中文摘要：

利用NCEP／NCAR再分析资料系统地分析了2005年与2006年冬季欧亚大陆的气温和东亚冬季风的差别及其与北半球准定常波活动的关系。分析结果表明：2005年冬季欧亚大陆中、高纬度地区气温偏低，东亚冬季风偏强；而2006年冬季欧亚大陆中、高纬度地区气温偏高，出现暖冬，东亚冬季风偏弱。分析结果还表明，这两年冬季东亚冬季风的差别不仅是由于西伯利亚高压和阿留申低压的变异所造成，而且是由于北极涛动（北半球环状模）的变化所造成。并且，作者还从这两年冬季北半球准定常行星波活动的差异，在动力理论上进一步讨论了这两年冬季北半球气候和东亚冬季风差异的机理。结果表明：2005年冬季北半球行星波活动为低指数，准定常行星波在高纬度往平流层传播加强，而往低纬度对流层上层传播减弱，造成了行星波E-P通量在高纬度地区对流层中、上层辐合加强，而在副热带地区对流层中、上层辐散加强，引起了北半球高纬度地区极锋急流减弱，而副热带急流加强，这有利于西伯利亚高压的发展，从而引起了东亚冬季风增强；相反，2006年冬季北半球行星波活动为高指数，准定常行星波在高纬度往平流层传播减弱，而往低纬度对流层上层传播加强，造成了行星波E-P通量在高纬度地区对流层中、上层辐散加强，而在副热带地区对流层中、上层辐合加强，引起了北半球高纬度地区极锋急流加强，而副热带急流减弱，这不利于西伯利亚高压的发展，从而引起了东亚冬季风减弱。

英文摘要：

The NCEP/NCAR reanalysis data are used to analyze the difference between the surface air-temperature in middle and high latitudes over the Eurasian continent and the East Asian winter monsoon in the winters of 2005 and 2006 （December- February） and their relations to the quasirstationary planetary wave activity during these two winters. The results show that the surface air-temperature in middle and high latitudes over the Eurasian continent was below normal, and the East Asian winter monsoon （EAWM） was strong in the winter of 2005; but in the winter of 2006, the surface air-temperature was above normal and anomalously warm winter occurred in this region, and the EAWM was weak. The results also show that the obvious difference of the EAWM between these two winters is closely associated with the Arctic Oscillation （AO）, and also the opposite variability of the Northern Annular Mode （NAM）. In the winter of 2005, the polar front jet stream over high latitudes of the Northern Hemisphere was weaker while the subtropical jet stream was stronger. This caused the stronger Siberian high and the Aleutian low, thus, the EAWM was strong. However, in the winter of 2006, the polar front jet stream over high latitudes of the Northern Hemisphere was stronger; while the subtropical jet stream was weaker, causing the weaker Siberian high and the Aleutian low, thus, the EAWM became weak. Furthermore, the physical mechanism of the difference of the boreal climate and the EAWM between these two winters is dynamically discussed further from the difference of quasi-stationary planetary wave activity. The results show that the planetary wave activity index （PWA index） over the Northern Hemisphere in the winter of 2005 was negative, i. e. , low PWA index, the propagation of quasi-stationary planetary waves into the stratosphere over high latitudes of the Northern Hemisphere was strong, while its propagation into the upper troposphere over low latitudes was weakened. This caused an anomalously strong convergence of E-P