摘要
结合西安旱涝等级和关中平原洪涝记录,利用经验模态分解方法(EMD),对西安标准SPI降水指数进行分析,研究了1926-2008年西安标准化降水指数值(SPI)对于关中平原旱涝事件的敏感性。结果表明:西安SPI序列所反映的近百年来旱涝事件与洪涝记录、旱涝等级间相互印证很好,西安SPI指数对关中平原的旱涝年很敏感。西安SPI振荡呈现出多时间尺度特征,主要变化为3～5a和年代际的振荡。3～5a体现关中平原的洪涝灾害平均特征,旱涝经历了"剧烈-和缓-剧烈"的变化,当前正在波幅较强时期,旱涝变率增大。SPI呈现了"低-高-低"的年代际变化,体现了关中平原经历了"旱-涝-旱"交替变化,当前正处于较为干旱的时期,具有变湿的趋势,但不显著。
The sensitivity of standard precipitation index （SPI） of Xi＇an to wet and drought events in Guanzhong plain is studied,combining with the index of wet and drought and flood disasters in the Guanzhong plain from 1926 to 2008,and the SPI of Xi＇an is analyzed by empirical mode decomposition（EMD）. The results show：in the last hundred years,wet and drought events described by SPI of Xi＇an and flood records and wet and drought index match well,which indicates that the SPI is pretty sensitive to the wet and drought events in Guanzhong plain; the oscillation of SPI has multiple scale,major variations are 3～5 a and inter-decadal scale. The scale of 3～5 a indicates the normal state of flood,and shows the alternate of wet and drought suffers severe-moderate-severe procedure,and now is strong position,this means the alternate is unstable. The variations of inter-decadal scale show low-high-low circle,suggesting an alternate of drought-wet-drought,and indicates now is drought period,but there is a wet trend without pass the statistics test.
出处
《水土保持研究》
CSCD
北大核心
2010年第3期40-43,共4页
Research of Soil and Water Conservation
基金
渭河流域气象预警中心重点项目(2009-Z1)
陕西省气象局研究型业务基金科研项目(2009M-20)
关键词
关中平原
旱涝振荡
标准化降水指数
经验模态分解
Guanzhong plain
wet and drought oscillation
standard precipitation index
empirical mode decomposition
