基于小波分析的黄河上游径流变化周期研究

为了研究黄河上游径流变化周期,在综合评述已用方法的前提下,引入了小波分析法;然后采用Morlet连续小波变换,对兰州和贵德2站84年(1920～2003年)年径流时间序列变化特征进行了多时间尺度分析,揭示出黄河上游年径流在不同时间尺度下的小波变换时频特征及其丰、枯交替变化的周期规律;进一步分析其径流变化规律,发现黄河上游年径流变化具有同步性,现正处于偏枯期;最后对分析结果进行小波系数过程线及方差图检验,得出黄河上游年径流具有32年的主周期变化规律,同时预测2007年后的17年(2008～2024年)时期内,将处于偏丰期。

Research on Period of Runoff Time Series in the Upper Reach of the Yellow River Based on Wavelet Analysis

Led into wavelet analysis method under the premise of comprehensive comment to used methods,and then based on the annual flow time series of 84 years(1920～2003) at Lanzhou and Guide survey stations in the upper reach of the Yellow River,variation characteristics of them were analysed by the multi-times cales method to research their flow rules,and period rule of their high and low flow alternating change was probed with the Morlet continue wavelet transformation.The synchronization characteristics of the annual flow time series in upper reach of the Yellow River can be demonstrated by further analyzing the flow variety trend plots,and now the annual flow is in low flow period.Finally the wavelate coefficient process plots and its square variety plots together tested that the major periods of the time series of the high and low annual flow in the different time scales were 32 years,and predicted that the major variant trend of the annual flow would been in the high flow period around 17 years(from 2008 to 2024).