北半球50 hPa大气低频振荡与突发性增温

THE RELATIONS BETWEEN ATMOSPHERIC LOW-FREQUENCY FLUCTUATION AT 50 hPa AND SUDDEN STRATOSPHERIC WARMING (SSW) IN WINTER OVER THE NORTHERN HEMISPHERE

本文利用５０ｈＰａ１９６９—１９７６年７个冬季的高度场资料进行了功率谱分析。分析发现３０—６０天低频振荡在高纬地区比中低纬更为显著；并且发现在阿留申高压北进的路径以及在极点上平流层突发性增温（ＳＳＷ）的强年比弱年的相关要高。这表明３０—６０天的振荡在上述地区与温度有着密切联系。我们选取１９７０—１９７１年冬季强突发性增温个例，进一步分析了平流层突发性增温过程中的基本特征。结果表明：３０—６０天的振荡对平流层突发性增温有相当大的贡献。

The power spectra of height at 50 hPa by using the data from seven winter seasons(1969 1976) are revealed,it is found that the typical time scale of 30 60-day oscillations is more obvious over high latitude than over middle and low latitude . The correlation coefficients of SSW are higher in strong SSW year than in weak SSW year over the path of Aleutian high moving northward and the polar point. it proves that 30 60-day oscillations over high latitude are tightly associated with SSW. The basic characteristics of SSW process are analysed by using the strong SSW data in winter of 1970 1971. The results show undoubtedly that there are larger contribution for 30 60-day oscillations of height to SSW.