近年秋季南美沿岸海表温度周期性下降对ENSO事件的可能影响  

The Impact of Seasonal Drops of SST in offshore along South America on ENSO Event in Autumn of Recent Years

作　　者：李威[1,2] 翟盘茂[2] 

机构地区：[1]北京大学物理学院,北京100871 [2]国家气候中心

出　　处：《气象》2007年第2期29-33,共5页Meteorological Monthly

摘　　要：文章分析了1950年以来赤道南美沿岸海表温度变化特点,发现1999年以来,Nino1+2区海表温度的年变化振幅呈增大趋势,使得赤道东太平洋东北地区每年出现周期性降温,这主要是由秋季月平均SST最低值偏低造成,这种长时间持续偏低是1950年以来首次出现。进一步的分析表明,近年来南美沿岸海表温度在秋季的周期性下降可能对ENSO暖事件发生产生了影响,使得2002/2003ENSO暖事件成为20世纪50年代以来由冷事件向暖事件转换历时最长的一次。Firstly, characteristics in the evolvement of SST in offshore of South America since 1950 were studied. It was found that the trends of annual undulation amplitude of monthly mean SST in Nino 1 ＋ 2 region kept increasing since 1999, which caused seasonal drops of SST in northeastern tropical East Pacific. The minimums of monthly mean SST obviously lower than normal in autumn are the major cause, and such a situation kept for so long time that it does not come forth before year 1950. Further study reveals that seasonal drops of SST in offshore of South America in autumn weakened the possibility of ENSO warm event, and made the 2002/ 2003 E1 Nino be an ENSO event which got through the longest time to transform from La Nina episode into E1 Nino episode since the 1950s.

关 键 词：赤道东太平洋 海表温度ENSO Ninol+2区 

分 类 号：P732[天文地球—海洋科学]