Evaluation of Different Estimation Methods of Reference Crop Evapotranspiration and Their Comparison with the Pan Evaporation Method case study: Islamabad-Gharb Area عنوان کوتاه

Subject Areas : Irrigation and drainage

mohammad amin parandin ¹ , seyed aliashraf sadraddini ²

1 - Water Engineering Group, agriculture Department, Tabriz University,Tabriz,Iran
2 - Professor of Water Engineering Group, Agriculture, Department University of Tabriz., Tabriz., Iran

Received: 2018-11-04 Accepted : 2021-12-31 Published : 2021-12-22

Keywords: ISLAMABAD GHARB, Blany-cridle method, The determination coefficient, The correlation coefficient, Evapotranspiration models,

Abstract :

An irrigation planning is set in order to determining the soil water balance and estimation of the water future consumption based on the calculation or measuremant of the Evapotranspiration values, which providing a possibility for prediction of a real time that corresponding to the moisture index of management Allowed Deficit (MAD) in soil. This study was conducted for evaluation different reference evapotranspiration models in Islamabad-Gharb area. for this purpose, the monthly data of Islamabad-Gharb synoptic Meteorology stations during a period of 30-year (1394-1364)were used. After restruction of the missed data and verification of the reference stations, values of the evapotranspiration were calculated with 9 valied formulas using REF-ET software. In order to determine the best method, the output values of the models were compared with evaporation pan data, using some statistical criterio. According to the results, the highest correlation coeficient (r=0.99) was obtained between the output data of the Blaney- Cradle model and evaporation pan. Also the minimum root mean square error (RMSE) values of 22.2 (mm/day) and 24.42 (mm/day) were belogend to the models of torque and Blaney- Cradle, respectively. Furthermore the highest efficiency (EF) value(0.93) was obtained for the both models of Blaney- Cradle and torque. Hence by considering the resulted minimum mean percentage error (MAPE) value (0.01) for Blaney-Cradle, this model was proposed as the most suitable model for application in the studied area.