22nd IAHR-APD CONGRESS 2020 IN SAPPORO

Session5: Irrigation and Drainages

5-1

Title: Study on prediction model of crop evapotranspiration based on weather forecast

Xin Han, Baozhang Zhang, Zheng Wei, He Chen, He Chen, Yinong Li, Taisheng Du


The prediction of crop evapotranspiration (𝐸𝑇𝑐) is critical for making reasonable irrigation plan and improving water use efficiency, and the meteorological factors have a great effect with the 𝐸𝑇𝑐. To construct the prediction model of 𝐸𝑇𝑐 in the whole growth period of winter wheat, the meteorological observation data of 2000-2015 and the historical weather forecast data of 2014-2015 were collected in Daxing District, Beijing, China. The modified Penman Monteith (PMT), Hargreaves (HAG) and McCloud (Mc) models were adopted to predict reference crop evapotranspiration (𝐸𝑇0), and then the 𝐸𝑇𝑐 prediction models were established based on the crop coefficient method (FAO-56). In addition, the prediction of 𝐸𝑇𝑐 was verified by the observed from Eddy Covariance. Results showed that, PMT, HAG, and Mc models had high prediction accuracy for 𝐸𝑇0,among which Mc model had the highest accuracy, with the R2 of more than 0.76, the absolute error and RMSE were less than 1.3mm/d, and the prediction accuracy (error < 1mm/d)was more than 74%. Among the 𝐸𝑇𝑐 prediction models verified by Eddy Covariance, Mc prediction model also had high accuracy, the consistency index were more than 0.78, MAE were less than 0.146mm/d, and the prediction accuracy (<2mm) were more than 80.59%, which could meet the estimation accuracy of 𝐸𝑇𝑐 in the study area.





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