基于经验模态分解方法和信息熵的水沙关系研究

Study on relationship between water and sediment based on empirical mode decomposition and information entropy

为研究黄河中游水沙关系及其细部演化特征,利用黄河中游控制性水文站——潼关水文站1919—2015年实测径流量和输沙量资料作为研究数据,采用经验模态分解方法分析径流和泥沙随机变化的复杂性,并运用信息熵理论计算不同时间尺度上径流和泥沙分解序列及原始序列的熵值、径流与泥沙各分量与其原始序列之间的互信息、径流与泥沙之间的互信息。结果表明:潼关水文站径流量与输沙量变化具有显著下降的趋势;径流量和输沙量在一定程度上表现为某种同步变化关系;径流量与输沙量的长周期分量及趋势项互信息较大,因此水沙关系宜采用长周期研究,趋势项分量数据信息阐述原始序列数据信息比较可靠。

In order to study the relationship between water and sediment in the middle reaches of the Yellow River and its detailed evolution characteristics, the empirical mode decomposition method was used to analyze the complexity of random variation of runoff and sediment load based on the measured runoff and sediment discharge data from 1919 to 2015 at Tongguan Hydrological Station, a controlling hydrological station in the middle reaches of the Yellow River. The information entropy theory was used to calculate the entropy values of the decomposition sequence and original sequence of runoff and sediment load at different time scales. The mutual information entropy values between runoff and sediment sequences and between their decomposition sequences and original sequences were calculated too. The results show that the change of runoff and sediment load at Tongguan Hydrological Station has a significant downward trend. The relationship between runoff and sediment load is synchronous to some extent. The long-period components and residual components of runoff and sediment load have great mutual information, so studies of the relationship between water and sediment should be focused on their long-period scales. The original data information can be described by the residual components reliably.