中国汛期区域旱涝与ENSO事件的遥相关研究

A Study of Teleconnections between Regional Floods/Droughts in China for Flood Season and ENSO Events

本文研究了中国２１个降水区域夏季旱涝与南方涛动指数（ＳＯＩ）的同期和滞后遥相关联系，并计算了每个区域的汛期（６－８月）降水量在１９５１－１９９１年期间与同期和前期南方涛动指数的相关系数。指出长江中下游地区的夏季洪涝与前一年秋季至当年同期长期持续负南方涛动指数有密切关系，该地区的早梅雨与前一年５月南方涛动指数显著相关。在中等偏强的厄尼诺年，中国夏季主要多雨带在江淮流域。若厄尼诺年所在的厄尼诺事件在上一年开始，则夏季主要多雨带在长江中下游和江淮地区，若在当年春季开始，则夏季主要多雨带在淮河流域和黄淮地区。在中等偏强厄尼诺年，不论其开始时间早晚，中国北方（西北和华北）大部地区则以干旱为主。在弱厄尼诺年，夏季主要多雨带位置偏北的较多。在厄尼诺现象结束后的第一个非厄尼诺年，夏季主要多雨带有南北两支，江淮和黄淮地区则以少雨干旱为主。

In this paper,the contemporary and lag teleconnections between summer floods/droughts of21 precipitation districts in China and southern oscillation index (SOl)are studied,and the coefficients of correlation between the precipitation of flood season of 21 districts and contemporary andlag SOl during 1951 - 1991 are calculated.It is found that the correlations between serious summer floods in the middle--lower valley ofYangtze River and lasting negative SOl from last autumn to this summer are evident,the correlations between SOI of last May and precipitation of this May(early Met--Yu) in the middle --lowervalley of Yangtze River and rainfall of flood season in southern part of the Yangtze River are notable,the correlations between SOl of last May-July and totall fain fall of this flood season (JJA)and its monthly rainfall in the Huai River valley are also significant.In summer major rainy-band are located in the Yangtze-Huai River valleys in the mediumstrong EL Nino years and its centre is located in the Huai River valley if EL Nino event begins inthis spring and its centre is located in the middle-lower valley of Yangtze River if the EL NinoEvent begins in last autumn or winter. There are droughts in most parts of North China and eastern part of Northwest China and South China during medium-strong EL Nino years. The rainfallof North China is above normal in weak EL Nino years.