黄河上游径流丰枯变化特征及其环流背景

为了揭示影响黄河上游径流丰枯变化的气候因子,为径流的长期、超长期预报与水资源的规划利用提供依据,利用相关台站的降水、径流观测资料,分析了黄河上游汛期径流的丰枯变化特征及其环流背景.结果表明:黄河上游(唐乃亥以上)流域丰、枯水段基本上是交替出现的,总体上枯水持续时间多于丰水,一个完整的丰枯循环周期大约在18 a左右.黄河上游径流的丰、枯,与大气环流的异常有着非常密切的关系,其中,西太平洋副热带高压偏西、偏强、偏北,青藏高原中部地区有西风槽存在是黄河上游汛期降水偏多、径流偏丰的两个重要因素.因此,基于汛期流量的丰枯与其所对应的环流背景之间的联系,可根据前期环流的演变特征对黄河上游汛期流量的丰枯做出大致预测.

Changes in High and Low Flow Cycles of the Upper Reaches of Yellow River and Their Circumfluence Backdrop

The changing characteristics of high and low flows of the runoff in the upper reaches of Yellow River and the circumfluence backdrop corresponding with the typical high and low flow years were analyzed according to some relational hydrologic and meteorological data,aimed at searching the weather factors that control the flood discharge in flood season,at affording warranty to the long-term and super long-term forecasts of flood discharge rate,and at programming the use of water resources in the upper reaches of Yellow River.It is revealed that cycles of high and low flows in the upper reaches of the river alternately occur,but the time of the high flow is less than that of low flow on the whole,and the period of an integrated high and low flow cycle is about 18 years in the upper reaches.There is a close relation between the high or low flow of the reaches and the abnormity of circumfluence.The subtropical high over the west Pacific extending to west and the westerly trough occurring in the mid and west of the Tibetan Plateau are the two important factors that bring abundant precipitation and more runoff in flood season of the upper reaches.Thus,the flood discharge rate in flood season of the reaches can be forecasted approximately based on the relations between the high or low flow and the abnormity of circumfluence and the characteristics of prophase circumfluence.