An application of three-band model for chlorophyll-a estimation in a turbid case-2 reservoir in Northern China

Three-band model was originally used to retrieve chlorophyll-a concentrations of terrestrial plant leaves. Since turbid productive waters also contain much chlorophyll-a, the model was then adjusted to aquatic medium. With a more accurate physical mechanism than statistical methods and a less complicated model than analytical methods, three-band model has obtained wide applications in chlorophyll-a monitor in water bodies. In this study, we applied the model into a turbid case-2 reservoir in northern China to investigate the applicability of three-band model for remote estimation of the reservoir´s chlorophyll-a level. A three-band model was built as C_chla = 1088*X +165.87, where X = [R_rs^-1 (711)-R_rs^-2 (721)]*R_rs (750), with the RMSE of chl-a estimation was less than 3 mg/m³ and r² =0.907. The adjusted model implied a good potential to chlorophyll-a concentration estimation in Guanting Reservoir, therefore could be used in the reservoir´s water environment monitor.