1960-2007年无定河流域径流情势变化及其归因分析

在气候变化和人类活动的双重影响下,流域径流过程会发生显著改变.利用M-K法、有序聚类法、Yamamoto法对无定河流域径流量进行水文变异诊断,利用IHA/RVA法对变异前后径流情势进行对比分析,并量化分析气候变化和人类活动对径流改变的影响.结果显示:1)1970-2007年无定河流域径流量呈现显著减小趋势,并在1971年发生减小突变;2)突变后径流情势发生改变,径流量年内分配、极端流量及其发生时间、频率、平均延时等均具有较高改变程度;3)枯水期平均流量、最小90日平均流量和高流量平均延时可作为识别无定河流域径流量突变的关键指标;4)无定河流域径流量的减少受到气候变化和人类活动的综合影响,且气候变化和人类活动对径流量减少的贡献率分别为36.57%和63.43%. 

Analysis of changes in annual streamflow and its influence factors in Wuding River basin in the last 50 years(1960-2007)

Climate change and human activities are two main factors affecting hydrological processes.Analyzing changes in streamflow and influence factors are of great significance for water resources management and comprehensive basin management,in the Chinese Wuding River basin.Hydrological and meteorological data in Wuding River basin were used to detect trends and abrupt changes in annual streamflow from 1960-2007,with the non-parametric Mann-Kendall test,cluster method for ordered samples,and Yamamoto method.IHA/RVA method was used to analyze hydrologic alterations.Water balance principle-based method was used to quantitatively assess impact of climate change on streamflow.A significant downward trend was found for annual streamflow,an abrupt change occurred in 1971.Streamflow regimes such as streamflow distribution,extreme flow (its time and frequency) were found to have changed to different degrees after abrupt change.Average flow in dry season,90-day maximum and high pulses' duration within each year could be used as indicators for hydrologic alterations.It was estimated that climate change accounted for 36.57％ of total reduction in mean annual streamflow from 1960-2007,the remainder was due to human activities.