中国旱涝史料的层次分析

文中用子波变换的方法对中国近５００年旱涝等级资料进行了分析，发现在不同气候层次上，旱涝变化的特征有所差异，高层次上的旱（涝）期常由若干个低层次的偏旱（涝）期组成；各层次上气候系统的动力行为也表现出不同的特征，要对气候的变化趋势作预测必须在具体层次上而言才有意义。不同层次间突变点的变化往往表现为层次升高时部分奇异点（突变点）退化为平常点，而层次降低时，又会发生平常点进化为奇异点的现象。此外，还发现中国总体上说偏涝期长于偏旱期，但不同地区又有所不同；中国南北方的旱涝演替存在一定的位相差。

LEVEL ANALYSIS OF DRYNESS AND WETNESS GRADES SERIES

In this paper,the waveletic analysis is used to focus on the dryness and wetness grades series in 500 years.The results show that the characters of xerasium are ditterent in different levels,dry (waterlogging) phase in upper level is made up of several dry (waterlogging) phase in lower level.The dynamic properties of climatic system in different level have different characters.The singular points often degenerate to normal points when the level changes from lower to upper,vice versa,the normal points will evolute to singular points.The results also show that the waterlogging semi period is longer than dry semi perid in generally,but it has different character in different area.It also find there is phase difference between the south and the north.