基于HHT和DFA的文峪河径流趋势分析与预测

Analysis and prediction of long-term runoff trend for the Wenyu River using Hilbert-Huang transform and detrended fluctuation analysis

【目的】文峪河是山西省吕梁地区的重要水源地之一,研究其径流量变化可为整个吕梁地区的水安全保障体系建设和区域社会经济规划与产业布局提供决策支持。【方法】应用Hilbert-Huang变换(HHT)方法、非趋势波动分析方法(DFA)以及BP神经网络预测方法,对文峪河中长期天然径流序列的周期变化特征、分形特征进行非线性分析,探讨了影响径流形成的降水、气温等气候要素对文峪河径流演变的影响,并进一步分析了厄尔尼诺现象、太阳黑子活动与文峪河径流变换的响应关系。以EMD分解结果和标度不变性为依据,对径流未来的演化发展趋势进行预测,并分析了未来流域水安全的态势。【结果】文峪河径流序列存在准2年、准4年、6～7年和13～14年的周期变化规律;文峪河径流变化受气候要素影响强烈,与厄尔尼诺现象、太阳黑子数存在良好的响应关系;文峪河年径流序列具有分形结构特征和趋势增强特征。【结论】未来文峪河年径流存在一个持续的缩减趋势,2050年文峪河水库坝址处的径流量可能将缩减至0.5亿m3左右,比坝址处多年平均径流量减少近65%,流域水安全局势堪忧。

The Wenyu River is one of the important water sources in Lüliang district,Shanxi province.The study of the river runoff is essential to improve the water security system and social economic planning and development in Lüliang region.【Method】Based on the natural runoff data（19522007）at dam site of Wenyuhe reservoir,Hilbert-Huang transform（HHT）method,detrended fluctuation analysis（DFA）and BP-ANN forecasting method were used to investigate the periodic variation,fractal structure and trend of the Wenyu River runoff.The role of climatic elements such as precipitation and temperature in the Wenyu River basin in the variation were analyzed as well.Furthermore,the relations of the runoff to Elnino events and sunspot activities were discussed.【Result】There were distinct periodic variations with scales of 2,4,6-7 and 13-14 years in the annual runoff series.The curves of the runoff to Elnino events and sunspot activities indicated general response relationship.Fractal structure and an enhancement trend were observed by DFA results.【Conclusion】This study found that the runoff value at dam site of the Wenyu River reservoir would reduce to 50 million m3 in 40years later,decreasing by 65% compared to multi-year average.