亚澳季风各子系统气候学特征的异同研究 I.夏季风流场结构  

The Comparison of Climatological Characteristics Among Asian and Australian Monsoon Subsystems.Part I.The Wind Structure of Summer Monsoon

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：《大气科学》2006年第6期1091-1102,共12页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学重点基金项目40231005;国家重点基础研究发展规划项目2006CB403600

摘　　要：利用1979-2003年的NCEP／NCAR再分析资料探讨了亚澳季风各夏季风子系统（南亚夏季风、东业复季风、北澳夏季风）流场结构及其季节演变的气候学特征。结果表明：南亚夏季风和北澳夏季风纯属热带季风，盛行纬向气流和纬向风垂直正切变，即低层西风、高层东风，但北澳夏季风的强度明显弱于南亚夏季风，而东亚夏季风由热带季风和副热带季风组成，盛行经向气流和经向风垂直正切变，即低层南风、高层北风，且纬向气流高低层配置相对复杂，相对北澳夏季风而言，南亚夏季风的低层西风强而深厚，而东亚夏季风的低层南风强而深厚。从热带季风区流场结构的季节演变过程看，这三个夏季风子系统均为垂直斜压结构。三者的共性还表现在热带季风区纬向气流高低层配置的季节性转向，即夏季风爆发时从低层东风、高层西风转换为低层西风、高层东风，夏季风撤退时从低层西风、高层东风转换为低层东风、高层西风。此外，南亚夏季风的季内变化平稳，而东亚夏季风和北澳夏季风的季内变化剧烈；东亚夏季风的经向跨度大、维持时间最长，而北澳夏季风的经向跨度小、维持时间最短。Using the NCEP/NCAR reanalysis data from 1979 to 2003, climatological characteristics of the wind structure and its seasonal evolution associated with various summer monsoon subsystems of the Asian-Australian monsoon, i. e. , the South Asian summer monsoon （SASM） over the area （0°- 25°N, 60°E- 100°E） and the East Asian summer monsoon （EASM） over the area （0°- 45°N, 100°E- 140°E） in boreal summer, and the North Australian summer monsoon （NASM） over the area （0°- 15°S, 110°E- 150°E） in austral summer, are respectively investigated in this study. The results show that both SASM and NASM purely belong to the tropical summer monsoons with strong zonal flow and vertical westerly shear, i. e. , low-level westerlies and high-level easterlies, and vertical westerly shear in the SASM region is distinctly stronger than that in the NASM region. EASM is composed of the tropical and subtropical summer monsoons with significant meridional flow and vertical southerly shear, i. e. , low-level southerlies and high-level northerlies, but the vertical structure of zonal flow in the EASM region is complex, including the vertical westerly shear in the tropical monsoon region to the south of 25°N such as the South China Sea （SCS） and the western Pacific and the vertical easterly shear in the subtropical monsoon region to the north of 25°N such as the mainland of China and South Japan. As compared with zonal or meridional flow in the NASM region, low-level westerlies in the SASM region and low-level southerlies in the EASM region are strong and profound. Totally, both SASM and NASM act as the latitudinal monsoon system but EASM mainly acts as the longitu- dinal monsoon system. Moreover, these analyses also reveal that the common features of these summer monsoon subsystems lie in seasonal reverse of the baroclinic structure of zonal flows in the tropical monsoon region, characterized by a wind switch from low-level easterlies and high-level westerlies to low-level westerlies and high-level easter

关 键 词：南亚夏季风 东亚夏季风 北澳夏季风 流场结构 季节演变 

分 类 号：P425[天文地球—大气科学及气象学]