北大西洋年代际振荡（AMO）气候影响的研究评述

北大西洋年代际振荡（theAtlantic Multidecadal Oscillation,AMO）是发生在北大西洋区域空间上具有海盆尺度、时间上具有多十年尺度的海表温度（sea surface temperature,SST）准周期性暖冷异常变化。它具有65～80a周期,振幅为0.4℃。AMO的形成与热盐环流的准周期性振荡有关,它是气候系统的一种自然变率。诸多研究表明,AMO在北大西洋局地气候及全球其他区域气候演变中发挥了重要影响。欧亚大陆的表面气温,美国大陆、巴西东北部、西非以及南亚的降水,北大西洋飓风等都与之密切相关。AMO对东亚季风气候的年代际变化有显著的调制作用,暖位相AMO增强东亚夏季风,减弱冬季风,冷位相则相反。本文总结了这方面的研究进展,讨论了AMO对未来气候预测的意义,认为最近20多年来我国冬季的显著增暖与AMO处于暖位相有关,是人类温室气体强迫与暖位相AMO（自然因子）两种增暖影响相叠加的结果。随着AMO逐渐转入冷位相,我国冬季变暖趋势将放慢,并有望于21世纪20年代中期逆转。

A Review of the Researches on the Atlantic Multidecadal Oscillation(AMO) and Its Climate Influence

The Atlantic Multidecadal Oscillation （ AMO）, which is the fluctuation pattern of North Atlantic sea surface temperature（SST） ,varies over basin spatial scale and multidecadal temporal scale. It has a period of 65--80 years and an amplitude of 0.4 ℃. The AMO is found arisen from internal variability of climate system, particularly linked to quasi-periodic fluctuation of the Thermohaline Circulation （THC）. Previous studies have revealed that the AMO has significant influences on the global and re- gional climate of the twentieth century including surface temperature in Eurasia, precipitation in North America,Northeast Brazil, African Sahel and India, as well as hurricanes in Atlantic. Furthermore, the AMO acts as a pacemaker of multidecadal climate variations of the East Asia. The warm-phase AMO intensifies the East Asian summer monsoon but weakens the winter monsoon, and vise versa. This article summarizes the progress of this aspect and discusses the AMO＇s implications for the climate projection in the future decades. It is argued that significant winter warming in China in the recent two decades has been arisen from both the anthropogenic forcing of greenhouse gas and the natural forcing domained by the AMO. Along with the AMO entering a cold phase, the winter warming in China is projected to slow down, or even reverse by the middle term of 2020s.