Inversion of Sea Surface Chlorophyll Concentration from Coastal Zone Imager Onboard China's Ocean Color Satellite HY-1C

Sea surface chlorophyll concentration is one of the critical parameters of ocean color. It serves as a fundamental indicator for assessing marine net primary productivity and eutrophication. However, obtaining accurate data and conducting rapid sea surface chlorophyll concentration measurements present significant challenges. This study is based on the Coastal Zone Imager (CZI) data from China's ocean color satellite HY-1C, which analyzes the sensitivity of spectral bands, and a remote sensing inversion model for sea surface chlorophyll concentration, which is suitable for the coastal waters of China, was constructed. The experimental results in the coastal waters near the Zhoushan Archipelago indicate the following: (1) The band combinations B3/B2 and B3/(B2 + B1) exhibit the highest correlation with sea surface chlorophyll concentration, with a correlation coefficient of 0.77. (2) The quadratic polynomial model (y = 105.42x2 - 175.67x + 75.167) constructed using B3/B2 as the independent variable demonstrates the highest inversion accuracy for sea surface chlorophyll concentration. The R2 value is 0.9107 and the mean absolute percentage error is 26.85%. This study plays a significant role in advancing the operational level of domestic ocean satellites and in monitoring coastal water quality.