Connection between November snow cover over Eastern Europe and winter precipitation over East Asia

摘要

In this study, the connected spatial and temporal features of winter precipitation over East Asia and November snow cover over Eurasia are analysed using the singular value decomposition (SVD) method. The results show that a strong consistent variation of winter precipitation occurs over East Asia, especially north of 35 degrees N, closely related to the snow cover change over Eastern Europe. Mechanism analysis indicates that the processes behind the physical link between the November snow cover over Eastern Europe and East Asian winter precipitation are different in December compared to January and February. In December, the persistence of the snow cover anomaly can memorize' the signal of the November snow cover and impact December circulation and precipitation over East Asia. During January-February, the snow cover anomaly disappears, while the variability of the polar vortex resulting from the interaction of the troposphere and stratosphere serves as a bridge connecting the November snow cover over Eastern Europe and the January-February precipitation over East Asia. Revealing the role of the November snow cover is significant not only for understanding East Asian winter precipitation variability but also for its prediction.