摘要
为了揭示８０年代以来发生ＥｌＮｉｎｏ事件形成的机制，利用一个两层半的热带海洋模式进行数值试验．结果表明：在特定的西向流场背景条件下，热带大气季节内时间尺度振荡强迫激发的赤道第二斜压模态的波动可以在向东传播的过程中出现停驻．波动传播停驻与多普勒效应有密切的关系．由于波动停驻海区海表面温度（ＳＳＴ）正异常增大，可促进其上空大气对流运动的发展，导致赤道中、西太平洋出现大范围西风异常，在赤道海洋中激发起第一斜压模态的Ｋｅｌｖｉｎ波．基于上述事实和数值试验结果，文章提出了一个阶段性海气相互作用激发ＥｌＮｉｎｏ事件发生的机制，热带中太平洋波动传播停驻导致的ＳＳＴ正异常在这个发生机制中起着关键的作用．
In order to reveal the developing mechanism of El Nio events since 1980′s, the numerical experiment is made by using a two and half layer tropical ocean model. The results show that under the background conditions of specific westward streamline field, the second baroclinic Kelvin wave triggered by intraseasonal time scale oscillation in the tropical atmosphere could stop propagating during its eastward propagation. There should be the close relation between the stop of propagation and Doppler effect. Because of the increasing of SST positive anomaly in the sea region, the convective activity of upper air could be accelerated to develop, and so that the westerly anomaly could occur over the central West Pacific, the first baroclinic Kelvin wave is triggered in the equatorial ocean. Based on the observation and numerical experiment results, the mechanism of staged atmosphere ocean interaction has been put forward to explain the El Nio events since 1980′s.
出处
《应用气象学报》
CSCD
北大核心
1997年第A00期201-208,共8页
Journal of Applied Meteorological Science
基金
国家自然科学基金
关键词
厄尔尼诺
海温异常
西风暴发
阶段性发展
Sea surface temperature amomalg Kelvin wave Westerly burst Staged development
