Observation and study on the whole process of cloud-to-ground lightning using narrowband radio interferometer

Qie

et al. 2010

Sci. China Earth Sci.

Self Cite

A time-of-arrival (TOA) system based on GPS technology for locating VHF radiation sources from lightning has been developed and used in observation sites in the northern Shandong Province, China. The 3D images of the lightning progression have been obtained successfully for the first time in China. The 3D-channel evolutions of typical negative CG, positive CG and IC lightning flashes have been discussed together with the data of fast electric field change. It was found that significant differences existed between the negative and positive CG lightning flashes in terms of the initiation and propagation of the radiation sources. The preliminary breakdown of a negative CG lightning flash propagated at a speed about 5.2×10 4 m/s. The stepped leader of negative CG lightning flashes was trigged by negative initial breakdown. Thereafter, it propagated downward at a speed of 1.3×10 5 m/s. The initial process of the positive CG lightning flashes was also a propagation process of negative streamer. These streamers propagated dominantly horizontally in the positive charge region and accumulated positive charges at the origin of the lightning, and as a consequence, initiated downward positive streamers. A new type of lightning discharge that was triggered by a narrow bipolar pulse (NBP) is discussed in this study. The NBP was originated at altitude of about 10.5 km in the upper positive charge region. As a distinct difference from normal IC flash, its channels extended horizontally all around and produced a lot of radiation sources. The source power of the NBP could approach 16.7 kW, which is much greater than that of normal lightning discharge ranging between 100 mW and 500 W. The 3D propagation of this new type of lightning discharge was observed and obtained for the first time in China. The possible initiation mechanism of this new type of lightning is discussed here. time-of-arrival (TOA) technique, three dimensional lightning locating system, discharge process, narrow bipolar pulse, new-type of IC lightning Citation:Zhang G S, Wang Y H, Qie X S, et al. Using lightning locating system based on time-of-arrival technique to study three-dimensional lightning discharge processes.Realization of three dimensional (3D) location of lightning radiation process provides a new approach to study meticulously the lightning discharge process, as well as the electrical structure of thunderstorms and their electrification mechanism. Lightning discharges are categorized as cloudto-ground (CG) and intracloud (IC) flashes. People are more concentrated on the CG flash since CG flash is the cause of most lightning damage, injury, and death. Many meaningful results [1-3] based on the lightning locating technology and

Section: Error Estimatesupporting

confidence: 87%

mentioning

confidence: 99%

Using lightning locating system based on time-of-arrival technique to study three-dimensional lightning discharge processes

Qie

et al. 2010

Sci. China Earth Sci.

Self Cite

“…K-change is with relative small EFC in latter part of lightning. Shao et al [5] and Zhang et al [4] suggested that the M-component is a special K-change connected to a good conductive channel. Ogawa and Brook [7] suggested that the K-change can be seen as small RS in cloud.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

“…DATA AND CLASSIFICATION OF RPBS The data in this paper were recorded by VHF receiver (with bandwidth between 267-273MHz) and broadband electric field change (EFC) detector (with bandwidth between 0-10MHz, and time constant of 100us) in Binzhou of Shandong province , China, in the summer of 2007 [3,4]. Both VHF radiation and broadband EFC signals were recorded with 50ns time resolution using 20MHz digitizer and accurately phase locked to 1 pulse per second output of a GPS receiver.…”

Section: Introductionmentioning

confidence: 99%

The regular pulses bursts in electromagnetic radiation from lightning

2010 Asia-Pacific International Symposium on Electromagnetic Compatibility

et al. 2010

Self Cite

A special lightning discharge phenomenon named as Regular Pulses Bursts (RPBs) is analysed. The result shows that the RPBs exist in all 69 lightning discharges within 30 minutes recording. The 190 RPBs in 6 typical lightning discharges are analysed in detail, the result indicates that its typical width of pulses is about 1μs, and inter-pulse interval varies from 4 to 8μs. Four types, namely normal RPBs, back RPBs, symmetry RPBs, and reversal RPBs are classified according to inter-pulse interval and pulse polarity. There is no obvious difference between RPBs in negative cloud to ground (CG) lightning and that in intracloud lightning(IC), but polarity change of most RPBs is frequent in positive CG. The results also show that the RPBs tend to occur in the latter portion of lightning discharges, and many cases are found to be associated with intensive VHF radiation. The waveform of the normal-type RPBs is similar to the dart-stepped leader in negative CG, which is considered caused by the recoil streamers. And the back-type RPBs may be caused by the leaders in cloud.

“…A 3D lightning radiation source locating system (LLR for short), based on the TOA technique, was developed in 2004 and it has recorded considerable amounts of data, analyses of which have been published in many papers (Zhang et al, 2008Li et al, 2012Li et al, , 2013Wu et al, 2013;Fan et al, 2014). The LLR can obtain both the location of lightning radiation sources in distant thunderstorms and the spatiotemporal characteristics of the 3D lightning discharge channel with high accuracy.…”

mentioning

confidence: 99%

Experimental study on location accuracy of a 3D VHF lightning-radiation-source locating network

et al. 2015

Sci. China Earth Sci.

Self Cite

This paper reports the investigation of the location accuracy of a three-dimensional (3D) lightning-radiation-source locating system using sounding balloon measurements. By comparing the information from the balloon-borne VHF transmitter flight path and locations using simple geometric models, the location uncertainties of sources both over and outside the network were estimated. For radiation sources inside the network and below an altitude of 7 km, the horizontal uncertainty was 12-48 m and the total mean value was 21 m (rms), and the vertical uncertainty was 20-78 m and the total mean value was 49 m (rms). Outside the network, the location uncertainties increased with distance. The geometric model showed that range and altitude errors increased as a function of the range squared whereas the range errors increased parabolically with distance, and that was confirmed by the covariance calculation results. The standard deviation was used inside the network and covariance was used outside the network. The results indicated that location errors from a simple geometric model exhibited good agreement with standard experimental data. The geometry of the network, set of measurements, and calculation method were verified as suitable. The chi-square values of the least squares goodness of fit algorithm were verified and the timing error (t rms ) of the fitting formula was estimated. The distribution of the chi-square values was less than 5, corresponding to a timing error of 50-66 ns (rms). 3D lightning-radiation-source locating network, location accuracy, standard deviation, geometric model, theoretical error Citation:The channel of lightning discharge can be located spatially and temporally using a 3D lightning locating system (Zhang et al., 2010). The locating system comprises multiple affiliated observational stations measuring the arrival times of lightning radiation sources (bandwidth 267-273 MHz) based on time-of-arrival (TOA) and GPS technology. The accuracy of the locations radiation source depends on the structures and terrain within the observation area and on the numbers and positions of the observational stations (network geometry). However, system measuring errors and random errors in the arrival times of the radiation sources lead to uncertainties between the measured and true values. Therefore, analysis of location uncertainty and network variation can help in the design and optimization of locating networks, correction of location results, and improvements in the method of location.The TOA measurement was developed in the last century. Proctor (1971, 1981) and Proctor et al. (1988) was a pioneer of using TOA to develop a system for locating 3D VHF radiation sources. He used a network of five stations arrayed along two nearly perpendicular baselines and used hyperbolic formulations to obtain estimates of the source locations. The geometric interpretation of the solutions and the