| 摘要: |
| 雷达是探测火星次表层结构和属性的重要手段。火星勘测轨道飞行器(Mars Reconnaissance Orbiter, MRO)搭载的SHARAD(Shallow Radar)在过去的近20年间已基本实现了对整个火星的环绕探测为探索火星提供了大量宝贵数据。然而,当前针对SHARAD雷达数据的反演和解释研究主要针对其中包含次表层反射的部分,占比最多的表面反射数据没有得到充分利用。2021年,美国“毅力号”火星车和我国“祝融号”火星车先后成功着陆在Jezero撞击坑和乌托邦(Utopia)平原南部。两者均搭载了探地雷达设备并采集了大量数据,为SHARAD表面反射数据的标定提供了关键依据。本文首先对SHARAD数据进行处理,剔除电离层、卫星姿态和地面粗糙度的影响。然后对“祝融号”上搭载的火星次表层探测雷达(Mars Rover Penetrating Radar, RoPeR)低频通道雷达数据进行处理和反演,用于标定SHARAD数据的表面反射功率。最后,基于SHARAD表面反射功率反演了火星乌托邦平原南部的介电常数分布图。结果表明乌托邦平原南部表面物质的相对介电常数较为均匀(3.5-4.5),但其南部高地的介电常数值略高于北部低地,这一差异可能与火星古代大洋的形成和沉积过程有关。 |
| 关键词: 火星 祝融号 次表层探测雷达 介电常数。 |
| DOI： |
| 分类号:TN959.7 |
| 基金项目:国家自然科学基金(No.52179126,No.52379099),广东省基础与应用基础研究(No.2024A1515010934) |
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| Permittivity map of the Southern Utopia on Mars inverted from SHARAD and RoPeR |
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孟旭, 刘海, 李鉴辉, 刘超, 王向宇
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| Abstract: |
| Radar is a crucial tool for detecting subsurface structures and properties on Mars. The Shallow Radar (SHARAD) onboard the Mars Reconnaissance Orbiter (MRO) has conducted almost comprehensive orbital surveys of Mars over the past two decades. SHARAD data is significantly important for detection of mars. However, the analysis of SHARAD data has primarily focused on subsurface reflections, while much of the available surface reflection data has not been fully utilized. In 2021, the Perseverance rover from the United States and China"s Zhurong rover successfully landed in Jezero Crater and southern Utopia Planitia, respectively. Both rovers were equipped with ground-penetrating radar systems and collected a large amount of data, providing crucial references for calibrating SHARAD surface reflection data. This paper first processes the SHARAD data to remove the effects of surface roughness, ionosphere interference, and satellite attitude. Then, the low-frequency channel radar data from the Mars Rover Penetrating Radar (RoPeR) on the Zhurong rover is processed and inverted to calibrate the surface reflection power of the SHARAD data. Finally, a permittivity distribution map of southern Utopia Planitia on Mars is generated based on the processed SHARAD surface reflection power. Results indicate that the permittivity map in southern Utopia Planitia is relatively uniform, ranging from 3.5 to 4.5. However, the dielectric constant values in the southern highlands are slightly higher than those in the northern lowlands. This difference may be attributed to sedimentation processes that occurred in the past. |
| Key words: mars SHARAD RoPeR dielectric permittivity. |