NCEP／NCAR再分析资料中南北半球大气质量交换的特征研究  

THE CHARACTERISTICS OF THE AIR MASS EXCHANGE BETWEEN THE NORTHERN AND SOUTHERN HEMISPHERE

作　　者：张燕[1] 黄菲[2] 宫晓庆[2] 

机构地区：[1]中国科学院南海海洋研究所,广东广州510301 [2]中国海洋大学,山东青岛266003

出　　处：《热带气象学报》2008年第1期74-80,共7页Journal of Tropical Meteorology

基　　金：国家自然科学基金(40305009);国家重点基础研究发展计划(2006CB403603);新世纪优秀人才支持计划项目(NCET-05-0591)

摘　　要：用1948～2000年共53年的NCEP/NCAR再分析资料,分析了南北半球大气质量交换的周期变化特征和两半球大气质量交换通道的空间分布。结果表明:两半球的大气质量交换从长时间来看基本上是平衡的。两半球质量交换的季节变化表现为明显的半年周期,冬季和夏季的交换比较显著,且以夏季为主;具有显著的十年际变化;年际变化特征总体来看不显著,只在1980年代～1990年代存在较为显著的2～5年的年际振荡。NCEP资料存在较大变更的三个时段(以1968、1979年为分界)的周期变化特征确实存在一定的差异。全球平均异常向南的越赤道质量输送不存在很强的季节依赖性,主要由低空北半球太平洋-大西洋副热带高压南侧东北信风和亚洲季风区对流层高层副热带高压南侧的越赤道东北气流决定,亚洲季风区冬季南下的冷空气也起到很大的作用;而异常向北的越赤道质量净输送则主要发生在夏季,主要由亚洲季风区越赤道西南季风决定,特别是索马里越赤道急流从对流层低层到高层整层的向北输送,同时对流层低层赤道中东太平洋-大西洋信风区的东南信风也有较大的贡献。The characteristics of the cross-equatorial air flows and the mass exchange between the Northern and Southern Hemispheric atmospheres are analyzed, and the way of the cross-equatorial air flows is discussed by the statistical analysis of NCEP/NCAR reanalysis data from 1948 to 2000. The mass transport between the two Hemispheres is consistent in 53 years on the whole. The results show that there is a remarkable seasonal variation with the period of six months, and the exchange mostly occur in winter and summer, especially in summer. There are distinct periods of decadal variations but interannual variations act less obviously, except for a 2-5-year oscillation in the 1980-1990s. The anomalous net mass transport to the Southern Hemisphere doesn＇t vary with the change of season but is dependent on the low-level boreal northeastern trade wind south of the Pacific and Atlantic subtropical highs and the upper-tropospheric northeastern cross-equatorial flow south of the subtropical highs over the Asian monsoon area. However, the anomalous net mass transport to the Northern Hemisphere mostly happens in the summer and is controlled by the southwestern cross-equatorial monsoon, especially by the Somali cross-equatorial jet＇s northern transport running through the whole layer from low to high levels of troposphere. At the same time, the southeastern lower-tropospheric trade wind over tropical central and eastern Pacific-Atlantic region also plays an important part.

关 键 词：两半球 大气质量交换 特征 

分 类 号：P434.5[天文地球—大气科学及气象学]