近60年来汾河入黄河水沙演变特征及驱动因素

Characteristics and Driving Factors of Runoff and Sediment Changes Fluxes into the Yellow River from Fenhe River in Recent 60 Years

基于汾河河津站1950～2005年的实测径流和输沙数据,采用Mann-Kendall检验等多种统计方法分析了汾河入黄河的水沙演变特征及驱动因素。结果表明:入黄河水沙量年际波动较大,呈明显减少趋势,且输沙减少的趋势性要强于径流;径流与输沙发生重要突变的时间都是1980年,说明径流量的减少在一定程度上直接影响着输沙量的变化。降水量的减少是径流减少的重要原因,但二者的变化并不是完全一致的,20世纪60年代以来尤其是1980年以后,降水对径流的影响有所减弱,在其他自然条件(如蒸发)相对不变的情况下,人类活动是径流减少的主要驱动因素。根据理论分析,受人类活动的影响,1961～1980年的累积减沙量为108610×104t,平均每年减少5430.50×104t,1981～2005年的累积减沙量为93324×104t,平均每年减少3732.96×104t。

Based on runoff and sediment load observed at Hejin station from 1950 to 2005,the characteristics and driving factors of runoff and sediment changes fluxes into the Yellow River from Fenhe River was analyzed. The results show that the annul changes of runoff and sediment was different in great scope. The declined trend of runoff and sediment were obvious which the latter’trend was stronger than the former’s. Using Mann-Kendall to analysis the trend and change point of runoff and sediment time series and the result illustrated that the important change points were all in 1980,the decrease of sediment was directly influenced by reduced runoff. The important reason of reduced runoff was the decrease of precipitation but the changes of the two were not synchronous. And the human activity was the main reason of the reduced runoff since 1960 especially 1980. Because of the influence of human activity,the accumulated reduced sediment was 108 610×104 t from 1961 to 1980 while the number from 1981 to 2005 was 93 324×104 t.