顾及太空风化效应的虹湾地区矿物含量反演

Lunar Mineral Abundance Inversion of Sinus Iridum Considering Space Weathering Effect

月表矿物含量反演是研究月球地质起源和演化的关键.太空风化作用普遍发生在月球表面,对矿物纯净光谱造成了不可忽视的影响,它弱化光谱吸收特征,降低反射率,影响矿物含量遥感反演精度.基于Relab光谱库和Hapke辐射传输模型,将月表4种矿物(单斜辉石、斜方辉石、斜长石、橄榄石)的二向性反射率转换成同向性的单次散射反照率,然后计算矿物的光学常数;再根据亚微观金属铁SMFe(submicroscopic metallic iron)的质量分数模拟6种不同程度太空风化效应,得到端元矿物的反射率光谱;最后基于上述方法,利用多端元线性分解方法和M3(moon mineralogy mapper,月球矿物绘图仪)高光谱数据反演不同风化程度下的矿物含量,得到月表虹湾地区辉石、斜长石、橄榄石3种矿物的含量分布.实验表明,利用多端元线性分解可以有效模拟太空风化效应对矿物光谱的影响,是研究太空风化效应影响下矿物识别及含量反演的一种行之有效的方法.

The inversion of lunar minerals is critical to study the Moon＇s geological origin and evolution.Space weathering generally occurs on the surface of the Moon with an assignable influence on the pure mineral spectra,which obscures the reflectance spectra feature of minerals and reduces the overall reflectance.The effect of space weathering should be removed when accurately investigating the lunar minerals using remote sensing technology.The level of the space weathering is proportional to the mass fraction of submicroscopic metallic iron（SMFe）.In this paper,the authors firstly transform the bidirectional reflectance into the isotropic single scattering albedo of four endmember minerals（clinopyroxene,orthopyroxene,plagioclase and olivine）in the Relab spectral library based on Hapke radiative transfer model,secondly,calculate the optical constants and absorption coefficient of each mineral,then simulate the reflectance spectra of these minerals under six space weathering levels according to SMFe mass fraction,thus we obtain endmember mineral reflectance under different space weathering levels.Finally we inverse mineral abundance with six multi-endmember linear unmixing models and the M3（moon mineralogy mapper）hyperspectral data and obtain the inversion abundance and distribution of pyroxene,plagioclase and olivine in Lunar Sinus Iridum.The results show that using multi-endmember linear unmixing method can effectively simulate the effects of space weathering on mineral spectra,and it is an useful way of mineral identification and abundance inversion with hyperspectral under the space weathering.