Inversion of chlorophyll concentration in Taihu Lake from HY-1C satellite images

As the third largest fresh lake in China, the eutrophication problem of Taihu Lake is particularly prominent, and it is important to monitor the water quality parameters of Taihu Lake by remote sensing monitoring measures. Chlorophyll concentration is an important indicator parameter of eutrophication. The coastal zone imager (CZI) of China's HY-1C satellite has the advantage of high spatial and temporal resolution. In this paper, based on the band ratio model and HY-1C satellite CZI data, the chlorophyll concentration of Taihu Lake in each month of 2021 is inversed. The missing value and the influence of singular value are filled by data screening and fusion averaging so that the data quality can be improved. The analysis of the spatial and temporal variation of chlorophyll shows that: the overall Taihu Lake chlorophyll concentration in 2021 was lower than in previous years, with the highest value of 19.0 μg/L; the average chlorophyll concentration in winter was high, about 13.0 μg/L, while the average chlorophyll concentration in summer was low, about 4.0 μg/L, due to the influence of long-term precipitation; the overall central and western regions of Taihu Lake had higher chlorophyll concentration, the southern region also displays high values in winter while the chlorophyll concentration is low in the northeastern region for a long term. This study provides reference values for water quality monitoring and governance in Taihu Lake.