使用 1966- 2015 年长江中下游地区 91 个气象站月降水资料, 采用线性倾向估计、Mann2Kendall 检验、距平分 析等方法分析了长江中下游地区近 50 年降水变化特征及其对两类 ENSO 事件的响应。结果表明, 近 50 年来长江 中下游地区夏季降水量以 21 04 mm/ a 的倾向率呈显著增加趋势, 年降水量在区域内呈东增西减的分布特征。厄尔 尼诺事件易造成长江中下游冬、春季降水异常偏多, 而拉尼娜事件发生时夏季降水大幅偏多。东部型厄尔尼诺发生 当年长江沿岸一带附近夏季降雨偏少, 中部型事件当年呈现南多北少的响应特征, 次年则转变为相反的空间分布。 中、东部型拉尼娜事件发生当年, 秋季降水分别显著偏多和偏少。东部型拉尼娜次年夏季降水普遍偏多, 以长江中 下游东部最为显著, 而中部型事件次年夏季降水则呈现东南多西北少的分布格局。

The monthly pr ecipitatio n data fr om 91 meteor olo gica l statio ns in the middle and lower reaches of t he Yangtze River from 1966 to 2015 wer e used to analyze the pr ecipitatio n v ariation in the r eg io n over the past 50 y ears and its r esponse to the two types of ENSO events. We used linear propensity estimation, Mann2Kendall test, and anomaly analysis. T he r esults show ed that the summer precipitation in the reg ion tended to increase at a rate of 21 04 mm/ a in the past 50 years. The annual pr ecipita2 tion showed an increasing tendency in the east and a decr easing tendency in the w est. El Niìo events were pro ne to cause an ab2 normally lar ge amount of precipitatio n in spring and w inter, whereas La Niì a events caused much mo re pr ecipitation in summer. In the y ea r of the Eastern Pacific ( EP) El Niì o, summer pr ecipitation along the Yang tze River was less than usual. In the year of the Centr al Pacif ic ( CP) El Niìo , summer pr ecipitation wo uld increase in the nort h and decrease in the south, w hereas the de2 cay ing y ear wo uld see an o pposite spatial patt ern. In the year of CP La Niì a, there was a sig nificant ly larg er amo unt of pr ecipita2 tion in autumn, w hereas in the y ear o f EP La Niìa, the amount was significantly smaller. In the decaying year of EP La Niì a, summer pr ecipitation w as generally mor e than usual, especially in the east of the reg ion; but in the decaying y ear o f CP La Niì a, summer pr ecipit ation w as mo re than usual in the southeast and less in the northwest

国家重点研发计划项目( 2017YFC0405603) ;/ 水电工程水文气象重大关键技术应用研究0 重大专项( DJ2ZDZX22016209 ) ; 三峡大 学科学基金资助项目( KJ2013B076)