116:(capping out at around 90%). However, this phenomenon also correlates to some long-term ozone depletion as well. Studies have revealed that 60 major electron precipitation events occurred from 2002 to 2012. Different measurement tools (see below) read different ozone depletion averages ranging from 5-90%. However, some of the tools (specifically the ones that reported lower averages) did not take accurate readings or missed a couple of years. Typically, ozone depletion resulting from electron precipitation is more common during the winter season. The largest EEP event from the studies during 2002 to 2012 was recorded in October 2003. This event caused an ozone depletion of up to 92%. It lasted for 15 days and the ozone layer was fully restored a couple of days afterwards. EEP ozone depletion studies are important for monitoring the safety of Earth's environment and variations in the
83:, caused by lightning or powerful transmitters, propagate through the radiation belt. When those VLF waves hit the electrons with the same frequency as an electron's gyrofrequency, the electron exits the radiation belt and "precipitates" (because it will not be able to re-enter the radiation belt) throughout the Earth's atmosphere and ionosphere.
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With Sub-ionospheric
Detection, a signal is sent from a VLF transmitter through the radiation belt to a VLF receiver on the other end. The VLF signal will cause some electrons to precipitate, thus disturbing the VLF signal before it reaches the VLF receiver on the other end. The VLF receiver measures
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In order to cause electron precipitation, transmitters must produce very powerful waves with wavelengths from 10 to 100 km. Naval communication arrays often cause transmitter-induced precipitation of electron radiation (TIPER) because powerful waves are needed to communicate through water. These
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In most cases, satellite measurements of electron precipitation are actually measurements of ozone depletion that is then linked to EEP events. The different instruments use a wide variety of methods to calculate ozone levels. While some of the methods may provide significantly inaccurate data, the
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Often, as an electron precipitates, it is directed into the upper atmosphere where it may collide with neutral particles, thus depleting the electron's energy. If an electron makes it through the upper atmosphere, it will continue into the ionosphere. Groups of precipitated electrons can change the
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VLF Remote
Sensing is a technique of monitoring electron precipitation by monitoring VLF transmissions from the U.S. Navy for "Trumi Events" (large changes of phase and amplitude of the waves). Although this method can monitor electron precipitation, it cannot monitor the ionization of said
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is released which can hit the trapped electrons in the radiation belt. The electrons are then dislodged and "precipitate" into the Earth's atmosphere. Because the EMP caused by lightning strikes is so powerful and occurs over a large range of spectrums, it is known to cause more electron
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shape and conductivity of the ionosphere by colliding with atoms or molecules (usually oxygen- or nitrogen-based particles) in the region. When colliding with an atom, the electron strips the atom of its other electrons creating an ion. Collisions with the air molecules also release
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The
Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) is a measurement instrument aboard NASA's Thermal Ionosphere Mesosphere Energetics Dynamics (TIMED) satellite. The instrument measures ozone (and other atmospheric conditions) through an
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PIPER is a
Stanford-made photometer specifically designed for capturing the photons emitted when ionization occurs in the ionosphere. Researchers can use this data to detect EEP events and measure the amount of precipitated electrons.
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occurs and certain communications may be disrupted. The lowered altitude of the ionosphere is temporary (unless electron precipitation is steady) while the ions and electrons rapidly react to form neutral particles.
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to take into account the strengths and weaknesses of a large set of different measurement methods. They then use that collected data to calculate when an EEP event is taking place and its effects on the atmosphere.
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equipment can be used in conjunction with other equipment to measure electron precipitation. Because x-rays are emitted during electron collisions, x-rays found in the ionosphere can be correlated to EEP events.
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powerful transmitters are operating at almost all times of the day. Occasionally, these waves will have the exact heading and frequency needed to cause an electron to precipitate from the radiation belt.
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The ionization process, caused by electron precipitation in the ionosphere, increases its electrical conductivity which in turn brings the bottom of the ionosphere to a lower altitude. When this happens,
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The next advancement of research of electron precipitation was performed by
Winckler with his group from the university of Minnesota. They used balloons that carried detectors into the atmosphere.
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Voss, H. D.; Imhof, W. L.; Walt, M.; Mobilia, J.; Gaines, E. E.; Reagan, J. B.; Inan, U. S.; Helliwell, R. A.; Carpenter, D. L. (1984-12-20). "Lightning-induced electron precipitation".
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The Medium Energy Proton
Electron Detector (MEPED) measures electrons in the Earth's radiation belt and can estimate the amount of precipitating electrons in the ionosphere.
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188:. It measures ozone amounts by using the emitted electromagnetic spectrum from surrounding stars combined with trigonometric calculations in a process called stellar
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from the State
University of Iowa with his group, were the first to use vehicles with sensors to study electron fluxes precipitating in the atmosphere with
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Lightning-induced electron precipitation (also referred to as LEP) occurs when lightning strikes the Earth. When a bolt of lightning strikes the ground, an
221:, measures microwave emission from the Earth's upper atmosphere. This data can help researchers find the levels of ozone depletion to an accuracy of 35%.
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Electron precipitation can be studied by using various tools and methods to calculate its effects on the atmosphere. Scientists use
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35:, thus creating communications interferences and other disturbances. Electrons trapped by Earth's magnetic field spiral around
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Electron precipitation can be caused by VLF waves from powerful transmitter based communications and lightning storms.
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waves propagate the radiation belts, the electrons exit the radiation belt and "precipitate" (or travel) into the
455:"Monitoring Energetic Electron Precipitation | ABOVE: an Array for Broadband Observations of VLF/ELF Emissions"
95:" effect. Because this occurs at such a high altitude, humans in aircraft are not affected by the radiation.
491:"Missing driver in the Sun–Earth connection from energetic electron precipitation impacts mesospheric ozone"
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547:"Ozone Depletion Information, Ozone Depletion Facts, Ozone Layer, Ozone Hole - National Geographic"
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and may remain trapped above Earth for an indefinite period of time (in some cases years). When
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Andersson, M. E.; Verronen, P. T.; Rodger, C. J.; Clilverd, M. A.; Seppälä, A. (2014-10-14).
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is the number of times it revolves around a field line. VLF waves traveling through the
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323:"Ground Observations of Lightning-Induced Electron Precipitation | Stanford VLF Group"
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400:"Transmitter-Induced Precipitation of Radiation Belt Electrons | Stanford VLF Group"
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these disturbances and uses the data to estimate amount of precipitated electrons.
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rockets. The rockets would reach a maximum height of 50 km. The
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Electron precipitation can lead to a substantial, short-term loss of
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average of all of the data combined is widely accepted as accurate.
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is a measurement instrument aboard the
European satellite
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Global Ozone
Monitoring by Occultation of Stars (GOMOS)
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precipitation than transmitter induced precipitation.
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Brown, R. R. (1966). "1966SSRv....5..311B Page 311".
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287:detected was later named after Van Allen in 1957.
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59:. Electron precipitation is regularly linked to
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167:Satellite measurements
17:Electron precipitation
604:Space Science Reviews
557:on September 28, 2011
495:Nature Communications
91:which provide a dim "
616:1966SSRv....5..311B
551:National Geographic
507:2014NatCo...5.5197A
363:1984Natur.312..740V
203:infrared radiometer
154:Measurement Methods
624:10.1007/BF02653249
580:saber.gats-inc.com
515:10.1038/ncomms6197
433:. 14 December 2010
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33:Earth's atmosphere
357:(5996): 740–742.
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561:2015-10-26
464:2015-10-21
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409:2015-10-21
332:2015-10-19
294:References
53:ionosphere
45:solar wind
31:enter the
632:120910695
29:electrons
652:Electron
646:Category
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501:: 5197.
431:GeoSpace
612:Bibcode
524:4214406
503:Bibcode
379:4302334
359:Bibcode
281:rockoon
272:History
186:Envisat
89:photons
71:Process
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351:Nature
251:X-rays
93:aurora
628:S2CID
375:S2CID
256:X-ray
242:PIPER
225:MEPED
196:SABER
176:GOMOS
124:Types
114:ozone
529:PMID
213:The
180:The
57:ions
620:doi
519:PMC
511:doi
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355:312
209:MLS
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