Suomi NPP VIIRS reflective solar band on-orbit radiometric stability and accuracy assessment using desert and Antarctica Dome C sites

The Visible Infrared Imaging Radiometer Suite (VIIRS) is a key instrument flying aboard Suomi NPP satellite. It is a follow on mission for NOAA series AVHRR and NASA MODIS. The radiometric stability and accuracy of VIIRS are critical to make its data useful for weather and climate applications. This study is focused on analyzing VIIRS radiometric performance using well established calibration sites and through the inter-comparison with other satellite instruments such as AQUA MODIS and Landsat 8 OLI. The paper analyzes stability of VIIRS reflective solar bands over more than two years by using sites such as Libya 4, Sudan 1 and Dome C. VIIRS absolute radiometric accuracy is quantified using AQUA MODIS over the above mentioned sites. For VIIRS band M11 (2.1 μm), since there is no matching MODIS band pair, this study uses matching SWIR band from Landsat 8 OLI as a reference to quantify the absolute calibration accuracy of M11. The study shows that VIIRS moderate resolution reflective solar bands are stable with better than 0.5% for most of the bands with uncertainty on the order of 1%. After accounting the spectral differences, the absolute radiometric bias estimated through VIIRS and MODIS inter-calibration is within 2% for bands M1-5 and M10 and about 3% for bands M7-8. Similarly, M11 bias estimated using VIIRS and OLI inter-comparison is 5.4%.