THE PROSPECTS OF USING THE MATLAB PACKAGE FOR MODELING LIGHTNING DISCHARGES IN POWER TRANSMITTING LINES

The possibilities of a simulation model of a power line section with a rated voltage of 220 kV created in the Matlab package under the influence of lightning discharges are described.

Cluster analysis of lightning discharges: based on Vereya-MR network data

Monitoring thunderstorm activity can help you solve many problems such as infrastructure facility protection, warning of hazardous phenomena associated with intense precipitation, study of conditions for the occurrence of thunderstorms and the degree of their influence on human activity, as well as the influence of thunderstorm activity on the formation of near-Earth space. We investigate the characteristics of thunderstorm cells by the method of cluster analysis. We take the Vereya-MR network data accumulated over a period from 2012 to 2018 as a basis. The Vereya-MR network considered in this paper is included in networks operating in the VLF-LF range (long and super-long radio waves). Reception points equipped with recording equipment, primary information processing systems, communication systems, precision time and positioning devices based on global satellite navigation systems are located throughout Russia. In the longitudinal-latitudinal thunderstorm distributions of interest, the dependence on the location of recording devices might be manifested. We compare the behavior of thunderstorms on the entire territory of the Russian Federation with those in the Baikal natural territory. We have established the power of thunderstorms over the Baikal region is lower. The daily variation in thunderstorm cells we obtained is consistent with the data from other works. There are no differences in other thunderstorm characteristics between the regions under study. This might be due to peculiarities of the analysis method. On the basis of the work performed, we propose sites for new points of our own lightning location network, as well as additional methods of cluster analysis.

Comparison of ground-based and satellite data on spatiotemporal distribution of lightning discharges under solar minimum

Worldwide maps of lightning activity have been obtained from the ground-based World Wide Lightning Location Network (WWLLN) for 2007–2009. We have compiled these maps separately for different seasons and UT periods, using WWLLN data on the time and coordinates of each of the recorded lightning. The total number of flashes of lightning in WWLLN data is by an order of magnitude smaller than in satellite data from Optical Transient Detector and the Lightning Imaging Sensor satellites. However, the key features of the spatial distribution and seasonal trends coincide well. The main difference observed is the absence of diurnal variation (similar to Carnegie curve) in WWLLN data against the satellite one. This concerns the global lightning number as well as its density in major thunderstorm regions. The solar local time dependence is also weak in WWLLN data. We show that in 2007–2009 the mean latitude of lightning observation is shifted to the summer hemisphere up to 10° from the annual mean value. From the beginning of 2007 to the end of 2009, the global monthly average number of flashes of lightning increased threefold. We attribute this fact primarily to improved processing techniques in WWLLN. The constructed maps are necessary for numerical simulation of the Global Electric Circuit.

Comparison of ground-based and satellite data on spatiotemporal distribution of lightning discharges under solar minimum

Worldwide maps of lightning activity have been obtained from the ground-based World Wide Lightning Location Network (WWLLN) for 2007–2009. We have compiled these maps separately for different seasons and UT periods, using WWLLN data on the time and coordinates of each of the recorded lightning. The total number of flashes of lightning in WWLLN data is by an order of magnitude smaller than in satellite data from Optical Transient Detector and the Lightning Imaging Sensor satellites. However, the key features of the spatial distribution and seasonal trends coincide well. The main difference observed is the absence of diurnal variation (similar to Carnegie curve) in WWLLN data against the satellite one. This concerns the global lightning number as well as its density in major thunderstorm regions. The solar local time dependence is also weak in WWLLN data. We show that in 2007–2009 the mean latitude of lightning observation is shifted to the summer hemisphere up to 10° from the annual mean value. From the beginning of 2007 to the end of 2009, the global monthly average number of flashes of lightning increased threefold. We attribute this fact primarily to improved processing techniques in WWLLN. The constructed maps are necessary for numerical simulation of the Global Electric Circuit.

Cluster analysis of lightning discharges: based on Vereya-MR network data

Monitoring thunderstorm activity can help you solve many problems such as infrastructure facility protection, warning of hazardous phenomena associated with intense precipitation, study of conditions for the occurrence of thunderstorms and the degree of their influence on human activity, as well as the influence of thunderstorm activity on the formation of near-Earth space. We investigate the characteristics of thunderstorm cells by the method of cluster analysis. We take the Vereya-MR network data accumulated over a period from 2012 to 2018 as a basis. The Vereya-MR network considered in this paper is included in networks operating in the VLF-LF range (long and super-long radio waves). Reception points equipped with recording equipment, primary information processing systems, communication systems, precision time and positioning devices based on global satellite navigation systems are located throughout Russia. In the longitudinal-latitudinal thunderstorm distributions of interest, the dependence on the location of recording devices might be manifested. We compare the behavior of thunderstorms on the entire territory of the Russian Federation with those in the Baikal natural territory. We have established the power of thunderstorms over the Baikal region is lower. The daily variation in thunderstorm cells we obtained is consistent with the data from other works. There are no differences in other thunderstorm characteristics between the regions under study. This might be due to peculiarities of the analysis method. On the basis of the work performed, we propose sites for new points of our own lightning location network, as well as additional methods of cluster analysis.

Outbreak of Negative Narrow Bipolar Events in Two Mid-Latitude Thunderstorms Featuring Overshooting Tops

Lightning discharges are the electrical production in thunderclouds. They radiate the bulk of radio signals in the very low-frequency and low-frequency (VLF/LF) that can be detected by ground-based receivers. One kind of special intra-cloud lightning discharges known as narrow bipolar events (NBEs) have been shown to be rare but closely linked to the convective activity that leads to hazardous weather. However, there is still lack of understanding on the meteorological conditions for thunderstorm-producing NBEs, especially for those of negative polarity, due to their rare occurrence. In this work, we aim to investigate what meteorological and electrical conditions of thunderclouds favor the production of negative NBEs. Combining with the VLF/LF radio signal measured by Jianghuai Area Sferic Array (JASA), S-band Doppler radar observation and balloon sounding data, two mid-latitude thunderstorms with outbreaks of negative NBEs at midnight in East China were analyzed. The comparison with the vertical radar profile shows that the bursts of negative NBEs occurred near thunderclouds with overshooting tops higher than 18 km. Manifestation of negative NBEs is observed with a relatively low spectrum width near thundercloud tops. Our findings suggest that the detection of negative NBEs would provide a unique electrical means to remotely probe overshooting tops with implications for the exchange of troposphere and stratosphere.

A Laboratory Investigation of the Probable Mechanisms of the Action of an Artificial Thunderstorm Cell on Model Aircraft Radomes

The results of experimental laboratory investigations of possible mechanisms of the impact of lightning and thunderclouds on aircraft radomes and equipment inside them are presented. An artificial thunderstorm cell of negative polarity and model aircraft radomes with lightning diverter strips have been used. Experiments have shown that the discharge processes in a radome model significantly depend on the magnitude of the charge that accumulates on the inner and outer surfaces of the radome shell. It is established that the accumulation of large-magnitude charges of different signs on the outer and/or inner surface of the radome (up to hundreds of µC/m2) shell leads to a multivariance of the mechanisms of development of discharge processes inside the radome model, along its surface, and in the space near it. Significant influence of the “reverse” discharge from the antenna model under the radome on the types of current impulses recorded on the antennas under impact of the artificial thunderstorm cell is established. Peculiarities of the discharge formation in the radome model when using solid and segmented diverter strips for its protection are revealed. Parameters of the current impulses registered on the diverter strips and the antennas have been determined. Based on the conducted research, the possible mechanisms of the impact of thunderclouds and lightning discharges on radio-transparent aircraft radomes and the equipment inside them are considered.

Characteristics of Regular Pulse Bursts Generated From Lightning Discharges

In this work, we studied the waveforms of all lightning discharges from about 15 min. Eighty-three percent of all lightning discharges contain particular waveforms called regular pulse bursts (RPBs), which have regular microsecond-scale electric or magnetic field pulses. Maximum proportion of RPBs occur in middle or rear of lightning discharges. Prior to or after RPBs, there is always a chaotic pulse period. The analysis indicated that RPBs are caused by a secondary discharge in the fractured old breakdown channel, likeness to dart-stepped leader occuring in negative cloud-to-ground discharge (-CG). Four types of RPBs, namely, category of normal RPBs, category of back RPBs, category of symmetric RPBs, and category of reversal RPBs, were sorted in the light of the evolution of the pulse amplitude, interval between neighboring pulses and pulse polarity. In addition, the difference between normal RPBs and back RPBs was considered to be caused by the distance between neighboring charge pockets and the magnitude of the charge in every charge pocket. The symmetric RPBs were considered to be caused by a discharge channel with a large central charge area. Reversal RPBs were considered to be caused by a bending channel or superposition of two or more RPBs. We located some RPBs in a typical intra-cloud flash (IC) in three-dimensional. The analysis showed that the developing velocity of RPBs ranged from approximately 1.2 × 106 m/s to 3.0 × 106 m/s, which slower less than both of the dart leader or dart-stepped leader process from previous studies. And we found it is several meters to dozens of meters that the lengths range of discharge step which between two adjacent pulses.

Electric charge in clouds at temperatures above 0° C

It is well-established that heavy rain can fall under certain conditions, from clouds whose temperatures are nowhere below the freezing point and where the Bergeron mechanism is pot applicable, and coalescence of droplets can provide the initial step in the growth of rain drops. It is, however, generally believed that lightning discharges occur in heavy cumulus or cumulonimbus clouds in which glaciations has begun to be apparent, and most of the theories so far advanced on the development of electric charges in the clouds assume the change of state to play a direct role in the electrification of the cloud.