Land evapotranspiration (ET) is an important process connecting soil, vegetation and the atmosphere, especially in regions that experience shortage in precipitation. Since 1999, the implementation of a large-scale vegetation restoration project has significantly improved the ecological environment of the Loess Plateau in China. However, the quantitative assessment of the contribution of vegetation restoration projects to long-term ET is still in its infancy. In this study, we investigated changes in land ET and associated driving factors from 1982 to 2014 in the Loess Plateau using Budyko-based partial differential methods. Overall, annual ET slightly increased by 0.28 mm/a and there were no large fluctuations after project implementation. An attribution analysis showed that precipitation was the driving factor of interannual variability of land ET throughout the study period; the average impacts of precipitation, potential evapotranspiration and vegetation restoration on ET change were 61.5%, 11.5% and 26.9%, respectively. These results provide an improved understanding of the relationship between vegetation condition change and climate variation on terrestrial ET in the study area and can support future decision-making regarding water resource availability.

中文翻译：

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基于Budyko假说的黄土高原土地蒸散变化归因分析

陆地蒸散（ET）是连接土壤、植被和大气的重要过程，特别是在降水不足的地区。1999年以来，大规模的植被恢复工程的实施，显着改善了我国黄土高原的生态环境。然而，植被恢复项目对长期ET贡献的定量评估仍处于起步阶段。在这项研究中，我们使用基于 Budyko 的偏微分方法调查了 1982 年至 2014 年黄土高原土地 ET 的变化和相关驱动因素。总体来看，年排放量小幅增加0.28 mm/a，项目实施后波动不大。归因分析表明，降水是整个研究期间陆地ET年际变化的驱动因素；降水、潜在蒸散和植被恢复对ET变化的平均影响分别为61.5%、11.5%和26.9%。这些结果有助于更好地了解植被状况变化与研究区陆地 ET 气候变化之间的关系，并可以支持未来有关水资源可用性的决策。