冬季东亚大槽异常与EINino的关系

THE RELATIONSHIP BETWEEN ANOMALOUS TROUGH OVER EAST ASIA AND EL NINO

通过对东亚大槽强度与ＥＩＮｉｎｏ事件的统计分析，揭露了在多数ＥＩＮｉｎｏ（反ＥＩＮｉｎｏ）事件的前期冬季，东亚大槽强度偏弱（偏强）的事实。对１０个ＥＩＮｉｎｏ事件的合成分析亦表明，ＥＩＮｉｎｏ前冬季东亚西太平洋中高纬地区５００ｈＰａ为显著的高度正距平。谱分析进一步指出，冬季东亚大槽强度与赤道东太平洋各季ＳＳＴ有密切的关系，它们都具有显著的３－４年周期振荡，且槽强度的变化超前于ＳＳＴ约４－８个月。

Based on statistical analyses,an interesting fact is revealed that in winters prior toEI Nino (La Nina) events occurred through 1951-1987,East Asia trough is weaker(stronger)than in the normal years. The composited field of 500 hPa height anomaliesfor 10 winters prior to EI Nino events also shows significant positive anomalies over EastAsia. The results of power spectrum and cross spectrum analyses indicate that the rela-tionships between the trough intensity and the SST of the eastern equatorial Pacific areobvious.Both the trough and the SST in seasons have the most significant 3-4 year pe-riod oscillation,respectively,and the oscillation of the trough precedes that of the SSTby 4-8 months.