The interchange of electricity between thunderclouds and the Earth

Prof. C. T. R. Wilson has suggested that the exchange of electricity between thunderclouds and the ground may be an important factor in the maintenance of the earth’s negative charge, the replenishment of which, in view of the fine-weather air-earth current, is an outstanding problem in atmospheric electricity. He has shown that such an exchange can take place in three ways, by the momentary currents due to lightning discharges between the cloud and the ground, by the convection currents carried by rain, and by the continuous currents carried by ions moving in the powerful electric fields below the cloud. This last effect may be expected to be considerable since such ions will be produced in quantity as a result of point-discharges from trees and bushes below the cloud. In the present paper an attempt is made to estimate the magnitudes of these three factors in the exchange. Before describing the measurements, it may be recalled that in two studies of the strong electric fields below these clouds, it has been found that negative potential gradients are very much more frequent and considerably stronger than positive ones. Indeed, occasions of strong positive fields below active thunderclouds are so rare as to be negligible, and the predominance of strong negative fields must cause the point-discharge currents to be mainly upwardly directed. The earth must therefore gain a negative charge from this effect.

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The electric fields of South African thunderstorms

Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character ◽

10.1098/rspa.1927.0038 ◽

1927 ◽

Vol 114 (767) ◽

pp. 229-243 ◽

Cited By ~ 35

Keyword(s):

South African ◽

Electric Fields ◽

Negative Charge ◽

Reverse Current ◽

Positive Polarity ◽

The Earth ◽

Fine Weather ◽

Lightning Discharges ◽

Positively Charged ◽

Made In

The quantitative study of the electrical changes taking place in thunderstorms was initiated and has been developed by Prof. C. T. R. Wilson in two important papers. Measurements of the electric fields due to charged clouds and of the field changes associated with lightning discharges have led him to put forward certain views according to which the thunderstorm is an important factor in the production and maintenance of several electro-meteorological phenomena with which it has not previously been considered connected. Chief amongst these is the negative charge on the surface of the earth, for the replenishment of which the views of Wilson require a certain preponderance of thunderclouds of positive polarity, i.e ., positively charged above and negatively charged below, over clouds of negative polarity, the ionisation currents between the bases of the clouds of the former type and the ground serving to maintain the earth’s charge at a steady value in spite of the reverse current flowing in regions of fine weather. It is necessary, in order to test this theory, that observations be made in different parts of the world to examine whether the required preponderance of clouds of positive polarity exist. For this purpose South Africa, which contributes largely to the world’s supply of thunderstorms, is very suitable.

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Vertical electric currents below thunderstorms and showers

Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character ◽

10.1098/rspa.1930.0077 ◽

1930 ◽

Vol 127 (806) ◽

pp. 567-590 ◽

Cited By ~ 47

Keyword(s):

Electric Fields ◽

Potential Gradient ◽

Heavy Rain ◽

Weather Conditions ◽

The Earth ◽

Continuous Record ◽

Long Time ◽

Potential Gradients ◽

Strong Electric Fields ◽

Definite Period

In a previous paper an account has been given of apparatus which was found to be suitable for studying the discharge of electricity from a raised metal point in the strong electric fields which occur at the surface of the ground during thunderstorms and showers. The two methods of observation which were employed consisted, first, in measuring the quantity of electricity of each sign which was discharged from the point in a definite period of time, usually the duration of a storm; and secondly, in obtaining a continuous record of the current from the point throughout a storm. Observations on a number of thunderstorms and showers over a period of several months, by the first method, showed that there was a considerable preponderance of upward discharges of positive electricity, indicating that negative gradients of potential predominated at the surface of the ground in such disturbed weather conditions. Some examples of records obtained by the second method were also given. In the present paper, results obtained by the first method over a period of two years are discussed, the observations including all occasions, during that time, on which intense electric fields existed at the observing station for a sufficiently long time to cause a measurable quantity of electricity to be discharged from the point. (The smallest quantity which would be detected by the integrating device is about 0·1 milli-coulomb.) The preponderance of negative potential gradients during periods of intense electric field has been confirmed over the longer period of time. Records obtained by the second method are also described, and their bearing on the question of the polarity of the clouds is discussed. For this purpose, the method of observation is simply a convenient way of obtaining an unambiguous continuous record of the sign of the potential gradient, and a rough estimate of its magnitude, throughout periods of heavy rain. Finally, the problem of the total interchange of electricity between the earth and the atmosphere from known causes is re-discussed, utilising the results already given.

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Currents carried by point-discharges beneath thunderclouds and showers

Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character ◽

10.1098/rspa.1927.0102 ◽

1927 ◽

Vol 115 (771) ◽

pp. 443-455 ◽

Cited By ~ 17

Keyword(s):

Electric Fields ◽

Great Majority ◽

Vertical Position ◽

Convection Current ◽

External Diameter ◽

Positive Polarity ◽

The Earth ◽

Fine Weather ◽

Point Discharge ◽

Total Exchange

1.— Introduction. The present paper describes experimental methods employed for investigating the sign and magnitude of the vertical current due to the point-discharge of electricity from an elevated metal point, during the intense electric fields associated with thunderstorms and showers. The results of preliminary observations extending over a period of about eight months are tabulated. It is found that there is a considerable net transfer of positive electricity upwards from the earth to the atmosphere by the discharge currents. The vertical discharge current is thus in the opposite direction to the normal fine-weather ionization current and to the convection current carried by various forms of precipitation. A comparison of the magnitude of the observed quantities with that of the fine-weather current indicates the important part played by the point-discharge currents in the total exchange of electricity between the earth and the atmosphere. Finally, the distribution of electric field below a cumulo-nimbus cloud deduced from the observed variations in magnitude and direction of the current, as the cloud passes overhead, strongly suggests that the great majority of shower-clouds and thunder-clouds observed were bipolar clouds of positive polarity, the upper charge was positive. 2.— The Discharging System. The discharging apparatus is carried at the top of a vertical wooden pole, whose base is attached by a hinge to a stout wooden stake, fixed vertically in the ground. The pole can thus be lowered to the ground for inspection of the insulation. When the pole is in its vertical position, the height of the discharging point above the surface of the ground is 8·3 metres. The lead carrying the current to the measuring apparatus consists of about 30 metres of lead-covered rubber insulated cable, of external diameter 5·6 mm. The able travels down the pole and thence, underground, to the hut containing the observing apparatus. The distance from the base of the pole to the hut is about 14 metres. Any disturbance of the field at the top of the pole, due to the presence of the hut is negligible.

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Some features of stepped and dart-stepped leaders near the ground in natural negative cloud-to-ground lightning discharges

Annales Geophysicae ◽

10.5194/angeo-20-863-2002 ◽

2002 ◽

Vol 20 (6) ◽

pp. 863-870 ◽

Cited By ~ 14

Author(s):

X. Qie ◽

Y. Yu ◽

C. Guo ◽

P. Laroche ◽

G. Zhang ◽

...

Keyword(s):

Electric Field ◽

Electric Fields ◽

Broad Band ◽

Atmospheric Electricity ◽

Antenna System ◽

Time Interval ◽

Return Stroke ◽

Radio Science ◽

Lightning Discharges ◽

Log Normal

Abstract. Characteristics of the electric fields produced by stepped and dart-stepped leaders 200 µs just prior to the return strokes during natural negative cloud-to-ground (CG) lightning discharges have been analyzed by using data from a broad-band slow antenna system with 0.08 µs time resolution in southeastern China. It has been found that the electric field changes between the last stepped leader and the first return stroke could be classified in three categories. The first type is characterized by a small pulse superimposed on the abrupt beginning of the return stroke, and accounts for 42% of all the cases. The second type accounts for 33.3% and is characterized by relatively smooth electric field changes between the last leader pulse and the following return stroke. The third type accounts for 24.7%, and is characterized by small pulses between the last recognizable leader pulse and the following return stroke. On the average, the time interval between the successive leader pulses prior to the first return strokes and subsequent return strokes was 15.8 µs and 9.4 µs, respectively. The distribution of time intervals between successive stepped leader pulses is quite similar to Gaussian distribution while that for dart-stepped leader pulses is more similar to a log-normal distribution. Other discharge features, such as the average time interval between the last leader step and the first return stroke peak, the ratio of the last leader pulse peak to that of the return stroke amplitude are also discussed in the paper.Key words. Meteology and atmospheric dynamics (atmospheric electricity; lightning) – Radio science (electromagnetic noise and interference)

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Atmospheric Electricity in the Solar System

Oxford Research Encyclopedia of Planetary Science ◽

10.1093/acrefore/9780190647926.013.112 ◽

2019 ◽

Cited By ~ 1

Author(s):

Karen Aplin ◽

Georg Fischer

Keyword(s):

Solar System ◽

Electric Fields ◽

Atmospheric Chemistry ◽

Atmospheric Electricity ◽

Electric Circuit ◽

Radiative Properties ◽

Cloud Formation ◽

Lightning Strikes ◽

The Earth ◽

Long Time

Electricity occurs in atmospheres across the Solar System planets and beyond, spanning spectacular lightning displays in clouds of water or dust, to more subtle effects of charge and electric fields. On Earth, lightning is likely to have existed for a long time, on the basis of evidence from fossilized lightning strikes in ancient rocks, but observations of planetary lightning are necessarily much more recent. The generation and observations of lightning and other atmospheric electrical processes, both from within-atmosphere measurements, and spacecraft remote sensing, can be readily studied using a comparative planetology approach, with the Earth as a model. All atmospheres contain charged molecules, electrons, and/or molecular clusters created by ionization from cosmic rays and other processes, which may affect an atmosphere’s energy balance both through aerosol and cloud formation and direct absorption of radiation. Several planets are anticipated to host a “global electric circuit” by analogy with the circuit occurring on the Earth, where thunderstorms drive the current of ions or electrons through weakly conductive parts of the atmosphere. This current flow may further modulate an atmosphere’s radiative properties through cloud and aerosol effects. Lightning could potentially have implications for life through its effects on atmospheric chemistry and particle transport. It has been observed on many of the Solar System planets (Earth, Jupiter, Saturn, Uranus, and Neptune), and it may also be present on Venus and Mars. On Earth, Jupiter, and Saturn, lightning is thought to be generated in deep water and ice clouds, but discharges can be generated in dust, as for terrestrial volcanic lightning, and on Mars. Other, less well-understood mechanisms causing discharges in non-water clouds also seem likely. The discovery of thousands of exoplanets has recently led to a range of further exotic possibilities for atmospheric electricity, though lightning detection beyond our Solar System remains a technical challenge to be solved.

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Charge analysis on lightning discharges to the ground in Chinese inland plateau (close to Tibet)

Annales Geophysicae ◽

10.1007/s00585-000-1340-z ◽

2000 ◽

Vol 18 (10) ◽

pp. 1340-1348 ◽

Cited By ~ 16

Author(s):

X. Qie ◽

Y. Yu ◽

X. Liu ◽

C. Guo ◽

D. Wang ◽

...

Keyword(s):

Negative Charge ◽

Atmospheric Electricity ◽

Tibet Plateau ◽

Return Stroke ◽

Convective Processes ◽

Long Duration ◽

Radar Echo ◽

Lightning Discharges ◽

Cloud To Ground Lightning ◽

Charge Analysis

Abstract. Since the summer of 1996, scientists from China and Japan have conducted a joint observation of natural cloud-to-ground lightning discharges in the Zhongchuan area that is located close to Qinghai-Xizang (Tibet) Plateau, China. It has been found that the long-duration of intracloud discharge processes, just before the first return stroke, lasted more than 120 ms for 85% of cloud-to-ground flashes in this area, with a mean duration of 189.7 ms and a maximum of 300 ms. We present the results of charge sources neutralized by four ground flashes and two intracloud discharge processes, just before the first return stroke, by using the data from a 5-site slow antenna network synchronized by GPS with 1 µs time resolution. The result shows that the altitudes of the neutralized negative charge for three negative ground flashes were between 2.7 to 5.4 km above the ground, while that of neutralized positive charges for one positive ground flash and one continuing current process were at about 2.0 km above the ground. The comparison with radar echo showed that the negative discharges initiated in the region greater than 20 dBZ or near the edge of the region with intense echoes greater than 40 dBZ, while positive discharge initiated in the weak echo region.Key words: Meterology and atmospheric dynamics (atmospheric electricity; convective processes; lightning)

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