从经向气流看亚澳季风的季节区域特征  

Seasonal and regional features of the Asian-Australian monsoon as revealed by meridional flow

作　　者：陈际龙[1] 黄荣辉[1] 

机构地区：[1]中国科学院大气物理研究所季风系统研究中心,北京100080

出　　处：《地球物理学报》2008年第1期70-76,共7页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(40705034;40575026和40725016);中国科学院知识创新工程领域前沿项目(IAP07118)资助

摘　　要：利用1979~2003年的NCEP/NCAR再分析资料探讨了亚澳季风区经向气流的季节性分支和结构特征.结果表明,亚澳季风区经向气流的垂直斜压结构由冬到夏发生季节性转向,即从冬季时的低层北风、高层南风转换为夏季时的低层南风、高层北风.季节反向的经向气流主体偏向北半球,其区域差异性在对流层中低层更为显著.以印度半岛和中南半岛为界,亚洲热带季风区中低层经向气流在冬夏季均呈现三通道特征,与此相应,亚澳季风区自西向东存在三支相对独立的经向环流分支,且冬夏季的差异均很显著,如冬季的中心高度自西向东递减、夏季的经向跨度自西向东递增等.Using the NCEP/NCAR reanalysis data for the period of 1979 - 2003, climatological characteristics of seasonal cycle and regional structure of the meridional flow associated with the Asian-Australian monsoon system are investigated. The results show that meridional flows in the Asian-Australian monsoon region display a seasonal reverse of the baroclinic structure in vertical direction, characterized by transition from low-level northerlies and high-level southerlies in boreal winter to low-level southerlies and high-level northerlies in boreal summer. The meridional flows with seasonal reverse mainly distribute over the Asian monsoon region and equatorial neighborhood, which exhibit significant regionality in the middle and lower troposphere. Consistent with three channels of meridional flows in the middle and lower troposphere over the Asian tropical monsoon region, three branches of meridional circulation are relatively independed, which are approximately divided by 75°E and 100°E and arranged from west to east in the Asian-Australian monsoon region. There are obvious differences among them in both winter and summer, such as eastward lowering of the meridional circulation center in boreal winter and eastward rising of the meridional circulation range in boreal summer.

关 键 词：亚澳季风 经向气流 季节循环 区域结构 经向环流 

分 类 号：P462[天文地球—大气科学及气象学]