NPP Visible/Infrared Imager Radiometer Suite (VIIRS) Radiometric Calibration - Tested Performance

The Visible/Infrared Imaging Radiometer Suite (VIIRS) collects radiometric and imagery data in 22 spectral bands within the visible and infrared spectrum ranging from 0.4 to 12.5 µm. As part of the NPOESS Preparatory Project (NPP), VIIRS will provide data used to generate 22 Environmental Data Records (EDRs), including two Key Performance Parameters (KPPs): Sea Surface Temperature (SST) and Imagery. The quality requirements imposed on these EDRs drive stringent radiometric requirements. Absolute radiometric uncertainties as tight as 0.4% are required for the VIIRS thermal emissive bands (3.7 to 12.5 µm). This paper describes the radiometric uncertainty requirements for the 7 VIIRS thermal emissive bands and the calibration methodology employed to meet these requirements, including the on-board calibration subsystems and the retrieval algorithm for generating calibrated radiance from instrument data. The instrument characteristics contributing to uncertainties in retrieved radiance are presented based on results from the recently completed pre-launch test program. The final roll-up of these uncertainties relative to the absolute radiometric requirements are shown, and compared against the results obtained from the radiance retrieval algorithm exercised during thermal-vacuum testing for a NIST traceable Blackbody Calibration Source.