In recent decades the Arctic surface air temperature (SAT) in autumn has been increasing steadily. In winter, however, instead of a linear trend, the Arctic SAT shows an abrupt change that occurred in 2004. During the years from 1979 to 2003, the first principle component (PC1) of winter Arctic SAT remains stable, and no significant increasing trend is detected. However, the PC1 changes abruptly from negative to positive phase in the winter of 2004. The enhanced Siberian high may have contributed to this abrupt change because the temporal evolution of Arctic temperature correlates significantly with sea level pressure variation in the northern Eurasian continent, and the atmospheric circulation anomaly related to the Siberian high from 2004 to 2013 favors a warmer Arctic. With the help of the meridional wind anomaly around the Siberian high, warmer air is transported to the high latitudes and therefore increases the Arctic temperature.
近三十年北极地区秋季气温呈线性上升，而冬季气温在2004年出现显著突变，突变后北极气温显著升高。冬季欧亚大陆西北部地区的海平面气压与同期北极气温有显著相关关系，该地区海平面气压的上升有利于冬季北极变暖.