两次大暴雨的新一代雷达产品和闪电特征分析

Character Analysis on CIN Radar Products and Lightning of Two Heavy Rainstorm

应用新一代雷达产品、闪电监测定位资料等对2007年河南省郑州、信阳两次突发大暴雨过程进行了对比分析。结果表明:高空冷涡后部的冷空气和副热带高压西北侧的暖湿气流在信阳地区交绥是信阳暴雨产生的主要原因,锋前暖区暖平流使地面出现热低压产生辐合,从而激发局地强对流是郑州暴雨产生的主要原因;地面冷锋是两次突发暴雨的触发机制,信阳、郑州均处于中尺度辐合线上强辐合上升运动处。从闪电参数看,信阳暴雨过程全部为负闪,郑州暴雨过程正闪比例为39%,且闪电总频次明显高于信阳。郑州暴雨是由快速发展的块状单体回波造成,信阳暴雨是由混合降水回波持续造成。新一代雷达平均径向速度特征对突发暴雨有很好的指示意义,分析径向速度图对提前发布暴雨预警信号有一定的参考价值。

The two abrupt heavy rainstorm processes were contrastively analyzed in detail between Zhengzhou and Xinyang in Henan province in 2007 using the CIN radar products and lightning monitor location data. The results indicated： the main cause of heavy rain in Xinyang is the convergence of the cold advection under the cold vortex and the warm-humid flow of the subtropical high belt northwest. Warm advection in the warm sector before the front made the ground produce thermal low pressure, which resulted in local severe convection in Zhengzhou. The surface cold front was trigger mechanism for this two abrupt heavy rain; Xinyang and Zhengzhou laid in the strong convergence ascending area on mesoscale convergence lines. From the lightning parameters compared to the Xinyang, the heavy rain processes in Xinyang were all negative lightning while the ratio of positive was 39% of Zhengzhou and the total lightning was higher obviously than Xinyang. The rainstorm in Zhengzhou was caused by the rapid single echo and the heavy rain in Xinyang was caused by the mixed precipitation echo. The new generation radar average radial velocity characteristic has good instruction significance to the abrupt rainstorm. The radial velocity chart analysis has some reference value for issuing rainstorm early warning signal in advance.