一次冰雹天气强对流(雹)云演变及超级单体结构的个例模拟研究

A Numerical Case Study on the Evolution of Hail Cloud and the Three-Dimensional Structure of Supercell

利用WRF中尺度数值模式,模拟了2005年5月31日发生在北京的冰雹强对流过程,成功地再现了冰雹天气发展过程中起重要作用的冷涡底部的小槽、低层暖湿舌、地形辐合线等中尺度系统;模拟的地面降水、强对流(雹)云移动路径与实况基本符合;模拟的一个长生命史强对流(雹)云的演变及单体结构与北京多普勒雷达观测的沿城市中轴线的雹云相似,具有超级单体概念模型给出回波墙—有界弱回波区(穹窿)—悬挂回波结构、对峙的倾斜上升下沉气流、分裂右移发展等特征。基于数值模拟结果,结合雷达观测,重点分析了这块雹云的演变过程,解剖了超级单体三维动力、热力及回波结构。

A severe hailstorm occurred in Beijing on 31 May 2005 are simulated using a high resolution mesoscale numerical model WRF（Weather Research and Forecast）. The results show that the main characteristic of case are successfully simulated, it is well reproduced from synoptic scale system to convective cell, the simulated trough on the bottom of cold vortex, the worm moisture tongue, the topographic flow convergence line, the accumulated precipitation, the evolution of the hail cloud and the convective cell structure are consistent with observation. The supercell plays a key role in hailstorm case. So the research on the formation, structure and evolution of supercell are very important. The simulated a long-lived hailstorm has a supercell and the structure of the supercell has features common to supercellular conception model, such as bounded weak echo, spliting, right moving and one giant pair of slantwise updraft and downdraft. We put emphasis on the evolution of this supercellular hailstorm cloud and the three-dimensional reflectivity and flow structure of the supercell. The intent is to understand the three-dimensional structure of supercell in our country＇s hail case, and the intent is to learn what structural factors of this supercell case allow hailstorm to be long-lived.