Variation of the East Asian Monsoon and the tropospheric biennial oscillation  

作　　者：LI ChongYin PAN Jing QUE ZhiPing 

机构地区：[1]State Key Laboratory of Numerical ModelingforAtmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics Chinese Academy of Sciences, Beijing 100029, China [2]Meteorological College, PLA University of Science and Technology, Nanjing 211101, China [3]Graduate University of Chinese Academy of Sciences, Beijing 100049, China

出　　处：《Chinese Science Bulletin》2011年第1期70-75,共6页

基　　金：supported by the National Natural Science Foundation of China (U0833602);the National Basic Research Program of China(2007CB411805 and 2010CB950400)

摘　　要：Study of the tropospheric biennial oscillation (TBO) has attracted significant interest since the 1980s.However,the mechanism that drives this process is still unclear.In the present study,ECMWF daily data were applied to evaluate variation of the East Asian monsoon and its relationship to the TBO.First,the general East Asian monsoon index (EAMI) was delineated on the basis of a selected area using the 850 hPa u and v components.This new index may describe not only the characteristics of summer monsoons,but also the features of winter monsoons,which is crucial to understand the transition process between summer and winter monsoons.The following analysis of EAMI shows that there is a close relationship between summer and winter monsoons.In general,strong East Asian winter monsoons are followed by strong East Asian summer monsoons,and weak winter monsoons lead to weak summer monsoons.While strong (weak) summer monsoons followed by weak (strong) winter monsoons form a kind of 2-year cycle,which may be the possible mechanism leading to the TBO over the East Asian region.Study of the tropospheric biennial oscillation （TBO） has attracted significant interest since the 1980s. However, the mechanism that drives this process is still unclear. In the present study, ECMWF daily data were applied to evaluate variation of the East Asian monsoon and its relationship to the TBO. First, the general East Asian monsoon index （EAMI） was delineated on the basis of a selected area using the 850 hPa u and v components. This new index may describe not only the characteristics of summer monsoons, but also the features of winter monsoons, which is crucial to understand the transition process between summer and winter monsoons. The following analysis of EAMI shows that there is a close relationship between summer and winter monsoons. In general, strong East Asian winter monsoons are followed by strong East Asian summer monsoons, and weak winter monsoons lead to weak summer monsoons. While strong （weak） summer monsoons followed by weak （strong） winter monsoons form a kind of 2-year cycle, which may be the possible mechanism leading to the TBO over the East Asian region.

关 键 词：东亚季风指数 对流层 振荡 夏季季风 中期天气预报 冬季风 面积计算 过渡过程 

分 类 号：P426[天文地球—大气科学及气象学] P421.31