基于雷达、卫星资料对河南省一次雷暴过程的地闪演变分析

Analysis of Cloud-to-Ground Lightning in a Tunderstorm in Henan Province Based on Radar and Satellite Data

利用地闪探测系统资料、多普勒雷达资料和卫星云图资料,分析了河南省一次雷暴过程的地闪特征及其与云体结构的关系,结果表明:在雷暴整个生命史中负地闪占据主导地位,占总地闪的99.5%;地闪平均强度与地闪频次存在负相关关系;初次地闪出现时雷暴强度迅速增强;40 d BZ强回波顶高、6 km高度50 dBZ强回波面积以及5 km高度之上50 dBZ强回波体积与地闪频次存在明显的正相关关系,在整个雷暴过程中的相关系数分别为0.80、0.91和0.93,而在雷暴不同发展阶段3种雷达参量与地闪频次的相关性有不同的变化趋势;地闪一般分布在6 km高度雷达回波≥40 dBZ、云顶亮温≤200 K的区域,有助于识别强对流区。

Based on the data of ground-based lightning location system,Doppler radar and satellite cloud images,the characteristics of cloud-to-ground(CG)lightning and its relationship with cloud structure in a thunderstorm process in Henan province have been studied.The results show that negative CG lightning dominates during the thunderstorm lifetime,and accounts for 99.5%of the total CG lightning.There is a negative correlation between the average intensity of CG lightning and the frequency of CG lightning.When the first CG flash appears,storm becomes stronger rapidly.It is found that the echo top height of 40 dBZ,the echo area of 50 dBZ at 6 km altitude and the echo volume of 50 d BZ above 5 km are positively correlated with CG lighting frequency.The correlation coefficients are 0.80,0.91 and 0.93 respectively in the whole process of thunderstorm,while the correlation coefficients have different trends in the different stages of the thunderstorm.CG lighting is generally distributed in areas where 6 km altitude radar echo is not less than 40 dBZ and cloud top temperature is lower than 200 K.CG lighting can well indicate or help to identify strong convective areas of a storm.