上游赤道西风在南海夏季风暴发中的重要作用

谢安; 刘霞; 叶谦

上游赤道西风在南海夏季风暴发中的重要作用

1.
北京大学地球物理系，国家气象中心

资助项目:

国家教委留学回国人员科研启动基金

详细信息

中图分类号: P425.42 P732.3
计量
- 摘要浏览量: 3316
- HTML全文浏览量: 153
- PDF下载量: 1197
- 被引次数: 0
出版历程
- 刊出日期: 1998-05-31

The Role of Upstream Equatorial Westerly Wind in the Summer Monsoon Onset over the South China Sea

Xie An,

1.
1) (Department of Geophysics, Peking University, Beijing 100871); 2) (National Meteorological Center, CMA, Beijing 100081); 3) (CIRES/NOAA, University of Colorado, Boulder, CO 80309–0449, USA)

摘要

摘要: 利用17年（1979～1995）的NMC全球格点分析资料及从NOAA极轨卫星观测的地球向外长波辐射（OLR）资料，研究了南海夏季风暴发的年际变化特征。用本文的定义标准，南海季风从1979年到1995年间暴发的平均日期是5月第4候。南海夏季风暴发前后，南海周围地区对夏季风暴发的直接影响来自南海上游70°～90°E的赤道西风的加强和北抬东伸，同时索马里越赤道气流的加强和阿拉伯海高压在海上消失通过影响赤道西风也间接影响到南海。其中阿拉伯海反气旋的消失可能是南海夏季风暴发的一个重要信号。南海夏季风暴发的年际变化较
- 南海夏季风;
- 赤道西风;
- 阿拉伯海反气旋
Abstract: Interannual variation of summer monsoon onset over the South China Sea (SCS) were studied based on the seventeen years (1979~1995) NMC global analysis data and Outgoing Longwave Radiation (OLR) data observed from NOAA polar-orbit satellites. Based on the criteria defind in this paper for the SCS summer monsoon onset, the average onset date from 1979 to 1995 was around the fourth pentad of May. During the SCS monsoon onset, the most direct impact from the vicinity of the SCS is the equatorial westerly winds in the Indian ocean through their eastward extension and northward movement. Meanwhile, there are also indirect impact of the enhancement of the Somali cross-equatorial flow and the vanishing of the Ariabian high at sea, which change the equatorial westerly winds, in the SCS onset. There are quite significant interannual variation in the SCS onset. It is shown that the impact of the equatorial westerly winds in the Indian ocean on the SCS summer monsoon onset and its interannual variation is very important. It has also been found that the interannual variation of the SCS onset are closely related with the ENSO events.
- SCS summer monsoon;
- Equatorial westerly winds;
- Ariabian high