Assessment of straylight correction performance for the VIIRS Day/Night Band using Dome-C and Greenland under lunar illumination

The day/night band (DNB) of the Visible Infrared Imaging Radiometer Suite (VIIRS) on board Suomi National Polar-orbiting Partnership (Suomi-NPP) represents a major advancement in night-time imaging capabilities. However, the DNB is sensitive to noise introduced from straylight, which appears as a grey haze in radiance images. This effect on the DNB is caused by solar illumination entering the optical path when the satellite passes through the day-night terminator projected on the Earth's surface. It results in an overall increase in the recorded radiance values. This effect is more significant during solstice. Straylight correction techniques have been implemented to remove this unwanted effect. This study presents an effective method to assess straylight correction performance for VIIRS DNB using DNB observations over Dome C in the Antarctic and Greenland under lunar illumination. Nadir observations of these high-latitude regions by VIIRS are selected during the perpetual night season over various lunar phases. Through cross-comparison between the lunar-phase dependence of DNB observations of events with straylight correction and those without straylight, the quality of straylight correction can be assessed. Using this method, DNB radiance data from two different sources, i.e. the National Oceanic and Atmospheric Administration (NOAA) Operational Interface and Data Processing Segment (IDPS) and the National Aeronautics and Space Administration (NASA) Land Product Evaluation and Algorithm Test Element (PEATE), were compared for their performance in straylight correction.