Improvements in the calibration of the SNPP VIIRS day-night band (Conference Presentation)

Abstract

We present improvements to the on-orbit calibration of the day-night band (DNB) of the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar-orbiting Partnership (SNPP) satellite. Most important among the improvements is the expansion of the “sweet spot” from 4 o to 7.8o to increase the number of the fully illuminated scans for calcuation. This allows for the completion of the on-orbit calibration using the solar diffuser (SD) within one orbit instead multiple orbits as required in the current standard approach. The bidirectional reflectance factor (BRF) of the SD and the vignetting function (VF) describing the transmission of the attenuation screen in front of the SD port are also examined and improved. Additional enhancements include the analysis of the out-of-band (OOB) contribution of the relative spectral response (RSR) and the adaptation of the previously improved SD degradation. The result shows that the improved DNB calibration coefficients are more stable, smooth and less noisy.