Accurate terrestrial evapotranspiration (ET) estimation over complex surfaces with spatial heterogeneity is crucial for local, regional, and global applications. Currently, a variety of global ET products with different spatiotemporal resolutions have been developed and evaluated. However, little is known about their performance in capturing the heterogeneity of ET over complex surfaces. Focusing on the Heihe River Basin (HRB), a typical arid and semi-arid region that is hydrologically vulnerable, this study compared ET from eleven global ET products (six remotely- sensed ET, two land surface model ET, one hydrological model-based ET, one reanalysis ET, and one synthesis ET) and one regional ET dataset against dense eddy covariance observations in terms of the magnitude, seasonal cycle, and spatial pattern. In general, the remotely-sensed ET and synthesis ET outperformed other categories, with the operational Simplified Surface Energy Balance (SSEBop), Penman-Monteith–Leuning (PML), Moderate Resolution Imaging Spectroradiometer (MOD16) and Global LAnd Surface Satellite (GLASS) performing relatively better (root mean square error ranging from 1.22–1.57 mm d^-1). Across all the land cover types, ET products reproduced a relatively feasible ET over the desert steppe, meadow, and barren, but substantially underestimated ET over ecosystems with high ET values but a low land area fraction over HRB (cropland, wetland, and forest). This highlights the importance of accurately representing the heterogeneity and local climates in the complex land surfaces for ET quantification in regional water resource management.

对具有空间异质性的复杂表面进行准确的陆地蒸散 (ET) 估计对于局部、区域和全球应用至关重要。目前，已经开发和评估了多种具有不同时空分辨率的全球 ET 产品。然而，关于它们在捕获复杂表面上 ET 的异质性方面的表现知之甚少。本研究以黑河流域（HRB）这一典型的水文脆弱干旱半干旱地区为研究对象，对比了 11 种全球 ET 产品（6 种遥感 ET、2 种地表模式 ET、1 种基于水文模型的 ET）的 ET。 ET、一项再分析 ET 和一项综合 ET) 和一个区域 ET 数据集，针对强度、季节周期和空间模式方面的密集涡旋协方差观测。一般来说，^-1）。在所有土地覆盖类型中，ET 产品在沙漠草原、草地和贫瘠土地上再现了相对可行的 ET，但大大低估了具有高 ET 值但 HRB（农田、湿地和森林）土地面积分数较低的生态系统的 ET . 这突出了准确表示复杂地表的异质性和当地气候对于区域水资源管理中 ET 量化的重要性。