基于嫦娥二号卫星微波辐射计亮温数据反演月壤介电常数

月壤介电常数是当前月球微波遥感探测的基础, 是月壤厚度、成分等信息提取不可或缺的参数.为了实现全月介电常数反演, 通过对嫦娥二号卫星微波辐射计亮温数据进行时角校正, 得到同一时角的全月微波亮温图.全月微波亮温表现出随月球地形、月壤成分及纬度变化的特征.基于校正后的微波辐射亮温, 结合辐射传输模型, 通过解算相关参数, 反演得到3GHz频率下全月介电常数分布.其中, 月海地区的介电常数实部高于月陆地区, 且月球极地区域介电常数实部偏低; 而介电常数虚部则在月海区域和艾肯盆地较高.通过模拟月表介电常数实验对反演结果进行温度校正, 得到22℃下全月介电常数.将反演结果和月壤真实样品的介电常数测量值进行比较评价.结果表明介电常数实部相对误差都低于11%;虚部相对误差偏大, 但其差值最大仅为0.02.因此, 基于嫦娥二号卫星微波辐射计亮温数据反演月表介电常数的方法是可行的. 

Dielectric Constant of Lunar Soil Derived from Cgang' E-2 Passive Microwave Radiometer Measurements

Dielectric constant of lunar soil is the basis of lunar microwave remote sensing detection and it is an indispensable parameter for information extraction of lunar regolith layer thickness and composition. With the aim to simulate dielectric constant for the whole moon, the correction of time angle on brightness temperature data captured by microwave radiometer on board of Chang'E-2 is carried out in the paper and the distribution map of the whole lunar surface microwave brightness temperature under the same time angle with various lunar terrains is obtained, soil compositions and latitudes is obtained. By applying the radiative transfer model to the corrected microwave temperature brightness, the distribution of dielectric constants for 3GHz channel in the whole moon is obtained. The real part of dielectric constant in the lunar mare region is higher than that in highland and this value is low in polar region. The imaginary part in lunar mare and Aitken basin are relatively higher. The dielectric constant data have been calibrated in the experiment to obtain dielectric constant temperature at 22℃. To compare the electric constant of real lunar soil samplings under normal temperature on Earth with inversed results, the results show as follows: the relative error of the real part of dielectric constant is less than 11%; the relative error of the imaginary part of dielectric constant is higher, but the maximum difference is below 0.02. So it is feasible to derive the dielectric constant inversion in the manner of utilizing brightness temperature data of microwave radiometer on board of Chang'E-2.