三层月壤模型的多通道微波辐射模拟与月壤厚度的反演

由月球表面数字高程试验性地构造了整个月球表面月壤厚度的分布.根据Clementine探月卫星的紫外-可见光光学数据,计算了整个月球表面月壤中FeO+TiO2含量分布,给出了整个月球表面月壤介电常数分布.由月球表层温度的观测结果以及月壤的导热特性,给出了月尘层与月壤层温度随纬度分布的经验公式.在这些条件的基础上,建立了月尘、月壤、月岩三层微波热辐射模型.由起伏逸散定理,模拟计算了该月球模型多通道辐射亮度温度.然后,以此辐射亮度温度模拟加随机噪声为理论观测值,按三层模型提出了月壤层厚度反演方法.由于高频通道穿透深度小,由高频通道的辐射亮度温度按照两层月尘-月壤微波热辐射模型反演月尘层与月壤层的物理温度,再由穿透深度较大的低频通道辐射亮度温度反演月壤层厚度.对于反演的相对误差也进行了讨论. 

Inversion of Lunar Regolith Layer Thickness Using Microwave Radiance Simulation of Three Layer Model and Clementine UV-VIS Data

A correspondence of the lunar regolith layer thickness to the lunar Digital Elevation Mapping(DEM)is proposed to construct the global distribution of lunar regolith layer thickness. Using Clementine UV-VIS multispectral data,the global spatial distribution of FeO TiO_2 content on the lunar regolith layer is calculated.Thus,dielectric permittivity of global lunar regolith layer can be obtained.Based on some measurements of physical temperature of the lunar surface,an empirical formula of physical temperature distribution over the lunar surface is presented.Based on aforementioned works,brightness temperature of lunar regolith layer in passive microwave remote sensing,which is planned for Chinese Chang-E lunar project,is numerically simulated by a three layer model using fluctuation dissipation theorem.Taking these simulations with random noise as observations,an inversion approach of the lunar regolith layer thickness is developed.Physical tem- perature of the top layer and the lower regolith can be inverted by the brightness temperature at high frequency channels using a two-layer model.The regolith layer thickness can be finally inverted by the brightness temperature at low frequency channel.Inversion error is also discussed.Numerical simulation and inversion approach in this paper make an evaluation of the performance for lunar passive microwave remote sensing,and can be applied to future data calibration and validation.