Suomi-NPP VIIRS lunar radiometric calibration observations

Lunar observations by the Suomi-NPP instrument VIIRS help improve our understanding of the radiometric calibration of the reflected solar bands (RSB). The spacecraft performs a scheduled roll maneuver approximately nine times per year to acquire lunar data at nearly constant phase angles. The instrument also captures lunar radiometric data at other times when the instrument Space View port serendipitously points at the Moon. In this paper, we present results only from the scheduled Moon observations, comparing the observed lunar irradiance to ROLO model results to provide calibration coefficients for each band, mirror side, and detector. These results can be evaluated directly to the primary RSB calibration method derived from the Solar Diffuser. This paper also discusses recent improvements to our methodology for measuring the lunar irradiance, including a new method for determining the lunar position within the field of view, an all-detector calibration methodology, and an assessment of the uncertainties in our lunar observations. This paper includes lunar observation data through June 2014.