南海夏季风爆发的环流特征及指标研究

A Study of Circulation Characteristics and Index of the South China Sea Summer Monsoon

使用美国NCEP/NCAR高度场和风场资料及外逸长波辐射（OLR）资料,分析了4～7月南亚和东亚上空环流场,给出了南海夏季风爆发的定义及1953～1999年季风爆发的时间序列,指出季风爆发存在3种类型的环流场,发现东印度洋赤道两侧涡旋对的出现对季风爆发有很好的指示意义。综合季风爆发过程中热力学和动力学要素的特征,建立了适合南海夏季风爆发的指数计算经验公式。

Based on the height and wind data of NCEP/ NCAR and OLR data, patterns of upper air circulation from April to July has been analyzed, and the South China Sea (SCS) Summer Monsoon Onset (SMO) have been defined. The empirical formula fitting to the onset index of the SCS SMO has been established, and the onset time and the intensity index sequence of monsoon during 1953-1999 were given by the analysis of characteristic of thermodynamics and dynamics factors during the process of SMO. The emergence and developmenl of symmetric vorlex pair at both sides of ihe equalor in Ihe tropical East Indian Ocean, which may excite the SCS SMO, can be taken as a short-term prediclion indicalor of SMO.