郑州近54年降水变化的多时间尺度分析

利用Morlet小波分析方法,对1951~2004年郑州市年降水距平时间序列的小波变化特征进行分析,揭示降水变化的多时间尺度结构,分析其中存在的主要周期振荡和突变点,并与功率谱分析结果进行比较。结果表明:郑州市年降水存在多时间尺度的周期变化特征,郑州市年平均降水存在3 a、准5 a、准9 a和准21 a的主周期。郑州市降水变化存在着明显的多时间尺度,即年代际尺度和年际尺度的周期性变化。郑州市降水变化还显示出自己的突变点分布及其位相结构。在降水量总趋势下降的前提下,2004年后的一段时间还将处在一个偏多期。

Multiple Time-Scale Analysis of Precipitation Variation in Zhengzhou during Last 54 Years

Through analyzing the time series of annual precipitation of Zhengzhou from 1951 to 2004 with Morlet wavelet transform,the multi time-scale structure and mutation points in precipitation change are revealed.The wavelet transform can clearly demonstrate all kinds of characteristics of precipitation time series.The precipitation of Zhengzhou has 3,5,9 and 21 year periods.The periodic variation of the annual precipitation time series is localized in time domain,having decadal or inter-annual periodic variation,and the annual precipitation of Zhengzhou has phasic and mutational characteristics.After 2004,the annual average precipitation of Zhengzhou was in the wet period.Some comparisons are made between wavelet transformation and power spectral analysis in data processing.It is found that wavelet transformation is better than power spectral analysis in time-frequency analysis.