Using the high-frequency lunar penetrating radar data obtained by the Chang’e-3 mission, we apply the frequency-shift method to calculate the decay rate of the electromagnetic wave in the regolith-like ejecta deposits of the Ziwei crater. The radar data are divided into segments according to the navigation points along the traverse route of the Yutu rover. For each segment, we calculate the bulk loss tangent of materials within the top ~ 50 ns of the radar data based on the frequency decreasing rate of the electromagnetic wave. The loss tangent varies from ~ 0.011–0.017 along the route of Yutu, and it is within the range of the measured loss tangent of Apollo regolith samples. Using the empirical relationship between loss tangent and TiO₂ + FeO content derived from the Apollo lunar samples, we estimate the TiO₂ + FeO content for the bulk regolith along the route of Yutu, which is ~ 23–30 wt.%. This value is comparable with that estimated using both orbital reflectance spectral data and in situ observation made by the Yutu rover. The loss tangent derived along the route of Yutu is larger than the average value of returned lunar samples, which is mainly caused by the larger content of TiO₂ + FeO at the landing site compared to the global average. Variations of the TiO₂ + FeO content along the route of Yutu are mainly due to the excavation of the Ziwei crater. The TiO₂ + FeO content map derived by the radar has a much higher spatial resolution compared to orbital observation, testifying the feasibility of this technique for regional geology study.

中文翻译：

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探月雷达揭示的Chang娥三号雨兔漫游车路线上的成分变化

利用the娥三号任务获得的高频探月雷达数据，我们采用频移方法来计算紫微陨石坑弹积状喷出矿中电磁波的衰减率。雷达数据根据Yutu漫游车的遍历路线上的导航点分为几部分。对于每个段，我们根据电磁波的频率下降率来计算雷达数据的顶部〜50 ns内的材料的损耗角正切值。沿Yutu路线，损耗角正切在〜0.011-0.017之间变化，并且在测得的阿波罗重水石样品的损耗角正切范围内。利用损失切线与阿波罗登月样品得出的TiO ₂ + FeO含量之间的经验关系，我们估算了TiO₂ + FeO含量的玉石沿路线的大部分块状〜23–30 wt。％。该值与使用轨道反射光谱数据和Yutu流浪者进行的现场观测所估计的值相当。雨图沿途的损耗角正切大于返回的月球样品的平均值，这主要是由于着陆点的TiO ₂ + FeO含量高于全球平均值。玉图路线沿途的TiO ₂ + FeO含量变化主要是由于紫微陨石坑的开挖。与轨道观测相比，雷达导出的TiO ₂ + FeO含量图具有更高的空间分辨率，证明了该技术在区域地质研究中的可行性。