中文摘要：

南海夏季风爆发的重要特征之一是标志着中国雨季的开始。准确预测南海夏季风的爆发时间对中国的降水预报具有重要参考意义。目前国内外大多采用南海低层850hPa高度区域动力学和热力学方法来判断南海夏季风爆发时间，这种判断方法具有普遍适用性，但在南海夏季风爆发期间，受台风（或热带低压系统）和副热带高压异常位置的影响，利用低层区域动力学和热力学方法来确定南海夏季风爆发时间似乎略显不足。综合大气环流方法和副热带高压异常变化特征分析等方法，客观确定了2012年南海夏季风爆发时间，为2012年我国汛期降水特点提供参考依据。最后简单回顾了采用印度洋海气热通量预测南海夏季风爆发时间的可行性，为南海夏季风爆发时间的深入研究及其机理探讨提供了又一新的途径和方法。

英文摘要：

The onset of the South China Sea summer monsoon （SCSSM） indicates the beginning of the rainy season in China. So the exact forecast of the onset of SCSSM is very important to the prediction of the precipitation of China. The method using regional dynamics and thermodynamics of the South China Sea at lower 850 hPa to judge the onset time of the SCSSM is common at home and abroad so far. It is a method of universal applicability. Under the influence of typhoon（or tropical low pressure system）and the abnormal position of subtropical high pressure during the SCSSM, this method seems to be insufficient. In this paper, the authors objectively determined the onset time of the SCSSM in 2012 that was first pentad in June by using atmospheric circulation method and analysis of subtropical high abnormal variation characteristics and so on. Lastly, we briefly overviewed the feasibility of using the Indian Ocean air-sea heat flux to predict the onset time of SCSSM,which is a new way and method for the further study and the mechanism discussion of the onset time of the SCSSM.