近半个世纪ENSO事件对长江三角洲地区气候的影响

Impacts of ENSO Events on Climatic Changes during Last50 Years in the Yangtze Delta

对上海、杭州和南京 1 951～ 2 0 0 1年日降水和气温资料作 χ2 检验 ,探讨ENSO事件与长江三角洲地区降水、气温的关系 ,结果表明ENSO事件与研究区年降水量、四季降水以及年最高气温关系远低于自由度为 3的 90 %置信度水平 ,二者无显著相关性。将ElNino分为两类后研究其对研究区年降水量、夏季降水量以及高温天气的影响 ,结果显示 ,第Ⅰ类ElNino影响年中研究区年降水量比常年偏高约 1 5. 6 % ,不易出现高温天气 ;第Ⅱ类ElNino影响年的年降水量比常年偏少 2 0 %～ 30 % ,但高温天气出现几率大。

The χ2 test is performed on the data set of daily precipitation and temperature of Shanghai, Hangzhou and Nanjing stations in the Yangtze Delta. The results indicate that there is no correlation between ENSO and the annual precipitation, seasonal precipitation and annual maximum temperature (not reach the significance level of 90%). If the ENSO is categorized into 3 types however, the results indicate that the El Nino type Ⅰ leads to more precipitation than normal year, about 15.6% more than the normal year, with lower occurrence possibility of higher-temperature climatic conditions; the El Nino Ⅱ type leads to precipitation 20%-30% less than that of the normal year, with higher occurrence probability higher-temperature climatic conditions.