Lightning Special Waveform Analysis And Preliminary Discussion On Associated Lightning

Narrow Bipolar Events(NBEs)and Regular Pulse Bursts(RPBs)are special lightning discharge processes in the atmosphere.In recent years,high-precision detection techniques promotes the understanding of the discharge process of special lightning processes developed at home and abroad greatly.Based on the previous researches and the higher precision waveform data,the NBEs automatic recognition is carried out with more parameters,which improves the reliability of NBEs automatic recognition.The waveform characteristics of NBEs and RPBs are analyzed and discussed,and the characteristics of special waveforms are enhanced.The basic two-cell thunderstorm electric field environment was simulated by using the mathematical physical model of Electrically Active Cells(EACs),Based on this,the interaction between the subsequent discharges and the discharge between different discharge cells was discussed,enhanced understanding of associated lightning.The main findings are as follows:Firstly,the waveform characteristics of NBEs are analyzed and introduced in detail from the NBEs automatic identification principle,feature parameter statistics and comparative analysis.The NBEs identification scheme designed in this paper adopts 9 parameters such as high-frequency amplitude ratio as the identification criterion of NBEs.67 cases were screened out narrow bipolar pulse,11 cases NBEs event occurs due to failure to effectively identify the position farther away from the station,the recognition rate is 87.01%,and the false recognition rate is 1.49%.On this basis,the statistical analysis of the identified NBEs shows that the rising edge of the NBEs waveform is 1.75?s,the falling edge is 2.80?s,the half-peak width is 2.35?s,the full peak width is 4.55?s,and the duration is 8.89?s.When NBEs occurs,there is no other discharge process in the first 1ms,indicating that the forward isolation of NBEs is good.And it has a good consistency with the results of previous studies.By handling lightning discharge waves in 15 min,it is found that 83% of lightning discharges are accompanied by Regular Pulse Bursts(RPBs).The 430 RPBs statistics during this period indicate that in these RPBs,the typical pulse width is about 1.0 ?s,the typical interval between adjacent pulses is 5.0 ?s,and the typical duration is several hundred microseconds.There will always be a chaotic burst of pulses before and after the RPBs.Most RPBs tend to occur in the middle and late stages of lightning discharge.According to the variation of pulse amplitude,adjacent pulse interval and pulse polarity,RPBs is divided into four types: normal RPBs,reverse RPBs,symmetric RPBs and reverse RPBs.And the difference between the four types of RPBs is caused by the amount of charge contained in the charge region,the distance,and the shape of the discharge channel.Finally,the parameters of the initial stage of the lightning discharge process are analyzed and compared with the results of other scholars.Based on the basic theory of lightning discharge in thunderstorm cloud,a simple mathematical model of double Electrically Active Cells(EACs)is established.The mathematical physical model of EACs is used to simulate the basic doublecell thunderstorm electric field environment.On this basis,the interaction between the subsequent discharges caused by the existing ionization channels and the discharges between different discharge cells is discussed,in order to provide theoretical support for the mechanism study of associated lightning.