Thunderstorm Lightning Research Articles

Seasonal and Regional Distribution of Lightning Fraction Over Indian Subcontinent

AbstractFour years of Indian Institute of Tropical Meteorology lightning location network lightning observation data are used to determine the seasonal and spatial (over different geographical locations) distribution of the ratio of intra‐cloud (IC) lightning to cloud‐to‐ground (CG) lightning in thunderstorms over the Indian subcontinent. The ratio is high (6–10) in the northwestern parts and low (0.5–3.5) in the northeastern parts. No prominent latitudinal variation of the IC to CG ratio exists, but a climatological seasonal variability exists over all regions. In the pre‐monsoon season (March–May), the mean ratio is observed to be 3.81 with a standard deviation of 0.79, and during the monsoon season (June–September), a value of 3.04 with a standard deviation of 0.50. Although convective available potential energy is the regulating factor, little dependency has been found between the ratio of IC to CG lightning (IC:CG ratio) and the total flash rate (f), as well as with cold cloud depths. The ratio is observed to be proportional to the total flash rate as f0.61. The cold cloud depth is most prominently linked with the regional and seasonal IC:CG ratio. The implication of these observed results has the importance of separating CG lightning flash from total and can be used in numerical models to give a proper prediction of CG lightning in hazard mitigation.

Thunderstorm tracking in Northwest Europe for enhanced hazard preparedness

AbstractThe tracking of thunderstorms provides critical information on their frequency and behaviour for early warning, prediction and preparedness. Thunderstorm tracking has previously been constrained by the boundaries of a particular country or has focused on a particular category such as severe thunderstorms and mesoscale convective systems. However, less severe thunderstorms also pose a risk to life and property and occur more frequently and thus warrant inclusion in investigations of thunderstorm behaviour. In this paper, we present a new thunderstorm event catalogue, including all detected thunderstorms with at least three lightning flashes, derived from a tracking methodology applied to Northwest Europe within the bounds of 48° to 65°N and 15°W to 10°E between 2008 and 2018. The catalogue is based on ATDnet lightning flash data which was clustered into thunderstorms using a spatio‐temporal proximity assessment lightning clustering code written in the R coding language. The thunderstorm lightning clusters enabled the production of thunderstorm behaviour statistics such as speed, direction of movement, lightning flashes per minute and duration. This revealed that in winter, thunderstorms are shorter lived and move faster than in summer as well as more typically tracking from the west rather than from the south‐west. Thunderstorm behaviour characteristics were attributed to weather pattern types for the first time, providing probabilistic data that can be attributed to synoptic conditions. This can improve preparedness and early warning. Such results demonstrate how this new thunderstorm event catalogue, which includes all types and severities of thunderstorms unconstrained by political boundaries, can provide additional important information to enhance understanding of thunderstorm behaviour in the region. Our lightning clustering method may be useful for similar studies in other locales.

Discharging Phenomena in different types of Lightning

There are two charge regions and charges can transfer from one region to another region. For lightning discharging process, the centers of two charges are separated by different distances and air as an insulator between them. The methods of the process of charge formation in differ-ent types of lightning are different. In volcanic lightning, it form closer to the ground and dis-charging process occurs between the two charge regions as the normal thunderstorm lightning does. The steeped leader starts at the structure and propagates upward in nuclear lightning. Their direction of branching is also upward and the return strokes do not initiate from upward moving leaders. It is similar to upward initiated thunderstorm lightning flashes from tall struc-tures and forms in several kilometers. In Earthquake lightning, a shifting of the positive and negative charge centers in the material, which then results in an external electric field. Even the different lightning signatures have been observed in our scientific community, the thunderstorm lightning is frequently observed and measured by the different methods such as electric field measurement, magnetic field measurement, photography and so on. Here, the method of elec-tric field measurement is used to measure the thunderstorm lightning. In all cases of lightning, the discharge phenomena take place between two different charged regions. The two regions of positive charges and negative charges are separated by a certain distance and the air between them is an insulator. When the sufficient charges store in the two charge regions, voltage is de-veloped between them. If the potential developed is sufficient for the electric breakdown of the air, then lightning phenomena occur. Hence, the discharging phenomena occur between the positive and negative charge regions for the different types of lightning.

A Terrestrial Gamma‐Ray Flash From the 2022 Hunga Tonga–Hunga Ha'apai Volcanic Eruption

AbstractThe Hunga Tonga–Hunga Ha'apai submarine volcano recently resumed activity. Violent eruptions on 14th and 15th January 2022 launched a tall ash plume that produced extremely high lightning rates. Here we report a terrestrial gamma‐ray flash (TGF) that was produced by the volcanic lightning and observed from space by the Fermi Gamma‐ray Burst Monitor (GBM). Observations by radio lightning networks and especially by the Geostationary Lightning Mapper show that the only lightning close enough to produce a TGF detectable by Fermi GBM was from the volcano's plume. With the observing duration of Fermi, observing a single TGF is consistent with the hypothesis that the volcanic lightning of this eruption produced TGFs at the average rate of thunderstorm lightning. The observation of a strong TGF from space also indicates that the electric field was oriented so as to accelerate electrons upward.

A parameterization of long-continuing-current (LCC) lightning in the lightning submodel LNOX (version 3.0) of the Modular Earth Submodel System (MESSy, version 2.54)

Abstract. Lightning flashes can produce a discharge in which a continuing electrical current flows for more than 40 ms. Such flashes are proposed to be the main precursors of lightning-ignited wildfires and also to trigger sprite discharges in the mesosphere. However, lightning parameterizations implemented in global atmospheric models do not include information about the continuing electrical current of flashes. The continuing current of lightning flashes cannot be detected by conventional lightning location systems. Instead, these so-called long-continuing-current (LCC) flashes are commonly observed by extremely low-frequency (ELF) sensors and by optical instruments located in space. Reports of LCC lightning flashes tend to occur in winter and oceanic thunderstorms, which suggests a connection between weak convection and the occurrence of this type of discharge. In this study, we develop a parameterization of LCC lightning flashes based on a climatology derived from optical lightning measurements reported by the Lightning Imaging Sensor (LIS) on board the International Space Station (ISS) between March 2017 and March 2020. We use meteorological data from reanalyses to develop a global parameterization that uses vertical velocity at the 450 hPa pressure level as a proxy for the ratio of LCC to total lightning in thunderstorms. We implement this parameterization into the LNOX submodel of the Modular Earth Submodel System (MESSy) for usage within the European Center HAMburg general circulation model (ECHAM)/MESSy Atmospheric Chemistry (EMAC) model and compare the observed and simulated climatologies of LCC lightning flashes using six different lightning parameterizations. We find that the best agreement between the simulated and observed spatial distribution is obtained when using a novel combined lightning parameterization based on the cloud-top height over land and on the convective precipitation over ocean.

Relationships between Electrification and Storm-Scale Properties Based on Idealized Simulations of an Intensifying Hurricane-Like Vortex

AbstractThis study investigates relationships between storm-scale properties and the electrification and lightning of two simulations of an intensifying idealized tropical cyclone (TC) using the cloud-resolving Collaborative Model for Multiscale Atmospheric Simulation (COMMAS). To produce an intensifying storm, an initial weak TC is subjected to a linear increase in sea surface temperature.As the TC intensifies, lightning flash rates increase in both the inner core (r ≤ 100 km) and outer region (100 < r ≤ 300 km). As time progresses, lightning in the outer region gradually decreases, while the inner-core lightning remains relatively steady. Bootstrapped correlation statistics using 1000 random samples between the pressure trace and time series of lightning rates shows a statistically significant negative correlation between inner-core lightning and TC intensification. Lightning rates in the outer bands were found to lag minimum surface pressure by 12 h.The increases in lightning in both the inner core and outer region coincided well with increases in 0.5 g kg−1 graupel and 5 m s−1 updraft volumes in each respective region. Correlation statistics with selected kinematic and microphysical variables known to be associated with lightning in thunderstorms, such as the ice water path, integrated updraft volume, and graupel volume, revealed that their increase in the inner core indicated an ongoing deepening, similar to the lightning. Trends in these proxy variables in the outer bands were also found to lag TC intensification by 12 h.Overall, the best linear relationships with lightning in either the inner core or the outer region were obtained with the 0.5 g kg−1 graupel volume and total graupel mass.

Physical properties of volcanic lightning: Constraints from magnetotelluric and video observations at Sakurajima volcano, Japan

Abstract The lightning generated by explosive volcanic eruptions is of interest not only as a promising technique for monitoring volcanic activity, but also for its broader implications and possible role in the origin of life on Earth, and its impact on the atmosphere and biosphere of the planet. However, at present the genetic mechanisms and physical properties of volcanic lightning remain poorly understood, as compared to our understanding of thundercloud lightning. Here, we present joint magnetotelluric (MT) data and video imagery that were used to investigate the physical properties of electrical discharges generated during explosive activity at Sakurajima volcano, Japan, and we compare these data with the characteristics of thundercloud lightning. Using two weeks of high-sensitivity, high-sample-rate MT data recorded in 2013, we detected weak electromagnetic signals radiated by volcanic lightning close to the crater. By carefully inspecting all MT waveforms that synchronized with visible flashes, and comparing with high-speed (3000 frame/s) and normal-speed (30 frame/s) videos, we identified two types of discharges. The first type consists of impulses (Type A) and is interpreted as cloud-to-ground (CG) lightning. The second type is characterized by weak electromagnetic variations with multiple peaks (Type B), and is interpreted as intra-cloud (IC) lightning. In addition, we observed a hybrid MT event wherein a continuous weak current accompanied Type A discharge. The observed features of volcanic lightning are similar to thunderstorm lightning, and the physical characteristics show that volcanic lightning can be treated as a miniature version of thunderstorm lightning in many respects. The overall duration, length, inter-stroke interval, peak current, and charge transfer all exhibit values 1–2 orders of magnitude smaller than those of thunderstorm lightning, thus suggesting a scaling relation between volcanic and thunderstorm lightning parameters that is independent of the type of charged particles. On the other hand, the polarities, which are estimated by long-time (3.4 yrs) MT (32 samples/s) and video (30 frame/s) observations, are different than those of normal thunderstorm lightning. These observations are consistent with the notion that charge structures in volcanic ash plumes are highly disordered and are characterized by numerous small charged regions with high charge density.

A thunderstorm cell-lightning activity analysis: The new concept of air mass catchment

Thunderstorm cell-lightning activity is discussed in terms of analysing a thunderstorm's lightning frequency–equipotential temperature relationship. Thunderstorms were tracked using Doppler radars in five-minute time steps. Lightning is assigned to the nearest thunderstorm cell, it is characterised by lightning frequency data using LINET. Equipotential temperature is not directly estimated, instead the notion of air mass catchment is introduced to represent it. It is shown in this paper that the thunderstorm cell with maximum lightning frequency in the current time step is almost always the so-called leading storm cell. The lightning frequency activity of the non-leading storm cells is not significant.

Application of the Schumann resonance spectral decomposition in characterizing the main African thunderstorm center

AbstractIn this paper we present a new method for quantifying the main tropical thunderstorm regions based on extremely low frequency (ELF) electromagnetic wave measurements from a single station—the Hylaty ELF station in Central Europe. Our approach is based on Schumann resonance (SR) measurements, which we apply as an example to thunderstorms in Africa. By solving the inverse problem, using the SR power spectrum templates derived analytically, we calculate distances to the most powerful thunderstorm centers and present simplified 1‐D thunderstorm lightning activity “maps” in absolute units C2m2/s. We briefly describe our method of SR power spectrum analysis and present how this method is used with real observational data. We obtained the monthly lightning activity maps of the African storm centers with a spatial resolution of 1° and temporal resolution of 10 min for January and August 2011. This allowed us to study the varying location and intensities of the African storm centers in different seasons of the year. A cross check of the obtained lightning activity maps with Tropical Rainfall Measuring Mission satellite data recorded by the Lightning Imaging Sensor and the derived correlation coefficients between SR and optical data were used to validate the proposed method. We note that modeling a maximum possible number of resonance modes in the SR power spectra (in our case, seven resonances) is essential in application of the proposed approach.

Search for possible relationship between volcanic ash particles and thunderstorm lightning activity

Explosive volcanic eruptions that eject columns of ash from the crater often generate lightning discharges strong enough to be remotely located by very low frequency radio waves. A fraction of volcanic ash particles can stay and disperse long enough to have an effect on weather phenomena days later such as thunderstorms and lightnings. In this work we report on lightning activity analysis over Europe following two recent series of volcanic eruptions in order to identify possible correlations between ash release and subsequent thunderstorm flash frequency. Our attempts gave negative results which can be related to the fact that we have limited information on local atmospheric variables of high enough resolution, however lightning frequency is apparently determined by very local circumstances.

Magnetotelluric pulses generated by volcanic lightning at Sakurajima volcano, Japan

Continuous magnetotelluric (MT) measurements were conducted at Sakurajima volcano, Japan, revealing syn‐eruption electric pulses (and sometimes accompanying geomagnetic pulses). Movies of the eruptions, recorded with timing provided by a GPS clock, show a large number of volcanic lightning flashes. Some MT pulses occurred simultaneously with lightning flashes. Pulses were observed more than 10 seconds after the onset of the eruption, and tend to occur during eruptions that emit volcanic ash to high altitudes. Pulses were more common during mild eruptions rather than during Vulcanian eruptions. The observations suggest that the dominant mechanism of volcanic lighting is similar to that of lightning in thunderstorms, in that it requires the collision of particles and subsequent separation of positive and negative charge.

Lightning‐induced lower‐hybrid turbulence and trapped Extremely Low Frequency (ELF) electromagnetic waves observed in deep equatorial plasma density depletions during intense magnetic storms

During the early phase of the intense magnetic storm of 7–11 November 2004, the DEMETER satellite encountered large‐scale equatorial plasma density depletions with density decreases of two or three orders of magnitude. Wave measurements carried out inside these depletions show the occurrence of broadband and localized lower‐hybrid turbulence triggered by whistlers propagating from thunderstorm lightning occurring below the orbit path. High‐sample‐rate waveforms reveal that this lower‐hybrid turbulence can evolve into localized large‐amplitude quasi‐monochromatic wave packets similar to lower‐hybrid structures that were, up to now, only observed in the auroral regions, usually on high‐latitude magnetic field lines associated with discrete aurora. These equatorial structures have typical amplitudes of up to 20 mV/m and durations of ∼20–30 ms. Simultaneous thermal ion measurements show that these bursts are often correlated with small‐scale density depletions of 5–10%. Although the lower‐hybrid structures are less intense than those observed in the auroral zone and although their energy source is different, our observations lend support to the idea that the formation of lower‐hybrid structures is an universal mechanism operating in inhomogeneous magnetized space plasmas in the presence of VLF whistler mode turbulence. Besides the lower‐hybrid turbulence, another interesting feature is the occurrence of strong narrowband electromagnetic ELF emissions with amplitudes of a few millivolts per meter at frequencies below the proton gyrofrequency. They are continuously observed throughout the entire depletion. These emissions occur not only within the depletions but also, although less intense, outside of them over a large latitudinal range. They are tentatively identified as magnetospheric line radiations (MLRs) commonly observed during magnetically disturbed periods. Similar events were observed on 15 May 2005 and on 24 August 2005 during two other intense magnetic storms.

Laboratory studies of the effect of cloud conditions on graupel/crystal charge transfer in thunderstorm electrification

AbstractCollisions between vapour‐grown ice crystals and a riming target, representing a graupel pellet falling in a thunderstorm, were shown by Reynolds, Brook and Gourley to transfer substantial charge, which they showed to be adequate to account for the development of charge centres leading to lightning in thunderstorms. Related experiments by Takahashi and Jayaratne et al. determined that the sign of charge transferred is dependent on the cloud liquid water content and on cloud temperature. There are marked differences between the results of Takahashi and Jayaratne in the details of the dependence they noted of the sign of graupel charging on cloud water and temperature. More recently, Pereyra et al. have shown that results somewhat similar in form to those of Takahashi are obtained by modifying the experimental technique used to prepare the clouds of ice crystals and supercooled water droplets used in the experiments.In order to help resolve the reason for the differences in charge transfer results in various studies, work has continued in the Manchester laboratory with a modified cloud chamber in which the cloud conditions of the crystals and droplets may be controlled independently. Results indicate a profound effect on the charge sign of the particle growth conditions in the two clouds involved. For example, by suitable adjustments to the water contents of the two clouds, graupel is charged negatively by rebounding ice crystal collisions at higher cloud water contents than have been noted previously. It is suggested that the most important influence on charge sign is the relative diffusional growth rate of the two ice surfaces at the moment of impact and that this is affected by an increase in cloud supersaturation experienced by the ice crystals during the cloud mixing process just prior to collision. A range of cloud conditions is used in the present work in order to help determine the reasons for the various results reported previously.Examination of some thunderstorm observations in the context of the present results points to the importance of mixing on the sign of the charge transferred during particle collisions when two cloud regions of different histories mix together. Copyright © 2006 Royal Meteorological Society

Time resolved study of simulated volcanic lightning by laser induced plasma in a plume of ablated basalt

Lightning activity is typically generated by explosive volcanic activity. In this work we report an experimental simulation of a volcanic lightning by focusing into a basaltic rock the emission of a pulsed Nd: YAG laser in air at atmospheric pressure (laser ablation). The temporal evolution of air breakdown in an ash plume was studied by emission spectroscopy and shadowgraphy. The electron temperature exceeds 18 × 103 K and the electron density reaches about 1018 cm−3. The production yield of nitric oxide by simulated volcanic lightning was determined by gas chromatography coupled to a mass spectrometer and no substantial difference was found with that of simulated thunderstorm lightning by laser induced plasma.

Terrestrial Degassing, Thermal Infrared Anomaly and Earthquakes

1 Satellite Thermal Infrared Anomaly and Earthquakes The friction of faults during earthquakes produces a large amount of heat, which sufficiently causes water and other fluid in rocks and soils along either side of the faults to gasify and produce a large amount of electric charge, similar to the lightning in thunderstorms. The strong discharge of electric field in lower part of the atmosphere, which is caused by

In situ aircraft measurements of enhanced levels of N2O associated with thunderstorm lightning

During the past few years, considerable research activity has concerned atmospheric lightning as a source of the oxides of nitrogen, nitric oxide (NO) and nitrous oxide (N2O)1–10. Most of this research has centred on NO and has established lightning as a major natural source of this important tropospheric species1–6,8–10. This research has been based mainly on theoretical calculations2,4–6,8,9, laboratory measurements3,10, and on a single measurement of enhanced levels of nitrogen dioxide (NO2), believed to have resulted from NO produced in thunderstorm lightning1. We report here the first series of measurements of enhanced levels of atmospheric N2O associated with thunderstorm lightning. N2O is an environmentally significant species since its reaction with excited oxygen (O(1D)) in the stratosphere produces NO which through the catalytic NOx cycle is responsible for about 65% of the total global destruction of ozone (O3) in the stratosphere11. In addition, due to its absorption at 7.8 µm in the atmospheric window, N2O absorbs and then re-emits Earth-emitted IR radiation which leads to an enhancement of the surface temperature, and, hence, has important implications for climate considerations12.