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Lightning is a natural phenomenon consisting of electrostatic discharges occurring through the atmosphere between two electrically charged regions. One or both regions are within the atmosphere, with the second region sometimes occurring on the land. Following the lightning, the regions become partially or wholly electrically neutralized.
Lightning involves a near-instantaneous release of energy on a scale averaging between 200 and 7 gigajoules. The air around the lightning flash rapidly heats to temperatures of about . There is an emission of electromagnetic radiation across a wide range of wavelengths, some visible as a bright flash. Lightning also causes thunder, a sound from the shock wave which develops as heated gases in the vicinity of the discharge experience a sudden increase in pressure.
The most common occurrence of a lightning event is known as a thunderstorm, though they can also commonly occur in other types of energetic weather systems, such as volcanic eruptions. Lightning influences the global atmospheric electrical circuit and atmospheric chemistry and is a natural ignition source of wildfires. Lightning is considered an Essential Climate Variable by the World Meteorological Organization, and its scientific study is called fulminology.
Many other observational variants are recognized, including: volcanic lightning, which can occur during volcanic eruptions; "heat lightning", which can be seen from a great distance but not heard; dry lightning, which can cause forest fires; and ball lightning, which is rarely observed scientifically.
The most direct effects of lightning on humans occur as a result of cloud-to-ground lightning, even though intra-cloud and cloud-to-cloud are more common. Intra-cloud and cloud-to-cloud lightning indirectly affect humans through their influence on atmospheric chemistry.
There are variations of each type, such as "positive" versus "negative" CG flashes, that have different physical characteristics common to each which can be measured.
(CG) lightning is a lightning discharge between a thundercloud and the ground. It is initiated by a stepped leader moving down from the cloud, which is met by a streamer moving up from the ground.
CG is the least common, but best understood of all types of lightning. It is easier to study scientifically because it terminates on a physical object, namely the ground, and lends itself to being measured by instruments on the ground. Of the three primary types of lightning, it poses the greatest threat to life and property, since it terminates on the ground or "strikes".
The overall discharge, termed a flash, is composed of a number of processes such as preliminary breakdown, stepped leaders, connecting leaders, return strokes, dart leaders, and subsequent return strokes. The conductivity of the electrical ground, be it soil, fresh water, or saline water, may affect the lightning discharge rate and thus visible characteristics.
Positive lightning is less common than negative lightning and on average makes up less than 5% of all lightning strikes.
There are a number of mechanisms theorized to result in the formation of positive lightning. These are mainly based on movement or intensification of charge centres in the cloud. Such changes in cloud charging may come about as a result of variations in vertical wind shear or precipitation, or dissipation of the storm. Positive flashes may also result from certain behaviour of in-cloud discharges, e.g. breaking off or branching from existing flashes.
Positive lightning strikes tend to be much more intense than their negative counterparts. An average bolt of negative lightning creates an electric current of 30,000 (30 kA), transferring a total 15 C () of electric charge and 1 joule of energy. Large bolts of positive lightning can create up to 120 kA and transfer 350 C.Hasbrouck, Richard. Mitigating Lightning Hazards , Science & Technology Review May 1996. Retrieved on April 26, 2009. The average positive ground flash has roughly double the peak current of a typical negative flash, and can produce peak currents up to 400 kA and charges of several hundred coulombs.V. A. Rakov, M. A. Uman, Positive and bipolar lightning discharges to ground, in: Light. Phys. Eff., Cambridge University Press, 2003: pp. 214–240 Furthermore, positive ground flashes with high peak currents are commonly followed by long continuing currents, a correlation not seen in negative ground flashes.
As a result of their greater power, positive lightning strikes are considerably more dangerous than negative strikes. Positive lightning produces both higher peak currents and longer continuing currents, making them capable of heating surfaces to much higher levels which increases the likelihood of a fire being ignited. The long distances positive lightning can propagate through clear air explains why they are known as "bolts from the blue", giving no warning to observers.
Positive lightning has also been shown to trigger the occurrence of upward lightning flashes from the tops of tall structures and is largely responsible for the initiation of sprites several tens of kilometers above ground level. Positive lightning tends to occur more frequently in , as with thundersnow, during intense and in the dissipation stage of a thunderstorm. Huge quantities of extremely low frequency (ELF) and very low frequency (VLF) are also generated.
Contrary to popular belief, positive lightning flashes do not necessarily originate from the anvil or the upper positive charge region and strike a rain-free area outside of the thunderstorm. This belief is based on the outdated idea that lightning leaders are unipolar and originate from their respective charge region. Despite the popular misconception that flashes originating from the anvil are positive, because they seem to originate from the positive charge region, observations have shown that these are in fact negative flashes. They begin as IC flashes within the cloud, the negative leader then exits the cloud from the positive charge region before propagating through clear air and striking the ground some distance away.
IC lightning most commonly occurs between the upper anvil portion and lower reaches of a given thunderstorm. This lightning can sometimes be observed at great distances at night as so-called "sheet lightning". In such instances, the observer may see only a flash of light without hearing any thunder.
Another term used for cloud–cloud or cloud–cloud–ground lightning is "Anvil Crawler", due to the habit of charge, typically originating beneath or within the anvil and scrambling through the upper cloud layers of a thunderstorm, often generating dramatic multiple branch strokes. These are usually seen as a thunderstorm passes over the observer or begins to decay. The most vivid crawler behavior occurs in well developed thunderstorms that feature extensive rear anvil shearing.
Lightning can also occur during , forest fires, , volcano, and even in the cold of winter, where the lightning is known as thundersnow. New Lightning Type Found Over Volcano? . News.nationalgeographic.com (February 2010). Retrieved on June 23, 2012. tropical cyclone typically generate some lightning, mainly in the rainbands as much as from the center.Pardo-Rodriguez, Lumari (Summer 2009) Lightning Activity in Atlantic Tropical Cyclones: Using the Long-Range Lightning Detection Network (LLDN) . MA Climate and Society, Columbia University Significant Opportunities in Atmospheric Research and Science Program. Hurricane Lightning , NASA, January 9, 2006. The Promise of Long-Range Lightning Detection in Better Understanding, Nowcasting, and Forecasting of Maritime Storms . Long Range Lightning Detection Network
Intense forest fires, such as those seen in the 2019–20 Australian bushfire season, can create their own weather systems that can produce lightning (also called Fire Lightning) and other weather phenomena. Intense heat from a fire causes air to rapidly rise within the smoke plume, causing the formation of pyrocumulonimbus clouds. Cooler air is drawn in by this turbulent, rising air, helping to cool the plume. The rising plume is further cooled by the lower atmospheric pressure at high altitude, allowing the moisture in it to condense into cloud. Pyrocumulonimbus clouds form in an unstable atmosphere. These weather systems can produce Dry thunderstorm, , intense winds, and dirty hail.
As well as the thermodynamic and dynamic conditions of the atmosphere, aerosol (e.g. dust or smoke) composition is thought to influence the frequency of lightning flashes in a storm. A specific example of this is that relatively high lightning frequency is seen along ship tracks.
Airplane contrails have also been observed to influence lightning to a small degree. The water vapor-dense contrails of airplanes may provide a lower resistance pathway through the atmosphere having some influence upon the establishment of an ionic pathway for a lightning flash to follow.Uman (1986) Ch. 4, pp. 26–34. Rocket exhaust plumes provided a pathway for lightning when it was witnessed striking the Apollo 12 rocket shortly after takeoff.
Thermonuclear explosions, by providing extra material for electrical conduction and a very turbulent localized atmosphere, have been seen triggering lightning flashes within the mushroom cloud. In addition, intense gamma radiation from large nuclear explosions may develop intensely charged regions in the surrounding air through Compton scattering. The intensely charged space charge regions create multiple clear-air lightning discharges shortly after the device detonates.
Some high energy cosmic rays produced by supernovas as well as solar particles from the solar wind, enter the atmosphere and electrify the air, which may create pathways for lightning channels.
The main charging area in a thunderstorm occurs in the central part of the storm where air is moving upward rapidly (updraft) and temperatures range from ; see Figure 1. In that area, the combination of temperature and rapid upward air movement produces a mixture of super-cooled cloud droplets (small water droplets below freezing), small ice crystals, and graupel (soft hail). The updraft carries the Supercooling cloud droplets and very small ice crystals upward. At the same time, the graupel, which is considerably larger and denser, tends to fall or be suspended in the rising air.
The differences in the movement of the cloud particles cause collisions to occur. When the rising ice crystals collide with graupel, the ice crystals become positively charged and the graupel becomes negatively charged; see Figure 2. The updraft carries the positively charged ice crystals upward toward the top of the storm cloud. The larger and denser graupel is either suspended in the middle of the thunderstorm cloud or falls toward the lower part of the storm. Typically, the upper part of the thunderstorm cloud becomes positively charged while the middle to lower part of the thunderstorm cloud becomes negatively charged. The above process of charge separation as a result of cloud particle collisions is normally referred to as the non-inductive charging mechanism.
The upward motions within the storm and winds at higher levels in the atmosphere tend to cause the small ice crystals (and positive charge) in the upper part of the thunderstorm cloud to spread out horizontally some distance from the thunderstorm cloud base. This part of the thunderstorm cloud is called the anvil. While this is the main charging process for the thunderstorm cloud, some of these charges can be redistributed by air movements within the storm (updrafts and downdrafts). In addition, there is a small but important positive charge buildup near the bottom of the thunderstorm cloud due to the precipitation and warmer temperatures. The positive-negative-positive charge regions commonly occur in mature thunderstorms, and referred to as the tripolar charge structure.
There are also other charging processes that may play a role in thunderstorms, but are generally thought to be less important. An inductive charging mechanism has been studied, and would arise from the polarization of cloud droplets in the presence of the fair-weather electric field. It has also been stated that uncharged, colliding water-drops can become charged because of charge transfer between them (as aqueous ions) in an electric field as would exist in a thunderstorm.
The induced separation of charge in pure liquid water has been known since the 1840s as has the electrification of pure liquid water by the triboelectric effect.Francis, G. W., "Electrostatic Experiments" Oleg D. Jefimenko, Editor, Electret Scientific Company, Star City, 2005 William Thomson (Lord Kelvin) demonstrated that charge separation in water occurs in the usual electric fields at the Earth's surface and developed a continuous electric field measuring device using that knowledge. The physical separation of charge into different regions using liquid water was demonstrated by Kelvin with the Kelvin water dropper. The most likely charge-carrying species were considered to be the aqueous hydrogen ion and the aqueous hydroxide ion. An electron is not stable in liquid water concerning a hydroxide ion plus dissolved hydrogen for the time scales involved in thunderstorms.Buxton, G. V., Greenstock, C. L., Helman, W. P. and Ross, A. B. "Critical Review of rate constants for reactions of hydrated electrons, hydrogen atoms and hydroxyl radicals (OH/O in aqueous solution." J. Phys. Chem. Ref. Data 17, 513–886 (1988). The electrical charging of solid water ice has also been considered. The charged species were again considered to be the hydrogen ion and the hydroxide ion.
When the local electric field exceeds the dielectric strength of damp air (about 3 MV/m), electrical discharge results in a strike, often followed by commensurate discharges branching from the same path. Mechanisms that cause the charges to build up to lightning are still a matter of scientific investigation. A 2016 study confirmed dielectric breakdown is involved. Lightning may be caused by the circulation of warm moisture-filled air through .Uman (1986) p. 61. Ice or water particles then accumulate charge as in a Van de Graaff generator.Rakov and Uman, p. 84.
As a thundercloud moves over the surface of the Earth, an equal electric charge, but of opposite polarity, is induced on the Earth's surface underneath the cloud. The induced positive surface charge, when measured against a fixed point, will be small as the thundercloud approaches, increasing as the center of the storm arrives and dropping as the thundercloud passes. The referential value of the induced surface charge could be roughly represented as a bell curve.
The oppositely charged regions create an electric field within the air between them. This electric field varies in relation to the strength of the surface charge on the base of the thundercloud – the greater the accumulated charge, the higher the electrical field.
The best-studied and understood form of lightning is cloud to ground (CG) lightning. Although more common, intra-cloud (IC) and cloud-to-cloud (CC) flashes are difficult to study because there are no fixed points to monitor inside the clouds. Also, because of the very low probability of lightning striking the same point repeatedly and consistently, scientific inquiry is difficult even in areas of high CG frequency.
It is possible for one end of the leader to fill the oppositely-charged well entirely while the other end is still active. When this happens, the leader end which filled the well may propagate outside of the thundercloud and result in either a cloud-to-air flash or a cloud-to-ground flash. In a typical cloud-to-ground flash, a bidirectional leader initiates between the main negative and lower positive charge regions in a thundercloud. The weaker positive charge region is filled quickly by the negative leader which then propagates toward the inductively-charged ground.
The positively and negatively charged leaders proceed in opposite directions, positive upwards within the cloud and Electric charge towards the earth. Both ionic channels proceed, in their respective directions, in a number of successive spurts. Each leader "pools" ions at the leading tips, shooting out one or more new leaders, momentarily pooling again to concentrate charged ions, then shooting out another leader. The negative leader continues to propagate and split as it heads downward, often speeding up as it gets closer to the Earth's surface.
About 90% of ionic channel lengths between "pools" are approximately in length.Goulde, R.H. (1977) "The lightning conductor", pp. 545–576 in Lightning Protection, R.H. Golde, Ed., Lightning, Vol. 2, Academic Press. The establishment of the ionic channel takes a comparatively long amount of time (hundreds of ) in comparison to the resulting discharge, which occurs within a few dozen microseconds. The electric current needed to establish the channel, measured in the tens or hundreds of , is dwarfed by subsequent currents during the actual discharge.
Initiation of the lightning leader is not well understood. The electric field strength within the thundercloud is not typically large enough to initiate this process by itself. Many hypotheses have been proposed. One hypothesis postulates that showers of relativistic electrons are created by cosmic rays and are then accelerated to higher velocities via a process called runaway breakdown. As these relativistic electrons collide and ionize neutral air molecules, they initiate leader formation. Another hypothesis involves locally enhanced electric fields being formed near elongated water droplets or ice crystals. Percolation theory, especially for the case of biased percolation, describes random connectivity phenomena, which produce an evolution of connected structures similar to that of lightning strikes. A streamer avalanche model has recently been favored by observational data taken by LOFAR during storms.
As negatively charged leaders approach, increasing the localized electric field strength, grounded objects already experiencing corona discharge will Corona breakdown and form upward streamers.
A large electric charge flows along the plasma channel, from the cloud to the ground, neutralising the positive ground charge as electrons flow away from the strike point to the surrounding area. This huge surge of current creates large radial voltage differences along the surface of the ground. Called step potentials, they are responsible for more injuries and deaths in groups of people or of other animals than the strike itself.Deamer, Kacey (August 30, 2016) More Than 300 Reindeer Killed By Lightning: Here's Why. Live Science Electricity takes every path available to it. Such step potentials will often cause current to flow through one leg and out another, electrocuting an unlucky human or animal standing near the point where the lightning strikes.
The electric current of the return stroke averages 30 kiloamperes for a typical negative CG flash, often referred to as "negative CG" lightning. In some cases, a ground-to-cloud (GC) lightning flash may originate from a positively charged region on the ground below a storm. These discharges normally originate from the tops of very tall structures, such as communications antennas. The rate at which the return stroke current travels has been found to be around 100,000 km/s (one-third of the speed of light). A typical cloud-to-ground lightning flash culminates in the formation of an electrically conducting plasma channel through the air in excess of tall, from within the cloud to the ground's surface.Uman (1986) p. 81.
The massive flow of electric current occurring during the return stroke combined with the rate at which it occurs (measured in microseconds) rapidly superheating the completed leader channel, forming a highly electrically conductive plasma channel. The core temperature of the plasma during the return stroke may exceed , causing it to radiate with a brilliant, blue-white color. Once the electric current stops flowing, the channel cools and dissipates over tens or hundreds of milliseconds, often disappearing as fragmented patches of glowing gas. The nearly instantaneous heating during the return stroke causes the air to expand explosively, producing a powerful shock wave which is heard as thunder.
Each re-strike is separated by a relatively large amount of time, typically 40 to 50 milliseconds, as other charged regions in the cloud are discharged in subsequent strokes. Re-strikes often cause a noticeable "strobe light" effect.Uman (1986) pp. 103–110.
To understand why multiple return strokes utilize the same lightning channel, one needs to understand the behavior of positive leaders, which a typical ground flash effectively becomes following the negative leader's connection with the ground. Positive leaders decay more rapidly than negative leaders do. For reasons not well understood, bidirectional leaders tend to initiate on the tips of the decayed positive leaders in which the negative end attempts to re-ionize the leader network. These leaders, also called recoil leaders, usually decay shortly after their formation. When they do manage to make contact with a conductive portion of the main leader network, a return stroke-like process occurs and a dart leader travels across all or a portion of the length of the original leader. The dart leaders making connections with the ground are what cause a majority of subsequent return strokes.
Each successive stroke is preceded by intermediate dart leader strokes that have a faster rise time but lower amplitude than the initial return stroke. Each subsequent stroke usually re-uses the discharge channel taken by the previous one, but the channel may be offset from its previous position as wind displaces the hot channel.Uman (1986) Ch. 9, p. 78.
Since recoil and dart leader processes do not occur on negative leaders, subsequent return strokes very seldom utilize the same channel on positive ground flashes which are explained later in the article.
The rapidly changing currents also create electromagnetic pulses (EMPs) that radiate outward from the ionic channel. This is a characteristic of all electrical discharges. The radiated pulses rapidly weaken as their distance from the origin increases. However, if they pass over conductive elements such as power lines, communication lines, or metallic pipes, they may induce a current which travels outward to its termination. The surge current is inversely related to the surge impedance: the higher in impedance, the lower the current. This is the Voltage spike that, more often than not, results in the destruction of delicate electronics, electrical appliances, or . Devices known as Surge protector attached in parallel with these lines can detect the lightning flash's transient irregular current, and, through alteration of its physical properties, route the spike to an attached earthing ground, thereby protecting the equipment from damage.
Many factors affect the frequency, distribution, strength and physical properties of a typical lightning flash in a particular region of the world. These factors include ground elevation, latitude, prevailing wind currents, relative humidity, and proximity to warm and cold bodies of water.
Lightning is usually produced by cumulonimbus clouds, which have bases that are typically above the ground and tops up to in height.
In general, CG lightning flashes account for only 25% of all total lightning flashes worldwide. The proportions of intra-cloud, cloud-to-cloud, and cloud-to-ground lightning may also vary by season at latitude. In the tropics, where the freezing level is generally higher in the atmosphere, only 10% of lightning flashes are CG. At the latitude of Norway (around 60° North latitude), where the freezing elevation is lower, 50% of lightning is CG.Uman (1986) Ch. 8, p. 68.
The place on Earth where lightning occurs most often is over Lake Maracaibo, wherein the Catatumbo lightning phenomenon produces 250 bolts of lightning a day. This activity occurs on average, 297 days a year.Fischetti, M. (2016) Lightning Hotspots, Scientific American 314: 76 (May 2016) The second most lightning density is near the village of Kifuka in the mountains of the eastern Democratic Republic of the Congo, where the elevation is around . On average, this region receives . Other lightning hotspots include Singapore and Lightning Alley in Central Florida.
Researchers at the University of Florida found that the final one-dimensional speeds of 10 flashes observed were between 1.0 and 1.4 m/s, with an average of 4.4 m/s.
According to the World Meteorological Organization, on April 29, 2020, a bolt 768 km (477.2 mi) long was observed in the southern U.S.—sixty km (37 mi) longer than the previous distance record (southern Brazil, October 31, 2018). A single flash in Uruguay and northern Argentina on June 18, 2020, lasted for 17.1 seconds—0.37 seconds longer than the previous record (March 4, 2019, also in northern Argentina).In 2025, scientists discovered the longest observed flash occurred in October 2017 across Texas and Kansas, measuring 829 km (515 mi). The flash, which was detected by NOAA’s Geostationary Lightning Mapper, touched ground in five states.
Lightning on Venus has been a controversial subject after decades of study. During the Soviet Venera and U.S. Pioneer program missions of the 1970s and 1980s, signals suggesting lightning may be present in the upper atmosphere were detected. The short Cassini–Huygens mission fly-by of Venus in 1999 detected no signs of lightning, but radio pulses recorded by the spacecraft Venus Express (which began orbiting Venus in April 2006) may originate from lightning on Venus.
Lightning at a sufficient distance may be seen and not heard; there is data that a lightning storm can be seen at over whereas the thunder travels about . Anecdotally, there are many examples of people describing a 'storm directly overhead' or 'all-around' and yet 'no thunder'. Since thunderclouds can be up to high, lightning occurring high up in the cloud may appear close but is actually too far away to produce noticeable thunder.
In other cases, the surrounding environment will change the shape of the source signal by absorbing some of its spectrum and converting it into a heat or re-transmitting it back as modified electromagnetic waves. (1984). 9780750626347, Butterworth-Heinemann. ISBN 9780750626347
A number of observations by space-based telescopes have revealed even higher energy gamma ray emissions, the so-called terrestrial gamma-ray flashes (TGFs). These observations pose a challenge to current theories of lightning, especially with the recent discovery of the clear signatures of antimatter produced in lightning. Recent research has shown that secondary species, produced by these TGFs, such as electrons, positrons, neutrons or protons, can gain energies of up to several tens of MeV.
Lightning-induced magnetic anomalies can be mapped in the ground, Archaeo-Physics, LLC | Lightning-induced magnetic anomalies on archaeological sites . Archaeophysics.com. Retrieved on June 23, 2012. and analysis of magnetized materials can confirm lightning was the source of the magnetization and provide an estimate of the peak current of the lightning discharge.
Lightning discharges generate a wide range of electromagnetic radiations, including radio-frequency pulses. The Earth-ionosphere waveguide traps electromagnetic VLF- and ELF waves. Electromagnetic pulses transmitted by lightning strikes propagate within that waveguide. The waveguide is dispersive, which means that their group velocity depends on frequency. The difference of the group time delay of a lightning pulse at adjacent frequencies is proportional to the distance between transmitter and receiver. Together with direction-finding methods, this allows locating lightning strikes up to distances of 10,000 km from their origin. Moreover, the eigenfrequencies of the Earth-ionospheric waveguide, the Schumann resonances at about 7.5 Hz, are used to determine the global thunderstorm activity.Volland, H. (ed) (1995) Handbook of Atmospheric Electrodynamics, CRC Press, Boca Raton, .
A number of countries have installed nationwide lightning detector networks. The United States federal
government has constructed a nationwide grid of such lightning detectors, allowing lightning discharges
to be tracked in real time throughout the continental U.S. NOAA page on how the U.S. national lightning detection system operates Real-time map of lightning discharges in U.S. The EUCLID detection network is a
combination of several national networks across Europe. Other examples of nations with lightning detection networks are India and Brazil. (2011). 9781457718977 ISBN 9781457718977
There are a range of global detection networks, which vary in their commercial and academic principles. Blitzortung (a private global detection system that consists of over 500 detection stations owned and operated by hobbyists/volunteers) provides near real-time lightning maps. The World Wide Lightning Location Network (WWLLN) is an academic led detection system. The Vaisala GLD360 network is a private enterprise.
In addition to ground-based lightning detection, several instruments aboard satellites have been constructed to observe lightning distribution. Some of the first satellite-based observations were made in the late 1970s. The global and tropical long-term climatology of lightning has been observed by the Optical Transient Detector (OTD), aboard the OrbView-1 satellite launched on April 3, 1995, and the subsequent Lightning Imaging Sensor (LIS) aboard TRMM launched on November 28, 1997. In addition, the ISS carried a LIS instrument for three years from March 2017.
Starting in 2016, the National Oceanic and Atmospheric Administration launched Geostationary Operational Environmental Satellite–R Series (GOES-R) weather satellites outfitted with Geostationary Lightning Mapper (GLM) instruments which are near-infrared optical transient detectors that can detect the momentary changes in an optical scene, indicating the presence of lightning. The lightning detection data can be converted into a real-time map of lightning activity across the Western Hemisphere; this mapping technique has been implemented by the United States National Weather Service. At the end of 2022, EUMETSAT launched the Lightning Imager (MTG-LI) on board the Meteosat Third Generation. This complements NOAA's GLM as MTG-LI will observe Europe and Africa.
A large share of the world's lightning occurs over Africa. While there are regional variations in how climate change affects lightning across the continent, one study predicts a small increase in the total amount of lightning across the continent with warming. More specifically, the total number of lightning days per year is predicted to decrease, while more cloud ice and stronger convection leads to more lightning strikes occurring on days when lightning does occur.
Lightning is much less common near the North and South Poles than in other regions. However, observations are beginning to show that lightning in the Arctic is increasing. and models suggest that climate change will continue to increase the frequency of lightning in the Arctic in future. The ratio of Arctic summertime lightning strikes has increased from 2010 to 2020 compared to the total lightning strikes in the world, indicating that the region is becoming more influenced by lightning.
Lightning activity is increased by particulate emissions (a form of air pollution). However, this only occurs up to a point (aerosol optical depth = 0.3). Once this threshold is crossed, lightning is then suppressed by further increases in particulates.
When lightning occurs, it generates rapid heating causing nitrogen and oxygen molecules in the atmosphere to break apart. This process leads to the formation of (NOx), which can subsequently result in the production of ozone, a greenhouse gas when occurring in the troposphere. However, lightning NOx also leads to increased amounts of Hydroxy group (OH) and hydroperoxyl (HO2) radicals. These reactive molecules initiate chemical reactions that break down greenhouse gases like methane, effectively cleaning the atmosphere.
Lightning leads to the production of tropospheric ozone and destruction of methane, both greenhouse gases and air pollutants. Therefore, the net impact of lightning on climate depends on the balance between this warming and cooling effect of the gases' effects on atmospheric chemistry. Predictions of this feedback can vary, resulting in either no change (net zero feedback), or a warming effect (positive feedback), depending on the method used to predict lightning.
Lightning is the major natural cause of wildfire, estimated to cause 10% of forest fires worldwide. Wildfire can contribute to climate change. Because wildfires emit greenhouse gases, and also affect vegetation cover (which affects how much sunlight is reflected), a lightning-wildfire feedback is possible. Multiple studies suggest there could be an increase in Taiga and Arctic lightning-ignited fires in response to climate change. There is evidence that arctic lightning wildfire feedback may also influence vegetation and permafrost cover. The impact of lightning on fires in the tropics remains uncertain.
In French and Italian, the expression for "Love at first sight" is coup de foudre and colpo di fulmine, respectively, which literally translated means "lightning strike".
Some political parties use lightning flashes as a symbol of power, such as the People's Action Party in Singapore, the British Union of Fascists during the 1930s, and the National States' Rights Party in the United States during the 1950s. Picture of John Kaspar of the National States Rights Party speaking in front of the party's lightning bolt flag (the flag was red, white, and blue) . Mauryk2.com (November 6, 2010). Retrieved on April 9, 2013. The Schutzstaffel, the paramilitary wing of the Nazi Party, used the Sig rune in their logo which symbolizes lightning. The German word Blitzkrieg, which means "lightning war", was a major offensive strategy of the German army during World War II.
The lightning bolt is a common insignia for military communications units. A lightning bolt is also the NATO symbol for a signal asset.
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