Jones Julie M, Widmann Martin
Institute for Coastal Research, GKSS Research Centre, 21502 Geesthacht, Germany.
Nature. 2004 Nov 18;432(7015):290-1. doi: 10.1038/432290b.
The principal extratropical atmospheric circulation mode in the Southern Hemisphere, the Antarctic oscillation (or Southern Hemisphere annular mode), represents fluctuations in the strength of the circumpolar vortex and has shown a trend towards a positive index in austral summer in recent decades, which has been linked to stratospheric ozone depletion and to increased atmospheric greenhouse-gas concentrations. Here we reconstruct the austral summer (December-January) Antarctic oscillation index from sea-level pressure measurements over the twentieth century and find that large positive values, and positive trends of a similar magnitude to those of past decades, also occurred around 1960, and that strong negative trends occurred afterwards. This positive Antarctic oscillation index and large positive trend during a period before ozone-depleting chemicals were released into the atmosphere and before marked anthropogenic warming, together with the later negative trend, indicate that natural forcing factors or internal mechanisms in the climate system must also strongly influence the state of the Antarctic oscillation.
南半球主要的温带大气环流模式，即南极涛动（或南半球环状模），代表了绕极涡旋强度的波动，并且在近几十年的南半球夏季呈现出指数为正的趋势，这与平流层臭氧损耗以及大气温室气体浓度增加有关。在此，我们根据20世纪海平面气压测量数据重建了南半球夏季（12月至1月）的南极涛动指数，发现大约在1960年也出现了较大的正值以及与过去几十年幅度相似的正趋势，且之后出现了强烈的负趋势。在消耗臭氧层化学物质释放到大气之前以及明显的人为变暖之前的一段时间内出现的这种正南极涛动指数和较大的正趋势，再加上后来的负趋势，表明气候系统中的自然强迫因素或内部机制也必定对南极涛动状态有强烈影响。
