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为了掌握泾河流域水沙演变规律,基于张家山水文站1956—2010年径流与输沙量数据,采用滑动平均法分析流域水沙变化,提出应用滑动相关系数法诊断水沙关系变异,与双累积曲线法相互验证,选取皮尔逊III型分布拟合变异前后水沙分布,基于Copula函数建立水沙联合分布,对比分析泾河流域水沙变化特征,研究不同时段水沙丰枯遭遇情况。结果表明:1水沙关系于20世纪80年代发生变异;2以1982年为分割点,相比于1956—1982年,1983—2010年水沙均值减小,设计频率P≤90%时水沙值均减小,P>90%时,径流减小,输沙量增加;3两阶段水沙丰枯同步频率大于丰枯异步频率,“水丰沙枯或水枯沙丰”遭遇组合概率最小,变异后时段(1983—2010年)各种遭遇组合频率分布更为均匀,水沙丰枯异步频率变大。
In order to grasp the evolution law of runoff and sediment in Jinghe River Basin, based on the data of runoff and sediment discharge from 1956 to 2010 in Zhangjiashan Hydrological Station, the runoff and sediment change of the basin was analyzed by the moving average method. The sliding correlation coefficient method was used to diagnose the variation of water and sediment, Double cumulative curves were used to verify each other. Pearson III distribution was used to select the distribution of water and sediment before and after the variation. Based on the Copula function, a joint distribution of water and sediment was established. The characteristics of water and sediment changes in Jinghe River Basin were compared and analyzed. The results showed that: 1 the relationship between water and sediment changed in the 1980s; 2 with 1982 as the dividing point, compared with 1956-1982 and 1983-2010, the mean value of water and sediment decreased, and the design frequency P≤90% The runoff decreased and the sediment load increased when P> 90%. The synchronization frequency of water, sediment and plume was greater than the frequency of abundance and dryness, The probability is the smallest. After the variation period (1983-2010), the frequencies of the various combinations encountered are more evenly distributed, and the frequency of the asynchronous precipitation is larger.