2011年7月2日宁夏局地大到暴雨诊断分析

Diagnostic analysis of a local heavy rain in Ningxia on July 2,2011

利用MICAPS(气象信息综合分析处理系统)所提供的常规资料、数值预报产品和天气雷达图资料,对2011年7月2日宁夏的一次局地大到暴雨天气过程进行诊断分析.结果表明,高空"东高西低"形势的建立为大到暴雨提供了有利的环境场,高低空急流的耦合,使得冷暖空气剧烈交绥造成该次强降水过程,大气不稳定指数的变化和θse的分布反映了大气的层结状态和不稳定能量积聚的状况;蒙古冷高压南压触发了不稳定能量,释放产生了局地大到暴雨天气,低空急流直接输送水汽和能量.低涡、切变线低层辐合、高层辐散的结构及位势不稳定特征为大到暴雨区强烈上升运动的发展和维持提供了有利的环境条件.

Using the conventional data and numerical weather forecast products provided by MICAPS（comprehensive analysis of weather information processing system）,with information on the radar map a local heavy rain in Ningxia on July 2,2011was studied.The results show that established situation of the east high west low in the upper-level provided favorable environment for the heavy rain.Coupling of jets in the upper and lower levels caused rainfall by making the warm and coldair mingle strongly.The changes of atmosphere instability index and the distribution of θse reflected the state of atmospheric stratification and the situation of instable energy accumulation;cold high pressure in Mongolia made the instable energy released to cause local heavy rainfall by moving south.Low-level jet transport vapor and energy directly.Vortex,shear line,convergence in low-level and divergence in high-level and the characteristics of potential instability provide favorable environment for the development and maintenance of strong upward motion in rainfall areas.