亚澳季风各子系统气候学特征的异同研究 II.夏季风水汽输送  

The Comparison of Climatological Characteristics among Asian and Australian Monsoon Subsystems.Part II: Water Vapor Transport by 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》2007年第5期766-778,共13页Chinese Journal of Atmospheric Sciences

基　　金：国家重点基础研究发展规划项目2006CB403600;中国科学院知识创新工程领域前沿项目IAP07118

摘　　要：利用1979-2002年的ERA-40和NCEP／NCAR逐日再分析资料以及CMAP降水资料探讨了亚澳季风各夏季风子系统（南亚夏季风、东亚夏季风、北澳夏季风）水汽输送的气候学特征及其与夏季降水的关系。分析表明：各夏季风子系统水汽输送通量主要取决于低层季风气流，南亚夏季风和北澳夏季风以纬向水汽输送为主，而东亚夏季风有很强的经向水汽输送。分析也证实，亚澳季风区的夏季风降水主；要源于水汽输送的辐合，而且ERA-40资料对夏季风水汽输送辐合的描述能力强于NCEP／NCAR资料。此外，受低层季风气流结构的影响，三夏季风子系统水汽输送辐合的动力机理存在明显差异，南亚夏季风和北澳夏季风的水汽输送辐合主要由低层西风气流的风场辐合所造成，而东亚夏季风的水汽输送辐合则由低层南风气流的风场辐合和季风湿平流共同作用造成。因此，东亚夏季风降水有别于南亚夏季风降水和北澳夏季风降水。Climatological characteristics of water vapor transport associated with various summer monsoon subsystems of the Asian-Australian monsoon, i. e. , the South Asian summer monsoon （SASM） over area （0°- 25°N, 60°E-100°E） and the East Asian summer monsoon （EASM） over area （0°- 45°N, 100°E - 140°E） in boreal summer, and the North Australian summer monsoon （NASM） over area （0°- 15°S, 110°E- 150°E） in austral summer, are investigated by using the ERA-40 daily reanalysis data, the NCEP/NCAR daily reanalysis data and the Climate Prediction Center （CPC） merged precipitation estimates for the period of 1979 - 2002. Due to concentration of voluminous water vapor in the lower troposphere over tropical oceans such as the tropical Indian Ocean and the western Pacific, water vapor transport fluxes integrated vertically from earth＇s surface to the tropopause in the Asian- Australian monsoon regions mainly depend on low-level flows of these monsoon subsystems. Since westerly flow prevails in the lower layers of the SASM and NASM subsystems, positive zonal water vapor transport, i. e. , eastward water vapor transport from the west, is major in the SASM and NASM regions. But the southerly flow prevails in the lower layers of the EASM subsystem, positive meridional water vapor transport, i. e. , northward water vapor transport from the south, is significant in the EASM regiorL Moreover, the analysis results also show that the monsoon rainfall in the SASM, NASM and EASM regions is mainly caused by the moisture flux convergence which can be better described by the ERA-40 reanalysis data than the NCEP/NCAR reanalysis data. Besides, it can be seen clearly that there are obvious differences in the dynamical mechanism of the moisture flux convergence among SASM, EASM and NASM subsystems, which is controlled by summer wind structure in various monsoon regions. The moisture flux convergence in the SASM and NASM regions is maily due to the convergence of low-level wester ly, but that in the EASM regio

关 键 词：南亚夏季风 东亚夏季风 北澳夏季风 水汽输送 季风降水 

分 类 号：P425[天文地球—大气科学及气象学]