LIGHTNING

1. LIGHTNING

2. Background Information • Lightning occurs about 2000 times at any one moment. • Thunderstorms thrive under certain conditions. The two most basic elements that cause a thunderstorm to develop are: • Moisture • Rapidly rising warm air • A lightning flash is composed of a series of strokes with an average of about four. The length and duration of each lightning stroke vary, but typically average about 30 microseconds. (The average peak power per stroke is about 1012 watts). Occurs when the air can’t insulate the charges any longer.

3. When the potential becomes great enough, electricity punches its way through air that normal insulates, and builds a narrow bridge of electrified gas or plasma. • The current burrows its way in search of an oppositely charged region where the imbalance can be relieved. When the two are joined, current flows freely and ionizes even more air on its path, thus creating the glowing hydra that we see as a lightning bolt. • NCAR found that clouds become electrified only after significant amounts of ice particles and supercooled water form at heights above the freezing level. • Negative cloud charge tends to develop in cells or blobs, rather than the uniform layers previously theorized.

4. Lightning Bolts • Happens in a series of stages. First, a faint step leader emerges from the base of the cloud, moving towards the ground in steps of 50 meters or so. Branching as it goes down, which is why so many lightning bolts "fork". • As the step leader nears the ground, it attracts "streamers" of positive charge from the ground. When it finally connects with one of these streamers, a brilliant return stroke occurs as the charge drains out of the ionized path. The return stroke travels upwards as the ground charge goes first. This process can be repeated up to 40 times, which is why so many seem to flicker.

5. Some chemistry about lightning • When lightning occurs, sometimes you can smell it. Intense heat & electrical current produce mini-chemical factory where O2 and N2 are broken down into ions. Some reform into O2 and N2 but a significant number form Nitrous oxide compounds. • O2 + N2 electric current + intense heat from lightningNO , NO2 , NOx O2 + N2

6. In the 1983 Global Troposphere Experiment, aircraft sampled the air inside two cumulonimbus clouds and found that the levels of NO had risen 50-fold, from 20 to 1000 parts per trillion. • If this proves to be true of all thunderclouds, then lightning especially cloud-to -cloud flashes closer to the stratosphere could be a significant producer of chemicals that deplete the Earth's protective ozone layer.

7. Theories • Scientists know that lightning occurs due to a separation of charged particles, but the mechanism behind acquiring the charges still remains unknown. There are a variety of theories which have been put forward. • The theories are: • Cosmic particles bombarding the atmosphere from space • Dust particles rubbing against each other • Large particle, small particle updraft theory (ICE) • Electro-release condensation theory

8. Cosmic Particle Theory • Some scientists suggest lightning is the result of cosmic particles coming from space • Least respected/documented theory If this were the case, why don’t we see an increase in the frequency of lightning at solar maximum, a decrease at solar minimum, or just an overall fluctuation in lightning frequencies?

9. Dust Particle Theory Some scientists suggest that dust particles from volcanic eruptions, forest fires or human induced pollution create this potential for lightning, by bumping into each other then separating the charged particles. If this were the case we would be able to see a marked increase in storm intensities when dust particles interacted with cloud nuclei. But dust particles do influence the type of lightning as discussed later concerning positive cloud to ground strikes.

10. Ice Theory • The most accepted view of how charge separation occurs…but not necessarily right. • Water cycle. Clouds can suspend millions of water/ice particles. • Collisions with other particles due to evaporation/condensation. • Electrons knocked off rising moisture - Collect at the bottom as positive moisture particles rise above them by strong updrafts • As moisture particles get higher, begin to freeze – giving them negative charge and then fall back down to earth. • The problem with this is that storms that contain no ice still produce lightning so their must be something else going on which explains why lightning occurs, although it still has to do with the water cycle.

11. Electro – Release Condensation • NASA has shown that there is a correlation between the volume of rain in a storm and the amount of lightning. • Although not established fact, it does fit the parameters for lightning. • The theory is based on the Mills Law of Electron Transfer Via Matter State Changes.

12. Mills Law of Electron Transfer Via Matter State Changes • States that when matter changes states, there will be a corresponding transfer of electrons. • Predicts condensing areas have negative areas or surplus of electrons. • Dissipating parts due to evaporation will have positive charge and loss of electrons. • Freezing/thawing. • Volume + rapidity of condensation determines the amount of lightning produced.

13. The Chemistry Of This • Water molecules in liquid state share electrons covalently enabling H2O molecules to exist at a lower energy level, the factor making them behave as a liquid. • H2Oliq + heat locks up e- in complete outer sub shell. • Molecule now free to act as a gas & refuses to share electrons, leaving behind fewer electrons to be shared by the rest of liquid water.

14. The Chemistry Continued. • As the gas H2O lose heat energy, also lose ability to maintain full outer shell of e- • Gas molecules forced to condense with each other, sharing e- • Giving up surplus of heat & e- can no longer afford to hold. • If condensation occurs quick + sufficient enough, a lightning storm will ensue.

15. Evidence For The Theory • Research by two separate teams, Studwell and Orville (1995) and Holle and Watson, (1996) discovered a majority of positive flashes, in areas of freezing rain. As water freezes it becomes negatively charged. Since freezing rain becomes frozen on contact with the ground, it imparts a negative charge to the ground on freezing. Any discharge would be a positive flash! • Laboratory experiments directed by E J Workman at the New Mexico Institute of mining and technology back up the freezing rain theory by showing that when dilute solutions of water are frozen, a large electric potential develops between the water and the ice. The experiments show that the ice gains a negative charge while the water retains a positive charge. Again exactly what the theory of Electron Transfer Via Matter State Change predicts.

16. Summary • Expect more storms on the plains + southern states of U.S where potential for large amounts of moisture can rise to great heights and cooled quickly, hot & cool air collide. • NW U.S and Canada plenty of moisture but not warm enough, so condensation has chance to bleed off resulting in drizzle with few storms. • Explains all the observable results shown by experiments

17. Houston, Lightning Capital of Texas • 12 year study by Texas A&M concluded that lightning strikes Houston more than anywhere else. • 4-5 million people in area plus 50% petroleum refineries in U.S create massive heat island. • Results in increased cumulous clouds formation and more intense storms. • 1.6 million cloud-to-ground flashes with 75% during summer

18. Other Facts from Houston • Air pollution considered a factor relating to lightning frequency. Affecting the mix of water and ice in a thunderstorm which affects the charging process. • Also aerosols from urban areas may increase the flash density which has been observed in Houston area.

19. Florida Scientist’s Research • According to Joseph Dwyer, physics Prof. at Florida tech. conditions we thought necessary for lightning do not occur in nature. • For generations we thought that the electric fields must be enormous to create such a charge. • Scientists have been searching for these for years but come up empty handed. • Not looking hard enough? No just don’t exist. • New limit in nature, like water in a bucket, stunted by gamma rays and anti-matter positrons.

20. Lightning and Tornadoes? • When scientists from a dozen universities + instruments took to a corn field on the Kansas/Colorado border they came up with some surprising results. • Most importantly, researchers witnessed several events within storms that seemed to predict when tornadoes form. They noticed several updraft areas where lightning would suddenly cease, then seconds later, a tornado would form. • Importance of this is better prediction by weather-forecasters for severe weather. Use of instruments to collect data on positive strikes - special radar stations

21. Apart from their results on positive cloud to ground strikes which I will discuss in a minute they found new clues which might explain strange lights observed in upper atmosphere above clouds called red sprites, blue jets, trolls and elves. • Sprites which can be seen by naked eye are glowing ribbons which rise high above blue jets, last for 3-10 milli. secs. But they only occur over positive cloud to ground strikes. A Sprite can exceed 10 million meters a second

22. Blue Jets • Blue jets are extremely energetic fields of charged particles that rise up to 30 miles from the tops of clouds. After they occur, lightning stops for several seconds. • These are very rare and not much is known about them but they can reach speeds of 100,000 metres a second.

23. Positive Cloud to Ground Strikes • In a positive-to-ground lightning strike, positive charges first rush from the cloud to the ground, creating a lightning channel through which electrons flow from the ground back up to the cloud. Such lightning strikes tend to carry more charge, last tens of seconds longer and be less branched than the more common negative-to-ground lightning. • The presence of smoke, dust, or pollution seems to encourage the development of positive flashes. This is probably because of the particles' effect on the number and sizes of ice crystals within storms. A study in the journal Science (10/2/98) examined thunderstorms in the Southern Plains during the spring of 1998, when smoke from Mexican forest fires was flowing northward over the region. Up to three times the usual number of positive flashes were observed in these smoke-altered storms.

24. Pavel Jungwirth Paper • Too much info but basically their work was on how different compounds affect the polarity of lightning strikes. • Under normal conditions, when sulfates dominate as cloud condensation nuclei, this ionic mechanism is consistent with the prevailing negative lightning in thunderstorms. But with the decrease of sulfate anions, the present mechanism predicts a shift towards positive charging. This fits well to a large range of observations of enhanced positive lightning, connected with smoke, rich in chlorides and nitrates, that could not be previously explained. • Performed tens of such collision simulations, have always observed transfer of several to several tens of water molecules, 1-8 ammonium cations, and 0-3 sulfate dianions from the graupel (snowflake crystals falling through very moist air) to the ice crystal. In all cases, the number of transferred ammonium cations was larger than twice the number of sulfate dianions. Consequently, these collisions led to positive charging of the ice crystal (and negative charging of the graupel).

25. Links to Aerosols and Forest Fires • Under certain atmospheric conditions (biomass burning or forest fires) a large amount of aerosols containing other soluble ions, such as potassium cations and chloride and nitrate anions are released into the atmosphere. • The present simulations indicate that replacing the sulfate dianion with monovalent anions such as chloride or nitrate leads to an opposite polarity of charging during graupel-ice crystal collisions, due to the change in the salt solution covering the graupel.

26. The fires in the south of Mexico in 1998 accumulated for a tripling of positive lightning over the U.S. The median peak current was increased by over 20 kA. Chemical analysis of the smoke that reached the USA, showed that the fraction of nitrate and organic anions was greater than in the ambient aerosols. • A very clear signal was also obtained from cumulimbus clouds fed directly from forest fires in the USA and Canada. Latham (1991) documented that a large prescribed fire in Canada caused a pyrocumulus storm that had produced exclusively 21 positive cloud to ground flashes, whereas other thunderclouds in the vicinity that did not ingest the smoke produced tens of “normal” negative flashes. • Canadian scientists suggested positive lightning was responsible for the fires because of their higher energy and they persist longer. Positive feedback loop.

27. NASA Discoveries • Lightning prefers afternoons, believed due to the land absorbing heat and causing strong convection. • Patterns change each year, tremendous variations outside the tropics. As summer progresses in N Hemis. Lightning moves further north. • Strong updrafts which cause lightning relate to stronger storms, predictions on type of storm. • C-C lightning more energetic than C-G more likely to produce violent storms.

28. This map depicts the ratio of cloud-to-cloud lightning to cloud-to-ground lightning over U.S. The red areas show where the ratio is as high as 10 cloud-to-cloud strikes for every ground strike. Blue areas indicate ratios as low as 1:1. red predicted to be more energetic/violent

29. Benefits of Lightning • This last section is something I found that links lightning strikes to health, but in a good way. • After a storm, the air feels clean and fresh, filled with negative ions. In a thunderstorm, positive ions precede a strike, followed by negative ions after it.

30. The air we breathe contains both + & - ions, a lack of or imbalance of these ions has been proven to affect us and our environment. • Research shows that most of us who live, work and travel in closed spaces suffer some degree of negative ion starvation or positive ion overabundance. This has become extremely evident to NASA in their space travel program.    • In cities like New York, Los Angeles, Hong Kong, Tokyo and Mexico City and many densely populated cities, there may be few or no detectable negative ions at all during heavy traffic and high pollution periods.

31. Winds of Depression • The natural production of ions may result from solar or cosmic radiation or the more mundane friction between air masses such as between rapidly moving hot, dry air and the ground. These are the "Witches Winds" that cause such discomfort periodically to the population in certain areas of the world. • In these areas, the seasonal winds have become legendary, bringing misery and chaos to many of the local people. In these places it has been known for generations, that the winds bring feelings of anxiety, stress, depression and sleepless nights. • Statistics show that when they blow, more road accidents happen and suicide rates increase. • So real is the problem that it has been known for judges to take this into consideration when sentencing, and for hospitals to postpone some operations until the winds cease!  

32. The Ion Effect • There are some amazing clues to how an excess of positive ions and a lack of negative ions can produce uncomfortable effects, Studied by the Dr. Albert Krueger, Professor Emeritus of the University of California at Berkeley. • Dr. Krueger demonstrated that small air ions are biologically active and can stimulate the over-production of the powerful neurotransmitter serotonin. Serotonin is a very active neurohormone causing profound nerve, glandular and digestive effects throughout the body.

33. Negative ions can provide major benefits for asthma, chronic fatigue syndrome, hay fever, allergies, sleep & snoring, depression, sinus, migraines, colds & flu, nausea, chemical sensitivity, cigarette smoke & other odors, computers & office pollution.  • The earth's atmosphere is absolutely full of ions. Nature was making them even before life began. • Western scientists believe that ionization, in the form of lightning, was probably instrumental in the formation of amino acids - essential components for the beginnings of life! 

34. Conclusions / What I have learnt • Non sulfate particles affect the amount of +ive lightning strikes. • Sprites + Jets • Links to tornado/weather prediction • Limitations of electric field size in the atmosphere. • Urban heat affect, increases convection of cool air with warm air.