Cheng-E2 (CE-2) Level 2C Microwave RadioMeter (MRM) map Channel 1 difference midday and midnight

The Level 2C Chang'E-2 (CE-2) Microwave RadioMeter (MRMs) data (Zheng et al., 2012; 2019; NAOC, 2016) were used in this study, following system calibration and geometric correction with Planetary Data System (McMahon, 1996). The MRM underwent onboard adjustments to ensure its reliability and accuracy using a two-point calibration method (for details see Chan et al., 2010; Wang et al., 2010; Zheng et al., 2012; Hu et al., 2014; Hu et al., 2017, Zheng et al., 2019). We used spherical harmonic fits for the Temperature Brightness (T_B) variations with local time (Wang et al., 2010) to suppress the lunar phase effect. Normalized T_B at midday and midnight were chosen to minimise the topographic effects on the emission (Hu et al., 2014). Surface temperature variations at midnight are dependent on the local differential heat energy storage and release accumulated by surface materials during the day, with a minimal contribution by internal sources (heat flow).