1951—2015年洞庭湖水沙演变及人类活动对径流影响的定量评估

Quantitative Assessment on Influence of Runoff and Sediment Evolution of Dongting Lake and Human Activities to the Runoff in the Period of 1951-2015

运用线性趋势法、M-K非参数检验法、滑动T检验法、小波分析法等对1951—2015年洞庭湖水沙演变特征进行了分析,并通过构建降水-径流经验模型,定量估算了气候变化和人类活动对洞庭湖入出湖径流量的影响率。结果表明:(1)洞庭湖入出湖水沙时间序列均呈现出下降趋势,其中以入湖输沙量的下降趋势最为显著,以404.46万t/a的速度减少,在研究时段内入出湖水沙均发生了突变并表现出不同尺度的周期性变化规律;(2)洞庭湖入湖水沙的Pearson相关系数为0.800,出湖水沙为0.696,表明洞庭湖水沙序列之间呈现出极显著的正相关关系;(3)在整个变异期,降水对入湖径流量变化的影响率为-1.03%、人类活动为101.03%,降水对出湖径流量变化的影响率为-7.67%、人类活动为107.67%,洞庭湖入出湖径流量减少主要是受人类活动的影响。

The paper analyzed the characteristics of runoff and sediment evolution of the Dongting Lake in the period of 1951-2015 by using linear trend method,M-K nonparametric test,moving T-test and wavelet analysis. It also quantitatively estimated the influence ration of climate change and human activities to the inflow and outflow of the lake through building the empirical model of precipitation-runoff. The outcomes show that a) the time series of runoff and sediment in and out of the lake shows a downward trend,of which the downward trend of sediment discharge into the lake is the most significant,decreasing at the rate of 4.044 6 million t/a. During the research period,both the inflow and outflow of runoff and sediment of the lake have been mutated and show periodic regularity of different scales;b) the Pearson correlation coefficient of runoff and sediment into the lake is 0.800 and out of the lake is 0.696,showing a significant positive correlation between runoff and sediment series of the lake and;c) in the whole period of variation,the influence rate of precipitation to the variation of inflow is-1.03%,human activities 101.03%,the influence rate of precipitation to the variation of outflow is-7.67% and human activities 107.67%,showing that the reduction of inflow and outflow of the lake mainly is caused by human activities.