初夏东北冷涡活动异常与北半球环流低频变化  

The Anomalous Cold Vortex Activity in Northeast China during the Early Summer and the Low-frequency Variability of the Northern Hemispheric Atmosphere Circulation

作　　者：廉毅[1] 布和朝鲁[2,3] 谢作威[2] 沈柏竹 李尚锋[1] 

机构地区：[1]吉林省气象科学研究所中高纬度环流系统与东亚季风研究开放实验室,长春130062 [2]中国科学院大气物理研究所国际气候与环境科学中心,北京100029 [3]中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室,北京100029

出　　处：《大气科学》2010年第2期429-439,共11页Chinese Journal of Atmospheric Sciences

基　　金：国家科技支撑计划(2007BAC29B01;2009BAC51B04);国家自然科学基金资助项目40575047;国家自然科学基金资助项目40975033;国家自然科学基金资助项目40705036

摘　　要：本文在典型个例分析的基础上,揭示了初夏东北冷涡活动显著异常与北半球环流低频变化之间的联系及其可能机理。主要结果为:(1)初夏东北冷涡活动显著异常与上游乌拉尔山附近和下游日本附近的持续性异常环流相对应。冷涡异常多年,在向下游频散Rossby波能量和瞬变涡动强迫过程的共同作用下,乌拉尔山附近盛行阻塞型环流。它一方面使极地冷空气向东北地区移动,另一方面通过Rossby波能量的传播,使东北冷涡活动加强。冷涡异常少年的环流情况则基本相反。(2)谐波分析和低频振荡分析表明,在冷涡异常多(少)年的5～6月,东北地区正(负)涡度位相占优,这与北太平洋超长波槽西退(东进)相对应。长波在北太平洋-北美-大西洋地区呈驻波型,与Rossby波能量传播匹配,亦有利于乌拉尔山附近的异常环流得以长时间维持。(3)5月份,乌拉尔山附近的异常环流信号对初夏东北冷涡活动的显著异常具有前兆性意义。Based on the typical case analysis,the linkage between the anomalous cold vortex activity in Northeast China during the early summer and the Northern Hemisphere low-frequency variability and the possible underlying mechanism are investigated.It is shown that：（1）The anomalous cold vortex activity in Northeast China in the early summer is quite in concert with persistent circulation anomalies near the Ural Mountains and Japan.During the strong cold vortex year,the persistent blocking-type circulation around the Ural Mountains is maintained both by the Rossby wave energy dispersion and anomalous transient eddy forcing.It,on the one hand,drives the polar cold air to move toward Northeast China and,on the other hand,amplifies the cold vortex through the Rossby wave energy dispersion.For the weak cold vortex year,the situation is basically reversed.（2）It is shown in Harmonic analysis and low-frequency oscillation analysis that while the cold vortex activity is strong（weak）from May to June,positive（negative）vorticity phase prevails over Northeast China,which corresponds well to the westward shift（eastward advance）of the ultra-long wave trough over the North Pacific.The persistent anomaly circulation around the Ural Mountains is maintained by the standing waves across the North Pacific-North America-the North Atlantic,through dispersion of the Rossby wave energy.（3）The anomalous circulation around the Ural Mountains in May constitutes a precursory signal to the cold vortex activity in Northeast China in the early summer.

关 键 词：东北冷涡 低频变化 谐波分析 ROSSBY波 

分 类 号：P461[天文地球—大气科学及气象学]