月球资源探测、开发及利用具有重要意义,因此对月球次表层结构与月表温度的研究历来是科学家们重视的课题。我国相继发射了“嫦娥一号”(CE-1)和“嫦娥二号”(CE-2)绕月卫星,在国际上首次搭载了多通道微波辐射计对全月表的热辐射进行测量,获得了月表面微波频段辐射亮度温度信息,并将下一步CE-3在月球虹湾地区登陆的计划提上日程。本文由辐射传输理论出发,结合分层月壤结构与电磁波的相互作用机理,充分考虑月球地质信息对热辐射的影响,由CE-1微波辐射计的辐射亮度温度对月壤厚度,月球表面物理温度昼夜变化以及影响月球表面温度昼夜变化及异常的因素做了探讨,同时提出了由CE-1微波辐射计观测结果直接确定月壤介电常数的方法,从微波热辐射的角度,对月球的地质信息的反演提供可行的方法。首先,针对CE-3可能登陆的虹湾地区的物理温度昼夜变化展开研究。根据CE-1的微波辐射计观测数据,由月球地面坐标系与以虹湾地区中心点为新极点的坐标系之间的转换关系,由CE-1微波辐射计数据中给出的太阳入射角和方位角信息来确定虹湾地区所处的月球当地时间,然后再利用CE-1微波辐射计高频通道19.35GHz和37.0GHz对虹湾地区的微波辐射观测结果,结合月壤三层微波辐射模型,反演了虹湾地区的物理温度,给出了虹湾地区月尘层与月壤层物理温度随月球时间的变化情况,并将物理温度的反演结果与“先知者号”(Diviner)红外探测仪的观测结果做了对比,对影响虹湾地区温度分布的因素做了讨论。其次,在月球两极等高纬度地区,由于太阳光线的倾角较大,因此月表地形对高纬度地区的温度分布会产生较大的影响。通过CE-1卫星多通道微波辐射计对月球两极的观测数据,可以对月球环形山地形影响下的辐射亮度温度分布做出讨论。事实上,影响月球表面的物理温度分布的因素有很多,除了地形与纬度外,同一地点的月表温度也随月壤深度变化而改变。选取赤道和沿经度150°W作为目标区域,在改进的具有物理温度分布廓线的月壤两层模型的辐射传输理论基础上,首先通过多通道微波辐射计高频通道数据,对月壤温度廓线进行反演,再结合穿透能力较强的低频通道观测数据,完成月壤厚度的反演,反演结果分别与以往物理温度随纬度变化的经验性分布以及月壤厚度的反演结果作了比较与验证。再次,通过地基天文望远镜进行的月食期间月球表面红外辐射图像扫描,发现在月食过程中太阳光照迅速消失的情况下,月表面有大量的温度异常“热点”,其热辐射要明显高于周围环境,而在CE-1对月球表面微波辐射亮度温度观测中,这些在月食期间红外辐射“热点”对应的是月球白天微波频段观测的“热点”,以及月球夜间微波热辐射的“冷点”。为了解释这些热辐射昼夜变化中出现的异常现象,并比较不同地区月球表面昼夜辐射温差的变化情况,选取了在相近纬度上两种典型的环形山区域：一是表面存在大量离散岩石块分布的新生环形山代表第谷环形山,另一是经历了长期陨石冲击粉碎与月球地质演变的不再有大量岩石块分布的典型环形山莫洛利卡斯环形山,讨论这两个区域内的“嫦娥一号”微波辐射亮度温度分布的昼夜变化,并与美国探月任务月球轨道勘测器中搭载的红外探测仪Diviner在对应区域的红外测量做了对比。以月表三层模型的辐射传输为基础,从“嫦娥一号”卫星微波辐射计数据反演了这两处环行山区域月壤层的物理温度的昼夜变化及其分布,将月表面物理温度昼夜变化与红外观测结果做了比较,解释了月球表面“热点”与“冷点”的异常现象与月表面新生环形山大量分布的高热传导高热惯性岩石块分布密切相关的原因,从月球地质信息的角度对月表温度分布的异常现象做出理论解释。再其次,月球表面月壤介质的介电特性等会影响电磁发射率以及电磁波在月壤介质中的反射和衰减,因此在实际观测的月表微波热辐射中也包含了月表的地质和介电特性等信息,这也是由CE-1微波辐射计观测数据来反演月表介电特性的物理基础。选取具备热流实验可以予以验证的Apollo15地区,以及赤道月陆地区,首先建立可靠的月壤体积密度廓线模型,由时域有限差分方法求解对应区域的一维热扩散方程,得到物理温度在各个月球时间,随月壤深度的变化。再通过CE-1四通道微波辐射计观测数据,在辐射传输理论的基础上,由最小二乘法反演得到月表对各个通道不同频率电磁波的反射率以及吸收系数,再由反射率及吸收系数与月壤介电常数的关系,确定月壤复介电常数,并将反演结果与以往通过Clementine或Lunar Prospector光学反射率数据反演得到的FeO与TiO2含量为基础来确定月壤介电常数的结果作了比较与验证。最后,作为本文被动微波遥感的扩展部分,还将对主动遥感手段的雷达探测仪成像原理进行介绍,并在此基础上开发了一款可视化软件,为用户提供友好的参数化界面,可以模拟产生表面起伏的环形山地形,并对该地形下的雷达探测仪回波进行模拟,来反映月球次表层结构在雷达探测仪回波中的表现,为由真实回波数据来反演行星次表层结构及分析物质成分等信息做理论准备。本文利用微波辐射传输理论,在月壤分层模型的基础上,将CE-1微波辐射计观测数据应用到对月表物理温度分布,月壤厚度反演以及月壤介电常数确定等工作中,将我国探月成果应用到实际月球参数反演中,希望能为今后探月事业的发展初步解决部分基本问题并提供一些理论依据。
[Abstract]:In the long geological evolution process, the surface of the moon due to volcano geological activities and the impact of foreign small meteorite bodies, and gradually formed a topographic structure to crater as the main landform, and the formation of the lunar regolith layer covering almost the entire surface of the moon. The moon is lack of atmosphere, long-term exposure in the regolith layer in the space environment to accept solar wind particles and cosmic rays, contains abundant chemical elements with economic value, such as available for human use of clean energy such as 3He, so the lunar regolith thickness inversion is an important index to estimate the energy of the moon. The moon's geological structure will not only have an impact on temperature distribution the surface of the moon, also recorded the history of formation and evolution of the moon, lunar exploration resources, plays an important role in the development and utilization, so the lunar subsurface structure and surface temperature Research has always been a subject that scientists have paid much attention to.
Our country has launched the "chang-e-i" (CE-1) and "the No. two" (CE-2) satellite to orbit the moon for the first time in the world, equipped with a multi channel microwave radiometer thermal radiation on the whole surface of the microwave measurement, April surface brightness temperature and frequency information, the next step will be landing CE-3 in the rainbow Moon Bay area is on the agenda.
The radiative transfer theory, combined with the hierarchical structure of lunar regolith and the electromagnetic wave interaction mechanism, fully consider the lunar geological information influence on thermal radiation, radiation brightness temperature of lunar regolith thickness by CE-1 microwave radiometer, the lunar surface temperature diurnal variation and effect of the lunar surface temperature diurnal variation and abnormal factors are discussed at the same time, put forward by CE-1 microwave radiation method to directly determine the regolith dielectric constant meter observation results, microwave radiation from the hot point of view, inversion geological information on the moon to provide a feasible method.
First of all, to study the physical temperature diurnal variation of CE-3 may be landing rainbow Bay area. According to the observation data of CE-1 meter microwave radiation from the lunar ground coordinates with rainbow Bay Area Center for conversion between the new pole coordinate system, by CE-1 microwave radiation counting according to the given in the solar incident angle and azimuth angle information to determine the local time at the rainbow Moon Bay area, and then use the CE-1 microwave radiometer observations of microwave radiation of high frequency channel of 19.35GHz and 37.0GHz on the rainbow Bay area, with three regolith layer microwave radiation model, physical temperature inversion of the rainbow Bay area, given the rainbow Bay area top layer and soil the physical layer temperature changes with time of the moon, and the inversion results and the physical temperature of the "prophet" (Diviner) infrared detector observation results were compared, the temperature distribution of rainbow Bay Area The factors were discussed.
Secondly, at the lunar poles and high latitude regions, because the angle of sun light is large, so the lunar terrain and high latitudes of the temperature distribution will have a greater impact. Meter observation data of the lunar poles by CE-1 satellite multi channel microwave radiation, can the brightness temperature distribution on the lunar crater topography under the influence will be discussed in detail. In fact, there are many factors that influence the lunar surface temperature distribution, in addition to topography and latitude, the same place with the surface temperature of lunar regolith depth changes. From the equator and along the longitude 150 degrees W as the target area, the improved temperature distribution of regolith profile two layer model the radiative transfer theory, first through multi channel microwave radiometer high frequency data, the lunar regolith temperature profile inversion, combined with low frequency channel observation data of strong penetration ability, complete The inversion results of lunar soil thickness are compared with the empirical distribution of previous physical temperature variations along with latitude and the results of the inversion of lunar soil thickness.
Again, this eclipse lunar surface infrared radiation image scanning by ground-based telescope, discovered in the eclipse of the sun light quickly disappear, there are a large number of abnormal temperature of "hot spots" month surface, the thermal radiation is higher than that of the surrounding environment, and in the CE-1 on the lunar surface microwave radiation brightness temperature observations. The infrared radiation during the eclipse "hot spot" is corresponding to the lunar day microwave observation "hot spots", as well as the moon night microwave thermal radiation "cold."
In order to explain these anomalies diurnal variations in thermal radiation, and to compare the changes in different regions of the lunar surface and radiation temperature difference, selected in similar two typical crater area latitude: one is the existence of a large number of discrete surface rocks distribution of new craters on behalf of Tycho, another is long meteorite impact crushing and the evolution of the lunar rocks distribution is no longer a large number of typical crater crater Castro Rowley Mo to discuss this, within the two regions of Chang'e-1 microwave radiation brightness temperature distribution of diurnal variations, and is equipped with the United States mission the Lunar Reconnaissance Orbiter in infrared detector Diviner in infrared measurement the corresponding regions are compared. On the radiative transfer model of three layers based on the lunar surface, from the satellite microwave data inversion of the two ring Hill radiation The diurnal variation and distribution of physical temperature of lunar regolith layer, the surface temperature may change and physical and infrared observations have been compared, explained the abnormal phenomenon of the surface of the moon "hot" and "cold" and a large number of new craters month surface distribution of high heat conduction and high thermal inertia rock mass distribution is closely related to the causes. To explain abnormal phenomena from the perspective of geological information on lunar surface temperature distribution.
Then, the surface of the moon regolith dielectric characteristics will affect the rate and the reflection of electromagnetic wave in the lunar regolith and attenuation of electromagnetic emission, it also includes the surface geology and dielectric properties and other information on the lunar surface microwave thermal radiation observed in physics, which is the basis of CE-1 by micro wave radiometer data to the electrical characteristics of lunar surface. With the selection of inversion of dielectric flux experiments can be verified in the Apollo15 area, and the monthly land area, first to establish a reliable soil bulk density profile model, one-dimensional heat by finite difference time domain method for solving the corresponding region of the diffusion equation, get the physical temperature in each time changes with the moon, the lunar regolith depth. Then the meter observation data through the CE-1 four channel microwave radiation, based on radiative transfer theory, get the surface of each channel with different frequency of electromagnetic wave by least squares inversion The emission rate and absorption coefficient, the reflectivity and absorption coefficient and regolith dielectric constant, determine the complex dielectric constant of lunar soil, and the inversion results with the past by FeO and the content of TiO2 Clementine or Lunar Prospector optical reflectance data inversion as the basis to determine the regolith dielectric constant is compared and verification.
The last part of this paper, as an extension of the passive microwave remote sensing, the radar detector imaging principle of active remote sensing methods are introduced, and based on the development of a visualization software, provide parameterized friendly interface for users, which can simulate the surface fluctuation of crater terrain, and the terrain under the radar echo sounder by simulation, to reflect the performance of lunar subsurface structure on radar echo in the grounds of the real echo data to retrieve the planet subsurface structure and analysis of material composition information theory.
This paper used the microwave radiative transfer theory, based on the hierarchical model of the lunar regolith, CE-1 microwave radiometer observation data is applied to the temperature distribution of the surface of the moon, the lunar regolith thickness inversion and regolith dielectric constant to determine the work, will be applied to actual lunar exploration achievements of China's lunar parameters inversion, the hope for the future development the lunar exploration career initially solved some basic issues and provide some theoretical basis.

【学位授予单位】：复旦大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：P184.5;V476.3

【参考文献】