Abstract:
The reversal of temperature anomalies from warm to cold and vice versa in the East Asian region is a significant climatic phenomenon occurring during the winter season under the context of global warming. Compared to the variability of seasonal-mean winter temperature anomalies, the climate prediction uncertainty for the reversal phenomenon is greater, and its adverse effects are more significant. In this study, seasonal empirical orthogonal decomposition and composite analysis were performed on atmospheric reanalysis data from the winters of 1980/81 to 2022/23 to investigate the interannual variability of the East Asian winter temperature anomaly reversal mode (TARM). The results indicate that although the different processes of the East Asian winter TARM are related to intraseasonal reversals of the Siberian High, the Eurasian teleconnection, and the Arctic vortex anomalies, the interannual variability of the “warm-to-cold” mode is significantly stronger than that of the “cold-to-warm” mode, suggesting a pronounced asymmetry in the interannual variability of TARM. In the “warm-to-cold” mode, the lower-level Siberian High strengthens over time: the positive phase of the East Atlantic–West Russia–like teleconnection in early winter shifts to a negative phase in late winter, leading to more active cold air. Conversely, in the “cold-to-warm” mode, the intensity of the winter Arctic vortex shifts from weak to strong, and subsequently, the Siberian High weakens, favoring the appearance of temperature anomalies that are cold in early winter and warm in late winter. Further analysis shows that the North Atlantic and tropical Indian Ocean sea surface temperature anomalies with La Niña are important factors influencing the “warm-to-cold” mode, while a reduction in the Barents–Kara sea ice in November acts as a precursor signal for the “cold-to-warm” mode. Therefore, the diversity of underlying atmospheric conditions is an important cause of the asymmetry of the East Asian winter TARM. Therefore, climate prediction for the East Asian winter TARM should consider the diversity of the underlying atmospheric conditions.