珠江三角洲大暴雨的多普勒特征及形成机制

利用广州CINRAD-SA新一代多普勒天气雷达资料,结合天气形势分析,研究了华南地区夏季短时大暴雨的发生、发展过程,特别是中小尺度系统引发短时大暴雨不同发展阶段的多普勒特征以及辐合强度与短时大暴雨的关系,并对短时大暴雨的发展机制进行了初步探讨.通过分析发现,短时大暴雨产生于低空强盛西南气流等有利条件下,近地层雨区附近的气旋式扰动有利于激发对流,抽吸作用、局地锋生对对流的维持和加强起到了十分重要的作用.在短时大暴雨发生初期及发展旺盛期,大多数都伴有逆风区、辐合带等多普勒特征,中气旋更是与高强度降水、地面强风等剧烈天气密切相关.

Doppler characteristics and cause mechanism of severe torrential rain in Pearl River Delta

An overview of conditions associated with the local very - short - range torrential rains is presented, with emphasis on the initiation and development characteristics of severe rainstorm using data from a new generation of Doppler weather radar ( CINRAD - SA) in Guangzhou, combined with evolution of environmental characteristics by conventional weather observation networks, most relevant to the forecasting of torrential rains. It is focus on analysis of the Doppler character occurring in different development stage of the torrential rains induced by meso - scale weather system and the relationship between intensity of convergence and torrential rains. It is found that the severe rainstorm occurring in favorable synoptic conditions with multi - cells echo band is consistent with its moving direction. The meso -cyclonic convergence (even the meso -cyclone feature) is found in strong cell with relative long life time. The "inverse -wind region" and the local frontogenesis play an important part in convection development and maintenance.