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Neigh C, McCorkel J, Campbell P, Ong L, Ly V, Landis D, Fry S, Middleton E.
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IEEE Geosci Remote Sens Lett. 2016 Dec;13(12):1797-1801. doi: 10.1109/lgrs.2016.2612539. Epub 2016 Oct 13.
Abstract
Spaceborne spectrometers require spectral-temporal stability characterization to aid validation of derived data products. EO-1 began orbital precession in 2011 after exhausting onboard fuel resources. In the Libya-4 Pseudo Invariant Calibration Site (PICS) this resulted in a progressive shift from a mean local equatorial crossing time of ~10:00 AM in 2011 to ~8:30 AM in late 2015. Here, we studied precession impacts to Hyperion surface reflectance products using three atmospheric correction approaches from 2004 to 2015. Combined difference estimates of surface reflectance were < 5% in the visible near infrared (VNIR) and < 10% for most of the shortwave infrared (SWIR). Combined coefficient of variation (CV) estimates in the VNIR ranged from 0.025 - 0.095, and in the SWIR ranged from 0.025 - 0.06, excluding bands near atmospheric absorption features. Reflectances produced with different atmospheric models were correlated (R (2)) in VNIR from 0.25 - 0.94 and SWIR from 0.12 - 0.88 (p < 0.01). The uncertainties in all models increased with terrain slope up to 15° and selecting dune flats could reduce errors. We conclude that these data remain a useful resource over this period. Keywords: . Link/DOI: 10.1109/lgrs.2016.2612539