Possible Mechanism for the Record‐Breaking Cold Event Over Northeastern China in December 2023: Role of Extreme Negative North Atlantic Oscillation

ABSTRACT In early winter of 2023 (December 9th–23rd), a record‐breaking cold event hits northeastern China (NEC), resulting in serious economic losses and significant disruptions to daily life. Our analysis suggests that this cold event is attributed to the preceding extreme negative phase of the North Atlantic Oscillation (NAO). The NAO‐related Barents–Kara Seas high (BKH) leads to the southward invasion of polar cold air into Siberia. The accumulation of cold air favors the enhancement of the Siberian high. In addition, at the upper level, the BKH induces upper‐level convergence and downward motion over Siberia. The accumulated cold air and downward motion jointly favor the development and maintenance of the historically strongest Siberian high in December 2023. Accordingly, the strong northerly winds associated with the strongest Siberian high transport cold air southward to NEC, resulting in the record‐breaking cold event over the region in December 2023.