The multidecadal regulation of wintertime extreme cold temperatures over Eurasia by the change of the North Atlantic sea surface temperature (SST) from 1950–1983 (P1) to 1984–2017 (P2) is examined in this paper. The warm Arctic–cold Siberia (WACS) trend pattern shows a distinct interdecadal transition from P1 to P2, which has a footprint of the Atlantic Multidecadal Oscillation (AMO). The positive trend of the WACS pattern during P2 coincides with the transition of AMO from its negative phase (AMO⁻) to positive phase (AMO⁺). The sea-ice reduction in Barents–Kara Seas (BKS) owing to AMO⁺ contributes to the BKS warming in the WACS pattern trend, while it also reduces the meridional potential vorticity gradient (PV_y) over Eurasia and increases the persistence of Ural blocking (UB), thus favoring a positive WACS trend, especially a Siberian cooling trend during P2. During P1, when the AMO changes from AMO⁺ to AMO⁻, a reversed WACS pattern trend is seen because UB shows a shortened duration due to intensified PV_y over Eurasia caused by increased BKS sea ice. In addition, the North Atlantic SST forcing on the WACS also shows a multiple time-scale feature. Embedded in the multidecadal timescale (≥ 50 years) of AMO, the North Atlantic SST tripole (NAT) pattern can also significantly influence the Siberian cold anomaly on decadal (10–30 years) time scales not by the BKS sea-ice decline. Even during the suppressed WACS trend period (P1) from AMO⁺ to AMO⁻, a positive WACS pattern is still seen during 1960–1970, which is mainly dominated by the NAT pattern through generating a negative-phase North Atlantic Oscillation with UB.

本文研究了1950–1983（P1）至1984–2017（P2）期间北大西洋海表温度（SST）变化对欧亚大陆冬季极端寒冷温度的多年代调节。温暖的北极-冷西伯利亚（WACS）趋势模式显示了从P1到P2的年代际过渡，这具有大西洋多年代际涛动（AMO）的足迹。在WACS图案期间P2与AMO从它的负相（AMO过渡一致的积极趋势^-正相（AMO）⁺）。由于AMO ^+而导致的巴伦支–卡拉海（BKS）海冰减少，促使WKS模式趋势中的BKS变暖，同时也降低了子午线潜在涡度梯度（PV _y）超过了欧亚大陆，并增加了乌拉尔阻塞（UB）的持续性，因此有利于WACS呈积极趋势，尤其是P2期间的西伯利亚降温趋势。P1期间，当从AMO AMO改变⁺到AMO ^- ，反转WACS图案趋势看出因为UB示出了缩短的时间长度，由于加强PV _ý欧亚引起BKS海冰增加。此外，WACS上的北大西洋SST强迫还显示了多个时标功能。嵌入AMO的多年代时间尺度（≥50年）中，北大西洋SST三极（NAT）模式也可以显着影响年代（10-30年）时间尺度上的西伯利亚冷异常，而不是受到BKS海冰下降的影响。即使在AMO ⁺抑制的WACS趋势期间（P1）到AMO ^- ，正WACS图案仍期间1960年至1970年，这主要是通过产生一个负相北大西洋振动性UB支配由NAT图案看到。