Strengthened relationship between the Antarctic Oscillation and ENSO after the mid-1990s during austral spring

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• 作者：Tingting Han ; Huijun Wang ; Jianqi Sun
• 关键词：ENSO ; Antarctic Oscillation ; South Pacific SST ; austral spring ; decadal change
• 刊名：Advances in Atmospheric Sciences
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：34
• 期：1
• 页码：54-65
• 全文大小：
• 刊物主题：Atmospheric Sciences; Meteorology; Geophysics/Geodesy;
• 出版者：Science Press
• ISSN：1861-9533
• 卷排序：34

文摘

This paper documents a decadal strengthened co-variability of the Antarctic Oscillation (AAO) and ENSO in austral spring after the mid-1990s. During the period 1979–93, the ENSO (AAO) spatial signatures are restricted to the tropics–midlatitudes (Antarctic–midlatitudes) of the Southern Hemisphere (SH), with a weak connection between the two oscillations. Comparatively, after the mid-1990s, the El Ni˜no-related atmospheric anomalies project on a negative AAO pattern with a barotropic structure in the mid–high latitudes of the SH. The expansion of El Ni˜no-related air temperature anomalies have a heightened impact on the meridional thermal structure of the SH, contributing to a weakened circumpolar westerly and strengthened subtropical jet. Meanwhile, the ENSO-related southern three-cell circulations expand poleward and then strongly couple the Antarctic and the tropics. Numerical simulation results suggest that the intensified connection between ENSO and SST in the South Pacific since the mid-1990s is responsible for the strengthened AAO–ENSO relationship.