摘要
根据1984—85年冬季欧洲中期预报中心的格点资料,采用带通滤波(30—60天)和合成分析方法研究了东亚西风急流的入口区和出口区的低频偶极子结构和亚太地区的低频涡旋活动特征。发现纬向风偶极子的低频循环伴随着东亚西风急流中心的东西摆动,在急流入口区的低频经圈环流对于纬向风振荡有重要作用。从乌拉尔经中亚到东亚存在一个西北一东南向的波列,源自乌拉尔地区的低频涡旋先是向南然后向东移动导致波列位相的转变。中太平洋地区存在一个经向波列,一对低频气旋和反气旋的逆时针打转导致该地区低频波列的转变。
The study is devoted to the structure of low-frequency dipole of the East-Asian westerly jet entrance and exit regions and to the characteristics of Asian/Pacific low-frequency vortex activities in terms of the bandpass filter for 30-60 days and composite technique and with the 1984—85 winter ECMWF grid data. Results show that the low-frequency cycle of the zonal wind dipole is accompanied by the east-west shift of the eastern Asian westerly jet core and low-frequency meridional circulation at the jet entrance is important to the oscillation in zonal wind. NW-SE wavetrain runs from Ural to mid Asia and then to East Asia and the low-frequency vortices of Ural origin travel southward and then eastward,leading to the change in phase of the wavetrain. Over the central Pacific there is a meridional wavetrain and the counterclockwise loop of the couple of cyclone and anticyclone gives rise to the change in the low-frequency wavetrain in this area.
出处
《南京气象学院学报》
CSCD
1993年第4期385-391,共7页
Journal of Nanjing Institute of Meteorology
基金
国家自然科学基金
关键词
低频
偶极子
涡旋活动
冬季
亚洲
low frequency
dipole
vortex activity
Asian/Pacific region
winter
