南京一次特大暴雨天气过程的中尺度特征

Meso-scale characteristic during the course of one heavy storm in Nanjing

分析了2007年7月7—8日南京特大暴雨天气过程的大尺度背景以及中尺度特征,发现中高纬阻塞形势的生消、冷暖气流的交汇、深厚的对流辐合场的形成等是强暴雨发生发展的主要因素。另外500 hPa中尺度流场汇合带、700 hPa中尺度扰动中心、雷暴云系、强雷达回波带以及强降水带走向相当一致,说明这次强暴雨过程具有明显的中尺度特征;发现500 hPa中尺度流场汇合带比卫星云图更能体现大范围的地闪分布,此发现对大范围的雷电预报有参考价值。

The large-scale background and meso-scale characteristic during the course of one heavy storm from July 7 to July 8 in Nanjing have been analyzed. The development of blocking pattern of middle and high latitude, confluence of warm and cold air stream, formation of deep convective convergence field and the moving of the main body of subtropical high were the main factors of that heavy storm. The confluence line of meso-scale streamline field at 500 hPa, the center of meso-scale disturbance at 700 hPa, the cloud system of thunderstorm, strong radar echo line and heavy rainfall line had the same trend, that means there＇s obvious meso-scale characteristic during that course of heavy storm. The large scale distribution of cloud-to-ground discharge could be reflected by the confluence line of meso-scale streamline field at 500 hPa better than the satellite figure.