Vicarious calibration model improves quantitative use of Fengyun‑3 ocean color data

Ocean‑color remote sensing has become an essential method for tracking the world’s oceanic carbon sinks and primary productivity, providing data that underpin climate models and fisheries management. By measuring the spectral characteristics of light reflected from the sea surface, satellites can infer concentrations of phytoplankton, dissolved organic matter, and other constituents that drive the marine carbon cycle.

However, the accuracy of on‑orbit calibration for current satellite sensors remains inadequate, and marine signals contribute only about ten percent of the total radiance captured by the instruments. This low signal‑to‑background ratio introduces substantial uncertainties into ocean‑color products, limiting their reliability for scientific and operational use. Improving sensor calibration and enhancing the detection of weak marine signals are therefore critical steps toward more precise monitoring of global ocean health.