Estimation of daily evapotranspiration using MODIS data to calculate instantaneous decoupling coefficient and resistances

Daily Evapotranspiration (ET) is of great significance among various practical applications in the fields of water management, drought monitoring and climate change study. This paper utilized instantaneous decoupling coefficient to estimate daily LE (used interchangeably with ET in this paper) with atmospheric and surface resistances calculated from MODIS data. The field data were used only at first to identify the errors induced by the parameter retrieval from remote sensing data. The estimated daily LE was compared with measured data and the result showed that the coefficient of determination (R²) was 0.960, with a root mean square error (RMSE) of 12 W/m² and a bias of −4 W/m². When MODIS data were involved in the calculation of decouple coefficient and resistances, the R² of the estimated daily LE was 0.949, with a RMSE of 33.1 W/m² and a bias of −17.9 W/m². Therefore, it is feasible and effective to obtain daily LE using instantaneous decoupling coefficient from remote sensing data.