Water Quality Monitoring of the Yangtze Estuary by Using GF-5 Hyperspectral Image

Ocean color remote sensing is one of the important means to monitor the spatial distribution of water quality parameters and to assess the estuarine environment. The successful launch of Gaofen-5 (GF-5) satellite provides researchers a high-resolution alternative for monitoring water quality. As the GF-5 satellite is put into use officially, to explore the practical capability of GF-5 satellite for water color remote sensing, this study takes the Yangtze river estuary as an example. Two GF-5 hyperspectral images acquired on March 27, 2019 are processed to estimate the chlorophyll-a concentration (C_chla) and suspended sediment concentration (SSC) in the Yangtze river estuary. Compared with water samples and other studies in Yangtze Estuary, the retrieved remote sensing reflectance (R_rs) is the same as the spectrum of high turbidity water body. Additionally, the obtained parameter value range and spatial distribution of Yangtze river estuary water quality parameters in dry season are consistent with previous studies and natural laws. The application effect of GF-5 hyperspectral image is ideal, and our future study will further exploit the potential of GF-5.