Global atmospheric electrical circuit

The global atmospheric electrical circuit is the course of continuous movement of atmospheric electricity between the ionosphere and the Earth. Through solar radiation, thunderstorms, and the fair-weather condition, the atmosphere is subject to a continual and substantial electrical current.

Lightning strikes the earth 40,000 times per day[1]

Principally, thunderstorms throughout the world carry negative charges to the earth, which is then discharged gradually through the air in fair weather.[1]

This atmospheric circuit is central to the study of atmospheric physics and meteorology. It is used in the prediction of thunderstorms,[2] and was central to the understanding of electricity. In the past it has been suggested as a source of available energy, or communications platform.

The global electrical circuit is also applied to the study of human health and air pollution, due to the interaction of negative ions and aerosols. The effect of global warming, and temperature-sensitivity of the Earth's electrical circuit is unknown.[3]

History
The Wardenclyffe Power Plant attempted to use the earth's electrical circuit for telecommunications

In the 18th century, scientists began understanding the link between lightning and electricity. In addition to the iconic kite experiments of Benjamin Franklin and Thomas-François Dalibard, some early studies of electric charges in a "cloudless atmosphere" were done by John Canton, Giambatista Beccaria, and John Read.[4]

In 1752, Louis-Guillaume Le Monnier observed electrification in fair weather. Various others performed measurements throughout the late 18th century, often finding consistent diurnal variations. During the 19th century, several long series of observations were made. Measurements near cities were heavily influenced by smoke pollution. In the early 20th century, balloon ascents provided information about the electric field in the upper atmosphere. Important work was done by the research vessel Carnegie, which produced standardised measurements around the world's oceans (where the air is relatively clean).

C. T. R. Wilson was the first to present a theory of a global circuit in 1920.

Mechanism

Lightning
Main article: Lightning

Lightning strikes the earth 40,000 times per day,[1] and can be thought to charge the earth like a battery. Thunderstorms generate an electrical potential difference between the earth's surface and the ionosphere, mainly by means of lightning. Because of this, the ionosphere is positively charged relative to the earth. Consequently, there is always a small current transporting charged particles between the ionosphere and the surface.

Fair weather condition

This current is carried by a small number of ions present in the atmosphere (generated mainly by cosmic rays in the upper atmosphere, and by radioactivity near the surface). Different locations, and meteorological conditions on the earth can have different electrical conductivity. Fair weather condition describes the state of atmospheric electricity where air carries this electrical current between the earth and the ionosphere.

Measurement

The voltages involved in the Earth's circuit are significant. At sea level, the typical potential gradient in fair weather is 120 V/m. Nonetheless, since the conductivity of air is limited, the associated currents are also limited. A typical value is 1800 A over the entire planet. When it is not rainy or stormy, the amount of electricity within the atmosphere is typically between 1000 and 1800 amps. In fair weather conditions, there are about 3.5 microamps per square kilometer (9 microamps per square mile).[5] This can produce a 200+ volt difference between the head and feet of a regular person.

Local turbulence, winds, and other fluctuations also cause small variations in the fair weather electric field, causing the fair-weather condition to be partially regional.[3]

Carnegie curve

The Earth's electrical current varies according to a daily pattern called the Carnegie curve, believed to be caused by the regular daily variations in atmospheric electrification associated with the earth's weather regions.[6] The pattern also shows seasonal variation, linked to the earth's solstices and equinoxes. It was named after the Carnegie Institution for Science.

See also

External sources

Publications
  • Le Monnier, L.-G.: "Observations sur l'Electricité de l'Air", Histoire de l'Académie royale des sciences (1752), pp. 233ff. 1752.
  • Sven Israelsson, On the Conception Fair Weather Condition in Atmospheric Electricity. 1977.
  • Ogawa, T., "Fair-weather electricity". J. Geophys. Res., 90, 5951–5960, 1985.
  • Wåhlin, L., "Elements of fair weather electricity". J. Geophys. Res., 99, 10767-10772, 1994
  • RB Bent, WCA Hutchinson, Electric space charge measurements and the electrode effect within the height of a 21 m mast. J. Atmos. Terr. Phys, 196.
  • Bespalov P.A., Chugunov Yu. V. and Davydenko S.S., Planetary electric generator under fair-weather condition with altitude-dependent atmospheric conductivity, Journal of Atmospheric and Terrestrial Physics, v.58, #5,pp. 605–611,1996
  • DG Yerg, KR Johnson, Short-period fluctuations in the fair weather electric field. J. Geophys. Res., 1974.
  • T Ogawa, Diurnal variation in atmospheric electricity. J. Geomag. Geoelect, 1960.
  • R Reiter, Relationships Between Atmospheric Electric Phenomena and Simultaneous Meteorological Conditions. 1960
  • J. Law, The ionisation of the atmosphere near the ground in fair weather. Quarterly Journal of the Royal Meteorological Society, 1963
  • T. Marshall, W.D. Rust, M. Stolzenburg, W. Roeder, P. Krehbim A study of enhanced fair-weather electric fields occurring soon after sunrise.
  • R Markson, Modulation of the earth's electric field by cosmic radiation. Nature, 1981
  • Clark, John Fulmer, The Fair Weather Atmospheric Electric Potential and its Gradient.
  • P. A. Bespalov, Yu. V. Chugunov and S. S. Davydenko, Planetary electric generator under fair-weather conditions with altitude-dependent atmospheric conductivity.
  • AM Selva, et al., A New Mechanism for the Maintenance of Fair Weather Electric Field and Cloud Electrification.
  • M. J. Rycroft, S. Israelssonb and C. Pricec, The global atmospheric electric circuit, solar activity and climate change.
  • A. Mary Selvam, A. S. Ramachandra Murty, G. K. Manohar, S. S. Kandalgaonkar, Bh. V.Ramana Murty, A New Mechanism for the Maintenance of Fair Weather Electric Field and Cloud Electrification. arXiv:physics/9910006
  • Ogawa, Toshio, Fair-Weather electricity. Journal of Geophysical Research, Volume 90, Issue D4, pp. 5951–5960.
  • An auroral effect on the fair weather electric field. Nature 278, 239–241 (15 March 1979); doi:10.1038/278239a0
  • Bespalov, P. A.; Chugunov, Yu. V., Plasmasphere rotation and origin of atmospheric electricity. Physics – Doklady, Volume 39, Issue 8, August 1994, pp. 553–555
  • Bespalov, P. A.; Chugunov, Yu. V.; Davydenko, S. S. Planetary electric generator under fair-weather conditions with altitude-dependent atmospheric conductivity. Journal of Atmospheric and Terrestrial Physics.
  • A.J. Bennett, R.G. Harrison, A simple atmospheric electrical instrument for educational use

Patents

References
  • Harrison, R.G. (2004). "The global atmospheric electrical circuit and climate". Surveys in Geophysics. 25 (5–6): 441–484. arXiv:physics/0506077. Bibcode:2004SGeo...25..441H. doi:10.1007/s10712-004-5439-8.
  • Singh, A.K. (2011). "Electrodynamical coupling of Earth's Atmosphere and Ionosphere: An Overview". International Journal of Geophysics. 2011: 1–13. doi:10.1155/2011/971302.
  1. Electricity in the Atmosphere – Feynman Lectures
  2. "Mission Instruments: Electric Fields". www.missioninstruments.com. Retrieved 5 November 2017.
  3. "Soaking in atmospheric electricity | Science Mission Directorate". science.nasa.gov. Retrieved 5 November 2017.
  4. Bennett, A. J.; Harrison, R. G. (1 October 2007). "Atmospheric electricity in different weather conditions". Weather. 62 (10): 277–283. Bibcode:2007Wthr...62..277B. doi:10.1002/wea.97. ISSN 1477-8696.
  5. Elert, Glenn. "Electric Current through the Atmosphere – The Physics Factbook". hypertextbook.com. Retrieved 3 November 2017.
  6. Harrison, R. Giles (1 March 2013). "The Carnegie Curve". Surveys in Geophysics. 34 (2): 209–232. Bibcode:2013SGeo...34..209H. doi:10.1007/s10712-012-9210-2. ISSN 0169-3298.
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