Assessing Hourly and Daily Reference Evapotranspiration from NASA POWER Data: Implications for Irrigation Water Requirement
This study demonstrates that calculating reference evapotranspiration (ET₀) using daily mean meteorological data from NASA POWER systematically overestimates irrigation water requirements compared to hourly-aggregated data, particularly during high-energy summer periods, due to the non-linear nature of the FAO-56 Penman-Monteith equation smoothing peak evaporative demands.