近500年中国旱涝时空分布特征的研究

A study of the temporal and spatial features of dryness & wetness last 500-year period in China

为了揭示我国旱涝的时空分布特征,采用滑动平均、经验正交函数(EOF)展开以及谱分析等统计分析方法对我国100个站近500a的旱涝资料进行分析.结果表明,中国旱涝变化在时间上和空间上存在着2个主要特征:从时间演变上看,中国旱涝变化有明显的周期性,其周期大约为24.75a,自1800年以来,出现逐渐干旱化的倾向;从空间分布上看,中国旱涝变化呈南北型分布,且南北中心不同,北方只有1个中心,但南方包括东南和西南2个中心.

To reveal the spatial and temporal distribution variation characteristics of drought and flood of China,the drought or flood data of 100 stations in China from 1470 to 1996 were analyzed by using statistical analysis methods,such as overlapping average,EOF expansion,spectral analysis,and so on.There are two main features about the spatial and temporal distribution variation as follows:(1) on the one hand,as far as temporal variation is concerned,the variation of dryness and wetness in China has significant period which is about (24.75) years,and it has been become more and more drought gradually since 1800;(2) on the other hand,from the space point of views,the main type of drought and flood in China on spatial distribution is latitudinal pattern,and the center of south and north is different because the latter has only one center but the former includes two centers,namely southeast and southwest.