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选取位于我国东北多年冻土区南缘的海拉尔河流域作为研究对象,根据海拉尔河水文站1958-2008年的逐月实测径流量资料,用径流量的年内年际变化、各季占年径流量的百分比、年内不均匀系数、集中度以及降水量-径流量双累积曲线等不同指标,分析研究了海拉尔河上游径流量年际变化和年内分配的规律.研究表明:近50 a来海拉尔河径流量总体上呈递减趋势,并且径流量的递减与面上降水量的递减总体上一致;春、秋季节径流量均呈现出下降趋势,冬季径流量呈增加趋势.冬季径流量增加可能是冬季积雪增多以及流域多年冻土退化,积雪对冻结的抑制有利于冬季的产流,从而使冬季产流增加所致.径流量年内分配不均匀程度增加,秋季径流量比重显著下降,水资源年内分布集中程度增加,这一现象可能是由于夏季风的减弱所致.通过运用双累积曲线法,研究区降水与径流的关系在1980年前后发生了明显变化,产流表现为增加趋势,但1999年后产流能力显著下降.
According to the monthly measured runoff data of Hailaer Hydrological Station from 1958 to 2008, the inter-annual variation of annual runoff and annual runoff , Annual non-uniform coefficient, concentration degree and precipitation-runoff double cumulative curve and so on, the interannual variation of upstream runoff and the distribution pattern during the year were analyzed.The results show that: in the past 50 years, the Hailaer River Trail In general, the decrease of runoff was consistent with the decrease of surface precipitation. The runoff in spring and autumn showed a decreasing trend and the runoff in winter showed an increasing trend. The increase of runoff in winter may be the result of winter plot The increase of snow and the degradation of permafrost in the basin, the inhibition of freezing by snow accumulation is favorable to the winter runoff, resulting in an increase of winter runoff. The distribution of runoff increased during the year and the proportion of autumn runoff decreased significantly. This phenomenon may be caused by the weakening of the summer monsoon. By using the double cumulative curve method, the precipitation and runoff in the study area The relationship changed obviously around 1980, and the runoff showed an increasing trend. However, the runoff capacity dropped significantly after 1999.