The accuracy of temporal upscaling of instantaneous evapotranspiration to daily values with seven upscaling methods

Abstract. This study evaluated the accuracy of seven upscaling methods in simulating daily latent heat flux (LE) from instantaneous values using observations 148 global sites under all sky conditions and at different times during day. Daily atmospheric transmissivity (τ) was used to represent conditions. The results showed that could accurately simulate LE values. mean median Nash–Sutcliffe efficiency were 0.80 0.85, respectively, corresponding determination coefficients 0.87 0.90, respectively. sine Gaussian function simulated with relatively higher accuracy, relative errors generally within ±10 %. evaporative fraction (EF) methods, which use potential evapotranspiration incoming shortwave radiation, performed better than other series. Overall, EF method had highest accuracy. However, extraterrestrial solar irradiance are recommended applications because minimal data requirements these their comparable or intra-day distribution greater consistency function. series did not improve significantly compared method. simulation a minor difference when same type method, for example, mathematical In any scheme, multi-time single-time value. Therefore, available, should be upscaling. show ability 09:00 15:00, particularly between 11:00 14:00. outside this time range poorly. These can high τ > 0.6; < 0.6, is affected by positively related transmissivity. Although every scheme most sites, lost tropical rainforest monsoon sites.