This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Ocean color remote sensing is a vital tool for monitoring global ocean carbon sinks and primary productivity. However, the on-orbit calibration accuracy of satellite sensors is insufficient, and weak marine signals account for only approximately 10% of the signals received by satellites, leading to significant uncertainties in ocean color remote-sensing applications.
China's Fengyun-3D (FY-3D) and Fengyun-3F (FY-3F) satellites, both equipped with Medium Resolution Spectral Imager (MERSI) sensors, have faced a persistent "weak signal, strong interference" dilemma in their ocean color observation channels, calling for a dedicated, targeted calibration solution. Recently, a joint research team led by the National Satellite Meteorological Center in China and the Aerospace Information Research Institute of the Chinese Academy of Sciences developed a vicarious calibration model for the MERSI sensors aboard FY-3D and FY-3F. The model effectively corrected radiometric biases in the ocean color channels of the two satellites, significantly improving the accuracy of retrieved ocean remote-sensing reflectance.
The findings mark a major step forward for Chinese satellite ocean color data, enhancing quantitative application capabilities, and were recently published in Atmospheric and Oceanic Science Letters. "Limited on-orbit sensor calibration, along with atmospheric interference, has introduced considerable biases in the observation of weak ocean signals, thereby restricting the quantitative application of ocean color remote sensing," explained Professor Chong Shi, corresponding author of the study. "Our approach leverages high-precision ground-based observations as a reference and integrates radiative transfer simulations with regression analysis to calibrate the ocean color channels.
By taking into account the sensors' spectral response characteristics, this method accurately disentangles atmospheric path-radiance contributions and corrects water-leaving radiance. This study is expected to provide more reliable remote-sensing data to support ocean color observation research." The research team plans to extend the proposed vicarious calibration framework to more complex aquatic environments, such as turbid coastal waters, and conduct time-series analyses to monitor the long-term stability of the calibration coefficients. The study not only establishes a basis for the quantitative use of FY-3 ocean color data but also provides a technical reference for calibrating China's ocean color remote-sensing data.
Ni An et al, Vicarious calibration of the weak-signal ocean color channels for the Fengyun-3/MERSI sensors, Atmospheric and Oceanic Science Letters (2026). DOI: 10.1016/j.aosl.2026.100869 Provided by Institute of Atmospheric Physics, Chinese Academy of Sciences Bachelor's in mathematical biology, Master's in creative writing. Well-traveled with unique perspectives on science and language.
Extract — continue reading at the source.
