基于Hapke辐射传输模型的月壤光谱模拟

由于月球采样点较少，月壤真实数据稀缺，限制了对月球科学问题的进一步研究。较全面系统地采集月壤样品在近期很难完成，开展月壤光谱模拟工作是月壤实测光谱的必要有益补充，可以为研究月壤光谱特征提供大量数据。基于Hapke模型，我们选取RELAB光谱库的斜长石、单斜辉石、斜方辉石、橄榄石、单质铁、钛铁矿、火山玻璃、熔融玻璃等典型月壤矿物，运用牛顿插值和最小二乘优化的方法，模拟了LSCC月壤数据的一定粒径、单质铁含量、观测条件及矿物混合比例下的混合光谱。模拟光谱与实测光谱拟合较好，相关系数均大于0.99，均方根误差在10-3数量级；模拟矿物丰度与实测矿物丰度基本一致；模拟SMFe含量与相对成熟度指数Is/FeO线性关系明显；模拟粒径基本落在实测粒径组范围内。最后，文中讨论了光谱吸收中心波长、吸收面积等光谱特征参数的模拟精度，以及高精度模拟光谱时光学常数的计算方法。

Spectra simulation of lunar regolith based on the Hapke radiative transfer model

Due to so few of landing site on the moon, the ground truth data of lunar soil is scarce, which limits the further study of the lunar science. Thus to carry out spectral simulation of lunar regolith is almost the only feasible way to research the spectral mechanism of lunar regolith and improve the reliability of composition inversion of lunar regolith, which also is essential and beneficial supplement to the measured spectra of lunar regolith. We selected plagioclase, clinopyroxene, orthopyroxene, olivine, metallic iron, ilmenite, volcanic glass and agglutinate acquired from RELAB spectral library as mineral end members, and simulated spectra of LSCC lunar regolith based on Hapke radiative transfer model, using Newton interpolation and least square optimization method. The simulated spectra and the measured spectra fits well with the correlation coefficients more than 0.99 and the root mean square error at the magnitude of 10-3. The simulated mineral abundance shows a good linear fitting with the measured abundance. The simulated SMFe content has a distinct linear relationship with the relative maturity index Is/FeO. The simulated particle size strictly falls within the measured particle size range. The simulation accuracy of spectral parameters, such as absorption center wavelength and absorption area, was discussed. We also discussed the calculation method of optical constants used for spectra simulation with high precision.