Lightning Phenomena Research Articles

A Review on Lightning and its effects on Trees

Lightning in mother’s nature show, which cannot be controlled. Lightning contacts the earth about more than 8 million times a day. Due to so many strikes, the probability of damage to the plants and trees is very high. The total available energy for an average lightning stroke is of the order of 108 Joule. Of the total available energy about 85-90% is dissipated in resistive part of the air column, which appears as heat energy to raise the temperature of column so high, that shock waves are produced due to expansion of the column and strong thunder is produced utilizing almost whole of this heat energy. These heat and shock waves generated during lightning process can damage or even kill the trees instantaneously. Lightning may cause wilting, yellowing, premature fruit drop and other severe injuries to trees. Also, the probability of a tree being struck by lightning depends on the tree size and morphology. This paper seeks to present a review on lightning phenomena, its effects on trees and also provides a brief information how difference among trees can influence lightning effect.

Various Types of Lightning Observed in Mountainous Region Recorded from Kathmandu, Nepal

Vertical electric fields of lightning, generated by thunderstorms manifest on the rugged terrain in the mountainous vicinity of Kathmandu, Nepal. Diverse forms of lightning occurrences have been meticulously documented from a hill station in Kathmandu spanning a three-year interval, commencing from 2015 through 2017. Throughout this duration, cloud-to-cloud lightning discharges constituted 62.8% of the occurrences, while cloud-to-ground lightning discharges accounted for 20.4%. Additionally, 9.5% of the observed events were characterized as unusual lightning phenomena, and 2.9% were attributed to breakdown events. The elevated hills and tall structures inherent to the mountainous landscape significantly influence lightning activity, contributing to a heightened frequency of ground flashes in contrast to other areas.

MCGLN: A multimodal ConvLSTM-GAN framework for lightning nowcasting utilizing multi-source spatiotemporal data

Lightning phenomena can instigate a cascade of calamities, encompassing fires, electrical infrastructure damage, and risks to human safety. Deep-learning-based lightning nowcasting models have demonstrated significant effectiveness in disaster prevention and mitigation. However, existing studies often neglect the impacts of surface features on lightning activities, and conventional lightning prediction techniques based on convolutional and recurrent networks face challenges such as the loss of feature information. Addressing these issues, this paper presents a novel model for lightning nowcasting, the Multimodal ConvLSTM-GAN for Lightning Nowcasting (MCGLN). This model integrates a Generative Adversarial Network (GAN) with a Convolutional Long Short-Term Memory network (ConvLSTM), utilizing multi-source data as inputs. It incorporates a spatiotemporal encoder-forecaster framework within the Generator to improve the capture of multidimensional spatiotemporal feature information, thus boosting predictive accuracy. MCGLN offers probabilistic prediction results, allowing users to customize warning thresholds following their specific tolerance for false and missed alarms. The performance of the MCGLN model is evaluated through empirical analysis, utilizing real lightning datasets sourced from Zhejiang and surrounding areas. Experimental results demonstrate that: (a) The MCGLN model outperforms existing methods in terms of detection capability and overall performance, showing significant improvements in the modeling process. (b) Increasing the number of data sources improves detection capabilities, reduces the probability of false alarms, and boosts the model performance. (c) The use of radar data enhances the recognition of high-probability lightning occurrences, and the inclusion of surface feature data increases the capture of terrestrial lightning genesis.

Lightning and Gravity Wave Signatures Produced by the Hunga‐Tonga Volcanic Eruption on Global Geomagnetic Data

AbstractAcoustic gravity waves (AGWs) have a significant impact on the thermosphere‐ionosphere (T‐I) system by increasing ionisation variability, transporting energy, velocity, momentum, and creating additional horizontal gradients in the T‐I, all of which influence electromagnetic wave propagation and cause changes in the geomagnetic field. Ground magnetic disturbance measurements can thus map the global and local spatial distribution of T‐I current systems. The Hunga‐Tonga volcano eruption released a tremendous amount of mass and energy into the atmosphere on 15 January 2022, causing AGWs. Furthermore, the related lightning strikes disrupt the Global electric circuit. In this study, we look at (a) global geomagnetic disturbances caused by AGW constrained by VTEC amplitudes at two different sectors, (b) Schuman resonances (SR) parameters derived from modulations of ELF observations caused by the intense lightning phenomena that accompanied the volcanic eruption. Our analysis shows that (a) registration timing of geomagnetic disturbance at each observatory indicates the different modes of propagation between 180 and 350 m/s, indicating low‐frequency AGW components, (b) noticeable changes in SR frequency modes (7–21 Hz) occurred in the total power between 04:15 and 05:45 UT hr at Patiyasar, India, linked to heightened lightning activity, (c) velocities are found to be similar at similar distances in the northern and southern hemispheres from Hunga‐Tonga, (d) time difference between the SR and geomagnetic disturbance signature at observatories is found to have no relation with distance from the eruption, (e) fluctuations in VTEC at the Indian and Russian sectors show that the geomagnetic disturbances are linked to ionospheric perturbations.

Lightning nowcasting with aerosol-informed machine learning and satellite-enriched dataset

Accurate and timely prediction of lightning occurrences plays a crucial role in safeguarding human well-being and the global environment. Machine-learning-based models have been previously employed for nowcasting lightning occurrence, offering advantages in computation efficiency. However, these models have been hindered by limited accuracy due to inadequate representation of the intricate mechanisms driving lightning and a restricted training dataset. To address these limitations, we present a machine learning approach that integrates aerosol features to more effectively capture lightning mechanisms, complemented by enriched satellite observations from the Geostationary Lightning Mapper (GLM). Through training a well-optimized LightGBM model, we successfully generate spatially continuous (0.25° by 0.25°) and hourly lightning nowcasts over the Contiguous United States (CONUS) during the summer season, surpassing the performance of competitive baselines. Model performance is evaluated using various metrics, including accuracy (94.3%), probability of detection (POD, 75.0%), false alarm ratio (FAR, 38.1%), area under curve of precision–recall curve (PRC-AUC, 0.727). In addition to the enriched dataset, the improved performance can be attributed to the inclusion of aerosol features, which has significantly enhanced the model. This crucial aspect has been overlooked in previous studies. Moreover, our model unravels the influence of aerosol composition and loading on lightning formation, indicating that high aerosol loading consisting of sulfates and organic compounds tends to enhance lightning activity, while black carbon inhibits it. These findings align with current scientific knowledge and demonstrate the immense potential for elucidating the complex mechanisms underlying aerosol-associated lightning phenomena.

Different Measurement System of Lightning

Lightning phenomena is the electrical discharging phenomena. The electromagnetic radiations due to lightning, having various frequencies with different wavelengths are produced. The measurement of lightning by different method like the photography method, current measurement method, electric and magnetic field measurements method and thunder measurement methods can be used. The lightning phenomena produced the waveforms of electric and magnetic field which are the basic parameters to understand the phenomena of lightning discharges. The pair of circular flat metallic plates, separated from each other by insulating material, and are used to capture the signature and measure the electromagnetic radiations produced due to lightning. The waveforms were recorded in the hilly and mountainous country, of Nepal. These types of waveforms are observed and recorded.

Pozorování nadoblačných blesků typu tygří elfové z observatoře Nýdek

This special variety of above-cloud lightning of the ELVES type (called elfové in Czech) was only discovered in 2013. As the name suggests, the phenomenon at first glance looks like the sky scratched by tiger claws. The observed horizontal lines are actually density waves in the atmosphere, at levels around the mesopause. The so-called atmospheric gravitational waves are visible, either as inhomogeneities of atmospheric light radiation (airglow) or, as in the case of tiger elves – due to a strong lightning, accompanied by a huge light circle – an elf. In the first years after the discovery of tiger elves, not much attention was paid to this phenomenon by the author. Capturing elf-type cloud lightning phenomena is not that common, so capturing tiger elves was a big challenge for the author. The first tiger elves were successfully observed by him in the 2017 season, which was very rich in above-cloud lightning. Since then, tiger elves have been captured in nearly every observing season, providing a rare view of structures in the upper mesosphere.

Technological Changes in Lightning Observation in the Electric Power and Energy Fields

Lightning protection for transmission and distribution lines and substations is a quite important issue from the viewpoint of improving the reliability of power systems. The social effect by a strong lightning which rarely occurs is so critical, so the understanding of the characteristic of natural lightning is necessary. It is desirable to directly observe the lightning for the reveal of its property, but it is a very difficult to predict where the lightning strikes on the ground. For this reason, the data sets of the direct observation result of the lightning are limited, and the detailed characteristic of the lightning phenomena has not been achieved. This paper introduces the technological change by looking back on the history of lightning observation from the past to the present.

On the Use of Electromagnetic Models and the 3D-FDTD Method in the Evaluation of Radiations Due to Lightning Strikes to Tall Objects

The purpose of this paper is the investigation of the use of a lightning return stroke current electromagnetic model and the Finite Difference Time Domain (FDTD) method, in three dimensions, in order to study the Lightning Electromagnetic Pulse (LEMP) due to lightning strikes to tall objects (towers). The proposed approach and the developed code are validated by the comparison with the measured data taken obtained in the specialized literature. The evaluation of the LEMP propagation, in presence of different values of ground conductivity, is finally presented and discussed. It is found out that the use of electromagnetic models, which are close to the physical reality of the lightning phenomena, yields reasonably accurate results. The obtained simulation results, using a calculation code developed on Matlab, have turned out to be in very good agreement with measurement data. It has been found out also that the spatiotemporal current distribution along the tower and the lightning channel is influenced by the conductivity variation. Indeed, the LEMP propagation is significantly affected by both lightning current change and ground conductivity variation. It can be noted that the simulation results obtained can be exploited in order to study the coupling problems between LEMP due to lightning strikes to tall objects with different electrical, electronic and telecommunication systems.

Ball Lightning as Plasma Vortexes: A Reinforcement of the Conjecture

The idea that ball lightning is a plasma manifestation has been put forth by many authors. One of the major drawbacks of this approach concerns the stability of these structures. After showing the theoretical existence of pure rotating electromagnetic waves in equilibrium, we argue that these can reasonably provide a robust stabilizing scaffolding for the development of ball lightning phenomena.

Interferometric imaging of intensely radiating negative leaders

The common phenomenon of lightning still harbors many secrets and only recently a new propagation mode was observed for negative leaders. While propagating in this `Intensely Radiating Negative Leader' (IRNL) mode a negative leader emits 100 times more very-high frequency (VHF) and broadband radiation than a more normal negative leader. We have reported that this mode occurs soon after initiation of all lightning flashes we have mapped as well as sometimes long thereafter. Because of the profuse emission of VHF the leader structure is very difficult to image. In this work we report on measurements made with the LOFAR radio telescope, an instrument primarily built for radio-astronomy observations. For this reason, as part of the present work, we have refined our time resolved interferometric 3-Dimensional (TRI-D) imaging to take into account the antenna function. The images from the TRI-D imager show that during an IRNL there is an ionization front with a diameter in excess of 500~m where strong corona bursts occur. This is very different from what is seen for a normal negative leader where the corona bursts happen at the tip, an area of typically 10~m in diameter. The observed massive ionization wave supports the idea that this mode is indicative of a dense charge pocket.

Accurate estimation of modern power system harmonics using a novel LSA hybridized recursive least square technique

Abstract This paper purposes a new type of hybrid technique depends on lightning search algorithm (LSA) and recursive least square (RLS) named as LSA-RLS to overcome the harmonic estimation issues in time varying modern power system signals buried with noises. LSA is based on a natural phenomenon of lightning. It consists of three types of projectiles: transition, space and lead projectiles. Transition projectiles create population, space projectiles do the exploration and the lead projectiles do the work of exploitation and find the optimal solution. The basic LSA algorithm is mixed with RLS algorithm in an adaptive way to estimate the states of the harmonic signals. Simulation and validation are made with real time data obtained from a converter fed D.C motor drive. The efficacy of the proposed algorithm is verified by comparing the simulation results of recently reported algorithms such as particle swarm optimization (PSO), differential evolution (DE), bacteria foraging optimization (BFO), gravity search algorithm hybridized recursive least square method (GSA-RLS). It is verified that proposed (LSA-RLS) technique is the best in terms of computational time, convergence, accuracy.

A distinct negative leader propagation mode

The common phenomenon of lightning still harbors many secrets such as what are the conditions for lightning initiation and what is driving the discharge to propagate over several tens of kilometers through the atmosphere forming conducting ionized channels called leaders. Since lightning is an electric discharge phenomenon, there are positively and negatively charged leaders. In this work we report on measurements made with the LOFAR radio telescope, an instrument primarily build for radio-astronomy observations. It is observed that a negative leader rather suddenly changes, for a few milliseconds, into a mode where it radiates 100 times more VHF power than typical negative leaders after which it spawns a large number of more typical negative leaders. This mode occurs during the initial stage, soon after initiation, of all lightning flashes we have mapped (about 25). For some flashes this mode occurs also well after initiation and we show one case where it is triggered twice, some 100 ms apart. We postulate that this is indicative of a small (order of 5 km^2) high charge pocket. Lightning thus appears to be initiated exclusively in the vicinity of such a small but dense charge pocket.

A Storm Safari in Subtropical South America: Proyecto RELAMPAGO

AbstractThis article provides an overview of the experimental design, execution, education and public outreach, data collection, and initial scientific results from the Remote Sensing of Electrification, Lightning, and Mesoscale/Microscale Processes with Adaptive Ground Observations (RELAMPAGO) field campaign. RELAMPAGO was a major field campaign conducted in the Córdoba and Mendoza provinces in Argentina and western Rio Grande do Sul State in Brazil in 2018–19 that involved more than 200 scientists and students from the United States, Argentina, and Brazil. This campaign was motivated by the physical processes and societal impacts of deep convection that frequently initiates in this region, often along the complex terrain of the Sierras de Córdoba and Andes, and often grows rapidly upscale into dangerous storms that impact society. Observed storms during the experiment produced copious hail, intense flash flooding, extreme lightning flash rates, and other unusual lightning phenomena, but few tornadoes. The five distinct scientific foci of RELAMPAGO—convection initiation, severe weather, upscale growth, hydrometeorology, and lightning and electrification—are described, as are the deployment strategies to observe physical processes relevant to these foci. The campaign’s international cooperation, forecasting efforts, and mission planning strategies enabled a successful data collection effort. In addition, the legacy of RELAMPAGO in South America, including extensive multinational education, public outreach, and social media data gathering associated with the campaign, is summarized.

Lightning to earthed structures: Striking distance variation with stroke polarity, structure geometry and altitude based on a theoretical approach

The striking distance and attractive radius of grounded structures to downward lightning strokes depend significantly on the polarity of the stroke. The paper quantifies the reduction of these parameters for positive lightning, together with their lower sensitivity to structure height with the exception of very tall structures. Recent published data on lightning phenomena enables new comparisons of this modelling with field data. Calculations show that the decrease of air pressure, humidity and temperature with increasing altitude results in an increase in striking distance and an increase in the risk of direct lightning strikes for structures in mountain or aviation environments.

Needle Propagation and Twinkling Characteristics

AbstractRecently, a new lightning phenomena, termed needles, has been observed in both VHF and in optical along positive lightning leaders. They appear as small (<100 m) leader branches that undergo dielectric breakdown at regular intervals (called twinkles). Providing a coherent and consistent explanation for this phenomenon is challenging as each twinkle is a form of negative breakdown that propagates away from the positive leader. In this study, we provide detailed observations of needles in VHF, observed during two lightning flashes. We show distributions of different needle properties, including twinkle propagation speeds, time between twinkles, and needle lengths, among others. We show a return stroke and multiple recoil leaders that quench needle activity. We also show that nearby needle activity does not seem to correlate together, and that needle twinkling can slow down by 10%–30% per twinkle. We conclude by presenting possibilities for how the positive leader could induce negative propagation away from the positive channel, and we argue that twinkles can propagate like a stepped leader or like a recoil leader depending on the temperature of the needle, which implies that needle twinkles can probably propagate without emitting VHF.

Electromagnetic interference hazards in flight and the 5G mobile phone: Review of critical issues in aviation security

This paper presents a partial review of potential harmful Electromagnetic Interference, EMI to aircraft systems. In broad terms this EMI may result from either of three possible sources: Portable Electronic Devices (PEDs), particularly mobile phones carried by flying passengers; sources of electromagnetic (EM) interference external to the aircraft; OR from a High Altitude Electronic Magnetic Pulse (HEMP) resulting from a nuclear detonation in the atmosphere – otherwise a simulation producing a similar result. All these types of EMI are potentially deadly and need to be mitigated in design as well as aviation security policies. The focus is on Intentional EMI (IEMI), and for the purpose of conciseness, this may include a mobile phone which is activated during any phase of flight, and capable of compromising the avionics instruments, and ultimately the safety of the aircraft and its passengers. Artificial EMI impacting aircraft systems is considered, excluding the natural EMI resulting from the phenomenon of lightning. The paper confirms the modern mobile phone (particularly a 5G phone) as a ‘high power intentional emitter’ capable of causing serious EMI. Inter alia, the issue of scarcity of data on EMI caused by PEDs during flight is outlined, along with some ‘ambivalence’ in the literature, the regulatory ‘approach’ impacting aviation safety, and a response to these challenges.

Lichtenberg algorithm: A novel hybrid physics-based meta-heuristic for global optimization

This paper proposes a novel global optimization algorithm called Lichtenberg Algorithm (LA), inspired by the Lichtenberg figures patterns. Optimization is an essential tool to minimize or maximize functions, obtaining optimal results on costs, mass, energy, gains, among others. Actual problems may be multimodal, nonlinear, and discontinuous and may not be minimized by classical analytical methods that depend on the gradient. In this context there are metaheuristics algorithms inspired by natural phenomena to optimize real problems. There is no algorithm that is the worst or the best, but more efficient for a given type of problem. Thus, an unprecedented metaheuristic algorithm was created inspired by the physical phenomenon of radial intra-cloud lightning and Lichtenberg figures, successfully exploiting the fractal power and it is different from many in the literature as it is a hybrid algorithm composed of methods of search based on population and trajectory. Several test functions, including a design problem in a welded beam, were used to verify the robustness and to validate the Lichtenberg Algorithm. In all cases, the results were satisfactory when compared to those in the literature. LA shown to be a powerful optimization tool for both unconstraint optimizations and real problems with linear and nonlinear constraints.

Inferences on upward leader characteristics from measured currents

We analyzed in detail currents associated with upward unconnected leaders (UULs) initiated from the Kennedy Space Center (KSC) Industrial Area Tower (IAT). Current measurements of UULs in natural lightning are relatively rare and provide important insights into the development and propagation of upward leaders. Eight UULs were initiated from the KSC-IAT between August 1, 2018 and November 15, 2019. All UULs were positive as they occurred in response to downward negative leaders that attached to ground near the tower. The KSC Mesoscale Eastern Range Lightning Information System (MERLIN) located these nearby strokes at distances ranging from 185 to 783 m from the tower, with the median being 538 m. The peak current for these strokes ranged from 13 to 69.3 kA, with the median being 26.7 kA. From the perspective of charge transferred, these UULs can be considered to be a bipolar lightning phenomenon; they transferred negative charge to ground between the inception of their current and the current-polarity reversal, following which, they effectively transferred positive charge to ground. We labeled the former time-period as the UUL development phase and the latter as the collapse phase. The median duration and charge transferred for the development phase were 789 μs and − 6.4 mC, respectively, and for the collapse phase were 388 μs and 4.7 mC, respectively. Overall, the net charge transferred to ground by UULs was negative. During the development phase, UUL-currents consisted of faster (total durations of the order of 10 μs) impulses overlaid on slower (millisecond-scale) “background” current. The background-to-peak UUL current-pulse amplitudes ranged from 3.4–289.2 A with the median being 30.1 A. The median pulse total duration and full-width at half-maximum (FWHM) were 14.1 μs and 4.9 μs, respectively. The median background-to-peak and 10-to-90% risetimes were 3.2 and 2.0 μs, respectively. Interpulse intervals ranged from 4.2–132.8 μs, with the median being 20 μs. Generally speaking, pulse amplitudes were larger, background currents were higher, and interpulse intervals were shorter at later times during UULs. It is likely that the UULs with higher background currents at later times were more closely approached by a downward leader branch versus the lower-current UULs.

High-speed video observations on fork lightning events in Malaysia

Malaysia is one of the countries with the highest lightning strikes incidence in the world. Yet, Malaysians are still taking a proper lightning protection indifferent manner. This might be due to lack of knowledge on lightning characteristics in Malaysia. Therefore, this study presents an unusual lightning phenomenon with multiple grounding points that might cause a disastrous event, called fork lightning. Between November and December 2018, there were three different patterns of fork lightning mechanism successfully recorded by using high speed camera with 2800 frame per second. Temporal analysis of the lightning progress had been done on the samples based only on the camera records which then played back by using Wondershare Filmora video editor. These three samples of fork lightning images were acquired among 37 lightning events recorded in this study. The first sample of fork lightning fully established the forked branch 0.35 ms before the return stroke occurred. On the contrary, second fork lightning established its forked branch 0.35 ms after the return stroke. Both forked branches for third sample simultaneously fully established with the return stroke event. Obviously, these events had striking the ground in up to ten milliseconds of time duration. Thus, there is always a possibility that they might cause serious damage and should not be neglected in designing a lightning protection system.