谢安,刘霞,YeQian. 1997. 赤道涡旋与南海夏季风爆发[J]. 气象学报, 55(5):611-619, doi:10.11676/qxxb1997.059
赤道涡旋与南海夏季风爆发
EQUATORIAL VORTEX AND THE ONSET OF SUMMER MONSOON OVER SOUTH CHINA SEA
投稿时间:1995-09-18  修订日期:1996-06-18
DOI:10.11676/qxxb1997.059
中文关键词:  南海夏季风爆发  赤道涡旋  东亚爆发涡  105°  E越赤道气流
英文关键词:Summer monsoon onset in the South China Sea  Equatorial vortex  East Asian onset vortex  Cross-equatorial flows at 105°  E
基金项目:中国气象局“季风”课题
作者单位
谢安 北京大学地球物理系暴雨监测和预测国家实验室, 北京, 100871 
刘霞 北京大学地球物理系暴雨监测和预测国家实验室, 北京, 100871 
YeQian CIRES, University of Colorado, Boulder, CO 80309, USA 
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中文摘要:
      文中应用1979-1995年共17a的850hPa风场资料和NOAA卫星的OLR资料,分析了南海夏季风爆发的特征。证实南海夏季风爆发,落后于同纬度的中南半岛和菲律宾岛屿地区。但在南海的东部和西部,季风爆发几乎是同时的,具有某种驻波的特征。文中还证实,大多数年份的4,5月间在105°E附近有赤道涡旋形成,这个涡旋引导它上游的赤道西风或南半球西风进入南海南部,为南海的季风爆发创造有利条件。这种涡旋不活跃的年份,季风爆发往往偏晚。它们之间可能存在某种联系。4月中旬,这个涡旋的形成和105°E越赤道气流的初步建立是同时的。进入5月份,这支越赤道气流逐渐加强。南海夏季风的活动与这支气流可能关系密切。如果称位于105°E附近的赤道涡旋为东亚的爆发涡旋,它显然与南亚季风的情况有较大差别。南亚的爆发涡旋与季风爆发的关系是直接的,而在东亚,则是间接的,这也说明了东亚季风比南亚季风更具有复杂性。
英文摘要:
      The characteristics of summer monsoon onset in the South China Sea (SCS) were investigated based on 17 years (1979-1995) NMC wind data and OLR data from NOAA. It is proved that the onset of summer monsoon occurs later in SCS region than in Indo-China peninsula and island areas of Philippines. But the summer monsoon in the eastern part of SCS onsets almost at the same time as that in the western part of SCS. This simultaneity has somewhat standing wave feature. It is also confirmed that in most years there is a equatorial vortex forming near 105°E in April or May and the vortex leads the equatorial westerly in its upper reaches and the westerly in the Southern Hemi-sphere to the southern part of SCS. This creats a favorable condition for onset of the SCS summer monsoon. In the years when the equatorial vortex is unactive, the summer monsoon in the SCS onsets late. There is some relationship between the equatorial vortex and the onset date of SCS summer monsoon. Inearly April, the forming of the vortex and the preliminary building of cross-equatorial flows at 105°E is simult aneous. In May, these cross-equatorial flows enhance gradually and the activity of SCS summer monsoon may be closely associated with these flows. If the 105°E equatorial vortex is called onset vortex of East Asia, it is sure that this vortex is different from that of South Asia. In South Asia the onset vortex relates with monsoon onset directly, but in East Asia it does indirectly. So this also shows that East Asia Monsoon is more complicated than Indian Monsoon.
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