Evaluation of in situ radiometric data processing for calibration and validation of satellite ocean color remote sensing

摘要

In situ data are essential for calibration, validation, and bio-optical algorithm development of ocean color remote sensing, as well as for studying and understanding of ocean optical, biological, and biogeochemical properties. Especially, calibration and validation of ocean color satellite data relies on high quality in situ data. In addition, objective evaluation of satellite ocean color products need well quality controlled in situ data from various bio-optical environments covering diverse aquatic waters. The goal of ocean color satellite sensors is to remotely derive accurate normalized water-leaving radiance spectra (nL_w(λ)), therefore other water biological and biogeochemical property data can be obtained using satellite-measured nL_w(λ) spectra. In this paper, we show results from analyzing in situ data processing procedure from the Marine Optical Buoy (MOBY) and NASA SeaWiFS Bio-optical Archive and Storage System (SeaBASS) used for satellite ocean color calibration and validation purposes. Various issues in determining final product of in situ radiometric data processing such as convolving nL_w(λ) with respect to satellite sensor spectral response functions, sensor effective band center wavelengths, and effects of Bi-directional Reflectance Distribution Function (BRDF) are analyzed and discussed. Performance of satellite-derived nL_w(λ) taking into consideration of various issues in the in situ data processing is also assessed.