Transition of Zonal Asymmetry of the Arctic Oscillation and the Antarctic Oscillation at the End of 1970s  

作　　者：刘珊 王会军 

机构地区：[1]Narisen-Zhu International Research Center,Institute of Atmospheric Physics,Chinese Academy of Sciences [2]Climate Change Research Center,Chinese Academy of Sciences [3]University of Chinese Academy of Sciences

出　　处：《Advances in Atmospheric Sciences》2013年第1期41-47,共7页大气科学进展（英文版）

基　　金：supported by National Natural Science Foundations of China(Grant No. 41130103);the 973 Program (Grant Nos.2009CB421406 and 2012CB955401)

摘　　要：In this study, the interdecadal changes in the zonal Antarctic Oscillation （AAO） were analyzed. To describe symmetry of both Arctic Oscillation （AO） and the zonal asymmetry, a local index of AO and AAO was defined using the normalized sea level pressure （SLP） differences between 40° and 65° （latitudes） in both hemispheres. The zonal covariability of local AO and AAO can well represent the zonal symmetry of AO and AAO. Results show that the zonal asymmetry of both AO and AAO significantly changed in the late 1970s. AO was less asymmetric in the zonal direction in the boreal winter season during the latter period, while in the boreal summer it became more asymmetric after 1979. The zonal symmetry of AAO in both austral summer and winter has also significantly decreased since the late 1970s. These changes may imply interdecadal transition in the atmospheric circulation at middle and high latitudes, which is of vital importance to understanding climate variability and predictability across the globe, including the African Asian Australian monsoon regions.In this study, the interdecadal changes in the zonal Antarctic Oscillation （AAO） were analyzed. To describe symmetry of both Arctic Oscillation （AO） and the zonal asymmetry, a local index of AO and AAO was defined using the normalized sea level pressure （SLP） differences between 40° and 65° （latitudes） in both hemispheres. The zonal covariability of local AO and AAO can well represent the zonal symmetry of AO and AAO. Results show that the zonal asymmetry of both AO and AAO significantly changed in the late 1970s. AO was less asymmetric in the zonal direction in the boreal winter season during the latter period, while in the boreal summer it became more asymmetric after 1979. The zonal symmetry of AAO in both austral summer and winter has also significantly decreased since the late 1970s. These changes may imply interdecadal transition in the atmospheric circulation at middle and high latitudes, which is of vital importance to understanding climate variability and predictability across the globe, including the African Asian Australian monsoon regions.

关 键 词：AO AAO zonal asymmetry interdecadal change seasonal variations 

分 类 号：P433[天文地球—大气科学及气象学]