A Study of Circulation Characteristics and Index of the South China Sea Summer Monsoon
南海夏季风爆发的环流特征及指标研究

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.