El Nino 和 La Nina 对中国降水影响的非对称性研究

THE ASYMMETRIC EFFECTS OF EI Nino AND La Nina ON PRECIPITATION OVER EAST CHINA

伴随着 El Nino 和 La Nina 事件的发生发展，我国东部地区季节降水异常的特征也发生变化。本文通过统计1951-2010年我国东部地区120个站点的月平均降水量资料，利用合成分析的方法，研究中国东部季节降水与 El Nino 和 La Nina 事件的关联。结果显示，El Nino 当年冬季和次年春夏季我国东部大部分地区以多雨为主，La Nina 年则相反；长江中下游地区降水显著异常偏多发生在 El Nino 次年春季，且此时长江流域以及河套地区降水量均显著增加，但 La Nina 次年春季该地区雨量无明显变化；El Nino 次年春季和 La Nina 次年夏季西南地区易发生干旱。结果表明 El Nino 和 La Nina 对中国东部季节降水的影响存在非对称性，对于部分地区具有一定的预测意义。

With the development of El Nino and La Nina,the characteristics of precipitation anomalies over East China change. This paper counts monthly mean precipitation data from 1951 to 2010 in 120 sites of eastern China,taking the advantage of the method of composite analysis,and studies seasonal precipitation’s relationship with the events of El Nino and La Nina. The results showed that：in the winter of El Ni？o year,it is rainy in most parts over East China,as well as in spring and summer of the following year. The precipitation of spring in El Nino’s following year is significantly above normal in the middle and lower reaches of the Yangtze River,at the same time,the rainfall also increases in Yangtze River Basin and Loop area,yet the precipitation in the spring of the following year of La Nina does not change significantly in the same area. In addition,southwest region is likely to suffer from drought in the spring of the following year of El Nino and summer of La Nina’s following year. The results of this analysis can be used to explain the asymmetric effects of El Nino and La Nina on seasonal rainfall over East China,which have some predictive significance for some areas.