【作者】 薛根元； 陈丽芳； 诸晓明；

【Author】 XUE Gen-yuan1, Chen Li-fang2,ZHU Xiao-ming3 (1.Meteorological Bureau of Zhejiang Province, Hangzhou, 310002; 2.Meteorological Bureau of Hangzhou City in Zhejiang Province , 310002 ; 3.Meteorological Bureau of Shaoxing City in Zhejiang Province, Shaoxing 312000)

【机构】 浙江省气象局； 浙江省杭州市气象台； 浙江省绍兴市气象台；

【摘要】 在对发生于2004年5月底华南前汛期一次大暴雨过程的环流背景分析基础上,应用中尺度数值模式,重点研究了形成大暴雨的中小尺度系统演变的物理机制与环境场条件,得到的主要结论有:前汛期的锋面同时兼有温度和湿度梯度;东北至日本海有较深的冷槽,长江中游有低涡生成发展,并与暖切变相联,有利于中尺度系统不断生成;深厚的中低层辐合层和较高的无辐散层为飑线产生提供了有利的上升运动条件,与中空槽相伴的强风核处于槽底以西,槽前强辐合成为飑线产生的关键;除孟加拉湾主要提供暴雨产生的水汽外,西太平洋和南海也向华南至江南地区输送水汽;夏季风强盛和副高加强导致雨带位置偏北;暴雨对于水汽的敏感性要早于涡度、散度、垂直速度等物理参数。更多还原

【Abstract】 After diagnosing and analyzing the heavy rainstorm occurring on 30 May,2004,which is infrequent when the rain belt moves towards the north in the pre-flood season in the southern China through the meteorological dynamics, the mesoscale numerical simulation method is applied to analyze the heavy rainstorm torrential rain. By researching the macro-scale circumfluence and the meso- and mini-scale system’s physical mechanism and the environment condition, the main results are obtained. The front of the pre-flood season has the gradients of temperature and humidity at the same time. There was the deeper and cold trough from the northwestern China to the Japan Sea. The low vortex develops in the middle reaches of the Yangtze River and it is also related with the warm shear-line , which is in favor of forming the mesoscale system. The thick non-divergence level and the convergence in the medium-level offers the advantageous conditions to the birth of squall line. The core of the strong wind locates to the west of the hollow trough which makes the convergence in front of the trough, which is the key to generate the squall line. The Bangladesh Gulf ,the West Pacific and South China Sea are all the sources of the water vapor which makes such the heavy rainstorm. The strong summer wind and the enhancement of the subtropical high pressure leads to the rain belt locating partial north. The occurrence of the sensitivity of water vapor to the torrential rain is ahead of the vorticity , divergence and the vertical speed, et al.更多还原