Recently Intensified Tropical‐Extratropical Linkage Modulated by Arctic Sea Ice Loss

• Published in: Geophysical research letters Vol. 52; no. 10
• Main Authors: Zhang, Xiang, Wu, Bingyi
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 28.05.2025; Wiley
• Subjects: Ablation; Arctic sea ice; Data analysis; interdecadal variations; Numerical simulations; Sea ice; Tropical circulation; Tropical environments; tropical‐extratropical linkage; Walker circulation; Winds; Zonal winds
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2024GL114436

Through data analysis and numerical simulations, this study reveals the winter Arctic Warming Pattern (AWP), characterized by anticyclonic anomalies over the North Pacific and the Urals, which plays a pivotal role in linking the Arctic and tropics. The AWP is significantly correlated with the tropical Pacific Walker Circulation (PWC). Since the decadal shift of the AWP in 2003, the relationship between the AWP and the PWC has intensified over the past two decades. Model simulations suggest that this enhanced AWP‐PWC linkage is attributed to the recent shift to a low Arctic sea ice state after 2004. The results show that the shrinking Arctic sea ice promotes the AWP, contributing to the robust responses of zonal winds over the Pacific, further enhancing the PWC and ultimately driving the recent intensification of the tropical‐extratropical linkage. Plain Language Summary The Arctic sea ice has undergone a rapid reduction since 1979, significantly influencing mid‐latitude weather and climate patterns. However, the impact of Arctic sea ice decline on tropical variability remains unclear. Our study reveals a distinct winter atmospheric circulation pattern, the “Arctic Warming Pattern” (AWP), featuring anticyclonic anomalies over the North Pacific and Ural Mountains. The AWP is strongly linked to the Pacific Walker Circulation (PWC), a dominant tropical atmospheric circulation. Since around 2003, this AWP‐PWC linkage has intensified. Model simulations suggest that the recent reduction in Arctic sea ice likely contributes to this intensification. The diminished sea ice promotes the AWP, which in turn induces robust Pacific zonal winds, thereby strengthening tropical‐extratropical linkage. Consequently, our findings emphasize the critical role of diminished Arctic sea ice in shaping winter atmospheric circulation and further influencing weather and climate in mid‐low latitudes over the past two decades. Key Points The Arctic's low‐ice state since 2004 has exerted increasing impacts on the tropics in recent two decades Arctic sea ice loss enhances the Arctic Warming Pattern (AWP), significantly linked to the Pacific Walker Circulation The recent AWP induces robust zonal wind responses in the Pacific Ocean, leading to an intensified tropical‐extratropical linkage