欧亚遥相关型位相变化对我国寒潮路径的影响

The effects of phase changes in Eurasian teleconnections on the tracks of the cold wave in China

利用1965—2015年冬半年NCEP/NCAR再分析资料以及中国地面气候资料日值数据集,借助FMM算法对影响我国的寒潮路径进行聚类分析,得到四类主要移动路径;并通过统计分析探讨欧亚遥相关型(EU)活跃位相与我国寒潮发生频次的关系及对路径选择的影响。结果表明:EU处于正位相活跃年时,寒潮活动增多,经向环流增强,冷空气干冷,第二类北路型寒潮频次和强寒潮事件相对增多;EU处于负位相活跃年时,纬向环流增强,冷空气湿润,第三类西北型寒潮频次相对增多,与第四类西路型寒潮的强寒潮事件增加。

On the basis of NCEP/NCAR reanalysis data and daily surface climate data for China from 1965 to 2015,the finite-mixed-model-based clustering algorithms were utilized to group tracks of cold wave intrusion over China.A statistical analysis was conducted on the relationship between the active variation of the Eurasian teleconnection pattern(EU)and the frequency of cold waves in China.In addition,the pattern variation probably affects the selection of tracks of cold waves.According to the results,total cold waves had increased relatively,meridional circulation tended to be enhanced,and cold air moved southward;this typical circulation pattern led to more times of total and strong cold waves events for Cluster-2 of north tracks during a positive EU winter.Contrary to this,in the negative EU phase,zonal circulation had increased relatively with the advent of moist cold air,and there was a higher frequency of strong cold waves events within Cluster-3 and Cluster-4.