气象干旱到不同等级水文干旱的传播阈值——以沁河流域为例北大核心CSCD

系统量化气象干旱到不同等级水文干旱的传播阈值对水文干旱早期预警与精细化管理具有指导作用。本文以黄土高原沁河流域为例,采用标准化降水指数和标准化径流指数表征气象干旱、水文干旱,运用游程理论识别干旱事件,并对干旱事件进行合并、剔除及气象干旱与水文干旱事件的匹配,同时使用贝叶斯网络结合Copula函数构建模型求解气象干旱到不同等级水文干旱的传播阈值。结果表明:随着水文干旱等级的升高,气象干旱到水文干旱的传播阈值增大,在传播过程中气象干旱强度削弱;沁河流域引发中度、重度及极端水文干旱对应的气象干旱历时阈值分别为12.8月、21.8月、30.9月,烈度阈值分别为14.2、22.4、30.0;沁河流域耐旱能力强与流域气象及下垫面条件有关。

Propagation threshold of meteorological drought to different levels of hydrological drought. A case study of Qinhe River basin

A systematic quantification of the thresholds for the propagation from meteorological drought to different levels of hydrological drought is useful in guiding the early warning and delicacy management of hydrological drought. In this paper, a standardized precipitation index and a standardized runoff index are used to characterize meteorological drought and hydrological drought, respectively, for the Qinhe River basin of Loess Plateau; the run theory is applied to identify drought events, and merge or reject drought events to match both types of drought events. Then, Bayesian networks combined with Copula functions are used to construct models to solve for the propagation thresholds. Results show that when the level of hydrological drought is raised, the threshold is elevated and the intensity of a meteorological drought is weakened in the propagation. For the Qinhe River basin, the duration thresholds of meteorological droughts are 12.8, 21.8 and 30.9 months for triggering moderate, severe and extreme hydrological droughts, respectively, corresponding to the intensity thresholds of 14.2, 22.4, and 30.0, respectively, and its drought tolerance ability is related to the basin meteorological and underlying surface conditions.