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Thermal anomaly spots (both hot and cold) have been found in the global 37-GHz brightness temperature (TB) map of the moon based on the Chang’E (CE) microwave radiometer measurements. To explain their origin, a rock model is proposed to simulate the TB variation against latitude along the profile of a fresh crater in a single track way, which is selected to highlight the topographic effect and avoid any modification to the data. A mixed upper layer made up of rock and soil (regolith and dust) was employed into our previous multilayer model. The thermal properties (thermal conductivity and heat capacity) of the mixture layer are presumed to be linear with the fraction of rocks. Given that high-frequency (37 GHz) measurements are chosen, only the meter size and larger rocks of the upper mixed layer are considered to avoid scattering effects. Several fresh craters poor/rich in ilmenite are selected as testing sites. Despite uncertainties in parameters such as rock abundance (RA), and iron and titanium abundances, three conclusions can be reached from these cases: 1) RA has a significant effect on both the TB value and TB variation trend against latitude; its contribution over some craters may be as high as 15 K; 2) the simulations based on our rock model fit the CE observations better than those when rocks are not included; and 3) the rock and ilmenite contributions could be the main cause for the cold and hot spots found in the CE microwave map. [ABSTRACT FROM AUTHOR]

To improve the retrieval accuracy of the lunar properties from microwave brightness temperature (TB) data sets of the lunar surface, TB measurements of the global moon need a calibration source to better estimate. In this letter, the standard for the calibration source is defined, and two possible calibration sources (the lunar center and Apollo 15) are proposed, which are based on a theoretical TB model. There is a difference of about 4 (3/37 GHz) and 11 K (7.8/19.35 GHz) between the simulated calibration source and Chang'E observation at the lunar center, and of about 7 K (3/7.8/19.35/37 GHz) at Apollo 15. The simulated calibration source (7.8/37 GHz) of the lunar center is within the range of the ground-based measurement. Note that the lunar center has been measured frequently by both ground-based and in-orbiter instruments, and the calibration source of the lunar center is the most possible and credible for the lunar surface. The uncertainty of the calibration source has been also analyzed. [ABSTRACT FROM PUBLISHER]