1990年以来湖南四水入洞庭湖总汛期径流量变化特征及驱动因素

Analysis of variations of total flood season's runoff into Dongting lake from four rivers in Hunan province and its factors of driving force since 1990s

分析湖南四水入湖总汛期径流量变化特征及其驱动因素能够为湖南省水资源开发管理和水旱灾害的防治提供重要的科学依据.应用滑动平均法和Mann-Kendall非参数趋势检验法分析了1990年以来湖南四水入湖总汛期径流量变化特征;应用降水-径流双累积曲线和主成分分析法分析了导致四水入湖总汛期径流量变化的驱动因素.结果表明:1)湖南四水入湖总汛期径流量年际分配不均匀,并以15.783×108 m3/a的速度递减;湖南四水入湖总汛期径流量"丰—枯"变化的时间拐点和突变点均发生在2004年.2)降水-径流双累积曲线显示出明显的向右下方的偏转,其衰减率为17.45%.3)致使湖南四水入湖总汛期径流量减少的驱动因素中,自然因素所占的比重为26.82%,人类活动因素所占比重为73.18%,是其主要驱动因素.

Analysis of variations of the total flood season＇s runoff into the Dongting lake from the four riv- ers in Hunan province and its factors of driving force can provide important scientific basis for Hunan prov- ince＇s water resources development and management and control of flood and drought disasters. The varia- tions of the total flood season＇s runoff into the Dongting lake from the four rivers in Hunan province are studied by moving average and Mann-Kendall mutation test. Besides, the factors of driving force which have led to changes in the total flood season＇s runoff into the Dongting lake from the four rivers are ana- lyzed by using double mass curve of annual runoff and precipitation, principal component analysis. The re- sults indicate that： 1） The distribution of the total flood season＇s runoff into the Dongting lake from the four rivers in Hunan province is quite uneven and has been declining at an annual rate of 15. 783X 108m3. For the total flood season＇s runoff into the Dongting lake from the four rivers in Hunan province, the inflection point of ＂high-low＂ change and the mutational site appeared in 2004. 2） The double mass curve of annual runoff and precipitation clearly displayed bottom-right deflexion, whose decay rate is 17.45%. 3） Among the factors of driving force of the total flood season＇s runoff into the Dongting lake from the four rivers in Hunan province, the natural factors accounted for 26.82%; and the human activities＇ factors accounted for 73.18%. And at present, the human activities＇ factors are the dominant key to the runoff re- duction of the total flood season＇s runoff into the Dongting lake.