不同空间型的El Nio对江淮流域夏季降水的影响  

THE INFLUENCE OF DIFFERENT SPATIAL EL NIO TYPES ON THE SUMMER PRECIPITATION OVER THE REACHES OF CHANGJIANG-HUAIHE RIVERS

作　　者：夏羽[1,2] 朱伟军[1] 章毅之[3] 

机构地区：[1]南京信息工程大学/气象灾害省部共建教育部重点实验室,江苏南京210044 [2]宜昌市气象局,湖北宜昌443000 [3]江西省气候中心,江西南昌330046

出　　处：《热带气象学报》2013年第6期963-972,共10页Journal of Tropical Meteorology

基　　金：国家自然科学基金资助项目(41075070);江苏高校优势学科建设工程资助项目(PAPD)共同资助

摘　　要：利用江淮流域1979—2010年夏季降水资料和海温资料等,研究了不同空间型的El Nio对江淮流域夏季降水的影响。结果表明,El Nio年江淮流域夏季降水异常为东部偏多西部偏少,El Nio Modok年为全区偏少,这与用江淮流域夏季降水和同期热带太平洋海温进行SVD分析的模态几乎一致。对东亚夏季风和环流场的分析结果表明其原因可能为:El Nio年东亚夏季风稍偏弱,长江中下游有异常上升运动,我国东北至西北太平洋海盆及江淮流域为负位势高度距平,华南至菲律宾海为正位势高度距平,江淮流域从低层到高层均为气旋性环流异常控制;而El Nio Modoki年为强东亚夏季风,且江淮流域有强烈的异常下沉运动,菲律宾、我国南海以及孟加拉湾北部均为显著的负位势高度距平,正距平中心位于日本及我国东海地区,菲律宾海地区及我国江淮流域低层的异常气旋式环流中心比El Nio年偏西且强度偏强,高层的异常反气旋环流中心也比El Nio年偏西、偏北,同时西太平洋副热带高压位置也较偏北。Using observed data sets from 1979 to 2010, the influence of different spatial E1 Nino types on the summer precipitation over the reaches of Changjiang-Huaihe Rivers is investigated. Results show that during the summer of the typical E1 Nino, the anomalous precipitation is above the climate mean state in the east but below it in the west, while the anomalous precipitation is below the climate mean state all over the region during E1 Nino Modoki. This spatial distribution is almost consistent with the mode of the SVD analysis for the precipitation and the tropical sea surface temperature. The reason may be as follows. As compared with that during El Nino Modoki, the EASM is much weaker during E1 Nino and the West Pacific Subtropical High is located more westward and southward. In the summer of E1 Nino, owing to teleconnection, a negative anomaly of 500 hPa geopotential height in the Northeast China as well as the reaches of Changjiang-Huaihe Rivers and anomalous ascent occur over the middle and lower reaches of Yangtze River, while the positive anomaly in the south of China to the Philippine Sea appears with intensive descending; In the summer of E1 Nino Modoki, a positive center is located in Japan and the East China Sea with significant descending, and a negative center in the South China Sea and the Philippine Sea. Moreover, the center of the cyclone during the year of E1 Nino is located over the Philippine Sea and the reaches of Changjiang-Huaihe Rivers from 850 hPa to 200 hPa, while the center of the cyclone during E1 Nino Modoki is more westward and stronger.

关 键 词：E1Nino Modok 夏季降水 SVD分析 环流异常 

分 类 号：P426.6[天文地球—大气科学及气象学]