黄河源径流演变特征及其对降水的响应

采用1960-2012年黄河源径流、降水数据，以过程线法、集中度和集中期等方法分析黄河沿以上、黄河沿-吉迈、吉迈-玛曲、玛曲-唐乃亥等4个区段降水、径流的演变特征，并从降水的产流能力、时滞相关和集中期响应等角度分析径流对降水的响应。结果表明：黄河源径流汛期占比年际变化趋势自上游各区段呈不显著的增加-减少-增加-减少的特征。吉迈以上径流量年际变化呈不显著增加，吉迈以下呈减少趋势。各区段径流集中期均有不同程度的提前。下游径流集中期早于上游。黄河源汛期降水占比呈不显著下降趋势。4个区段自上游降水年际变化呈显著增加-显著增加-不显著减少-不显著增加的特征。降水的集中度分布较径流更为集中，且有不显著减少趋势。各区段降水的产流能力在20世纪80年代末至90年代中期出现弱化趋势，中上游在2005年左右降水的产流能力转为较分析时段初期有增强的趋势，而中下游一直较分析时段初期减小。不同区段年径流量与不同统计时段降水量的依存关系不同。黄河源玛曲以上径流相对于降水的集中期滞后天数呈不显著减少，玛曲-唐乃亥滞后天数略有增加。

Runoff Change and Responses to Precipitation in the Source Regions of the Yellow River

The runoff change and responses to precipitation in the source regions,-huangheyan, Huangheyan-Jimai, Jimai-Maqu and Maqu-Tangnaihai, of the Yellow River were investigated. The results showed that:The flood season runoff varied annually in the studied area as a whole. The runoff increased in the Jimai station, but decreased in Jimai-tangnaihai. Concentrated period of runoff in all segments came earlier and the trend in the downstream was more obvious than that in the upstream. The flood season precipitation declined with a significant increase, significant increase, decrease, significant increase for the four segments, respectively. The concentration degree of precipitation was higher than that of runoff. The runoff generation capacity of precipitation weakened from the late 1980s to the middle 1990s.The runoff generation capacity of precipitation increased around 2005 compared with the early stage of the analysis period in the middle and upper reaches. While reduced in middle and lower reaches. The relationship between annual runoff and precipitation in different periods were different. Lagging days of concentrated period of runoff relative to precipitation reduced in Maqu, but increased in Maqu-Tangnaihai.