摘要
利用１９５０～１９８９年４０年的全球月平均资料，详细讨论了东亚冬季风的年际变化特征，分析结果表明东亚冬季风年际变化中包含有明显的ＥＮＳＯ信号，也就是说东亚冬季风活动与ＥＮＳＯ的发生有明显的关系，大多数ＥＩＮino事件爆发后东亚冬季风偏弱，而大多数ＬａＮｉｎａ爆发后东亚冬季风偏强。通过对这４０年间的１０次ＥＩＮｉｎｏ和７次ＬａＮｉｎａ事件的合成分析，结果表明ＥＩＮino。冬半年东亚５００ｈＰａ位势高度为正距平、海平面气压为负距平，即东亚冬季风偏弱，阿留申及北美地区呈现出明显的类似ＰＮＡ型的异常环流形势；ＬａＮｉｎａ冬半年东亚以至于北半球大气环流异常形势与ＥＩＮｉｎｏ的相反。同时资料分析也表明，在大多数ＥＩＮｉｎｏ（ＬａＮｉｎａ）爆发前东亚冬季风偏强（弱）。另外，功率谱分析结果表明，东亚冬季风有显著的３～５年和准２年的变化周期，这从另一方面说明了东亚冬季风的年际异常中包含有显著的ＥＮＳＯ信息。
The interannual variability of winter monsoon in East Asia is investigated in detailwith the observed global month mean data from 1950 to 1989. Analysis results clearly show thatthe anomalous activities of winter monsoon in East Asia have the obvious relationship with theoccurrence of ENSO (EI Nino, La Nina). In other words, winter monsoon in East Asia becomesweaker after most EI Nino events occurred, and becomes stronger after most La Nina events occurred. During the past 40 years, there are 10 EI Nino cases and 7 La Nina cases. Through composite analyses for the two kinds of cases, respectively, it is shown that there are positive departure of500 hpa geopotential height and negative anomaly of sea level pressure in East Asia, which meanEast--Asian winter monsoon becomes weaker in the EI Nino wintertime. The anomalous circulation situation is well analogous to the observed PNA pattern in the Aleutian and North Americanarea. In the La Nina wintertime, the signs of the anomalous circulation in the Northern Hemisphere, especially in East Asia, are opposite to those during the same period with EI Nino. In themeantime, the analyses of the observed data also display that East--Asian winter monsoon is verystrong (weak) before EI Nino (La Nina) events burst out. Analyses of power spectrum clearly showthat the interannual variation of winter monsoon has 3- 5 years and quasi--biennial cycles. In other words, ENSO signals are included in the interannual anomaly of winter monsoon in East Asia.
出处
《大气科学》
CSCD
北大核心
1999年第3期276-285,共10页
Chinese Journal of Atmospheric Sciences
基金
国家自然科学基金!49635180
关键词
东亚
冬季风
年际变化
气候异常
厄尔尼诺
季风
ENSO, winter monsoon ,East Asia, interannual variability ,climate anomaly
