Actual evapotranspiration (AET) is a key factor in land-atmosphere interactions and a major hydrological cycle component. Variations in AET have resulted from a combination of climate change (CC) and human activities (HA). Quantifying the contributions of these two factors to AET dynamics is essential for better understanding hydrometeorological and ecohydrological processes under both natural and anthropogenic conditions. In this study, an analytical framework was adopted for AET variance analysis, and the influences of CC and HA on regional AET variabilities were separated by using this method. AET variance is determined by the variance in CC (\({\sigma }_{AETc}^{2}\)) and HA (\({\sigma }_{AETh}^{2}\)); the former is estimated through a synthesis of the variance/covariance of potential evapotranspiration (ET₀) and precipitation (P), and the latter is determined from the residual between the total AET variance and \({\sigma }_{AETc}^{2}\). Based on a 36-year dataset (1980–2015), this framework is applied to the different regions of the Tao River Basin (TRB). The results reveal that climate was the primary factor influencing AET variance in most parts of the basin. Precipitation (P) dominated the \({\sigma }_{AETc}^{2}\) and had a positive effect, while the interactions between P and ET₀ tended to suppress this effect, especially in the semihumid areas of the TRB. The contribution rates of CC and HA to basin AET variance were estimated to be 0.76 and 0.24, respectively. The developed analytical framework and its application are beneficial to the management and exploitation of water resources from the perspective of basin ecohydrology.

实际蒸散量（AET）是陆地与大气相互作用的关键因素，也是主要的水文循环要素。AET的变化是气候变化（CC）和人类活动（HA）共同造成的。量化这两个因素对AET动力学的贡献对于更好地了解自然和人为条件下的水文气象和生态水文过程至关重要。在这项研究中，采用了一个分析框架进行AET方差分析，并使用该方法分离了CC和HA对区域AET变异性的影响。AET方差由CC（\（{\ sigma} _ {AETc} ^ {2} \））和HA（\（{\ sigma} _ {AETh} ^ {2} \）的方差确定）; 前者是通过潜在蒸散量（ET ₀）和降水量（P）的方差/协方差的综合来估算的，而后者是通过总AET方差和\（{\ sigma} _ {AETc} ^ {2} \）。基于36年的数据集（1980-2015年），该框架适用于to河流域（TRB）的不同区域。结果表明，气候是影响盆地大部分地区AET变化的主要因素。降水（P）占主导地位\（{\ sigma} _ {AETc} ^ {2} \）并产生积极影响，而P和ET之间的相互作用为₀倾向于抑制这种影响，尤其是在TRB的半湿润地区。CC和HA对流域AET方差的贡献率分别估计为0.76和0.24。从流域生态水文学的角度看，建立的分析框架及其应用对水资源的管理和开发是有益的。