近50年开封市降水变化特征的小波分析

利用Morlet小波分析了1961—2010年开封市年降水量距平的小波变化特征,揭示开封市降水量变化的多时间尺度结构.结果表明:开封市年降水量存在多时间尺度的周期变化特征,有6个特征明显的时间尺度,分别是1~2 a、3~4 a、5 a、7 a、9~12 a和15~18 a.其中5 a、7 a、9~12 a和15~18 a的时间尺度在整个时域内都很明显,年际尺度的主周期为7 a,年代际尺度主周期为10 a;开封市降水变化还表现出突变的特点;近50年来,开封市年降水量气候倾向率为6 mm/10 a,年降水量呈增多趋势,未来2~3年内年降水量将处于一个偏多期.

Wavelet Analysis on Precipitation Variation in Kaifeng in Last 50 Years

Analyzing the time series of annual precipitation of Kaifeng from 1961 to 2010 with Morlet wavetet transform, the time-scale structure in precipitation change are revealed. The result shows that,there are six chara- cteristic time scales precipitation of Kaifeng, wlich are 1-2 years, 3-4 years, 5 years, 7 years,9-12 years and 15- 18 years. Time scales of 5 years,7 years,9-12 years, 15-18 year are obviously in the whole period-the main annual period is 7 years, the main decadal period is 10 years： the annual precipitation of Kaifeng has mutational characteristics. The precipitation climatic tendency of Kaifeng is 6 mm per 10 years. The annual average precipitation of Kaifeng has a growing trend and will be in the wet period in the next 2-3 years.