Reference Evapotranspiration Estimation in Tropical Region using Penman-Monteith Equation and Evolutionary Computation

Evapotranspiration is the combined processes of evaporation and transpiration that give means the process of water loss to the atmosphere. Reference evapotranspiration (ETo) estimation is of importance in planning and management of water resource systems for irrigation purposes. Due to its importance, the accurate modeling of ETo is of vital importance to estimate crop water requirement and its availability. This study presents a system identification and differential evolution approach, for modeling daily and monthly ETo in peninsular of Malaysia, for a month period August 2011. The data set comprising dry bulb temperature, relative humidity, wind speed, and solar radiation was utilized for estimating ETo using FAO-56 Penman-Monteith equation as the reference. The modeling results were analyzed and compared with the traditional Penman Monteith (PM) method. Based on the analyses, the approach used was found that the models of ETo is adequate, understandable, and suited to estimate the dynamics of the evapotranspiration process. The performance of the model is comparable with that of the PM method.