Abstract Accurately quantifying the daily evapotranspiration of the region is one of the essential steps for studying the water cycle and regulating water resources. Nowadays, the combination of hydrologic model and remote sensing technology is considered to be an advanced means to estimate evapotranspiration and hydrological processes on a regional scale. However, continuous daily evapotranspiration cannot be simulated based on remote sensing image products. In this study, we developed a new model, SWH − METRIC model, by combining the SWH model with the Mapping Evapotranspiration at High Resolution with Internalized Calibration (METRIC) model, to simulate continuous daily actual evapotranspiration (ET) with high spatiotemporal resolution. The new model solved the problem of ET discontinuity calculated by remote sensing images and hydrological models. Regarding the results, the simulation of the SWH − METRIC model had a high consistency with the eddy covariance measurements, with an average R2 of 0.70 and a root mean square error of 0.67 mm day−1, and was superior to the SWH model. Finally, The SWH-METRIC model was used to estimate continuous ET in the Loess Plateau in northern Shaanxi (LPNS), China. Meanwhile, considering the interaction between the climate and the rugged terrain of the LPNS, the ANUSPLIN procedure was used to spatially interpolate the input meteorological factors of the model, and the temporal resolution of the simulated ET was 1 day and the spatial resolution was 1 km. The SWH-METRIC model can improve the simulation accuracy and spatiotemporal resolution of ET and contribute to study the response mechanism of climate change to ecosystem. It can provide a useful reference for the fine quantification and management of agricultural water consumption.

中文翻译：

---

结合SWH模型和METRIC模型估算高时空分辨率实际蒸散量

摘要 准确量化该地区的日蒸散量是研究水循环和调节水资源的重要步骤之一。目前，水文模型与遥感技术的结合被认为是估算区域尺度蒸散和水文过程的先进手段。然而，基于遥感图像产品无法模拟连续的每日蒸散量。在本研究中，我们通过将 SWH 模型与具有内部校准的高分辨率映射蒸散 (METRIC) 模型相结合，开发了一种新模型 SWH − METRIC 模型，以模拟具有高时空分辨率的连续每日实际蒸散 (ET)。新模型解决了遥感影像和水文模型计算ET不连续的问题。关于结果，SWH-METRIC模型的模拟与涡度协方差测量具有高度一致性，平均R2为0.70，均方根误差为0.67 mm day-1，优于SWH模型。最后，利用SWH-METRIC模型估算了陕北黄土高原(LPNS)的连续ET。同时，考虑到气候与LPNS崎岖地形的相互作用，采用ANUSPLIN程序对模型输入气象因子进行空间插值，模拟ET时间分辨率为1天，空间分辨率为1 km . SWH-METRIC模型可以提高ET的模拟精度和时空分辨率，有助于研究气候变化对生态系统的响应机制。可为农业用水量的精细量化和管理提供有益参考。