Fig. 1. Study area and observation sites

Fig. 2. Vertical viewing geometry of reflectance spectral measurement of river water

Fig. 3. Continuous-time remote sensing reflectance spectral curves

Fig. 4. Remote sensing reflectance spectral curves at characteristic wavelengths

Fig. 5. Remote sensing reflectance of river water after spatio-temporal matching

Fig. 6. Linear relationship between measured chlorophyll concentration and measured remote sensing reflectance

Fig. 7. Linear relationship between measured turbidity and measured remote sensing reflectance

Fig. 8. Linear relationship between measured CDOM concentration and measured remote sensing reflectance

Fig. 9. (a)The relationship between measured remote sensing reflectance and Sentinel-2B remote sensing reflectance after Sen2Cor at mospheric correction; (b) the relationship between measured remote sensing reflectance and Sentinel-2B remote sensing reflectance after FLAASH atmospheric correction