2008年初我国南方雨雪低温天气的中期过程分析--Ⅲ：青藏高原-孟加拉湾气压槽  

On the Medium-Range Process of the Rainy,Snowy and Cold Weather of South China in Early 2008 Part Ⅲ:Pressure Trough over the Tibetan Plateau/Bay of Bengal

作　　者：纪立人[1] 布和朝鲁[1] 施宁[2] 谢作威[1] 

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446-458,共13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;国家重点基础研究发展规划项目2006CB403601

摘　　要：针对2008年1月24日～2月2日我国南方地区雨雪低温过程,分析了其中期演变特征及其可能机理。在亚非副热带地区,Rossby波能量从北非东北侧传播到东亚地区,引起青藏高原附近气压槽的加深和西太平洋副热带高压的加强及北扩,并与亚洲北部的高压脊配合,造成了这次较长时间的雨雪低温过程。东北大西洋和西欧的反气旋式异常环流为亚非副热带急流Rossby波与欧亚高纬度Rossby波活动的主要波源区。在对流层上层,贝加尔湖一带的高压脊在过程之前已形成,而在这次过程中缓慢减弱,来自上游Rossby波能量主要起抵消摩擦耗散的作用。西太平洋副热带高压在偏北位置上维持主要由来自青藏高原和孟加拉湾地区Ross-by波能量的注入所致。亚洲冷高压系统的强度、位置及形态决定了这次我国南方地区低温过程的重要特性。This study is aimed at the medium-range evolution features and possible mechanism of the rainy,snowy and cold weather of South China during January 24 to February 2,2008.In the Asian-African subtropical area,Rossby wave packet emanating from northeast Africa propagates to East Asia.Consequently,it results in the deepening of pressure trough around the Tibetan Plateau/Bay of Bengal as well as the enhancement and northward expansion of western Pacific subtropical high.Cooperating with the invasion of the North Asian high ridge,the trough and subtropical high finally caused a persistent snowy and cold weather process.The anticyclonic anomaly circulations over the northeastern Atlantic/West Europe facilitate a primary wave source for Rossby wave activities both in the subtropical and the mid-and high-latitude region.In the upper troposphere,the high ridge over the Lake Baikal has been formed previously and gradually diminishes during this period.Therefore,the Rossby wave energy replenishment from the upstream mainly counteract against its frictional dissipation.The maintenance of western Pacific subtropical high in its northward position could be mainly attributed to the Rossby wave energy from Tibetan Plateau/Bay of Bengal.The strength,location,and shape of the Asian cold high are responsible for the key features of the low-temperature process.

关 键 词：雨雪低温过程 ROSSBY波 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]