地基微波辐射计遥感人工触发闪电的观测研究

REMOTE SENSING OF ARTIFICIALLY TRIGGERED LIGHTNING WITH GROUND-BASED MICROWAVE RADIOMETER

为了深入研究雷电产生的微波热辐射特征,从2016年初夏开始利用地基微波辐射计在中国气象局雷电野外科学实验基地开展了连续4年的观测实验,根据雷电热效应的特征,制定了观测方案,并为地基微波辐射计设置了“引雷观测模式”。结果表明,地基微波辐射计具有对雷电热效应产生响应的能力。2017—2019年,辐射计一共成功捕获了30次人工触发闪电,观测效率逐年增长,平均为71.4%;微波亮温脉冲幅度的最大值约125K。结合其中28次触发事件的雷电流数据,分析了亮温脉冲幅度和雷电流积分量之间的相关性,并发现了最大亮温脉冲幅度与总电流作用积分之间可能存在指数关系。根据亮温观测数据估算了雷电热效应的持续时间,平均约0.5 s,其中25次触发事件的雷电流热效应持续时间与雷电流持续时间变化较为一致,相关系数约0.73。

In order to study the characteristics of microwave thermal radiation produced by lightning,we used ground-based microwave radiometer to carry out 4-year observation experiments at the Guangzhou Field Experiment Site for Lightning Research and Testing since the early summer of 2016.According to the general characteristics of lightning heating effect,the observation scheme and the lightning observation mode are established.The results show that the ground-based microwave radiometer has the ability to respond to the lightning heating effect.From 2017 to 2019,the radiometer has successfully captured 30 artificially triggered lightning events,the observation efficiency has increased year by year,with an average of 71.4%,and the maximum amplitude of microwave brightness temperature pulse can reach about 125K.Based on the lightning current data of 28 triggered lightning events,the correlation between the brightness temperature pulse amplitude and the lightning current integral value is analyzed,and there may be an exponential relationship between the maximum brightness temperature pulse amplitude and the total current action integral.Based on the observational data of brightness temperature,the duration of lightning heating effect is estimated to be about 0.5s on average.It is found that the lightning heating effect duration of 25 triggered lightning events is consistent with the change of lightning current duration,and the correlation coefficient is about 0.73.