基于ECHAM5的21世纪北极涛动的变化特征

Variability of the AO in the 21st Century by ECHAM5 Model

摘要: 基于德国马普气象研究所(Max Planck Institute for Meteorology)，由政府间气候变化专门委员会第五次评估报告得出的地球数值模拟系统大气模式分量ECHAM5的输出结果，对RCP2.6、RCP4.5和RCP8.5三种情景下未来21世纪北极涛动(AO)的变化特征进行探究，同时对21世纪冬季北纬20度以北的海平面气压距平场做EOF分解发现：在RCP4.5情景下，北极涛动模态北大西洋正距平中心强度明显高于其他两种情景下的强度，且方差贡献率也最大；RCP8.5情景下，负气压距平区域出现了两个负中心，一个偏向于东半球，另一个偏向于西半球。同时，借助经验正交函数(EOF)分解、功率谱分析、交叉谱分析分析了我国西北地区冬季气温与冬季北极涛动(AO)的年代际特征及其关系。结果表明：冬季北极涛动指数具有明显的年代际变化特征；并且北极涛动指数与西北地区冬季温度具有一致的上升(下降)趋势。

Abstract: Based on the ECHAM5 output results of the earth’s numerical simulation system by the Max Planck Institute for Meteorology, we study the variability of the Arctic Oscillation (AO) in the three scena-rios (RCP2.6, RCP4.5, RCP8.5) in the 21st century. The results show that both the positive intensity in North Atlantic and the variance contribution in RCP4.5 are much larger than that in the other scenarios. In RCP8.5, the negative center divides into two areas, which are in the eastern and the western hemispheres separately. Meanwhile, we analyze the winter temperatures in Northwest China and the winter Arctic Oscillation (AO) by using the empirical orthogonal function (EOF) de-composition, power spectrum and Cross spectrum. The results show that: the Arctic Oscillation Index has obvious decadal changes. Besides, winter temperatures and the Arctic Oscillation Index have a consistent increase (decrease) trend.