Investigating Water Productivity for Winter Wheat Using the SEBAL Model

WEI Qiang; ZHANG Wuping; WU Ya'nan; SUN Jinghua

doi:10.13522/j.cnki.ggps.2017.07.008

Abstract：The surface energy balance algorithm for land (SEBAL) model is a model developed based on land surface energy balance. It was used in this paper to estimate water productivity for winter wheat in Jinzhong City, Shanxi Province of China. We first calculated net radiation flux, soil heat flux, sensible heat flux based on the Landsat8 images and then estimated the evapotranspiration (ET) from them. Crop growth and production were ob-tained from statistical database and they were then rasterized in the central Shanxi Province. The water productivi-ty for winter wheat was calculated using measured yield and estimated ET. The results showed that the daily ET as from 0.41 to 7.22 mm/d. The accuracy of the model was assessed by comparing the daily ET cal culated from the SEBAL model with that calculated from the Penman-Monteith equation. The estimated ET at Taigu, Yushe and Jiexiu using the Penman-Monteith formula was 2.57, 3.48, 3.43 mm/d respectively, while the ET calculated from the SEBAL model for the three locations was 2.93, 3.82, 3.17 mm/d respectively, with a maximum devia-tion of approximately 10％. The average and maximum water productivity in the studied area was 0.94 kg/m3 and 2.50 kg/m3 respectively, which are rational. The model therefore provides a guidance for improving water use effi-ciency in central Shanxi Province.