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Li, Chi, Xue, Yong, Liu, Quanhua, Ouazzane, Karim and Zhang, Jiahua (2015) Using SeaWiFS measurements to evaluate long-term radiometric stability of pseudo-invariant calibration sites. IEEE geoscience and remote sensing letters, 12 (1). pp. 125-129. ISSN 1545-598X
Pseudo-invariant calibration sites (PICSs) have been widely applied to satellite sensor radiometric calibrations and inter-comparisons. However, the stability of those sites is rarely evaluated comprehensively. We adopted the lifetime SeaViewing Wide Field-of-View Sensor (SeaWiFS) radiance data from 1997 to 2010 to monitor the stability of the SeaWiFS reflectance at the top of atmosphere (TOA) over six CEOS (the Committee on Earth Observation Satellites) reference standard PICSs. Cloud-free and spatially homogeneous time series of the mean spectral TOA reflectance (ρTOA) at eight SeaWiFS channels over these sites are generated together with corresponding observing geometries. We then fit the derived SeaWiFS ρTOA time series to the Ross-Li Bidirectional reflectance distribution functions (BRDF) model after screening out outliers to characterize the directional reflectivity effects. Time Series of BRDF-normalized spectral TOA reflectance (RTOA) is presented and quantitatively analyzed afterwards. Overall good stability during the SeaWiFS operation period is exhibited, while both root mean square (RMS) and trend slope analysis reveal spectral dependence of the PICSs’ stability, i.e. the uncertainty and changing extent of RTOA appear to be larger at shortwave visible (SV) channels (~3%) compared to that of red/near infrared (NIR) bands (~1.5%). The derived results could be utilized or consulted for various calibration applications such as Advanced Very High Resolution Radiometer (AVHRR) recalibration.
Available under License Creative Commons Attribution Non-commercial No Derivatives.
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