东北地区冬季气温对海温异常响应的研究

利用HadISST OI海温和中国东北地区92站逐日气温资料,使用广义平衡反馈分析方法(GEFA)结合EOF分析方法(GEFA-EOF)研究了近50a中国东北地区冬季气温对海表温度异常(SSTA)的响应.结果表明:对于热带和北半球中纬度5个海盆来说,东北地区冬季气温异常与同期热带大西洋和北大西洋海温异常有密切关系,与其他海盆关系不显著;热带大西洋的"正—负—正"三极型模态(TA3)以及北大西洋纬向上"正—负—正"三极型模态(NA3)分别对东北地区冬季气温的异常偏低和偏高有显著的强迫作用,且对北部地区的强迫作用大于南部地区.热带大西洋和北大西洋对东北地区冬季气温异常影响的可能途径为:热带大西洋TA3模态通过在北半球激发的"正—负—正"的遥相关波列,致使东亚大槽移至贝加尔湖地区,有利于极地冷空气南下至东北地区,导致该地区的冷冬;北大西洋的"正—负—正"三极型模态(NA3)直接响应使得东亚大槽减弱消失,极地冷空气南下受阻,导致该地区冬季气温异常偏高.

Response of winter air temperature in Northeast China to SST anomaly

By using SST data from HadISST OI and a dataset of daily winter temperature from 92 stations in Northeast China,the relationships between Sea Surface Temperature Anomaly(SSTA) and winter air temperature in Northeast China have been studied using the Generalized Equilibrium Feedback Assessment (GEFA) method combined with the Empirical Orthogonal Function analysis (GEFA-EOF).The results show that among the five sub-basins in the tropical or northern hemisphere,winter air temperature anomaly are closely related to the synchronous SSTAs of Tropical Atlantic and North Atlantic,and have nothing to do with that of other basins.The negative and positive winter air temperature anomaly in Northeast China is strengthened by the positive-negative-positive three-pole mode of Tropical Atlantic SSTAs (TA3),and the positive-negative-positive three-pole mode of North Atlantic SSTAs (NA3),respectively,while the strengthening effect is more obvious in northern areas than in southern areas of Northeast China.The possible pathway can be explained as following,the TA3 mode stimulates the positive-negative-positive teleconnection wave train in the northern hemisphere,which results in the East Asia major trough moving to the Lake Baikal,thus facilitates the polar cold air moving south to Northeast China;while the direct response of NA3 mode of North Atlantic SSTAs weakens or even eliminates the East Asia major trough,which hinders the polar cold air from moving south and results in warm winter in Northeast China.