Intensified Interannual Variability of Arctic Sea Ice Modulated by Strengthened North Atlantic Oscillation Leads to an Enhanced Impact on Asian Winter Cold Extremes

Abstract Arctic sea ice concentration (SIC) exhibits significant interannual variability despite a persistent decline due to global warming. This variability is influenced by atmospheric internal variability such as the North Atlantic Oscillation (NAO) and the Pacific‐North American pattern (PNA). Our analysis reveals that late summer NAO interannual anomalies have become increasingly volatile from 1979 to 2023, with the post‐2000 standard deviation 71% higher than the pre‐2000 period, while the PNA shows little decadal change. During positive NAO phases, warm, moisture‐laden air from the North Atlantic contributes to increased Arctic sea ice melt. The strengthened interannual volatility of the late summer NAO leads to intensified autumn Arctic SIC variability, consequently amplifying the impact of Arctic sea ice on Asian winter cold extremes (AWCE), with more sea ice melt in autumn corresponding to a greater frequency of AWCE over a broader area in the post‐2000 period compared to the pre‐2000 period.