Fig. 7: Daily mean proportion of nitrate sources on each reservoir during the 48 h window of ETM+ and MSI.

a Comparison of MS proportion. b Comparison of SN proportion. c Comparison of AD proportion. d Comparison of SF proportion. e Overall comparison of long time series of sources proportion on LJ. f Overall comparison of long time series of sources proportion on NS. g Overall comparison of long time series of sources proportion on QW. In both (a, b, c, d), the blue areas represent the maximum and minimum ranges of the simulated value of ETM+, the red areas represent the maximum and minimum ranges of the simulated value of MSI, the solid blue line represents the daily mean of the simulation of ETM+, the solid red line represents the daily mean of the simulation of MSI, the black dashed line represents the difference between ETM+ and MSI’s daily simulated mean value. In both (e), (f) and (g), the red boxes and dots represent the simulation result of ETM+, the blue boxes and dots represent the simulation result of MSI.