COMPARATIVE ANALYSIS OF THE PYSEBAL MODEL AND LYSIMETER FOR ESTIMATING ACTUAL EVAPOTRANSPIRATION OF SOYBEAN CROP IN ADANA, TURKEY

Abstract

Accurate estimation of evapotranspiration (ET) is an important factor in water management, especially in irrigated agriculture. Accurate irrigation scheduling requires accurate estimation of ET. The objective of this study was to estimate the actual evapotranspiration (ET a ) by the pySEBAL model and to compare it with the actual evapotranspiration measured by the lysimeter method of soybean crop in Adana, Turkey. Five Landsat 5 Thematic Mapper (TM) images and weather data were used for this study to estimate actual evapotranspiration by the pySEBAL model. The results showed a good relationship between ET a estimated by the pySEBAL model and ET a measured by the lysimeter method, with an R 2 of 0.73, an RMSE of 0.51 mm.day −1 , an MBE of 0.04 mm.day −1 and a Willmott’s index of agreement (d) of 0.90. Based on this study, there is a good relationship between the actual evapotranspiration estimated by the pySEBAL model and the actual evapotranspiration measured by the lysimeter method. Consequently, ET a of soybean crop can be estimated with high accuracy by the pySEBAL model in Adana, Turkey.