Tycho crater is the most prominent crater of Copernican era. In this paper, the spatial and temporal features of the microwave thermal emission (MTE) at Tycho area are studied with the microwave sounder (CELMS) data combined with TiO2 abundance, surface slope and roughness, rock abundance data of lunar regolith. The results indicate that MTE at the south part of Tycho crater (Region A) is strongly affected by the surface temperature, and the temperature difference between the exterior and interior of the lunar regolith layer is fairly large. While MTE at the north part of Tycho crater floor (Region B) is weakly affected by the surface temperature, and the temperature difference between the exterior and interior is rather small. Moreover, the vertical structure of the lunar regolith at the east part of Region B is different from that at the west. Furthermore, the radiation here reaches the thermal equilibrium state after 3 A. M. in the morning, which is of essential significance to study the thermal structure characteristic of the Moon. The lunar regolith at the ejecta blanket is similar to that at Region B, while its thermal storage capacity is much higher than that of other places. The correlation analysis presents that the surface roughness and rock abundance have the largest impact on the MTE, followed by surface slope and TiO2 abundance.

Tycho撞击坑作为月球最具代表性的哥白尼纪撞击坑,其微波热辐射特性的研究对于分析与其同期形成的大型撞击坑的热演化过程具有重要的参考价值.本文基于嫦娥二号微波辐射计(CELMS)数据为代表的月壤微波热辐射数据,结合月壤TiO2含量、表面坡度和粗糙度、岩块丰度等资料,系统分析了Tycho地区微波热辐射的特征.结果表明,Tycho撞击坑南坡(A区)的微波热辐射受月表温度影响很大,月壤表层和深部的温度差值也很大;坑底平原北部(B区)的微波热辐射受月表温度影响很小,月壤表层和深部的温度差值也很小;该东部和西部的月壤结构在垂直方向上是有变化的;在凌晨3时以后该区达到热平衡状态,是未来进一步研究月壤内部热流特性的理想区域;溅射毯地区月壤物质在表层与B区相近,且具有较强的储热能力.统计结果表明,表面粗糙度和岩块丰度对月壤微波热辐射的影响最大,坡度次之,TiO2含量的影响最小.

基于嫦娥系列卫星微波辐射计数据的月壤厚度反演是中国月球科学研究的重要目标之一.基于辐射传输方程,数值模拟了不同频率、(FeO+TiO2)含量和表面温度条件下厚度对月壤微波辐射亮温的影响;基于嫦娥二号卫星微波辐射计(Chang'E Lunar Microwave Sounder,CELMS)数据,结合Apollo计划获取的月壤厚度资料及其他月壤厚度资料,系统分析了厚度对CELMS观测数据的影响.结果表明:频率、(FeO+ TiO2)含量、表面温度对亮温的影响远大于厚度对亮温的影响,是基于CELMS数据进行月壤厚度反演的重要影响因素;低频、低(FeO+TiO2)含量、低温条件下,厚度对CELMS数据的影响最大;利用3 GHz、凌晨时刻的CELMS数据进行月陆地区月壤厚度反演可行.研究结果对基于嫦娥系列卫星CELMS数据的月壤厚度反演具有重要参考意义.

As Mare Orientale is the youngest and best preserved multiring impact basin on the Moon,it is of essential importance to study its composition and structure for clues to the processes and histories of older,more degraded features.In this paper,the (FeO + TiO 2 )abundance derived from Clementine UV-VIS data and the CELMS data from Chang’e-2 satellite are employed to study the microwave emission features of the Mare Orientale. The results indicate that the regions with high CELMS data and high brightness temperature difference agree well with high (FeO + TiO 2 )abundance both on noon and on midnight.However,the change of the area with high CELMS data and high brightness temperature difference with the frequency indicates that the composition of the lunar regolith is varied with depth.The (FeO+TiO 2 )abundance in Maunder Crater is low,whereas the CELMS data and the brightness temperature differences in the low frequencies and the high frequencies show distinctly different features,which indicates that the composition of the lunar regolith here in the upper layer and the lower layer may be different.The abnormal microwave emission apparently exists in the regions (10°S /106°W),(5°S /104°W)and (13°S /103°W)in highland with low (FeO + TiO 2 )abundance,which is likely related to the temperature gradient of the deep regolith.The microwave emission features in these areas are of special significance to study the evolution of the Mare Orientale.