基于小波的黄河上游天然年径流变化特性分析

Analysis of Natural Annal flow Time Seris in the Upper Reach of the Yellow River Based on Wavelet Transform

为了研究黄河径流演变规律,用小波分析法对黄河青铜峡270多年(1724～1997)的年径流时间序列变化进行了多尺度分析,展示了在不同时间尺度下,黄河上游年径流丰、枯变化的过程。揭示了其年径流具有128年、64年和32年左右周期性变化,这3个主要周期的变化,主导着黄河上游天然年径流变化的特性。研究也表明,自1997年以来,黄河天然年径流变化的大趋势是处于接近或低于其多年平均水平,并会延续若干年。

Based on the annual flow time series of 274 years (1724～1997) at Qing Tong-xia station of upper reach of the Yellow River , variations in multi-time scales and jump characteristics of the time series are probed with Morlet wavelet transform. Wavelet transform can clearly demonstrate many kinds of characteristics of the time series : the trend, jump and major periods.The variant process of the high and low annual flow are also shown in the different time scales. The major periods of the time series are about 128 years?64 years and 32 years ; and the major variant trend of the annual flow has been in the low flow since 1997. These results are important for feature research of the Yellow River.