In-depth knowledge of the hydrological conditions of basins in arid regions can help to maintain the long-term water security. The mechanisms of runoff generation and flow paths in different landscape areas are not fully known due to spatial variability. We have explored the mechanisms by which spatial variability affects the runoff recharge sources in the Xiying River Basin. The results showed that the spatial variability of the sources and generation mechanisms of runoff in the arid mountain flow-producing zone is the result of the combined effect of different landscape, elevation and meteorological elements. In the upstream area, the short mean transit time (MTT) combined with the high contribution of recharge from the meltwater (29.32%) and the proportion of pre-event water (between 60% and 90%) means that runoff production processes are strongly controlled by meltwater recharge and precipitation events. The MTT and the proportion of pre-event water in the midstream area are ranked in the middle of the three landscape areas, but the highest contribution of precipitation (16.57%) indicates the importance of precipitation to runoff production processes. In the downstream area, the MTT is the longest and the proportion of pre-event water is the smallest, and groundwater remains the basis for long-term stability of runoff (groundwater contribution rate: 40.62%). By enhancing the spatial resolution for identifying runoff recharge sources can reduce the model uncertainty by 69%. Thus, taking full account of the spatial heterogeneity in arid regions is an important initiative to achieve scientific water resources management.

中文翻译：

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干旱山区产流区径流补给源空间变异及影响机制

深入了解干旱地区流域的水文状况有助于维护长期的水安全。由于空间变异性，不同景观区域的径流产生和流动路径的机制尚不完全清楚。我们探讨了空间变异性影响西营河流域径流补给源的机制。结果表明，干旱山区产流区径流来源和产生机制的空间变异性是不同景观、海拔和气象要素共同作用的结果。在上游地区，较短的平均传输时间 (MTT) 与融水补给的高贡献相结合 (29. 32%）和事件前水的比例（在 60% 和 90% 之间）意味着径流产生过程受到融水补给和降水事件的强烈控制。中游区域的MTT和事前水的比例在三个景观区域中排名中间，但降水的贡献最高（16.57%）表明降水对产流过程的重要性。在下游地区，MTT最长，事前水比例最小，地下水仍然是径流长期稳定的基础（地下水贡献率：40.62%）。通过提高识别径流补给源的空间分辨率，可以将模型不确定性降低 69%。因此，