Changes of potential evapotranspiration and its sensitivity across China under future climate scenarios

Global warming can exacerbate changes in the hydrological cycle. Understanding future changes in potential evapotranspiration (PET) under global warming is highly significant to irrigation planning and water resource management. Here, we use the Mann-Kendall test and Sobol’ method to analyze the spatiotemporal variations in PET and identify factors controlling its changes for two climate change scenarios during 2021–2050. Sobol’ method describes the ability of individual variables to affect PET and describes the impact of the interaction between variables. Results show that the most sensitive meteorological variable in the Songhuajiang River basin, Yangtze River basin, Zhujiang River basin, Southeast river basins, and Southwest river basins is solar radiation (Ra). At the same time, it is the maximum temperature (Tmax) in the remaining basins. Under a high radiative forcing, PET is more sensitive to Ra. PET is greatly affected by the interactions between Ra and other meteorological variables in the basins located in the northern part of China. In contrast, it is the interactions between temperature and others in the remaining basins. In summer and autumn, PET is more sensitive to Ra than in spring and winter in northern China. Our findings can provide helpful information for the development and utilization of water resources in China.