Estimation of reference crop evapotranspiration in Sichuan Basin based on improved Makkink model
WU Zongjun1, CUI Ningbo1,2*, HU Xiaotao2, GONG Daozhi3, WANG Yaosheng3, FENG Yu1,3, XING Liwen1, ZHU Bin1, ZOU Qingyao1
1. State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, Sichuan 610065, China; 2. Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A & F University, Yangling, Shaanxi 712100, China; 3. National Engineering Laboratory of Efficient Crop Water Use and Disaster Reduction, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Abstract：In order to effectively improve the prediction accuracy of ET0 in the Sichuan Basin, the daily meteorological data of 16 representative meteorological stations in the Sichuan Basin from 1961 to 2019 were selected. The Makkink model was improved based on differential evolution algorithm to calibrate the empirical parameters of the radiation model, and the ET0 in the Sichuan Basin was estimated. The improved Makkink model(M1—M6)and Jennsen-Haise(JH)and Irmak(IK)models were evaluated on daily and monthly scales. The results showed that: on the daily scale, the simulation results of the improved Makkink(M1—M6)model(R2 range 0.77-0.87)are more accurate than those of JH and IK models(R2 range 0.74-0.76). Among the improved Makkink model, the M4 model has the highest estimation accuracy, and the medians of comprehensive index GPI is 1.05. On the monthly scale, the simulation results of the improved Makkink model estimates the results(error range 3.59-15.71 mm/month)are better than the JH and IK models(error range 6.84-25.31 mm/month), among which the M4 model has the best estimation accuracy, and the medians of comprehensive index GPI is 1.72. In general, it is recommended that the M4 model with temperature and relative humidity as input data to calculate ET0 in Sichuan Basin.
