Terrestrial evaporation (ET) estimates from the water balance framework and large-scale modeling have been widely used in the evaluation and prediction of hydrological regimes. However, each method has its inherent limitations, including the external bias introduced by forcing variables, simplified functional relationships, and unconsidered human modules. A systematic comparison between water balance ET and modeled ET remains unexplored. Here, we quantify and attribute the difference between water balance estimations of ET and model-simulated ET (i.e., DET) on a global scale. We apply an unprecedentedly unique probabilistic ensemble of 84,042 DET estimates (2002–2021) based on all currently available datasets on water balance components. Satisfactory performance is found from the validation of the water balance-derived ET against several benchmarking ET products. We identify the regions with significantly positive DET in South and East Asia, Southern and Northern Africa, and southwestern parts of North America, with a global mean of 7 mm/a (5 % spread range: –2 to 16 mm/a). The patterns are primarily contributed by human water use and reservoir construction. We also report negative DET in the majority of South America, which may be related to human-induced deforestation. In addition, the seasonality of DET reflects the significant role of irrigation in regional ET dynamics. Variance analysis indicates higher uncertainties of DET in humid zones, mainly contributed by precipitation and simulated ET. Our uncertainty-constrained DET estimates have potential implications for assessing global and regional water availability, benchmarking climate and hydrological models, and developing sustainable mitigation and adaptation strategies.

中文翻译：

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在全球范围内比较水平衡框架和多个模型的蒸发


来自水平衡框架和大规模建模的陆地蒸发 （ET） 估计已广泛用于水文状况的评估和预测。然而，每种方法都有其固有的局限性，包括强制变量、简化的函数关系和未考虑的人工模块引入的外部偏差。水平衡 ET 和建模 ET 之间的系统比较仍未探索。在这里，我们在全球范围内量化并归因 ET 的水平衡估计与模型模拟的 ET （即 DET） 之间的差异。我们根据目前所有可用的水平衡组成部分数据集，应用了 84,042 个 DET 估计（2002-2021 年）的前所未有的独特概率集合。通过对水平衡衍生的 ET 与几个基准 ET 产品的验证，可以发现令人满意的性能。我们确定了南亚和东亚、南非和北非以及北美西南部 DET 显著阳性的地区，全球平均值为 7 mm/a（5% 传播范围：-2 至 16 mm/a）。这些模式主要是由人类用水和水库建设造成的。我们还报告了南美洲大部分地区的 DET 为负值，这可能与人为造成的森林砍伐有关。此外，DET 的季节性反映了灌溉在区域 ET 动态中的重要作用。方差分析表明，潮湿地区 DET 的不确定性较高，主要由降水和模拟 ET 贡献。我们受不确定性约束的 DET 估计值对评估全球和区域水资源可用性、对气候和水文模型进行基准测试以及制定可持续的缓解和适应策略具有潜在影响。