近50年渭河关中地区地表径流变化及其归因分析?

采用流域水文过程模拟和水文气象统计学相结合的方法,归因分析了近50a来渭河关中地区地表径流的变化.通过对关中地区1958—2008年水文气象要素进行趋势检验分析,发现近50a来该区域地表径流量呈现显著下降趋势,而降雨量和潜在蒸散发量没有明显的变化,说明径流的变化主要受人类活动的影响,并用Mann-Kendall法检验出1990年为径流过程的突变点.基于此,构建SIMHYD月降雨—径流水文模型,以1958—1989年为模拟预处理期,1990—2008年为模拟检测期,通过模拟分析获得气候变化和人类活动对径流影响的归因分析结果.同时采用改进的气候弹性系数法对上述径流变化归因分析进行验证,也得到了近似的结果.结果表明,气候变化对径流减少的影响程度为18%~22%,而人类活动为78%~82%.

Streamflow changes of Weihe River in Guanzhong area in the past 50 years

Impacts of climate variability and human activities on streamflow in Weihe River catchment were quantified by hydrological process simulation and statistical analysis.Data from 1 958 to 2008 were analyzed by Mann-Kendall method to test trends of meteorological and hydrological elements.A significant decreasing trend in streamflow was found, while rainfall and potential evapotranspiration showed no significant trend, suggesting that changes in streamflow were mainly caused by human activities.The abrupt time point of streamflow change was 1 990.SIMHYD rainfall-runoff model was constructed to simulate streamflow from 1 958 to 1 989 and from 1 990 to 2008. SIMHYD was calibrated and validated by monthly meteorological and hydrological observation data from 1 958 1 989 (pre-treatment period).The model was then used to simulate streamflow in a testing period from 1 990 to 2008,to obtain quantitative assessment of effects of climate variability and human activities.Improved climate elasticity approach was also used to analyze contribution of runoff change.These two methods were compared and verified,similar results were obtained.The contribution of climate variation to decrease in streamflow was found to be 18% 22%,and human activities 78% 82%.