The Arctic Oscillation (AO) has been observed to undergo distinct decadal structural fluctuations that significantly influence regional weather and climate. Understanding the drivers and mechanisms behind the AO’s spatial nonstationarity is critical for improving climate predictions related to the AO. We present evidence that the Atlantic Multidecadal Oscillation (AMO) plays a pivotal role in modulating AO’s Pacific center in recent decades. The poleward amplified cooling associated with negative AMO enhances the north-south temperature gradient and results the strengthened westerly winds and stratospheric polar vortex (SPV) responses, which reflects more planetary waves from the North Pacific to the North Atlantic. This enhances the atmospheric coupling between these regions and leads to a more pronounced Pacific center within the AO pattern. Numerical simulations from ECHAM5 and 35 CMIP6 models further corroborate the essential role of the AMO. These findings advance our understanding of the mechanisms driving the variability of the AO pattern.

据观察，北极涛动 （AO） 经历了明显的年代际结构波动，这对区域天气和气候产生了重大影响。了解 AO 空间不稳定背后的驱动因素和机制对于改进与 AO 相关的气候预测至关重要。我们提出的证据表明，近几十年来大西洋年代际振荡 （AMO） 在调节 AO 的太平洋中心方面起着关键作用。与负 AMO 相关的极地放大冷却增强了南北温度梯度，并导致增强的西风和平流层极涡 （SPV） 响应，从而反射了从北太平洋到北大西洋的更多行星波。这增强了这些区域之间的大气耦合，并导致 AO 模式中更明显的太平洋中心。ECHAM5 和 35 个 CMIP6 模型的数值模拟进一步证实了 AMO 的重要作用。这些发现促进了我们对驱动 AO 模式可变性的机制的理解。