长江上游降水对三峡水库蓄水关键月入库流量的影响

论文基于长江上游271个气象站点1961—2017年逐日降水量数据及三峡水库日入库流量资料,辅以差异t检验、合成分析、相关分析和聚类分析等方法,就长江上游降水对三峡水库入库流量的影响进行了分析,结果表明：① 三峡水库蓄水期关键月的入库流量受同年8月及9月的降水影响最为明显;② 依据降水特征将长江上游进行分区的结果是在沿江及以南遵循自然流域划分,长江以北则不同,6个区分别为：I区(嘉陵江流域南部)、II区(金沙江上游、岷沱江北部、嘉陵江北部)、III区(重庆—宜昌)、IV区(乌江)、V区(宜宾—重庆)、VI区(金沙江流域中下游);③ 6个区对三峡水库蓄水关键月的入库流量贡献：I区和III区的降水量最大,汇流距离短,相较其他4个区,贡献最大;II区站点稀疏,降水量最少,汇流距离长,贡献最小;其他3个区(IV、V、VI区)贡献相近;④ 分析2003年以来蓄水期遭遇的3次流量峰值超50000 m³/s的洪水过程,其中2014年9月11—18日I区出现连续强降水,同时叠加III区过程性强降水,导致了19—20日三峡水库入库出现超过50000 m³/s的超大洪峰,证实了I区和III区降水对三峡入库流量的高贡献影响分析结论可靠,该结论也对三峡水库合理蓄水调度具有一定的参考价值。

Influences of precipitation in the upper reaches of the Yangtze River on the key monthly inflow of the Three Gorges Reservoir

Based on the data of daily precipitation of 271 meteorological stations in the upper reaches of the Yangtze River and the data of the Three Gorges Reservoir inflows during 1961-2017, this study analyzed the influence of precipitation in the upper reaches of the Yangtze River on the inflow of the Three Gorges Reservoir by using t-test, synthetic analysis, correlation analysis, and cluster analysis. The results show that: 1) The precipitation in August and September has the greatest influence on the key monthly inflow of the Three Gorges Reservoir. 2) According to the precipitation characteristics, the upper reaches of the Yangtze River can be divided into six zones, in which the regions along and in the south of the Yangtze River is divided based on the natural watersheds: Zone I (the south of the Jialing River), Zone II (the upper reaches of the Jinsha River, the north of the Mintuojiang River, and the north of the Jialing River), Zone III (Chongqing-Yichang), Zone IV (the Wu River), Zone V (Yibin-Chongqing), and Zone VI (the middle and lower reaches of the Jinsha River). 3) The contributions of the six zones to the key monthly inflow of the Three Gorges Reservoir are as follow: with the largest precipitation and the shortest catchment distance, Zone I and Zone III have the greatest contribution in these six zones; Zone II has sparse and unevenly distributed stations, and due to the lowest precipitation and longest catchment distance, it makes the least contribution; and the remaining three zones (Zone IV, V, and VI ) make similar contributions. 4) The analysis on the three great floods with peak flow over 50000 m³/s since the Three Gorges Reservoir began to fill in 2003 finds that the continuous heavy precipitation in Zone I during 11 to 18 September 2014 and the intermittent heavy precipitation in Zone III were the root causes for the occurrence of the super food with peak flow exceeding 50000 m³/s. It also proves that the result drawn by analyzing the influence of the contribution of the precipitation in Zone I and Zone III is reliable and can provide references for the rational dispatching of water storage in the Three Gorges Reservoir.