上海地区近136年气温和降水量变化的多尺度分析

Multiple Time Scales Analysis of Temperature and Precipitation Variation in Shanghai for the Recent 136 Years

论文主要利用墨西哥帽小波变换和经验模态分解(EMD)等方法对1873—2008年上海地区年平均气温和年降水量序列进行分析。以期认识上海气候在不同尺度下的振荡结构和周期特征。结果表明:上海近136 a来增温趋势明显,特别是在20世纪80年代以后增速超过以往。而40年代的暖期和60年代的冷期构成上海20世纪气温变化的主要特征。城市化的发展对城郊气温变化差异的影响十分显著。上海的年降水量主要是以短时间尺度的振荡为主,其中以40 a左右的波动为主要周期。小波变换的结果表明在长时间尺度上降水将增加,而短时间尺度上则相反。

Mexican Hat form wavelet transformation and Empirical Mode Decomposition（EMD） are mainly used to investigate the 1873-2008 data of Shanghai yearly average temperature and annual precipitation at multi-time scales.The oscillating structure and periodic characteristic of Shanghai climate at multi-scales are expected to be understood.The result shows that,the increasing trend of Shanghai annual temperature is obvious,especially after the 1980s when the increasing speed is faster than ever before.The warm period of the 1940s and the cold period of the 1960s constitute the main features of the 20th century temperature changes in Shanghai.The influence of temperature variations between urban and suburban area caused by urbanization is obvious.Annual precipitation of Shanghai is oscillating mainly at micro-scale while fluctuation cycles are around 40 years.The wavelet transform results show that the precipitation will be increasing in large-scale but declining in micro-scale.