| Field evapotranspiration is a key factor in the hydrological cycle of agro-ecosystem.Timely and accurate estimation of field evapotranspiration is helpful for managers to develop reasonable field management plans and ensure regional food security.As one of the granaries in western China,water shortage in Ningxia province is an important factor restricting the development of local agriculture at present.How to improve the utilization efficiency of water resources and alleviate the contradiction between supply and demand of agricultural water is an urgent problem to be solved.In this paper,the typical corn growing area in Qingtongxia irrigation area was taken as the research object to estimate the daily evapotranspiration in this area,providing data support for local water-saving irrigation.(1)In this study,the sensitivity analysis of WOFOST--summer corn parameters was carried out by combining the 2022 meteorological data and soil data in the test area with EFAST method.According to the sensitivity index,the localization processing of WOFOST--summer corn crop parameters was carried out by means of actual observation calculation,trial and error method and reference to previous research results.The results showed that PCC,RMSE.NRMSE and CRM of simulating summer maize leaf area index were 0.95.0.50 m-2·m-2,14.90%and-0.09.respectively.The PCC,RMSE,NRMSE and CRM of simulating the dry matter weight of each organ of summer maize were 0.95～0.99,301.13～1 271.93 kg·hm2,14.94%～17.53%and-0.11～0.04,respectively.The results showed that the WOFOST model could well simulate the growth state of summer maize such as leaf area index and dry matter weight in the experimental area,so it was considered that the model could simulate crop transpiration well.(2)Using the three-temperature model to invert daily evapotranspiration,crop transpiration and soil evaporation in the test area,the variation trends of daily evapotranspiration and crop transpiration were as follows:rapid increase from seedling stage to jointing stage,slow fluctuation increase from late jointing stage to spinneret stage,and rapid decrease from spinneret stage to maturity stage.Soil evaporation decreased during the growth period,but increased after irrigation.By comparing the simulation results of the three-temperature model with the ground observation data,it is found that there is a large error in remote sensing inversion of evapotranspiration.The PCC,RMSE.NRMSE and NCSE of daily crop transpiration in remote sensing inversion test area were 0.71.1.94mm/d,100.94%and-1.05,respectively.The PCC,RMSE,NRMSE and NCSE of daily evaporation were-0.27,1.84mm/d.127.78%and-2.60,respectively.The PCC.RMSE.NRMSE and NCSE of daily evapotranspiration were 0.61,1.76mm/d,52.51%and-0.48,respectively.(3)The output transpiration rate of WOFOST model and the soil evaporation rate observed by the lysimeter were respectively analyzed by time series harmonics.The treated crop transpiration and soil evaporation were used as the objective function,and the difference between the objective function value and the remote sensing inversion of crop transpiration(soil evaporation)at the corresponding time was used to construct a compensation function to determine the evapotranspiration data of remote sensing inversion.The results showed that the PCC,RMSE.NRMSE and NCSE were 0.71,1.12mm/d.58.35%and 0.31,respectively.The PCC,RMSE.NRMSE and NCSE of soil evaporation were 0.56.0.99mm/d,69.22%and-0.06,respectively.The PCC,RMSE,NRMSE and NCSE of daily evapotranspiration were 0.85,0.78mm/d,23.20%and 0.71,respectively.The simulation accuracy was significantly improved compared with that before the rate setting.The results show that the localized WOFOST model can be used for the calibration of remote sensing evapotranspiration and has a good calibration effect,and has a good calibration effect. |
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