Analysis of potential evapotranspiration model using global climate data in Makassar city

Global climate change has demanded us to optimize natural resources, especially water resources in agriculture. Water requirement for developing agricultural commodities is influenced by weather conditions. Calculation of the value of potential evapotranspiration (ETp) is necessary to estimate plants' water requirements in an area. Several models for calculating ETp are more straightforward and require fewer input data. However, the model's accuracy is still relatively low because it is not following local climatic conditions. The purpose of this study is to test several potential evapotranspiration models to obtain a simpler ETp model that requires less data input and follows the standards issued by FAO. The ETp model analysis in this study uses the Blaney-Criddle, Hargraves, Remanenko, Kharuffa, Turc, Penman model, which is then compared with the Penman-Monteith ETp model, which is the standard for measuring ETp by FAO. The results showed that solar radiation had the best linear relationship among other climatic parameters in calculating the FAO ETp value. The relationship between weather parameters and the ETp value of Penman-Monteith shows that temperature, solar radiation, and wind speed are positively correlated with the ETp value. In contrast, relative humidity is negatively correlated with the ETp value. ETp analysis on several models shows that the Turc model is the closest to the FAO ETp model with the highest coefficient of determination and the lowest RMSE value compared to other models and has input parameters of temperature and solar radiation. Meanwhile, the Blaney-Criddle, Kahruffa, and Remanenko model is not recommended to analyze the ETp value in Makassar because it has the lowest coefficient of determination compared to other models.