The heat production of radioactive elements drives the thermal evolution of the moon, and the heat production rate (HPR) based on Th, K, and U elements is also a crucial parameter constituting the current lunar heat flow. Exploring the distribution and source of HPR on the lunar surface can furnish evidence for the analysis of the moon’s evolutionary history and thermochemical structure, while the distinctive HPR states of the lunar basins that have undergone complex geological activities can provide more evolutionary information. Consequently, the data of heat producing elements in the gamma-ray spectrum of Chang’e-2 were inverted, and the HPR distribution status in lunar major basins, South Pole-Aitken, Smythii, Nubium, Humorum, Cognitum, Nectaris, Serenitatis, Crisium, Imbrium, and Orientale, was calculated and analyzed to reveal the causes of HPR anomalies and better describe the evolutionary history of lunar materials. There are three main sources of high HPR materials in lunar basins based on their HPR distribution patterns: (1) Ejecta excavated by large-scale impact events; (2) Magma with high HPR materials produced by volcanic activity within the basin itself; (3) The high HPR materials carried to the lunar surface by the volcanic activity of Procellarum KREEP Terrane and then transported and deposited into the surrounding basins. In addition, the distribution of high HPR materials in the lunar crust and asthenosphere is extremely uneven across the entire Moon, and they originate from different source than the Fe-Ti-rich magmas.

Lacus Mortis has been clarified as the landing site of the Astrobotic Mission One lander mission. In this work, the Chang’E-2 microwave radiometer data was first introduced to evaluate thermophysical features of surface deposits in Lacus Mortis. Several findings are noted as follows. (1) Microwave radiometer data shows abnormal thermophysical parameters existing in shallow layer of mare surface. (2) In crater unit, a strong relationship between microwave performances and other parameters including rock abundance and elevation is shown.

Brightness temperature (TB) derived from the Chang’e-2 microwave radiometer (MRM) data has provided a useful way to study the thermal and dielectric properties of the subsurface deposits on the Moon. However, the obvious TB change with the latitude, named latitude effect, has highly limited the application of the MRM data. To solve this problem, a new TB mapping method, named normalized TB (nTB) mapping method, is developed, which is defined as the ratio between the TB and the standard TB at the same point. Based on the newly derived global nTB maps, we identified and classified four types of subsurface deposits with distinct dielectric properties, two of which indicate the abnormally high heat flux or the existence of the granitic systems and the existence of the surface rocks, respectively. Moreover, the nTB at the daytime demonstrates a strong correlation with both the TiO2 and FeO abundances of subsurface deposits, the latter of which has been severely underestimated by the previous studies directly using MRM data. This work is significant to improve the understanding of the basaltic volcanism and thermal evolution of the Moon.

Sinus Medii has various geological features, and its location in the central part of the lunar nearside is ideal for calibrating ground-based lunar observation instruments. In this work, the Chang’E-2 (CE-2) microwave radiometer (MRM) data were used to evaluate the microwave thermal properties of the surface deposits in Sinus Medii combined with the previous geological results based on optical data. The findings are as follows: (1) a lunar calibration site (4.98°W, 3.02°N) is found where the TB performances show a good agreement with the compositions of the surface deposits, (2) a TB anomaly (0.24°W, 0.76°N) was found which may be related to high rock abundance in a crater, and (3) a possible cryptomare is revealed in the light plain southeast of Sinus Medii. This study of the microwave thermal properties in Sinus Medii helps search for calibration sites for ground-based observation instruments.

Mare Smythii is a special basin, which is one of the oldest mare basins with the considerably young mare basalts and the high density of floor-fractured craters. In this paper, the Chang’E-2 (CE) lunar microwave radiometer (MRM) data was used to evaluate the thermophysical features of the floor deposits in mare Smythii. Based on the theoretical simulation and the previous geological results, several special findings are noted as follows. (1) The substrate temperature in mare Smythii is likely fairly high. (2) The regolith thermophysical parameters change greatly with depth in the northeast unit, and there probably exists a special material in the shallow layer of the lunar regolith with strong thermal absorption ability. These special findings will be of fundamental significance to improve understanding the thermal evolution of the Moon.

King crater is a Copernican crater located near the equator in the western highlands of the lunar farside. The study of the microwave brightness temperature (TB) in this region is of great significance for exploring the interior structure of the lunar farside. The Chang’e-2 (CE-2) microwave radiometer (MRM) is mainly used to obtain TB data on the lunar surface under four channels. This study uses the ordinary Kriging algorithm to interpolate the midday and midnight MRM data of this region and generates the TB maps and TB difference (dTB) maps for each channel in two moments. Combined with UVVIS data from Clementine satellite and Diviner data from LRO satellite, the characteristics of microwave thermal radiation are discussed. The results show that (FeO+TiO2) abundance (FTA) and rock abundance (RA) are important factors affecting thermal radiation anomalies in the King crater. It also provides evidence for the formation of the King-Bruno anomalous belt, which is believed to be significantly related to the formation of the King crater.

The Chang’e-1/2 satellites carried microwave radiometers (MRM), which supplied unique passive microwave data, supplementing visible, thermal infrared, and radar data in current lunar studies. However, the application of MRM data is constrained by the limited amount of the original dataset, which cannot express spatial variations at given local times. In this study, we present a novel approach to constructing a local-time brightness temperature (TB) model using barycentric interpolation based on Delaunay tetrahedralization. This model enables the generation of a complete TB dataset, producing TB maps that are both continuous and self-consistent in both spatial and temporal domains. Compared to the traditional methods, those generated in this work avoid a ~7-K bias on a global scale. Furthermore, the interpolated maps offer superior representations of the TB over time for various lunar surfaces. The preliminary evaluations on global and regional scales hint important application of MRM data in studying the geological features of the Moon.

In this study, two special thermal behaviors are discovered and identified with the brightness temperature (TB) derived from Chang'e-2 MRM data. First, there exists a 37-GHz TB at noon, which is not related to the topography. Second, there exists a low 3.0-GHz TB anomaly. After comparison the distribution pattern and the correlation coefficients between the rock abundance, or FeO and$\text{TiO}_{2}$abundances, we ascribe the special thermal behaviors to be a composition-related TB anomaly, which likely reflects the heterogeneity of the lunar crust in vertical direction.

Studying Tsiolkovskiy crater with mare basalt in the floor helps to better understand the volcanic evolution and geological events on the lunar far side. In this work, the thermal behaviors of the surface materials in Tsiolkovskiy are evlated with the microwave radiometer data from Chang'e-2 satellite. The main results are as follows. (1) The thermal behaviors in the central peak coincide with those of rocks. (2) A small patch with higher substrate temperature is discovered in the southwestern part of crater floor with basaltic material. (3) The difference between the eastern and western half of Tsiolkovskiy crater is pointed out according to the brightness temperature behaviors.

Studying Korolev basin may provide meaningful information about the Megabasin on the lunar surface. In this study, the brightness temperature (TB) maps derived with Chang'e-2 microwave radiometer data are used to study the thermophysical features of the surface materials within and outside Korolev basin. Here, for the first time, a high TB anomaly in the highland crater is revealed with the TB data. Moreover, four surface units are indicated by the TB performances at day and night, which likely reflects the thermophysical features of the ejecta mainly from Orientale, Hertzsprung, and Apollo events. This study is essential to improve understanding the surface and thermal evolution of the highland craters.

The influence of rocks on the microwave thermal emission (MTE) of the lunar regolith has not been fully studied with the four-channel microwave radiometer (MRM) data onboard Chang’e-1/2 satellites. To highlight the influence of the rocks on the MTE of the regolith, the Hertzsprung basin located near the lunar equator in highland regions is selected as the study area. The comparison between the brightness temperature (TB) maps derived from the Chang’e-2 MRM data and rock abundance (RA) map derived from the Diviner data postulates three special issues about the correlation between the MTE features and the regolith with rocks. Then, aimed to interpret the issues, two new layered regolith models and the corresponding radiative transfer models are constructed. The main results are as follows. First, the observation and the simulation both verify that the regolith with rocks will provide a cold TB anomaly at night and at low frequencies at daytime, but result in a hot anomaly at high-frequency at daytime. Moreover, the temperature profiles of the regolith with surface and hidden rocks are evaluated with the theoretical model. Second, the simulation results verify the existence of the hidden rocks in the lunar regolith assumed when studying the TB performances of the Hertzsprung basin. Third, the rock distribution revealed by the TB maps shows a different view compared to that estimated by the Diviner data in space and values, and the change of the TB with frequencies postulates a new view about the variation of the RA with depth. This study hints that the MRM data probably provide a new way to quantitatively estimate the RA values of the lunar regolith, and the results will be meaningful to improve understanding of the evolution of the impact craters.

Buried craters within tens of meters of lunar regolith are rarely studied but are significant for understanding the evolution of surface processes on the Moon. Here, we first report the evidence of an intact buried crater within the layered strata at Chang’E-4 (CE-4) landing site revealed by the lunar penetrating radar (LPR). The time–frequency comparative analysis method based on the variational mode decomposition (VMD) and the rock quantitative analysis method based on the local unit correlation (LUC) are proposed and applied to the processing and analysis of LPR data within 15 lunar days. The results presented by the two methods provide evidence of a buried crater at the CE-4 landing site and simultaneously reveal the rock-concentrated structure within the buried crater. According to the results, it is considered that the filling materials within the buried crater have survived the impaction and gardening during the formation of the overlying fine-grained regolith. Recent works have proposed that the near-surface material at the CE-4 landing site is mainly the lunar mantle materials excavated from the nearby Finsen crater. Therefore, the buried crater probably preserves the initial lunar mantle materials.

The cold anomaly represents the special thermophysical features of the lunar regolith, which is only studied with the LRO Diviner thermal infrared (TIR) data. In this paper, sampled a typical TIR cold anomaly, the China Chang' E-2 lunar microwave radiometer data are employed to evaluate the regolith thermophysical features in microwave domain. The results indicate that the special material only exists in the shallow layer, and the thickness is larger than 31 cm but less than 77 cm. Moreover, the special material presents a high correlation with the rocks in the microwave domain, opposite to the findings from Diviner TIR data.

The cause of the hot anomaly is one of the important scientific aims of the current lunar studies. In this study, aimed at a rock-related hot anomaly revealed by the Diviner thermal infrared data, the brightness temperature (TB) derived from the Chang'e-2 microwave sounder (CELMS) data is employed to evaluate its thermophysical features of the regolith. According to the TB performances, the ilmenite-rich material is identified in the region. Thus, we denied the rock influence and ascribed the region as a potential cryptomare. This study provides a new way to evaluate the thermophysical features of the lunar regolith with the CELMS data.

Mare Nubium is one of the most ancient circular impact basins on the Moon with the lava flow units ranging from Imbrian to Eratosthenian. In this paper, the China Chang'E-2 lunar microwave radiometer data are employed to evaluate the basaltic units of the Mare Nubium. The results indicate that the relationship between the brightness temperature difference (dTB) performances and the basaltic units is rather weak. Moreover, the low dTB anomaly in the middle-western part is interpreted as the floor deposits produced during the formation of Mare Nubium.

The high-speed railway from Harbin to Dalian was plays an important role for the development of the Harbin-Changchun megalopolis. In this paper, based on sentinel-1A /B data from 2016 to 2019, the surface deformation of the highspeed railway from Changchun to Harbin were firstly evaluated using time-series ps-insar method. The results indicate that the surface deformation is not dangerous for the safe operation of the railway. Moreover, the surface depressions near Dehuixi station and Zhuchengzi town are potentially dangerous for the safe of the railway. finally, the cause of the surface deformation along the railway is mainly attributed to the human activity and the seasonal subgrade frost heave in the seasonal frozen soil.

Mare Moscoviense (148°E, 27°N) is one of the few large maria on the lunar farside. In this paper, the China Chang'E-2 Microwave Sounder (CELMS) data were employed to study the microwave thermal emission features of Moscoviense basin. The findings are as follows. (1) The four basaltic units present distinctly different TBperformances at noon and midnight; (2) A new understanding about the basaltic units is made according to the classification results using the maximum likelihood method; (3) The substrate temperature of Moscoviense basin is likely much higher than what we know. The results will be of great significances to understand the mare volcanism on the lunar farside.

In this study, the Chang'E-2 microwave radiometer (CELMS) data are employed to study the thermophysical features of the regolith in the western lunar farside, including Giordano Bruno - the youngest lunar crater of its size. The results are as follows. Firstly, the distribution of the rocks with depth is different in Bruno, King, and Necho craters. Secondly, abundant cold anomalies and one hidden hot anomaly are discovered. Thirdly, at least seven hidden linear structures are discovered, some of which hinting the impacting process of Bruno crater.

The landing area of Chang'E-4 is initially selected as the Von Kármán crater inside the South Pole-Aitken basin on the lunar farside. The research would outline science opportunities based on the microwave radiometer data by the field theory. The SVD analyses between the brightness temperature fields of 3 GHz and 37 GHz were done with versus time series data which were calculated by hour angle correction in the Von Kármán crater. The results showed that the main factors affecting the spatiotemporal distribution of brightness temperature are roughness, but less affected by FTA. According to the spatial and temporal distribution of brightness temperature anomalies, the site A(Fig 8) was selected as the preselected landing area for Chang'E-4., which is located in the dense isoline region of the heterogeneous correlation map.

Apollo Basin locates within the large South Pole-Aitken Basin (SPA). The study on Apollo Basin will provides some interesting information about the composition and thermal state of the shallow Moon crust. In this paper, the normalized brightness temperature (nTB) maps and the (FeO + TiO2) abundance (FTA) were systematically combined to study the thermal behaviors of Apollo Basin. The results firstly indicate a strong correlation between the nTB behaviors and the FTA. Secondly, the low nTB behaviors hint the homogeneity of the Moon crust in the thermophysical parameters. Finally, the abnormally high nTB behaviors in the western of the Basin floor probably imply the existence of the pyroclastic deposits.

Knowledge of the thermal state will provide essential information to better understand the thermal evolution of the Moon. In this paper, four typical Copernican craters, including Copernicus, Aristarchus, Tycho and Jackson, are selected and their thermal behaviors are evaluated with the CE-2 CELMS data. The results indicate that: (1) There exists a strong correlation between the TBdistribution at noon and the topography. (2) The changes of the regolith thermophysical parameters with depth are rather complex in the four typical craters. (3) The TBat midnight is more suitable to study the regolith thermophysical features. (4) The shallow layer of the lunar crust is likely cold.

Land surface temperature (LST) is a key variable in the processes of energy and water balance between Earth's surface and atmosphere. To date, considerable researches have been focused on this issue, especially the thermal infrared (TIR) methods. Whereas TIR measurements are only limited to clear-sky condition, no observation is possible under cloudy conditions. While, passive microwave (PMW) as an alternative to the TIR measurements can penetrate the clouds. In this paper, the optical LST was derived from AMSR-E brightness temperatures by building a strong linear relationship over the continental United States. Unlike the previous studies, the algorithm was conducted by further using the corresponding ground measured LSTs which consist of both clear and cloudy conditions. The linear relationships were built on three sub-regions which is defined by NDVIs. The results show that the root-mean-square error (RMSE) of derived LST ranges from 2.50K to 3.23K for ascending overpass and 1.54K to 2.71K for descending track. This accuracy is proven to be better than existing work.

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 TiO2abundance, 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 TiO2abundance.

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 current Moon research. In this paper, the CELMS data from Chang'E-2 satellite are employed to reveal the microwave thermal emission features of the Mare Orientale. The results indicate that the regions with high TBand high TBdifference are strongly influenced by FTA, but FTA is not the only factor. Moreover, the lunar regolith structure is not even at the mare basin. Furthermore, there exist abundant abnormal TBand high TBdifference regions which could hardly be explained by the current Moon research.