近百年东亚季风长期变化中主周期振荡的奇异谱分析

运用海平面气压场资料，计算１８７３—１９９０年的东亚冬、夏季风强度指数，并利用奇异谱分析方法（ＳＳＡ）对这百年的东亚季风长期变化的周期活动进行了研究。研究表明：东亚冬、夏季风都存在准２ａ（ＱＢＯ）、３—６ａ（ＬＦＯ）的年际振荡，１６—１８ａ（ＩＤＯ）的年代际振荡和长期变化趋势。各振荡分量都具有年代际的差别，这种特征ＱＢＯ表现得最典型。冬季风的ＱＢＯ在１９２０年代前振幅较小，且大约呈现１２ａ的大振幅和６ａ的小振幅波状的周期变化；夏季风的ＱＢＯ振幅变化与冬季风相反，且大约呈现６ａ的大振幅和３ａ的小振幅波状的周期变化。夏季风中的年代际变化影响较小。

THE SINGULAR SPECTRAL ANALYSIS OF PERIODIC OSCILLATION IN LONG-TERM VARIATION OF EAST ASIAN MONSOON IN RECENT CENTURY

Based on sea level pressure data from 1873 to 1990,the East Asian monsoon intensity index is caculated to discuss the periodic oscillation of East Asian monsoon long term variation in recent century by using the method of singular spectral analysis (SSA).The results indicate that the long term variation in East Asian monsoon shows the interannual oscillation of the quasi biennial (QBO) and 3-6 years (LFO) and the interdecadal oscillation of 16-18 years (IDO);that these oscillation components exhibit the interdecadal variation,and the QBO is remarkable especially;that the amplitude of QBO in winter monsoon is smaller before 1920s and shows the wavelike changing with greater amplitude of about 12 years and smaller of about 6 years;that the summer monsoon changing is opposite to winter monsoon with about 6 years greater and about 3 years smaller;and that the interdecadal variation in summer monsoon is dominant.