The NOAA-20 Visible Infrared Imager Radiometer Suite (VIIRS) was launched on November 18, 2017. VIIRS has been scheduled to view the Moon approximately monthly with a spacecraft roll maneuver after its NADIR door open on December 13, 2017. To reduce the uncertainty of the radiometric calibration due to the view geometry, the lunar phase angles of the scheduled lunar observations are confined in the range from -51.5° to -50.5°, which is same as the range used for SNPP VIIRS lunar calibration and where the negative sign for the phase angles indicates that the VIIRS views a waxing moon. Different from the MODIS lunar observations but same as those of SNPP VIIRS, the scheduled VIIRS lunar observations occur on the day side of the Earth. The lunar observations can be used to identify inoperable detectors. They can be used to check if there are crosstalk contaminations among the instrument’s bands and to track on-orbit changes in the Reflective Solar Bands (RSB) detector gains. In this paper, we report our results using the lunar observations to identify inoperable detectors, to examine the on-orbit crosstalk effects among NOAA-20 VIIRS bands, to track the VIIRS RSB gain changes in first few months on-orbit, and to compare the gain changes derived from lunar and SD/SDSM calibration.
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