Modeling of Reference Evapotranspiration in Middle South Saurashtra Region of India Using Dominant meteorological Variables

In this paper attempt is made to estimate reference evapotranspiration (ETo) from standard meteorological observations. The FAO-56 Penman-Monteith method is the most physical, reliable and mostly used as a standard to verify other empirical methods. However, it needs a lot of different input parameters. Hence, in the present study, a model based on most dominant meteorological variables influencing ETo is proposed to estimate ETo in the Middle South Saurashtra region of Gujarat (India). The performance of five different alternative methods and proposed model is compared keeping the FAO-56 Penman-Monteith method as reference. The models are evaluated by using Nash-Sutcliffe efficiency coefficient (E), (R2), (dr), (RSR) and (MAE) statistical criterions. The results show that the developed model and Hargreaves and Samani (1985) method provide the most reliable results in estimation of (ETo), and it can be recommended for estimating (ETo) in the study region. &nbsp