Impact of the December North Atlantic Oscillation on the following February East Asian trough

During winter, the December North Atlantic Oscillation (NAO) has an impact on the following February East Asian trough (EAT), and a significant positive correlation exists between them. It is shown that the circulation anomalies affected by the December NAO for December and for the following January are primarily confined to the Euro-Atlantic sector while they extend to East Asia during the following February, and this is related to anomalous wave trains originating from the southwestern Atlantic and spreading to the northeastern Atlantic, northern Europe, western Siberia, and East Asia. When the NAO is positive phase in December, the sea surface temperature (SST) tripole pattern is forced by persistence positive NAO from December to the following January, contributing to pronounced positive SST anomalies in midlatitude areas of the North Atlantic during the following February. The pronounced positive SST anomalies found during this period can generate feedback for atmospheric anomalies, and the westerly winds are enhanced (reduced) to the north (south) side of the positive SST anomalies, which result from strengthened (weakened) baroclinicity there. In addition, the Rossby wave source over the northeastern Atlantic shows a positive anomaly, establishing a link between the positive SST anomalies in midlatitude areas of the North Atlantic and the deepened EAT downstream.