2008年初我国南方雨雪低温天气的中期过程分析--Ⅰ：亚非副热带急流低频波  

On the Medium-Range Process of the Rainy,Snowy and Cold Weather of South China in Early 2008 Part Ⅰ:Low-Frequency Waves Embedded in the Asian-African Subtropical Jet

作　　者：布和朝鲁[1] 纪立人[1] 施宁[2] 

机构地区：[1]中国科学院大气物理研究所灾害性气候研究与预测中心 [2]南京信息工程大学大气科学学院,南京210044

出　　处：《气候与环境研究》2008年第4期419-433,共15页Climatic and Environmental Research

基　　金：中国科学院大气物理研究所创新基金领域前沿项目IAP07120;国家重点基础研究规划项目2006CB403601

摘　　要：在中期时间尺度上分析了2008年1月10～16日我国南方雨雪过程特征及其可能机理,得到了以下结果：1）3个环流系统的演变过程相互匹配,共同造成了此次雨雪过程,它们分别为南支槽在我国南方地区的形成和加深、西太平洋副热带高压的北扩以及叶尼塞地区高压脊的东扩南侵;2）源自东北大西洋和西欧的Rossby波能量沿亚非副热带急流向下游传播,导致南支槽在我国南方地区形成和加深;3）与西太平洋副热带高压北扩所对应的异常环流中心,其实质为副热带急流扰动,来自上游南支槽区的Rossby波能量频散是其形成维持的主要原因,它也受来自贝加尔湖地区及热带西太平洋对流区的Rossby波能量的影响;4）亚非副热带纬向基本流制约着其一系列异常环流中心的纬向联系,里海冷堆及异常中心的形成恰好对应着南支槽在我国南方地区的加深和西太平洋副热带高压的北扩。The characteristics and possible mechanism of the snowy and rainy weather process of South China from January 10 to January 16 in 2008 are studied on the medium-range time scale.It is shown that： 1） The snowy and rainy weather is primarily caused by the formation and deepening of the southern branch trough of westlies over South China,the northward expansion of the western Pacific subtropical high,and the eastward expansion and southward invasion of the Yenisey high,in which the collaboration of these three evolution process is crucial;2） Rossby wave energy originated from the northeast Atlantic propagates along the Asian-African subtropical jet and finally leads to the formation and deepening of the southern branch trough over South China.3） The nature of the anomaly center corresponding to the northward expansion of the western Pacific subtropical high is a low-frequency disturbance of the subtropical jet.It is primarily maintained by the Rossby wave energy coming from the upstream southern trough.In addition,Rossby wave packets from Lake Baikal as well as the tropical western Pacific also play an important role for its formation and maintenance.4） The zonal basic flow of Asian-African subtropical band determines the zonal phase-relationship of several anomaly centers embedded in the subtropical westerly band.The formation of the anomaly center associated with the cold dome at the Caspian Sea exactly corresponds to the deepening of southern branch trough over South China and the northward expansion of the western Pacific subtropical high.

关 键 词：副热带急流 ROSSBY波 南支槽 西太平洋副热带高压 

分 类 号：P448[天文地球—大气科学及气象学]