Ushering in the New Era of Radiometric Intercomparison of Multispectral Sensors with Precision SNO Analysis
AbstractA “nadir-only” framework of the radiometric intercomparison of multispectral sensors using simultaneous nadir overpasses (SNOs) is examined at the 1-km regimes and below using four polar-orbiting multispectral sensors: the twin MODerate-resolution Imaging Spectroradiometer (MODIS) in the Terra and Aqua satellites, the Visible Imaging Infrared Radiometer Suite (VIIRS) in the Suomi National Polar-orbiting Partnership (SNPP) satellite, and the Ocean and Land Colour Instrument (OLCI) in the Sentinel-3A satellite. The study is carried out in the context of isolating the on-orbit calibration of the reflective solar bands (RSBs) under the “nadir-only” restriction. With a homogeneity-ranked, sample size constrained procedure designed to minimize scene-based variability and noise, the overall approach successfully stabilizes the radiometric ratio and tightens the precision of each SNO-generated comparison event. Improvements to the multiyear comparison time series are demonstrated for different conditions of area size, sample size, and other refinements. The time series demonstrate the capability at 1% precision or better under general conditions but can attain as low as 0.2% in best cases. Solar zenith angle is examined not to be important in the “nadir-only” framework, but the spectral mismatch between two bands can give rise to significant yearly modulation in the comparison time series. A broad-scaled scene-based variability of ~2%, the “scaling phenomenon”, is shown to have pervasive presence in both northern and the southern polar regions to impact inter-RSB comparison. Finally, this paper highlights the multi-instrument cross-comparisons that are certain to take on a more important role in the coming era of high-performing multispectral instruments. View Full-Text
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Chu, M.; Dodd, J. Ushering in the New Era of Radiometric Intercomparison of Multispectral Sensors with Precision SNO Analysis. Climate 2019, 7, 81.
Chu M, Dodd J. Ushering in the New Era of Radiometric Intercomparison of Multispectral Sensors with Precision SNO Analysis. Climate. 2019; 7(6):81.Chicago/Turabian Style
Chu, Mike; Dodd, Jennifer. 2019. "Ushering in the New Era of Radiometric Intercomparison of Multispectral Sensors with Precision SNO Analysis." Climate 7, no. 6: 81.
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