Tropical Pacific as a Pacemaker of Recent Decadal Anticyclonic Intensification Over the Barents–Kara Sea
Zhongfang Liu, Guillaume Gastineau, Zhongwang Wei, Wanling Xu, Rui Wang, Xiaogang HeAbstract
Under anthropogenic warming, a strengthened wintertime anticyclonic anomaly over the Barents–Kara Sea (BKS) has emerged as a hallmark of recent Arctic climate change. While local forcing from sea ice loss has been widely emphasized, the quantitative contribution of remote tropical forcing remains poorly constrained. Here we demonstrate that decadal La Niña–like cooling in the eastern tropical Pacific has been a key remote driver of this circulation change. This Niña–like cooling reorganizes tropical convection and excites a stationary Rossby wave train, generating a trans‐basin response that induces an anticyclonic anomaly over the BKS. This mechanism accounts for 27 ± 17% of the circulation trend and interacts with anthropogenic forcing to amplify Arctic climate change. Our results underscore the critical role of tropical Pacific decadal variability in recent regional Arctic circulation changes, with implications for climate in the Arctic and beyond.