Evaluation of SEBAL and SEBS Algorithms in the Estimation of Maize Evapotranspiration

Abstract

Crop evapotranspiration (ET) is an important parameter for agricultural water management. This parameter can be estimated by multiplying of reference crop evapotranspiration (ETO) and crop coefficient. Usually ETO is calculated based on (daily) weather data at the weather stations. Considering the spatial variations of the weather parameters and subsequently of ET, application of the methods which can consider these variations are interested. Developed algorithms to estimate ET based on satellite images is one of those methods. The aim of the current study was to assess the accuracy of estimated ET based on SEBAL and SEBS algorithms using LANDSAT TM images in Mahidasht, Kermanshah province, Iran. For this purpose, the ET of maize was calculated using four images of LANDSAT during the maize growing season in year 2010. At the same time, the actual ET of maize was measured in a Lysimeter in the same region. Results indicating reasonable match between measured and calculated crop evapotranspiration by both algorithms. The maximum difference between the calculated evapotranspiration by SEBAL and SEBS algorithms with measured values by Lysimeter were about 9.79% and 4.56% of measured ET, respectively.