台湾春雨对强ElNio事件的响应

根据台湾地区6个测站的51年(1950～2000年)逐月降水资料和美国NCEP／NCAR再分析资料．分析了台湾地区春季降水异常对1982年至1983年间、1997年至1998年间2次强El Nin^～o事件的响应特征。分析表明，台湾春季降水对强El Nin^～o事件有明显的响应，在强El Nin^～o年，台湾春季降水异常偏多。强El Nin^～o年的冬季和春季，南亚和我国华南高空出现强西风，且南支西风扰动活跃，导致华南地区及台湾地区冬春降水增多。在强El Nin^～o年的对流层低层，台湾东南侧太平洋上反气旋环流加强。导致台湾地区低层西南气流强盛，从而有利于台湾降水的增加。

Response of Rainfall over Taiwan in Spring to Intensive El Nin ~ o Events

By use of the mo nthly mean precipi ta tion reco rds o f 6 statio ns in Taiwan regio n f rom 1950 to 2000 and the NCEP /N CAR re-analysis data, the response of Taiw an rainfall in spring to El Nin ~ o ev ents that occur red in 1982 /1983 a nd 1997 /1998 is studied. The resul ts indica te that these two El Ni~no ev ents hav e o bvio us effect s on Taiwa n rainfal l in spring seaso n and cause excessive spring rains ov er Taiw an. In intensive El Ni~no years, the upper w esterly f low a nd i ts disturbance ov er South and So utheast Asia are much st rong er in spring seaso n, so the rainfall ov er South China and Taiwa n i s heavier tha n no rmal. Meanw hi le, in the low er t roposphere, the anticyclonic ci rculatio n to the southeast o f Taiwa n and ov er Western Pacific is intensified, so stro ng er southw esterly f low occurs ov er Taiw an and is fav o rable to th e increase of Taiwan rainfall in spring season.