Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi'an, 710127, China.
Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi'an, 710127, China; Institute of Qinling Mountains, Northwest University, Xi'an, 710127, China; Yellow River Institute of Shaanxi Province, Northwest University, Xi'an, 710127, China.
J Environ Manage. 2023 Nov 1;345:118843. doi: 10.1016/j.jenvman.2023.118843. Epub 2023 Aug 18.
Runoff and baseflow are two hydrological elements most closely involved in water-resource management. Defining the response of runoff/baseflow to meteorological drought (MD) is helpful for designing precise drought resisting measures. Thus, Pearson correlation coefficients and mutual information scores between runoff/baseflow and MD in five sub-basins of the Weihe River Basin (WRB) were estimated on a weekly scale, and the best response times of runoff/baseflow to MD on annual and calendar months were determined according to the maximum degree of response. Furthermore, the spatial and seasonal differences in response characteristics in the WRB were discussed and the baseflow index (BFI) was introduced to further explain the propagation process of MD to runoff/baseflow. The results showed that (1) in addition to the response time, the transition sequences of MD propagating to runoff and baseflow varied across basins due to the specific basin properties; (2) Response time of runoff to MD was related to BFI value and showed significant seasonality and hydrological periodicity. In summer and autumn (wet season), the response was faster and stronger, whereas the opposite occurred in winter and spring (normal/dry season); (3) BFI values indicated the main path of drought propagation, explaining the variation in response time between basins and seasons; hence, it can be used to simply and effectively determine the propagation speed of MD to runoff. This study clarified the response characteristics of the runoff process to MD and enhanced our understanding of the drought propagation process, which is crucial for mitigating and managing drought-related hazards.
径流量和基流量是与水资源管理最密切相关的两个水文要素。定义径流量/基流量对气象干旱 (MD) 的响应有助于设计精确的抗旱措施。因此，基于渭河流域 (WRB) 5 个子流域每周尺度的径流量/基流量与 MD 的 Pearson 相关系数和互信息得分，根据最大响应程度确定了径流量/基流量对 MD 的最佳响应时间。此外，还讨论了 WRB 中响应特征的时空差异，并引入基流指数 (BFI) 进一步解释 MD 向径流量/基流量的传播过程。结果表明：(1) 除了响应时间外，由于流域特性的不同，MD 传播到径流量和基流量的转换序列在流域之间也有所不同；(2) 径流量对 MD 的响应时间与 BFI 值有关，表现出明显的季节性和水文周期性。在夏季和秋季（湿季），响应更快更强，而在冬季和春季（正常/旱季）则相反；(3) BFI 值指示了干旱传播的主要路径，解释了流域和季节之间响应时间的变化；因此，它可以用来简单有效地确定 MD 对径流量的传播速度。本研究阐明了径流量过程对 MD 的响应特征，增强了我们对干旱传播过程的理解，这对于减轻和管理与干旱相关的灾害至关重要。
