Lunar brightness temperature for calibration of microwave humidity sounders

Calibration and validation (CAL/VAL) is a key technology for quantitative application of space-borne remote sensing data. However, the complex space environment can cause many uncertainties and degrade calibration accuracy. In-flight calibration is always needed. The thermal emission of the Moon is stable over hundreds of years because there is no atmosphere and no significant physical or chemical change on its surface. The deep space view of the Microwave Humidity Sounder onboard NOAA-18 has vi...