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2003年z2期
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The formation process and cloud physical characteristics for a typical downburst-producing thunderstorm in Beijing
The formation process and cloud physical characteristics for a typical downburst-producing thunderstorm in Beijing
摘要
The formation process and characteristics of cloud physical structure of a severe thunderstorm accompanied with strong wind on 23 August, 2001 in Beijing was studied using PSU/NCAR mesoscale model (MM5)coupling with a severe storm model with hail-bin microphysics. The results show that the specific topography and distribution features of cold/warm current in the Beijing region played prominent roles in forming, developing and maintaining the severe storm. Due to solar radiation heating and topographic lifting, the convective cells were easily formed when the westerly airflow passed over high mountainous regions in Beijing. The warm and wet air entered the cloud from its frontage and enhanced the convection, and formed a large amount of graupel/hail particles at the middle and upper portion of the clouds. The precipitation was primarily formed due to melting of graupel/hail particles. The strong downdraft was mainly produced by negative buoyancy due to loading,melting of graupel/hail particles as well as evaporative cooling of rain water. The divergent airflow induced by the strong downdraft led to the disastrous burst winds at the surface and also forced lifting of warm and wet airflow in the moving direction of the storm and formed new clouds that further promoted and maintained the storm development.
年，卷(期)：
2003, 48(z2)
分类号：
P4
机标分类号：
R94
O61
在线出版日期：
2004年12月16日
基金项目：
(2001BA610A-06,2001BA901A41):科技部重点项目(40333033,40175001):国家自然科学基金(KZCX3-SW-213):中国科学院知识创新工程项目，
