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.

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.

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.

Although estimating the Earth radiation budget (ERB) by satellite platforms have become more and more reliable, it is still difficult to carry out conclusive evidence that supports whether the Earth is warming. As the important component of ERB, the measurement requirements of Earth's outgoing radiation are to acquire global-scale absolute calibration data. Observing Earth's outgoing radiation on the lunar surface is a feasible way to improve the consistency and continuity of such data. Since the Moon is a celestial body and the sensor can be equipped anywhere on the near-side of the Moon, the site selection issue of a Moon-based platform will be the most vital step. This paper mainly discusses the site selection issue of a Moon-based Earth radiation budget experiment platform from the perspective of Earth observation geometry. By analyzing observation performance, geolocation accuracy, radiation response and solar invasion effects, we suggest that the mid-high latitude will be a better position to equip sensors.

Moon-based platform is a potential platform that can realize the observations of large-scale geoscience phenomenon. Unlike existing earth observation platforms, the moon-based platform is equipped on a natural celestial body. Its position is calculated by the lunar position and libration derived from the planetary ephemeris. However, limited to the astrometric model and accuracy of observational data, no planetary ephemeris can provide absolutely accurate data, and this will lead to a platform's position error. This letter investigates the impacts of the platform's position error on geolocation for a moon-based sensor. We first made comparisons to the lunar position and libration derived from different planetary ephemerides so as to evaluate the magnitude of the platform's position error. Then, the Monte Carlo method was applied to simulate the platform's position error. According to the geometric model, the effects of the platform's position error on geolocation were presented. The results showed the effects of lunar libration error are associated with position on the lunar surface, while the differences of lunar position error effects are not evidently shown in different positions on the lunar surface. Furthermore, high-latitude regions of the moon are demonstrated to have less impact on the platform's position error, which would be suitable for equipping earth observation sensors.

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.

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.

Into the 21st century, the human exploration of the moon increasingly frequent, China, the United States, Russia, India, Japan and other countries have joined the ranks of lunar exploration which provided a lot of data. And the platforms of Digital Moon are rewritten based on third-party plug-ins, which is poor in real-time, operability and interaction. On this research the web platform of Digital Moon is built based on WebGL specification for rendering 3D graphics within any compatible web browser without the use of plug-ins. So that the paltform is suitable for many kinds of browers, and it is convenient to the public to understand the moon and help the scientist to explore the universe.

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.