Statistical characteristics of the double ridges of subtropical high in the Northern Hemisphere

作     者：ZHAN Ruifen1,2,3, LI Jianping1 & HE Jinhai2 1. State Key Laboratory of Numerical Modeling for Atmospheric Sci- ences and Geophysical Fluid Dynamics (LASG), Institute of Atmos- pheric Physics, Chinese Academy of Sciences, Beijing 100029, China 2. Department of Atmospheric Sciences, Institute of Meteorology, Nan- jing University of Information Science and Technology, Nanjing 210044, China 3. Graduate School of the Chinese Academy of Sciences, Beijing 100039, China 

出 版 物：《Science Bulletin》 (科学通报(英文版))

年 卷 期：2005年第20期

页      面：82-87页

学科分类：07[理学] 070601[理学-气象学] 0706[理学-大气科学] 

主　　题：subtropical high double ridges statistical characteristics meridional movement. 

摘      要：The generality and some climatological charac- teristics of the double ridge systems of subtropical high (SH) are investigated statistically by using the daily NCEP/NCAR reanalysis data from 1958 to 1998. The results show that the SH double-ridge event is a common phenomenon in the Northern Hemisphere, with the distinct seasonal and re- gional features, that is, the majority of SH double-ridge geneses concentrate over the eastern North India Ocean- western North Pacific as well as the central North Pacific in the period from mid-July to mid-September. Especially over the western North Pacific subtropics, the SH double-ridge events are extremely active. It is found that the life cycle of most double-ridge events of western Pacific subtropical high (WPSH) is shorter but some still last longer. The WPSH dou- ble-ridge events occur most frequently from July to Septem- ber, while there is a paucity of occurrences during Novem- ber-March. Also, it is shown that the WPSH double-ridge events have a strong interannual variation with a certain periodicity which possesses a remarkably abrupt change in the mid-1970s. Additionally, the relationship between the WPSH double ridges and the meridional movement of WPSH is discussed.