Aydın, Yusuf2019-12-262019-12-262019Aydın, Y. 2019. Determination of reference ETo by using different Kp equations based on Class A Pan evaporation in Southeastern Anatolia Project (GAP) region. Applied Ecology and Environmental Research, 17(6) 15117-15129.1589-1623/1785-0037https://hdl.handle.net/20.500.12604/2471An accurate estimation of ET is very important and the ET estimation method that is suited to the region should be used. Evapotranspiration (ET) is calculated by multiplying reference ETo with the crop coefficient for the studied plant (Kc) or its pan evaporation coefficient (Kp). The purpose of this study was to use the Kp equations developed based on the Pan evaporation principle for estimating ETo values and determining the best Kp equation for the GAP region by making comparisons via the standard method. Kp-Pere method (RMSE: 0.48, MAE: 0.30, MR: 0.64 and PE: 3.19) displayed a better performance than Kp-Sny (RMSE: 1.08, MAE: 0.70, MR: 0.80 and PE: 29.35) in the semi-arid climate conditions of the GAP region. It was determined according to the regression analysis results that the Kp-Sny equation is better than Kp-Pere by a margin of 2.1%. Accordingly, Kp-Pere equation based on Pan evaporation can be used as an alternative to the standard method for determining reference ETo in the semi-arid conditions of the GAP region. Similarly, Kp-Sny equation together with Kp-Pere can be used as substitutes for the standard ETo-PM method since it requires less climate data.eninfo:eu-repo/semantics/openAccessevapotranspirationreference ETomethods comparisonsFAO-PM equationpan evaporation coefficientSnyder and Pereira equationsArticle1761511715129Q4WOS:000505251300168Q32-s2.0-8507732587910.15666/aeer/1706_1511715129