秃尾河流域径流对降水变化的响应特征

摘要

In order to study the response characteristics of runoff to precipitation in Tuwei river basin,the response of runoff to precipitation at different length of time was explored on the basis of the relationship analysis of annual and seasonal rainfall-runoff obtained through double mass curve and correlation analysis,and a quantitative analysis was made on the degree of the response of runoff to precipitation changes with multiple linear regression method.Results showed:(1) Annual runoff decreased significantly,while the annual precipitation decreased at first and then increased.(2) Seasonal runoff significantly decreased,and the variation of annual runoff was in accord with summer runoff.Precipitation in spring increased,decreased in stummer,decreased at first and increased then in autumn and winter.Variation of annual precipitation was mainly affected precipitation in summer and autumn.(3) The correlation between nnoff in summer and precipitation in summer was the most significant,and the weakest in winter.Annual runoff was relevant most to the maximum precipitation of one month,which was followed by summer.(4) Compared to the baseline period,during soil and water conservation effect period (1978-1998) response proportion of runoff to precipitation change was 27.4％,and human activities and other factors accounted for 72.6％,13.9％ of which was water intake.In resources development period (1999-2000),response proportion of annual runoff to precipitation was 21.4％,and human activities and other factors accounted for 78.6％,17.4％ of which was water intake.Human activities were the major factor accounting for runoff reduction since the large-scale activities of human beings.The proportion of water taking increased,and the effect of rainfall on runoff decreased.%利用双累积曲线法、相关分析法分别对年和季降水径流关系进行了分析,探讨了径流与不同时段降水的响应关系,并通过多元线性回归法定量分析了径流对降水变化的响应程度.结果表明:(1)秃尾河流域年径流呈显著减少,年降水呈先减少后增加的趋势.(2)秃尾河流域四季径流均显著减少,夏季径流变化与年径流变化趋势一致;降水量则春季增加,夏季减少,而秋季和冬季降水先减少后增加,年降水变化主要受夏季和秋季降水变化的影响.(3)秃尾河流域夏季径流对同期降水的相关程度最强,冬季最弱;年径流与最大一个月降水的相关程度最高,其次为夏季.(4)相比于基准期,水土保持效应时期(1978-1998年),径流对降水变化的响应比重为27.4％,人类活动等其他因素的比重为72.6％,其中取用水比重为13.9％;资源开发期(1999-2000年),午径流对降水的响应比重为21.4％,人类活动等其他因素比重78.6％,其中取用水活动比重为17.4％.自人类大规模活动以来,人类活动始终是径流减少的主要影响因素,其中取用水比重有所增加;降水因素对径流减少的作用减小.