SNPP VIIRS RSB on-orbit radiometric calibration algorithms Version 2.0 and the performances, part 2: the performances

In part I (Lei et al., J. Appl. Remote Sens., Vol. 14, Issue 4), we gave detailed reviews of the algorithms Version 2.0 used for the on-orbit radiometric calibration of the reflective solar bands (RSBs) of the first Visible Infrared Imaging Radiometer Suite (VIIRS) instrument. These algorithms improve the accuracy of the measured on-orbit change factor of the solar diffuser bidirectional reflectance distribution function, the H-factor, and reveal that the H-factor is angle dependent. With the help of lunar observations and the improved H-factor, the algorithms give more accurate values for the RSB detector on-orbit F-factor changes (F-factor is a correction factor to the initially retrieved scene spectral radiance). We review the RSB radiometric calibration performances. We show the H-factor temporal trend, the estimated uncertainty of the retrieved H-factor, and the F-factor temporal trend. Additionally, we show the detector signal-to-noise ratio (SNR), the estimated uncertainty of the top-of-the-atmosphere solar spectral reflectance, the reflectance temporal trend for the Libya 4 desert, and the differences in the reflectances among the Suomi National Polar-orbiting Partnership (SNPP) and the NOAA-20 VIIRS and the Aqua Moderate-Resolution Imaging Spectroradiometer (MODIS). Our results show that, although the SNRs trend downward, they exceed the requirements by large margins. The reflectances from the Libya 4 desert show that the SNPP VIIRS' reflectance is higher than those of the Aqua MODIS and the NOAA-20 VIIRS. (C) 2020 Society of Photo-Optical Instrumentation Engineers (SPIE)