环境变化下荆南三口河系水文干旱演变特征及归因分析

环境变化下水文干旱研究是水科学研究领域的热点问题之一。根据荆南三口河系1956-2017年5个水文站和22个气象站实测数据，采用标准化径流指数（Standardized Runoff Index，SRI）、降水-径流多元非线性模型、累积量斜率变化率比较法辅以Mann-Kendall检验法等方法，分析环境变化前后荆南三口河系62年水文干旱演变特征，并定量分解气候变化（降水量、蒸发量）和人类活动对径流量衰减的影响。结果表明：荆南三口河系整体干旱频率较高，变化期干旱事件发生频次多且等级高，多尺度干旱平均频率达42.96%，稳定期极少出现干旱现象；三口地区年径流量、年蒸发量在长时间序列上均呈下降趋势，年降水量较为稳定，年径流量检验的突变年份为1970年、1985年和2003年；人类活动是促使三口河系年径流量逐渐衰减的主要原因，1971-1985年、1986-2003年和2004-2017年三个时期人类活动对径流量变化（水文干旱演变）影响的贡献率依次为91.14%、103.73%、78.33%。

Evolution features of hydrologic drought of the three outlets of the Southern Jing River and its attribution under changing environment

Hydrologic drought under changing environment has attracted researchers in the field of hydrology. Based on the hydrological/climate data of rivers in the Southern Jing River in 1956-2017 collected from five hydrometric stations and 22 meteorological stations,in this article Standardized Runoff Index(SRI),precipitationrunoff multivariate nonlinear model,comparation of rate of change in the cumulative slope and Mann-Kendall test have employed to study the changing trend of hydrologic drought in the Southern Jing River under the changing environment of the lately 62-years and to quantitatively determine the different contribution proportion of climate change (e. g. precipitation and evaporation) and human activities on the runoff decreasing. Results showed that the Southern Jing River region had suffered a relatively high frequency of drought. Severe drought events had happened frequently during the changing period of environment and multi-scale mean drought rate reached 42.96%,while drought had seldomly occurred during the stable period of environment. In the long-time scale both the annual runoff and evaporation had decreased while the annual precipitation had maintained its stability. The mutation years of runoff detected by test were 1970,1985 and 2003. Human activities were the main force causing decrease of runoff in the Southern Jing River;its contribution to runoff change(hydrologic drought evolution)during the periods of 1971-1985,1986-2003 and 2004-2017 were 91.14%,103.73% and 78.33%,respectively.