Analysis and Calibration of Empirical Relationships for Estimating Evapotranspiration in Qatar: Case Study

Abstract

AbstractKnowledge of evapotranspiration (ETo), which is the process of water loss from vegetated soils due to evaporation and transpiration, is important in real-time irrigation management and water-resource allocation, particularly in water-scarce regions. In this study, several methods used in estimating evapotranspiration, including the Blaney-Criddle, Hargreaves-Samani, Jensen-Haise, Linacre, and Turc methods were calibrated and validated against the Penman-Monteith model, which is considered as the standard method of estimating evapotranspiration. The paper utilizes data from the Doha International Airport meteorological station over a period of 30 years (January 1985–December 2014). ETo values were estimated using the different methods. These values were then compared to those obtained by the Penman-Monteith method. Using appropriate indicators, the Turc method was found to be the best for estimating ETo over Doha (R2=0.9519, RMSE=1.4511 mm day−1, and MAE=1.1633 mm day−1). The Turc method comes in...