基于SkyIrriet-mSEBS模型的华北平原蒸散发估算及时空演变规律研究OA

Evapotranspiration(ET)is a critical process in the hydrological cycle,exhibiting significant spatiotempo-ral variability.It profoundly influences vegetation distribution and productivity,climate systems,and water resource patterns.Therefore,accurate estimation of ET is of great importance for achieving sustainable water resource manage-ment.Taking the North China Plain—one of China's most important grain-producing regions—as the study area,this research first integrated the irrigation water monitoring and forecasting model(SkyIrriet)to develop a sub-model of the modified Surface Energy Balance System(mSEBS),named SkyIrriet-mSEBS,by enhancing key parameters and model structures.Using this model,daily evapotranspiration(ET)at a 500-meter spatial resolution from 2001 to 2022 was monitored.The ET estimates were validated using observational data from four eddy covariance flux tower sites.The results showed that while the model slightly overestimated ET(Mean Bias Error,MBE=0.25 mm/d),its overall performance was satisfactory,demonstrating a strong correlation with flux observations(R=0.76)and a rela-tively low Root Mean Square Error(RMSE=1.02 mm/d).This study also utilized flux data to compare the accuracy of the mSEBS model against the original SEBS model,and conducted an accuracy evaluation by comparing the mSEBS model with mainstream ET datasets,including PML_v2,MOD16A2,and GLEAM_v3.7b,as well.Furthermore,a spatiotemporal evolution of annual ET from 2001 to 2022 was conducted.The findings indicated that annual ET over the North China Plain significantly increased at a rate of 1.75 mm/a.Spatially,ET showed a general decreasing trend accompanied by a degree of spatial fluctuation.Hurst exponent analysis suggested that the future trend of annual ET in this region is characterized by pronounced anti-persistence,with 51.39%of the areas showing an upward ET trend in the future.These results demonstrate the research's potential applicability in irrigation management,water conser-vation,and the rational allocation of water resources.