【摘要】 利用 3维强风暴冰雹分档模式 (IPA- HBM)对 2 0 0 1年 8月 2 3日北京的一次伴有大风、暴雨和冰雹的强对流天气过程进行模拟和分析 ,并与部分观测资料进行了比较分析。结果表明 ,该模式对此次强风暴的生命史、降水分布、降雹的大小等要素做了较好的模拟 ,并能够模拟出伴随强风暴过程所产生的强下沉气流和及地面强风速切变 (下击暴流 )。从云微物理学角度分析了此次局地性大风的形成原因 ,认为由高空冰雹粒子的拖曳产生的负浮力作用是促发强下沉气流产生的主要原因 ,其次是冰雹的融化和雨水蒸发冷却对下沉气流起加速作用 ,冰雹的拖曳和融化作用对下沉气流具有决定性作用。强风暴所产生的爆发性强下沉气流最终导致了局地大风的形成更多还原

【Abstract】 A severe convective storm accompanied with strong wind,heavy rain and hail on 23 August 2001 in Beijing was simulated by a three dimensional cloud model,and was compared with the observed data.It showed that this model could simulate the characteristics of the severe storm such as life cycle,rainfall distribution and hail size,and also could simulate the strong downdraft and wind shear(downburst).The mechanism of the downburst formation was analyzied based on the cloud microphysics of the simulated storm and it was found that this downburst was primarily promoted by negative buoyancy which is produced by the trailing of hail in upair,and also enhanced by cooling resulted from hail melting and rain evaporation.And the trailing and melting of hail played a decisive role in producing the downburst,while the gale was caused by the severe downburst.更多还原