ارزيابي روشهاي برآورد تبخير- تعرق در مناطق خشك ايران

Evaluation of the Accuracy of Empirical Method of Estimating Reference Evapotranspiration

Evapotranspiration (ET) is one of the most necessary and important parameters in estimating crop water requirement as well as for designing irrigation systems. Determining reference ET accurately and using that in calculating the amount of required water for irrigation leads to more efficiency and saving water in agricaltural section. For calculating ET lysimeter is used widely in different parts of the world. Kerman university jihad built one electronic weighing lysimeter in Kernaai agriculture college in 1998. In this study, various methods of estimating grass ET were compared using data from the lysimeter and meteorological data from the university jihad weather station (reference) and Kerman airport weather station (non-reference). Comparing the ET values from the lysimeter and the results obtained from various methods showed that Penman-Monteith, Penman FAO-24 and Penman-FAO-PPP resulted the best estimation and Jensen-Haise was the least accurate. In the non- reference station Pristuly-Tylor. Penmanl948 and Bliney-Criddle-FAO resulted the best estimation and Penman Kimberly 1972 was the least accurate.