摘要
源于清代宫廷档案《晴雨录》资料的《北京250年降水》2中记载了北京地区1725-1904年降水日数,是研究该时段北京地区降水日数周期性的重要资料。文中结合该资料对北京地区年降水日数和各季节降水日数进行了周期性分析。互补集合经验模态函数(Complete Ensemble Empirical Mode Decomposition,CEEMD)能将时间序列分解为不同时间尺度上的本征模态函数(Intrinsic Mode Function,IMF),从而得到序列在不同时间尺度上的周期。文中采用CEEMD方法将北京地区年降水日数分解为不同时间尺度上的周期,发现其具有明显的年际和年代际周期,并采用功率谱对春、夏、秋、冬四季的降水日数进行周期性分析,发现其具有显著的年际周期性。采用小波互相关系数和小波位相谱来对降水日数和降水量情况的相关关系进行分析,发现两者在年代际尺度上的相关程度明显高于年际尺度上,且年代际尺度上的位相差异比年际尺度上的位相差异更大。
Precipitation data in Beijing for 250 years derived from the royal archives Records of Clear and Rain Weather in Qing Dynasty was used to analyze the periodicity of the precipitation days in Beijing. Complete Ensemble Empirical Mode Decomposition was applied to analyze the nonlinear and non- stationary of signal; it decomposed the original signal to a series of Intrinsic Mode Function in different timescales to obtain the periodicity of the series in multiple scales; so the method was taken in this research to analyze the periodicity of annual precipitation days. It was found that the precipitation days had significant periodicity in inter- annual scale and inter- decadal scale. Power spectral was used to analyze the periodicity of precipitation days in spring,summer,autumn and winter,it showed that they had obvious inter- annual periodicity. Wavelet cross- correlation and cross- wavelet phase were used to study the relation between precipitation days and precipitation in Beijing,and it was found that they had higher correlation in inter- decadal scale than the inter- annual scale,their phases were different in also bigger in inter- decadal scale.
出处
《干旱区资源与环境》
CSSCI
CSCD
北大核心
2016年第5期150-155,共6页
Journal of Arid Land Resources and Environment
基金
国家自然基金项目中国明清时期气候灾害时空特征演变挖掘研究(编号:41271410
41071253)资助
关键词
降水日数
周期性
CEEMD
功率谱
小波相关
precipitation days
periodicity
CEEMD
power spectral
wavelet coherence
