近百年来的南极绕极波变化特征

采用2011年发布的20世纪全球大气环流再分析资料,结合长期观测序列,分析了百余年来大气中南极绕极波的强弱变化和传播过程。结果显示,南极绕极波有显著的年代际变化,在1940~1960年和1980~2000年附近出现和活跃,而在其他年代消失。东南太平洋南极绕极波振幅最强,该区域的海气耦合过程可能是绕极波信号增强的关键之一。初步揭示了百年来南极绕极波和南极涛动的对应关系,偏强的南极涛动有利于南极绕极波的出现,但并非决定绕极波产生的唯一因素。

Characteristics of the Antarctic Circumpolar Wave during Recent 100 Years

The phenomenon known as the Antarctic Circumpolar Wave (ACW) was determined to have occurred during the last two decades of the 21th century. In this study, a new reanalysis dataset of 20th century reanalysis Version 2 (20CRV2) spanning 1871-2008 and several long-term observation series were used to investigate the interdecadal fluctuation and transmission of the ACW since 1871. The results indicate an obvious interdecadal variation of the ACW signal, which occurred in 1940-1960 and in 1980-2000 and disappeared during the other periods. The greatest amplitude of the ACW was detected near the southeast Pacific, implying the essential influence of ocean-atmosphere interaction at this region to the emergence of the ACW. Moreover, it was determined that a noticeable ACW phenomenon appeared during the period in which the Antarctic Oscillation (AO) was relatively stronger, which indicates that the enhanced AO may intensify the circumpolar westerly and benefit the emergence of the ACW.