An overview of Earth's global electric circuit and atmospheric conductivity
The Earth’s global atmospheric electric circuit depends on the upper and lower atmospheric boundaries formed by the ionosphere and the planetary surface. Thunderstorms and electrified rain clouds drive a DC current (∼1 kA) around the circuit, with the current carried by molecular cluster ions; light...
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ftunivreading:oai:centaur.reading.ac.uk:1306 2024-05-19T07:32:01+00:00 An overview of Earth's global electric circuit and atmospheric conductivity Rycroft, Michael J. Harrison, R. Giles Nicoll, K. A. Mareev, Evgeny A. 2008-06 https://centaur.reading.ac.uk/1306/ https://doi.org/10.1007/s11214-008-9368-6 unknown Springer Rycroft, M. J., Harrison, R. G. <https://centaur.reading.ac.uk/view/creators/90000018.html> orcid:0000-0003-0693-347X , Nicoll, K. A. <https://centaur.reading.ac.uk/view/creators/90003611.html> and Mareev, E. A. (2008) An overview of Earth's global electric circuit and atmospheric conductivity. Space Science Reviews, 137 (1-4). pp. 83-105. ISSN 0038-6308 doi: https://doi.org/10.1007/s11214-008-9368-6 <https://doi.org/10.1007/s11214-008-9368-6> 551 Geology hydrology meteorology Article PeerReviewed 2008 ftunivreading https://doi.org/10.1007/s11214-008-9368-6 2024-04-24T00:08:20Z The Earth’s global atmospheric electric circuit depends on the upper and lower atmospheric boundaries formed by the ionosphere and the planetary surface. Thunderstorms and electrified rain clouds drive a DC current (∼1 kA) around the circuit, with the current carried by molecular cluster ions; lightning phenomena drive the AC global circuit. The Earth’s near-surface conductivity ranges from 10−7 S m−1 (for poorly conducting rocks) to 10−2 S m−1 (for clay or wet limestone), with a mean value of 3.2 S m−1 for the ocean. Air conductivity inside a thundercloud, and in fair weather regions, depends on location (especially geomagnetic latitude), aerosol pollution and height, and varies from ∼10−14 S m−1 just above the surface to 10−7 S m−1 in the ionosphere at ∼80 km altitude. Ionospheric conductivity is a tensor quantity due to the geomagnetic field, and is determined by parameters such as electron density and electron–neutral particle collision frequency. In the current source regions, point discharge (coronal) currents play an important role below electrified clouds; the solar wind-magnetosphere dynamo and the unipolar dynamo due to the terrestrial rotating dipole moment also apply atmospheric potential differences. Detailed measurements made near the Earth’s surface show that Ohm’s law relates the vertical electric field and current density to air conductivity. Stratospheric balloon measurements launched from Antarctica confirm that the downward current density is ∼1 pA m−2 under fair weather conditions. Fortuitously, a Solar Energetic Particle (SEP) event arrived at Earth during one such balloon flight, changing the observed atmospheric conductivity and electric fields markedly. Recent modelling considers lightning discharge effects on the ionosphere’s electric potential (∼+250 kV with respect to the Earth’s surface) and hence on the fair weather potential gradient (typically ∼130 V m−1 close to the Earth’s surface. We conclude that cloud-to-ground (CG) lightning discharges make only a small contribution to the ... Article in Journal/Newspaper Antarc* Antarctica CentAUR: Central Archive at the University of Reading Space Science Reviews 137 1-4 83 105 |
institution |
Open Polar |
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CentAUR: Central Archive at the University of Reading |
op_collection_id |
ftunivreading |
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topic |
551 Geology hydrology meteorology |
spellingShingle |
551 Geology hydrology meteorology Rycroft, Michael J. Harrison, R. Giles Nicoll, K. A. Mareev, Evgeny A. An overview of Earth's global electric circuit and atmospheric conductivity |
topic_facet |
551 Geology hydrology meteorology |
description |
The Earth’s global atmospheric electric circuit depends on the upper and lower atmospheric boundaries formed by the ionosphere and the planetary surface. Thunderstorms and electrified rain clouds drive a DC current (∼1 kA) around the circuit, with the current carried by molecular cluster ions; lightning phenomena drive the AC global circuit. The Earth’s near-surface conductivity ranges from 10−7 S m−1 (for poorly conducting rocks) to 10−2 S m−1 (for clay or wet limestone), with a mean value of 3.2 S m−1 for the ocean. Air conductivity inside a thundercloud, and in fair weather regions, depends on location (especially geomagnetic latitude), aerosol pollution and height, and varies from ∼10−14 S m−1 just above the surface to 10−7 S m−1 in the ionosphere at ∼80 km altitude. Ionospheric conductivity is a tensor quantity due to the geomagnetic field, and is determined by parameters such as electron density and electron–neutral particle collision frequency. In the current source regions, point discharge (coronal) currents play an important role below electrified clouds; the solar wind-magnetosphere dynamo and the unipolar dynamo due to the terrestrial rotating dipole moment also apply atmospheric potential differences. Detailed measurements made near the Earth’s surface show that Ohm’s law relates the vertical electric field and current density to air conductivity. Stratospheric balloon measurements launched from Antarctica confirm that the downward current density is ∼1 pA m−2 under fair weather conditions. Fortuitously, a Solar Energetic Particle (SEP) event arrived at Earth during one such balloon flight, changing the observed atmospheric conductivity and electric fields markedly. Recent modelling considers lightning discharge effects on the ionosphere’s electric potential (∼+250 kV with respect to the Earth’s surface) and hence on the fair weather potential gradient (typically ∼130 V m−1 close to the Earth’s surface. We conclude that cloud-to-ground (CG) lightning discharges make only a small contribution to the ... |
format |
Article in Journal/Newspaper |
author |
Rycroft, Michael J. Harrison, R. Giles Nicoll, K. A. Mareev, Evgeny A. |
author_facet |
Rycroft, Michael J. Harrison, R. Giles Nicoll, K. A. Mareev, Evgeny A. |
author_sort |
Rycroft, Michael J. |
title |
An overview of Earth's global electric circuit and atmospheric conductivity |
title_short |
An overview of Earth's global electric circuit and atmospheric conductivity |
title_full |
An overview of Earth's global electric circuit and atmospheric conductivity |
title_fullStr |
An overview of Earth's global electric circuit and atmospheric conductivity |
title_full_unstemmed |
An overview of Earth's global electric circuit and atmospheric conductivity |
title_sort |
overview of earth's global electric circuit and atmospheric conductivity |
publisher |
Springer |
publishDate |
2008 |
url |
https://centaur.reading.ac.uk/1306/ https://doi.org/10.1007/s11214-008-9368-6 |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_relation |
Rycroft, M. J., Harrison, R. G. <https://centaur.reading.ac.uk/view/creators/90000018.html> orcid:0000-0003-0693-347X , Nicoll, K. A. <https://centaur.reading.ac.uk/view/creators/90003611.html> and Mareev, E. A. (2008) An overview of Earth's global electric circuit and atmospheric conductivity. Space Science Reviews, 137 (1-4). pp. 83-105. ISSN 0038-6308 doi: https://doi.org/10.1007/s11214-008-9368-6 <https://doi.org/10.1007/s11214-008-9368-6> |
op_doi |
https://doi.org/10.1007/s11214-008-9368-6 |
container_title |
Space Science Reviews |
container_volume |
137 |
container_issue |
1-4 |
container_start_page |
83 |
op_container_end_page |
105 |
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1799469944744706048 |