基于小波变换的北京地区1724～2009年降水量多尺度分析

基于小波分析方法,对1724~2009年北京气象站年降水量序列的变化特征进行了分析。结果表明,北京地区年降水量在其计算时域内各时间尺度分布不均匀,具有明显的局部化特征;其中,19~23a的时间尺度,震荡中心分别在1889年和1979年;35~37a左右的时间尺度主要发生在1920~1928年、1950~1960年和1983~1991年;83~87a的时间尺度在整个计算时域上均有发生,1769~1859年间表现明显。分析结果显示北京地区年降水量具有21a、35a和86a左右的主周期,其中86a左右的周期振荡最强,为第一主周期。计算的趋势表明,未来10余年北京仍属于降水偏少的时期。

Multi-scale Analysis of Annual Precipitation in Beijing Area from 1724 to 2009 Based on Wavelet Transformation

The variation characteristics of the annual precipitation in Beijing area from 1724 to 2009 were analyzed by using wavelet transformation method.The analysis results show that annual precipitation in Beijing area represents a non-uniform time-scale distribution in its calculation period with a obvious local features,in which 19-23 years scale mainly occurred in years around 1889 and 1979,35-37 years scale mainly occurred in the periods of 1920-1928,1950-1960,1983-1991.The 83-87 years scale occurred throughout the calculation period with an obvious center of oscillation within the period of 1769-1859.In different time scales,the alternated change is different in the situation that the precipitation on the high side and low side.Simultaneously,the analysis shows that the sequence of precipitation in Beijing area has a main period of 21 years,35 years and 86 years,and the period of 86 years is the first primary period,followed by 35 years and 21 years.The prediction of variation trend shows that it will still belong to a period of lower precipitation for Beijing area in the coming decade.