Forecasting daily reference evapotranspiration using the Blaney–Criddle model and temperature forecasts

Abstract

ABSTRACTAccurate daily reference evapotranspiration (ETo) forecast is essential for real-time irrigation scheduling. An attempt was made to forecast ETo using the Blaney–Criddle (BC) model and temperature forecasts in this study. Daily meteorological data for the period 2000–2014 at five stations in East China were collected to calibrate and validate the BC model against the FAO56 Penman–Monteith (FAO56-PM) model. Temperature forecasts up to 7 days’ lead time for 2012–2014 were input to the calibrated BC model to forecast ETo. It is found that the performance of the BC model for ETo forecast is further improved at all stations after monthly calibration. Average accuracy of forecasted ETo (error within 1.5 mm d−1) ranged from 82.7% to 89.3%, average values of mean absolute error (MAE) varied between 0.73 and 0.82 mm d−1, average values of root mean square error (RMSE) ranged from 0.95 to 1.08 mm d−1, and average values of the correlation coefficient (R) and concordance index (d) were more than 0.75 and 0.89, respectively. Furthermore, the error in ETo forecast caused by error in temperature forecast is acceptable. The encouraging results indicate that the proposed method can be an alternative and effective solution for forecasting daily ETo in East China.