夏季南海季风槽与印度季风槽的气候特征之比较

亚洲夏季风槽包括两大重要组成部分,即南海夏季风槽和印度夏季风槽.两个季风槽同属于热带夏季风系统,具有热带辐合带的性质.但由于所处地理位置、海陆分布、受到的影响系统不同等原因,两个季风槽有明显的异同点.利用气候平均资料分析,揭示南海夏季风槽和印度季风槽的结构特征和演变特征的异同点,有利于提高对亚洲夏季风系统的认识.作者首先讨论了结构特征方面的差异,从季风槽的对流特征、环流场配置特征、热力结构特征等方面探讨了两个季风槽的区别,分析结果表明南海夏季风槽和印度夏季风槽在结构特征方面区别不算很大,都具有热带季风辐合带的典型结构,低层辐合,高层辐散,有明显的季风经圈环流,热力结构特征均是低层偏冷,中高层偏暖.相对来说,印度夏季风槽比南海夏季风槽强且深厚.其次对南海夏季风槽和印度夏季风槽的演变的气候特征所进行的分析表明,季风槽建立时间与季风爆发时间是一致的.南海夏季风槽爆发早且突然,撤退缓慢,维持时间长;印度夏季风槽则是渐进式的爆发,撤退迅速,维持时间较短.两个季风槽的温湿演变特征也有所不同.

Comparison of Climate Characteristics Between Two Summer Monsoon Troughs over the South China Sea and India

The Asian summer monsoon trough consists of two major components: the South China Sea(SCS) summer monsoon trough and the Indian summer monsoon trough.Although they both belong to the tropical monsoon systems,and carry the characteristics of the tropical convergence zones,there are significant differences and similarities due to the geographic locations,land/sea,impressed systems,etc.From a climate perspective,this paper focuses on the structural similarities and differences between the South China Sea and Indian monsoon troughs,and also addresses the differences in the evolution of the troughs.First,the similarities and differences of the three dimensional configurations of the two troughs are presented.The results show there are no significant differences between these two troughs.Both carry the characterisics of the tropical convergence zones,that is,convergence in the tough area in the low layers,divergence in the high layers and monsoon vertical circulations.In regard to the thermal feature,it is cold in the trough zones in the low layers and warm in the medium and high layers.The Indian summer monsoon trough is stronger than the SCS one in most factors.Second,the climatological evolution characteristics of both troughs are analyzed.The results show that the occurrence of the summer monsoon trough is in accordance with the monsoon onset.The SCS summer monsoon trough occurs early,retreats late and maintains longer,while the Indian summer monsoon trough occurs late,retreats quickly and maintains shorter.There are also some differences in the temperature and humidity evolution process.