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收集密云水库流域多年降水量与径流量的资料,采用统计分析的方法,分析降水量、降水时空分布规律及频率特征、径流量年内、年际变化特征。结果表明:密云水库流域降水量的年际变化很不均匀,年内变化主要集中在6—9月;径流量呈减少态势,尤其1999年以后减小趋势更为明显,其演变规律表现出明显的阶段性,1979年和1999年是两个显著的突变点。通过对比分析认为,该地区降水量与径流量的关系随着时间的推移明显减弱,径流量受多种因素影响。
Collecting the data of precipitation and runoff for many years in Miyun Reservoir watershed, using the methods of statistical analysis, analyzing the temporal and spatial distribution of precipitation, the frequency and precipitation characteristics, annual and annual runoff variation characteristics. The results show that the annual variation of precipitation in Miyun Reservoir Basin is very uneven, and the variation mainly concentrates in June-September. The runoff decreases, especially after 1999, the decreasing trend is more obvious, and the evolution law shows obvious Phased, 1979 and 1999 are two significant mutation points. Through comparative analysis, the relationship between precipitation and runoff in this area is obviously weakened with time, and runoff is affected by many factors.