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Impacts of the Angular Dependence of the Solar Diffuser BRDF Degradation Factor on the SNPP VIIRS Reflective Solar Band On-Orbit Radiometric CalibrationUsing an onboard sunlit solar diffuser (SD) as the primary radiance source, the visible infrared imaging radiometer suite (VIIRS) on the Suomi National Polar-orbiting Partnership satellite regularly performs radiometric calibration of its reflective solar bands (RSBs). The SD bidirectional reflectance distribution function (BRDF) value decreases over time. A numerical degradation factor is used to quantify the degradation and is determined by an onboard SD stability monitor (SDSM), which observes the sun and the sunlit SD at almost the same time. We had shown previously that the BRDF degradation factor was angle-dependent. Consequently, due to that the SDSM and the RSB view the SD at very different angles relative to both the solar and the SD surface normal vectors, directly applying the BRDF degradation factor determined by the SDSM to the VIIRS RSB calibration can result in large systematic errors. We develop a phenomenological model to calculate the BRDF degradation factor for the RSB SD view from the degradation factor for the SDSM SD view. Using the yearly undulations observed in the VIIRS detector gains for the M1-M4 bands calculated with the SD BRDF degradation factor for the SDSM SD view and the difference between the VIIRS detector gains calculated from the SD and the lunar observations, we obtain the model parameter values and thus establish the relation between the BRDF degradation factors for the RSB and the SDSM SD view directions.
Document ID
20170003583
Document Type
Reprint (Version printed in journal)
Authors
Lei, Ning (Science Systems and Applications, Inc. Lanham, MD, United States)
Xiong, Xiaoxiong (NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
April 17, 2017
Publication Date
June 20, 2016
Publication Information
Publication: IEEE Transactions on Geoscience and Remote Sensing
Volume: 55
Issue: 3
ISSN: 0196-2892
Subject Category
Earth Resources and Remote Sensing
Space Sciences (General)
Report/Patent Number
GSFC-E-DAA-TN41600
Distribution Limits
Public
Copyright
Other