When fully illuminated by the Sun, the solar diffuser (SD) onboard of the NOAA-20 Visible Infrared Imaging Radiometer Suite (VIIRS) instrument provides a radiance source to allow for radiometric calibration of the VIIRS’s reflective solar bands (RSBs). Once on-orbit, due to solar bombardment and the space environment, the SD’s bidirectional reflectance distribution function (BRDF) changes its value. The change is denoted by a factor, known as the H-factor, that is time and wavelength dependent, as well as both incident and out-going angle dependent. Here, we use regular on-orbit solar diffuser stability monitor (SDSM) data to determine the solar angular dependence for the H-factor along the SD-to-SDSM direction. We compare the dependence with that for the VIIRS on the Suomi National Polar-orbiting Partnership satellite and apply the dependence ratio to obtain the N20 VIIRS SD H-factor along the SD-telescope direction.

Date Published: 9 September 2019
PDF: 7 pages
Proc. SPIE 11127, Earth Observing Systems XXIV, 111271Q (9 September 2019); doi: 10.1117/12.2529783

Published in SPIE Proceedings Vol. 11127:
Earth Observing Systems XXIV
James J. Butler; Xiaoxiong (Jack) Xiong; Xingfa Gu, Editor(s)