厄尔尼诺事件延长原因的初步分析

A PRELIMINARY ANALYSIS FOR THE REASON OF LONGER DURATION EL NINO EVENTS

利用我国及美国国家气象局提供的热带太平洋月平均海温、水位、地球向外长波辐射和850hPa纬向风资料,对1980年以来的三次厄尔尼诺(El Ni(?)o)事件延长原因及其特征作一分析和探讨。文章指出,El Ni(?)o事件延长的原因主要是:在El Ni(?)o事件发生后,热带太平洋大气环流半年左右的韵律活动及在赤道南、北两侧明显的大气振荡加强,从而使大气的El Ni(?)o异常过程间隔半年相继发生。

On the basis of monthly mean sea surface temperature and sea level anomaly in the tropical Pacific, as well as longwave radiation and 850 hPa zonal wind anomaly over the tropical Pacific provided by the Climate Analysis Center and TOGA Sea Level Center of USA, and National Meteorology Bureau of China, the reason and the feature for 1986-1987 prolonged El Nino event are analyzed, and compared with 1982-1983 and 1991-1992 prolonged El Nino events.It is pointed out that the main reason for the longer duration of El Nino events is due to the variation of atmospheric circulation with half a year cycle over the tropical Pacific and strengthened atmospheric fluctuation over both sides at the north and south of the equator, which make anomalous atmospheric parameters subsequently occur with half a year time interval.