Characteristics of the North Atlantic Oscillation and Its Impact on East Asia

Abstract

本文利用NCEP/NCAR近70年(1948~2020年)的海平面气压、气温、位势高度等再分析资料和GPCP近50年(1979~2020年)全球月平均降水资料，讨论了北大西洋涛动及其正负相位转换过程的基本特征，研究表明：NAO全年均存在但在冬季最强，且NAO正负相位的转换对东亚大气环流形式有着显著影响。采用相关分析和合成分析方法，对冬夏两季的NAO与东亚地区的环流形势、冬季气温和夏季降水进行研究，发现北大西洋涛动与东亚地区的气候有着明显的相关性，且因季节不同，对冬夏两季东亚地区的气候影响也不同。当北大西洋涛动表现较强时，东亚冬季风偏弱，夏季风偏强，东亚地区冬季气温整体偏高，夏季东亚北部地区降水偏多，南部及西南部降水偏少；反之，当北大西洋涛动较弱时，东亚冬季风偏强，夏季风偏弱，东亚冬季气温偏低，夏季东亚北部地区降水偏少，南部偏多。 In order to further study the characteristics of the North Atlantic Oscillation (NAO) and its influence on East Asia, this paper discusses the basic features of the North Atlantic Oscillation and its positive and negative phases conversion process by using the monthly average reanalysis data of sea level pressure, temperature and potential height of NCEP/NCAR in the past 70 years (1948~2020) and the global monthly average precipitation data of GPCP in the past 50 years (1979~2020). Research shows that NAO exists all year round but performs best in winter, and the phase conversion of NAO has significant effects on the atmospheric circulation in East Asia. After that, we used correlation analysis and synthetic analysis methods to study the relationship between NAO and the circulation situation in East Asia, winter temperature and summer precipitation in the different seasons. The results show that there is a significant correlation between the North Atlantic Oscillation and the climate of East Asia, and its influence performed quite differently in winter and summer. When the North Atlantic Oscillation is strong, the East Asian winter monsoon is weak and the summer monsoon is strong. The overall winter temperature in East Asia is relatively high. In summer, there is more precipitation in the northern part of East Asia and less precipitation in the south and southwest; conversely, when the North Atlantic Oscillation is weak, the East Asian winter monsoon is strong, the summer monsoon is weak, the East Asian winter temperature is relatively low, and in summer the northern part of East Asia has less precipitation and the southern part is more.