为探究气候变化和人类活动对黄河流域蒸散发的影响程度，研究基于最新的ERA5-Land数据，分析了黄河流域1961—2020年蒸散发及相关要素的时空演变特征。结合改进的水量-能量空间坐标分解法对实际蒸散发变化进行定量归因。结果表明，改进的水量-能量空间坐标分解法原理更加清晰，计算简单，可操作性更强。1961—2020年黄河流域实际蒸散发量和降水量均呈现显著减少趋势，减少率分别为4.5和15.9 mm/10a，而潜在蒸散发量和干燥指数则表现出显著增加趋势，增加率分别为24.4 mm /10a和0.078/10a。实际蒸散发量的减少主要集中在黄河中、下游地区，而黄河源区有一定的增加趋势。定量归因结果显示，气候变化导致实际蒸散发量减少，贡献率为79%，而下垫面变化造成实际蒸散发量增加，贡献率为21%，因此，气候变化是黄河流域实际蒸散发变化的主要驱动因素。此外，研究期望为黄河流域未来的水资源开发利用和高质量发展提供科学参考。
英文摘要:
In order to investigate the impacts of climate change and human activities on evapotranspiration (ET) over the Yellow Rive Basin (YRB), the spatial and temporal evolution of ET during the period of 1961-2020 and its influencing factors were analyzed based on the latest ERA5 Land reanalysis data. Then, the improved water-energy spatial coordinate decomposition method was adopted to quantify the contributions of climate change and underlying surface change to the variation of actual ET over the YRB. The results show that the water-energy spatial coordinate decomposition method used in this study is clear in principle, simple in calculation, and practicable in application. Moreover,the actual ET and precipitation decreased significantly from 1960-2020 over the YRB, with the decreasing rates of 4.5 and 15.9 mm/10a, respectively. However, the potential ET and aridity index showed significant increasing trends, with the increasing rates of 24.4 mm/10a and 0.078/10a, respectively. The decrease of actual ET was mainly seen in the middle and lower reaches of the Yellow River; whereas a certain increase was spotted in the source area. The quantitative attribution analysis indicate that climate change caused the decrease of the actual ET, with a contribution rate of 79%; while the underlying surface variation was responsible for the increase of the actual ET, with a contribution rate of 21%. Therefore, climate change is the main influencing factor of actual ET. The study is expected to provide a technical reference for the water resources utilization and high-quality development over the YRB in the future.