Remote sensing estimation of the concentration and sources of coloured dissolved organic matter based on MODIS: A case study of Erhai lake

The use of satellite remote sensing to estimate coloured dissolved organic matter (CDOM) and identify its potential sources is important for monitoring lake water quality implementing management strategies. In this study, taking Erhai Lake as an example based on MODIS/Aqua images in-situ measured data, we used empirical semi-empirical methods develop algorithms CDOM the fluorescence index (FI370) from reflectance (Rrs(λ)). temporal spatial distributions concentration FI370 in during 2013–2019 were retrieved. results show following. (1) band ratio (Rrs(469)+Rrs(645))/Rrs(555) model could absorption coefficient at 412 nm (aCDOM(412)) (R2=0.507), it was relatively stable. Using Rrs(645)/Rrs(469) combined with chlorophyll-a (Chl-a) APProach by ELimination (APPEL) model, a inversion performed satisfactory accuracy (R2=0.550) more accurate than algorithm (R2=0.505). (2) During period 2013–2019, generally decreased northern central southern parts lake, higher summer autumn spring winter. western coastal waters lower central, eastern lake. winter that summer. affected both terrestrial internal sources, their relative contributions not same different seasons. (3) For Chl-a concentrations, models had better retrieval effects, i.e., Rrs(645))/Rrs(555) best performance when Chl-a<10 μg/L Chl-a>10 μg/L, respectively. established study offer improved quantifications Lake, providing support efficient