1948—2004年全球平均Hadley环流强度指数与特征

Global Mean Hadley Circulation Intensity Index during 1948—2004 and Its Characteristics

利用NCEP/NCAR逐月平均风场资料,研究了全球平均Hadley环流特征。利用3层4个关键区的风定义并计算了1948年1月—2004年12月的全球纬向平均的南/北半球和全球Hadley环流逐月强度指数。结果表明:计算的Hadley环流指数可以合理地表示Hadley环流的强度;北半球Hadley环流除7—9月(南半球除5月)外都呈增强趋势;南/北半球的年平均Hadley环流也是增强的。年际相关分析表明:Hadley环流指数与SOI有非常高的负相关,Hadley环流强度的年际变化与ENSO关系密切。

The characteristic of global zonal mean Hadley circulation has been investigated by using the NCEP/NCAR monthly wind reanalysis data from 1948 to 2004. The intensity index of Hadley circulation is defined and calculated by using the 3 levels wind data in 4 key regions for the southern/northern hemisphere and the global. Results indicate that the index calculated can represent the Hadley circulation intensity reasonably. The monthly Hadley circulation indices showed an increasing trend in the northern hemisphere except for the months from July to September, in the southern hemisphere except for May. The yearly averaged indexes were both increased obviously over the southern and northern hemisphere. Interannual correlation analysis shows a significant negative correlation between Hadley circulation index and SOI. The interannual variation of Hadley circulation intensity was close related with ENSO.