利用NCEP/NCAR再分析资料，统计了近50年500，300，200和100 hPa等压面上北半球及4个分区冬季极涡面积和强度指数，并讨论了各层等压面上不同区域极涡面积比例变化特点和500 hPa极涡中心位置变化特征，揭示了冬季各层极涡之间同期和滞后关系，分析了冬季极涡面积与中国平均温度和极端气温的关系。结果表明：（1）北半球极涡面积、 强度均经历了先扩张后收缩的变化，20世纪80年代中后期气候变暖以后4层等压面上发生了极涡面积缩小，90年代中期发生强度减弱的年代际突变，只是较面积变化而言，强度年代际变化较弱，极涡面积和强度在年代际上相关显著。（2）位于平流层低层（100 hPa）的极涡年平均面积、 强度最大，并且随季节变化幅度也是最大，尤以Ⅰ区（亚洲大陆区）、 Ⅳ区（大西洋欧洲大陆区）更为显著。就年内变化而言，100 hPa极涡面积极大值的出现落后于其他层，极小值的出现又早于其他层，并且冬季前期100 hPa极涡面积对其后期500，300和200 hPa的变化有一定影响。（3）4层极涡面积都偏离Ⅳ区，500 hPa极涡基本偏向Ⅱ区（太平洋区）、 Ⅲ区（北美大陆区），300，200和100 hPa偏向Ⅰ、 Ⅱ区，500 hPa极涡中心多位于Ⅱ区或Ⅲ区。（4）在全球变暖背景下，近50年中国冬季平均气温、 暖日（夜）呈现明显的增加趋势，冷日（夜）呈明显的减少趋势，并且突变都发生在20世纪80年代中期。（5）中国冬季平均气温、 极端气温指数与极涡面积相关关系以500 hPa最为显著。分区来看与500 hPaⅠ区相关最为明显，300 hPaⅠ区、 200 hPaⅠ区和100 hPa Ⅳ区次之。极涡从平流层低层（100 hPa）到对流层中层（500 hPa）是从IV区到I区逐渐影响中国冬季气温。（6）500 hPaⅠ区极涡面积的扩大有利于除东北以外中国大部分地区冷日/夜（暖日/夜）次数的增加（减少），而100 hPa Ⅲ、 Ⅳ区、 500 hPa Ⅳ区面积的扩大有利于中国北方大部分地区冷日/夜（暖日/夜）次数增加（减少），且极涡面积与冷（暖）夜的相关系数要高于与冷（暖）日的，与冷日（夜）的相关系数要好于与暖日（夜）的。

Using NCEP/NCAR reanalysis data, the variation of the area, intensity and location of the whole and four regions of Northern Hemisphere polar vortex on 500, 300, 200 and 100 hPa in winter is investigated. Meanwhile, the change of the percentage of polar vortex area in different layers and the variation characteristics of the main location of 500 hPa polar vortex are discussed. Finally the synchronous and later correlation between the area and intensity of each level polar vortex and their relation with winter average and extreme temperature are analyzed. The results are as followings: (1) The area size and intensity of Northern hemisphere polar vortex in winter at four levels increased at the beginning, which is followed by a decreasing trend, and the area mutated occurred in the middle 1980s as the beginning of the global warming and intensity mutated occurred in the middle of 1990s. Compared with the area, inter-decadal change of the intensity is weak. And the area and intensity of polar vortex at different layers have significant inter-decadal correlation. (2) The area of polar vortex on 100 hPa is the biggest, and the intensity is strong at the same level, both of which have the largest seasonal amplitude, especially in region Ⅰ and Ⅳ. As to the annual variation, the maximum polar vortex area appears later while the minimum area appears earlier than other layers. And winter polar vortex area index on 100 hPa has a certain influence on the ones on 500, 300 and 200 hPa in the next winter. (3) The polar vortex area of four layers all deviate from region Ⅳ (the Atlantic and Europe continental), and 500 hPa polar vortex deviate into region Ⅱ and Ⅲ (the Pacific Ocean and the continent of North America area), polar vortex on 300, 200 and 100 hPa deviate into region Ⅰand Ⅱ (the Asian mainland and the Pacific Ocean), the center of 500 hPa polar vortex almost located in region Ⅱ or Ⅲ. (4) In recent 50 years, under the background of global warming, the average temperature in winter and the occurrence of warm day (night) have a significant increasing trend, cold day (night) reduced significantly and the mutation occurred in the middle of 1980s. (5) The winter average temperature and extreme temperature index have a significant correlation with the 500 hPa polar vortex area. The correlation between the temperature and area of the region Ⅰ on 500 hPa is the most significant, the region Ⅰ on 300, 200 hPa and region Ⅳ on 100 hPa take the second place, which shows that the impact of polar vortex area on the winter temperatures is from the region Ⅳ on 100 hPa (Europe continent) in bottom of stratosphere to the region Ⅰ on 500 hPa (Asia continent) in the troposphere. (6) The expansion of polar vortex area of region Ⅰ on 500 hPa lead to increases (decreases) the occurrence of cold day/night (warm day/night) in most of China except the northeast, while the expansion of the polar vortex area of region Ⅲ, Ⅳ on 100 hPa and region Ⅳ on 500 hPa lead to increases (decreases) the occurrence of cold day/night (warm day/night) in northern China. And the correlation between polar vortex area and occurrence of cold (warm) night is better than cold (warm) day, while the correlation between polar vortex area and cold day (night) is better than warm day (night).