云南冷锋切变型暴雨的中尺度特征分析

Study on a Rainstorm and It's Mesoscale Characters Caused by Cold Front Shear in Yunnan

利用T106数值预报产品资料,通过中尺度滤波方法,提取云南冷锋切变型暴雨过程中的中尺度降水系统,对其有关物理量的特征及演变进行了分析。研究发现,通过中尺度滤波方法,可以从常规的数值预报产品资料中有效分离出直接导致暴雨的中尺度天气系统,通过对这些中尺度系统的分析及追踪,可以为暴雨预报提供更为客观的预报依据;水汽的强辐合时段与暴雨降落时段有较好的对应关系,暴雨落区比水汽的强辐合区域要稍偏向于水汽输送的下游方向;在该型暴雨的发生过程中,北部冷平流具有十分重要的作用,但南部暖平流的作用也不可忽视。

By using the T106 data and filter method, the mesoscale precipitation systems have been found, and the characters and variations of some meteorological elements also have been analyzed. It is found that by analying and tracing the mesoscale systems, the rainstorm forecasting could be more accurate. The strong convergence of moisture corresponds to the rainstorm well in time and position. We must pay attention to the southern＇warm thermal advection as well as the northern cold thermal advection in the cold front shear type rainstorm process.