赣江流域气象干旱与水文干旱特征及其概率关系

Characteristics and probability relationship between meteorological drought and hydrological drought in Ganjiang River Basin

为探明赣江流域气象干旱与水文干旱之间的关系,基于赣江流域1960~2018年降水和径流量资料,分别计算标准化降水指数(SPI)和径流指数(SSI),基于游程理论识别气象干旱和水文干旱事件并分析干旱特征变化过程,同时利用Copula函数和条件概率分布分析干旱重现期以及气象干旱与水文干旱概率关系。结果表明:①6个月时间尺度下SPI和SSI相关性最好,水文干旱对气象干旱无滞后,水文干旱严重于气象干旱,2000年以后水文干旱呈加重趋势;②相同单变量重现期下,气象干旱联合重现期大于水文干旱,同现重现期小于水文干旱;③随着气象干旱加重,不同等级的水文干旱发生概率增加,发生气象干旱情况下引发水文干旱的概率为0.892。研究结果可为赣江流域抗旱预警提供参考。

In order to explore the relationship between meteorological drought and hydrological drought in the Ganjiang River Basin,based on the precipitation and runoff data of the Ganjiang River Basin from 1960 to 2018,the standardized precipitation index(SPI)and runoff index(SSI)were calculated respectively.The meteorological and hydrological drought events were identified through the run-length theory,and changing process of drought characteristics was analyzed.At the same time,the Copula function and conditional probability distribution were used to analyze the drought recurrence period and the probabilities relationship between meteorological and hydrological drought.The results showed that the correlation between SPI and SSI was the best on a 6-month time scale.Hydrological drought did not lag behind meteorological drought and was more serious than meteorological drought.After 2000,the hydrological drought showed an aggravating trend.Under the same univariate recurrence period,the joint recurrence period of meteorological drought was greater than that of hydrological drought,and the co-recurrence period of meteorological drought was smaller than that of hydrological drought.With the aggravation of meteorological drought,the occurrence probability of different levels of hydrological drought increased,and the probability of hydrological drought caused by meteorological drought was 0.892.The research results can provide a reference for early warning of drought resistance in the Ganjiang River Basin.