月表矿物二向性反射模型研究

发布时间：2018-04-12 09:08

本文选题：二向性反射 + Hapke模型　；参考：《吉林大学》2012年硕士论文

【摘要】：月球表面的二向性反射特征是进行月表矿物含量类别判定和含量反演的重要依据。在月球探测活动中，不同的光度模型被用来模拟月表的二向性反射行为和分析月表光谱数据。Hapke模型是行星探测中常用的光度模型，它是颗粒介质辐射传输模型的近似解析解，不仅成功地实现了对月球、水星等太阳系内行星表面的反射光谱的模拟和光学参数求解，更重要的是实现了从反射率到单次反照率及多种反射率的转化。B. Hapke提出并验证了介质单次反照率是组成介质的端元颗粒单次反照率的线性加权和，权值为各种颗粒在单位面积上的相对横截面积。其推广至矿物含量反演中即混合矿物的单次反照率是各端元矿物单次反照率的线性加权和。 Hapke模型在描述介质表面宏观粗糙度对反射率影响时，只考虑了平均坡度因素，而没有考虑到坡向和周围地形对反射率的影响。研究首先推导了三维向量空间中坡面上观测点受坡度和坡向同时影响下的太阳入射角和出射角的计算公式，并按照来源不同，对周围地形对观测点的辐亮度“增益”效应进行了逐项分析，得出适合月球表面Sandmeier辐亮度求解方程，以此推导理想平坦月表反射率最终求解公式。由此，建立了综合考虑坡度、坡向两种宏观地形因素影响下月表的Hapke模型。在进行月表矿物含量反演之前，通过实验研究了月表四种主要造岩矿物—斜长石、橄榄石、单斜辉石、斜方辉石的二向反射特性及光谱混合特性。首先研究了观测几何条件对反射率的影响：设定入射角，出射角的变化范围为0~60°，方位角范围为0~360°，测量了四种矿物在不同观测条件组合下的反射率光谱。其次研究了矿物颗粒大小对反射率的影响：将矿物研磨为96~120μm、120~150μm、150~180μm、180~250μm四种粒度，分别测量了矿物在四种粒度下的反射率光谱。通过分析反射率光谱，发现几何观测条件不是影响矿物反射率的敏感因素，而粒度则对矿物的反射率有着显著的影响，并呈现统一的变化规律。之后，进行了光谱混合实验模拟：选用了120~150μm的斜长石和单斜辉石作为端元矿物，按照不同比例均匀混合成四组混合矿物，分别测量了端元矿物和混合矿物的反射率，使用原始Hapke模型和各向同性Hapke模型反演了端元矿物和混合矿物的反照率，证明了混合矿物的反照率近似为端元矿物反照率的线性加权和。各向同性Hapke模型模拟结果同原始Hapke模型模拟结果精度相比差距不大，整体误差为8%，可认为是在同一水平上，能够解决当前月表高光谱普遍缺乏同一地区多角度观测信息而无法直接使用原始Hapke模型进行矿物含量反演这一难题。最后，以引入宏观地形改正的各向同性Hapke模型为理论基础，最小二乘法为运算法则，使用印度探月卫星“Chandrayaan-1”上搭载的M3(Moon MineralogyMapper)探测器获取的月球表面高光谱数据，以Apollo17号地区为实验区域，，验证了引入宏观地形改正的各向同性Hapke模型在矿物含量反演中的适用性，并完成了“嫦娥”三号首选登陆区域—虹湾的矿物含量分布。
[Abstract]:The surface of the moon to the two characteristics of reflection is an important basis for categories of lunar minerals and determine the content of inversion. In lunar exploration, different photometric model was used to simulate the surface two to reflex behavior and analysis of surface spectral data.Hapke model is commonly used in the photometric model for planetary exploration, it is the approximate analytic solution of particles radiative transfer model, not only successfully on the moon, for simulation and optical parameters of reflectance spectra of mercury and other planets in our solar system on the surface, it is more important to realize the reflectivity of the single scattering albedo and multiple reflectance conversion of.B. Hapke is presented and verified medium rate is linear and weighted single albedo the rate of endmember particles medium single albedo, weights for various particle relative cross section in the unit area of the area. It is extended to the mineral content in mixed mineral inversion The single albedo is the linear weighted sum of the single albedo of each end element.
The Hapke model in describing the medium surface roughness on the reflectivity of the macro, only consider the average slope factor, without considering the influence of slope and the surrounding terrain on reflectivity is deduced. The research on three-dimensional vector space on the observation point by the slope and at the same time, under the influence of the solar incident angle and calculating shot angle, and in accordance with the different source of radiance around the terrain on the observation point gain effect were analyzed, obtained for the lunar surface Sandmeier radiance equation, deduced the ideal reflectivity formula for solving the final flat surface. Therefore, considering the slope, slope to two macro terrain factors affecting Hapke under the model of the lunar surface.
Before the inversion of lunar minerals, through the experimental study of lunar surface four main rock forming minerals and plagioclase, olivine, clinopyroxene, orthopyroxene and mixed to two reflectance spectral characteristics. First the influence of observation geometry on reflectivity: set the angle of incidence, a range of incident angle of 0~60 degrees. The azimuth angle is in the range of 0~360 DEG, reflectance spectrum measurement of four kinds of minerals in different observation condition. Secondly study the effect of mineral particle size on the reflectivity: 96~120 mineral materials m, 120~150 m, 150~180 m, 180~250 m four particle size, mineral reflectance in four kinds of granularity the measured reflectance spectra respectively. Through the analysis, we found that conditions of geometry is not sensitive factors influence reflectance and minerals, has a significant effect on grain size of minerals reflectivity, and presents a unified change Law. After simulated experiment, spectral mixture: choose the 120~150 m of plagioclase and clinopyroxene as endmember minerals, according to different proportion evenly mixed into four groups of mixed minerals, measured reflectivity of endmember minerals and mixed minerals, using the original Hapke model and isotropic Hapke model inversion albedo endmember mineral and mixed minerals, proved that the linear weighted sum of albedo approximation for endmember mineral albedo of mixed minerals. The isotropic Hapke model simulation results with the original Hapke model simulation accuracy is not compared to the gap, the overall error is 8%, that is on the same level, can solve the current lack of lunar hyperspectral multi angle observation information from one area to directly use the original Hapke model is the problem of mineral content inversion.
Finally, with the introduction of isotropic Hapke model of macro topographic correction theory, least squares algorithm, using the India lunar satellite equipped with "Chandrayaan-1" on M3 (Moon MineralogyMapper) lunar surface hyperspectral data detector to obtain, in the Apollo17 area as the experimental area, verify the applicability of the isotropic Hapke macro model the terrain correction in mineral content inversion, and completed the "distribution of mineral content of Chang'e No. three" preferred landing area - Rainbow Bay.

【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：P184.5

【参考文献】