【摘要】 利用NCEP/NCAR 1950—2002年500 hPa月平均再分析高度场资料计算出北半球及各分区的月平均极涡面积、强度,讨论了它们与我国气温的相关。结果表明:北半球500 hPa年平均和4季的极涡面积大小与我国多数站点同期气温呈负相关,尤其在年平均及冬季状况下最显著,1—12月极涡面积与气温的负相关呈由减弱到增强的变化趋势;而极涡强度与我国同期气温的相关性相对较弱,在秋冬季不少地区出现正相关,1—12月极涡强度与气温负相关性的变化趋势是由增强到减弱。利用奇异值分解研究极涡对后期我国气温的影响后发现,极涡指数与后期我国气温呈负相关,但不同季节差异较大。当冬季Ⅳ区极涡面积显著缩小、北半球极涡总强度明显增强时,长江中下游以北及东北地区下一年春季气温通常上升;春季Ⅰ区极涡面积、强度异常偏大,则夏季华南沿海、西南及河套地区气温比常年偏低;若春季北半球极涡强度减弱、夏季亚洲区极涡面积收缩,则其后的秋季华北气温相对较高。更多还原

【Abstract】 The area size and intensity of 500hPa north polar vortex and four quadrants are estimated from 1950 to 2002 based upon the 53-year NCEP/NCAR reanalysis monthly mean geopotential height data.The relationship between the polar vortex and air temperature in China is analysed.Results show that there is a negative correlation between the annual and seasonal areas of polar vortex and the air temperature in the same period,especially for year and winter,and from January to December,the above negative correlation has a trend from weakening to strengthening.The association of the air temperature with the intensity of polar vortex is not so strong as with area,in autumn and winter the positive correlation occurres over some regions,and from January to December,the negative correlation shows an opposite trend from strengthening to weakening.Finally,the influence of polar vortex on the subsequent air temperature in China is discussed by using SVD.It is found that the polar vortex has negative effect on the subsequent air temperature,but there is some difference in different seasons.For example,if the vortex in region Ⅳ shrinks anomalously in winter and the intensity of north polar vortex remarkably strengthens,the next spring air temperature will become higher in Northeast China and the area north of the mid-and low-reaches of the Yangtze River.When the size and intensity of the vortex in region Ⅰ are anomalously large in spring,summer air temperature will be lower than normal in Southwest China,the coast area of South China,and the Hetao region.Prominent weakening of the north polar vortex in spring and remarkable shrinking of the vortex over region Ⅰ in summer lead to the rising of autumn air temperature in South China.更多还原