降水丰枯变化和产流条件改变对汾河径流影响的定量研究

Quantitative Assessment for Impacts of Precipitation Variation and Runoff-Yield Change on Fenhe River Runoff

定量分析汾河径流锐减的形成原因是汾河流域水资源可持续利用与管理中迫切需要解决的问题。本项研究首先采用降水-径流双累积曲线对汾河流域产流条件演变过程进行了两个时期的划分;然后采用距平百分比法对汾河流域年降水系列进行了丰枯状态划分,并建立了汾河河津站年径流量与当年降水量、上一年降水量之间的多元动态回归模型;并运用该模型定量分析了降水丰枯变化和产流条件改变对汾河径流的影响程度。结果表明:在1956—1973年间的产流条件下,降水变化使得河津站年均径流量平均减少约22.71%;在1974—2008年间的产流条件下,降水变化使得河津站年均径流量在平、枯两种年份平均减少了约18.95%;在1956—1973年间的年降水为平水或枯水条件下,产流条件改变使得河津站年均径流量减少了约47.11%;在1974—2008年间的降水条件下,产流条件改变使得河津站年均径流量减少了约55.20%。

Quantitative analysis of the sharp decrease of runoff is an urgent problem to be solved in the water resources sustainable utilization and management in Fenhe basin. Firstly, double cumulative curve of precipitation and runoff was applied to divide the evolution process of runoff yield mechanism in the basin intotwo periods of 1956-1973 and 1974-2008,and the precipitation series of the basin was divided into wet,normal and dry state by means of anomaly method. On the basis of the analysis mentioned above,the multivariate dynamic regression model was established between the runoff of the current year,the precipitation of the current year and the previous year. And the multivariate dynamic regression model was applied to the quantitative assessment for the impact of the precipitation variation and runoff-yield change on Fenhe River runoff. The result showed that,under the runoff-yield condition of Fenhe basin during 1956-1973,precipitation changes caused the annual runoff volume of Hejin hydrologic station reduced by an average of about 22. 71%,while under the runoff-yield condition during 1974-2008,precipitation changes in the normal and dry state years caused the annual runoff volume of Hejin station decreasing by an average of about 18. 95%; under the condition of precipitation in the normal and dry state years from 1956 to 1973,the runoff-yield change of Fenhe basin led to a decrease of runoff volume about 47. 11%,while under the condition of precipitation during 1974-2008,the runoff-yield change of Fenhe basin led to a decrease of runoff volume about 55. 20%.