Generators in atmospheric electricity

Summary The definition of a generator in atmospheric electricity is considered, and various phenomena are discussed as to whether they can be described as generators.     

An investigation of short-term solar wind modulation of atmospheric electricity at Mauna Loa Observatory

A search has been made for short-term signatures in the global electric circuit of solar wind modulated inputs into the atmosphere, using atmospheric electricity observations made at Mauna Loa, Hawaii, in 1976–1984. The short-term events were Forbush decreases of the galactic cosmic ray flux (characterized by decreases in neutron monitor count rates); geomagnetic disturbances (characterized by the Ap index); and ring current changes (characterized by the Dst index). Each set of events was designated by a set of key days, which were used in superposed epoch analyses of the time-series of daily averages of the atmospheric electricity parameters.The observations consisted of measurements of air-earth current density, potential gradient, positive conductivity, and negative conductivity. The Mauna Loa observatory is at an altitude of 3.4 km in a relatively clean and dust free oceanic environment. The meteorologically-induced electrical noise there is less than at most other atmospheric electricity observatories, with the exception of high altitude sites on the polar ice caps. Nevertheless the noise level was still a problem even after making superposed epoch analyses using several tens of events. We find responses similar to those expected from solar wind inputs but of marginal statistical significance. Diurnal and annual variations were found to be well defined, and consistent with those found by others.     

Considerations regarding solar and lunar modulation of geophysical parameters,atmospheric electricity and thunderstorms

Summary The basic thesis of this paper is that the proper scope of meteorology should include, besides the earth's atmosphere, the sun's atmosphere (the solar corona), the associated interplanetary magnetic field, and lunar modulation of this environment. Recent advances in space science have enabled us to make direct measurements in this region for the first time. The shape and characteristics of the magnetosphere have been completely redefined during the last ten years from a simple magnetic dipole to the present model with an elongated tail stretched out by the solar wind. The interplanetary magnetic field has been defined with its spiral structure and sectors tied into the solar surface. This provides a magnetic link between the sun and earth. It is probable that extra-terrestrial factors do play a role in regulating weather, although the extent of this influence remains to be determined. Possibly such effects are most significant or easily detectable in the realm of atmospheric electricity. In view of the limitations in our present knowledge of all the variables responsible for regulating weather, it would seem appropriate to pursue the study of extra-terrestrial influences. Such research could lead to a better understanding of atmospheric circulation, precipitation mechanisms and thunderstorms. The field of meteorology which might particularly benefit from such research is long range weather forecasting.     

The effects of condensation nuclei in atmospheric electricity

Summary The effects of condensation nuclei in the atmosphere are discussed, particularly in relation to the «sunrise effect» and it is shown that the introduction of positively charged nuclei is the only process yet suggested that can explain the observed results.     

近地表大气电场观测试验场建设

作为地震前兆电磁观测手段之一,震前大气电场异常观测研究在我国已开展多年,为了进一步研究近地表大气电场与震前异常的关系,设立了国家科技支撑计划课题专题"近地表大气电场、地电场综合观测试验研究".文章介绍了试验场所用的KDC-01型大气电场仪,近地表大气电场观测试验场在大祝前兆台阵中的建设情况,以及产出数据的初步分析结果.     

The evidence for auroral effects on atmospheric electricity

Summary The possibility of atmospheric electrical effects due to the aurora has been considered by investigators since 1875. An unsatisfactory theoretical basis for an explanation of observed effects and the measurements of only a few of the related parameters for short periods of time has led to uncertainty in the matter. Nevertheless, since the IGY²), new discoveries related to the aurora portray an unusual complexity, and a wide range of energy input. When considered with recent discussions on atmospheric electrification some interesting interpretations of the observed effects are suggested. On the ground, large negative excursions of the atmospheric electric field (E) during fair weather, and above 100 mb³) peculiar increases in negative ion densities and variations in air-earth current density (I) all appear to be related to auroral activity. A difference in (I) measured simultaneously at geomagnetic latitudes 55° and 68°N which is greater than what one would expect from a difference in conductivity due to cosmic rays may also be due to the aurora. Several models of the observed effects will be considered: (1) the high influx of negative space charge, i.e. a precipitation of around 10¹⁴ elementary charges m^–2 s^–1; (2) the auroral bremsstrahlung flux acts as an atmospheric current generator; (3) plasma instability in the auroral electrojet; (4) a combination of (2) and (3). The infrequent observation of the auroral effects on atmospheric electricity is probably due to limitations in detecting an extreme local fluctuation in such a large-scale complex phenomenon.     

Discussion of the fundamental problem of atmospheric electricity

Summary The fundamental problem of atmospheric electricity is given by the question to the cause of the electrical current which can be observed everywhere in the terrestrial atmosphere. The classical picture which emerged in the 1920's, also called sometimes the spherical capacitor theory, is shown to be unproven or even disproven by measuring results available until now. The constituting elements of the classical picture are investigated individually, and conclusions are drawn from these considerations. The outcome is that we indeed have a globally controlled current flow vertically through the atmosphere, but that the connection to the thunderstorm activity is tenuous and, in fact, contradicted by proper interpretation of available measurements. On the other hand, thunderstorms do generate electric currents which feed into the global current circuit, and the amount could very well be sufficient, but we do not have sufficient evidence to be able to decide this question.—The author stresses the necessity to improve the measurement techniques and indicates how to do it, he even calls for an abandonment of outmoded methods which are sometimes misleading and in their results often confusing, but nevertheless still practiced at many places. The Atmospheric Electricity Ten-Year Program is discussed as the natural consequence derived from the present situation.

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Zusammenfassung Das grundlegende luftelektrische Problem ist die Frage nach dem Ursprung des elektrischen Stromes der überall in der Atmosphäre beobachtet werden kann. Das klassische Bild welches in den 1920er Jahren entstand und auch als Kugelkondensator-Theorie bezeichnet wird, wird als unbewiesen dargestellt, ja, sogar als durch die bisher vorliegenden Messergebnisse widerlegt. Die Elemente, welche zusammen das klassische Bild ausmachen, werden einzeln untersucht, und Schlüsse werden aus diesen Untersuchungen gezogen. Das Ergebnis ist, dass wir tatsächlich einen Vertikalstrom haben, der weltweit gesteuert wird, dass aber die Verbindung zur Weltgewittertätigkeit unsicher ist und, genauer betrachtet, von einer sorgfältigen Auslegung der Messergebnisse widerlegt wird. Auf der anderen Seite erzeugen die Gewitter tatsächlich elektrische Ströme, und es scheint als ob deren Stärke ungefähr passend ist, aber unser Kenntnis reicht nicht aus, um das nachzuweisen.—Verfasser betont die Notwendigkeit, die Messmethoden zu verbessern und er zeigt auf wie, ungefähr, das getan werden kann, er ruft sogar dazu auf, die alten und überholten Methoden abzuschaffen weil sie manchmal falsche Schlüsse hervorrufen und gewöhnlich zu verwirrenden Auslegungen führen, trotzdem aber noch vielerorts angewandt werden. Das luftelektrische Zehnjahresprogramm wird als natürliche Folge der gegenwärtigen Situation dargestellt.

     

Introductory remarks on the classical picture of atmospheric electricity

The classical picture of atmospheric electricity portrays in a simple way, if not too simple a way, a closely knit complex of theories and hypotheses, and perhaps even speculations, centered around the fundamental question of where the electricity of the atmosphere comes from. This picture probably has been accepted with less reservation by the scientific world outside of the narrower circle of scientists active in atmospheric electricity research than by the experts of this circle who alwavs have been aware that the features of this picture never have been really proven by observation, and hardly offer more than a qualitative possibility for an explanation of measuring results. Nevertheless, this concept still represents the best approximation available. The chance that its general validity will be proven in the future is certainly better than 50%. At the same time, contradictions to the classical picture have been found; and it is assumed now that certain modifications of it may be necessary, in particular with respect to short-time averages.The classical picture is composed of several features which may be listed, vaguely, as follows: spherical capacitor hypothesis for the electrical state in the troposhere, stratosphere, and part of the mesosphere; the ionosphere being (seen from below) an equipotential surface, and forming a Faraday cage; the global thunderstorm activity being the generator charging up the spherical capacitor; atmospheric electric conductivity monotonously increasing with height once the exchange layer is left behind; atmospheric ions, once formed, being stable until recombination. Each of these features consists of a number of elements.In this paper, the existence of some of the main elements will be investigated; and the significance of measurements and observations leading to the classical picture will be discused. While modifications and alternatives to the classical picture will be the objective of some of the papers to follow during this symposium, some more general additions and, also, some alternatives not likely to be covered later on will be indicated in this introductory paper.Under the title Review of the Fundamental Problem of Atmospheric Electricity publication planned for the Hans-Israël-Memorial-Issue of PAGEOPH (1971).     

On the conception ‘Fair weather condition’ in atmospheric electricity

Measurements of atmospheric electrical and meteorological parameters during different meteorological conditions indicate that the use of the conception Fair weather condition in atmospheric electricity is discussable. Fair weather contains a very broad stability range, from very unstable to strong stable stability of the atmosphere. For turbulent fluctuations of the electric parameters (the most local variations) the variations are determined by the micrometeorological processes for all stability conditions.These fluctuations represent frequencies greater than one period per four minutes. For lower frequencies (less local variations), however, the stability dependency increases. During stable conditions the electric field and vertical current density were nearly wholly influenced by the charges and their transfer in the nearest layer. During near-neutral and unstable conditions the electrical parameters were influenced by more separated sources. Measurements of how well Ohm's law was fulfilled also indicate the difficulties by using the conception fair weather. The measurements also indicate the importance of taking the convection current density into consideration in studies of the electric charge transfer in the atmosphere.In the more large scale of variations measurements of the electric field by radiosoundings show that 88% of the ionospheric potential is derived from the troposphere, where the meteorological processes are of fundamental character for the atmospheric electrical phenomena. The relatively great stability of the diurnal variation of the large scale or global electric field is also valid for the meteorological processes in this scale of variations.     

Solar wind influence on atmospheric processes in winter Antarctica

Galactic cosmic rays (GCRs) altered by solar wind are traditionally regarded as the most plausible agent of solar activity influence on the Earth's atmosphere. However, it is well known that severe reductions in the GCRs flux, known as Forbush decreases (FDs), are caused by solar wind of high speed and density, which sweeps away the GCRs on its way. Since the FD beginnings are registered at the Earth's orbit simultaneously with dramatic disturbances in the solar wind, the atmospheric effects, assigned to FDs, can be, in reality, the results of the solar wind influence on the atmospheric processes. This paper presents a summary of the experimental results demonstrating the strong influence of the interplanetary electric field on atmospheric processes in central Antarctica, where the large-scale system of vertical circulation is formed during winter seasons. The influence is realized through acceleration of the air masses, descending into the lower atmosphere from the troposphere, and the formation of cloudiness above the Antarctic Ridge, where the descending air masses enter the surface layer. The acceleration is followed by a sharp increase of the atmospheric pressure near-pole region, which gives rise to the katabatic wind strengthening above the entire Antarctica. The cloudiness formation results in the sudden warmings in the surface atmosphere, since the cloud layer efficiently backscatters the long wavelength radiation from the ice sheet, but does not affect the adiabatic warming process of the descending tropospheric air masses. When the drainage flow strengthening the circumpolar vortex around the periphery of the Antarctic continent decays, the surface easterlies typical of the coast stations during the winter season are replaced by southerlies and the cold Antarctic air masses flow out to the Southern ocean.     

Results of twenty years of atmospheric electricity research at Ibadan

The results of atmospheric electric measurements over a twenty year period (1961–1980) are reviewed for Ibadan situated in the tropical rain forest of Nigeria. The aim is to present the data in an easily accessible form.     

Acoustic tomography in the atmospheric surface layer

Acoustic tomography is presented as a technique for remote monitoring of meteorological quantities. This method and a special algorithm of analysis can directly produce area-averaged values of meteorological parameters. As a result consistent data will be obtained for validation of numerical atmospheric micro-scale models. Such a measuring system can complement conventional point measurements over different surfaces. The procedure of acoustic tomography uses the horizontal propagation of sound waves in the atmospheric surface layer. Therefore, to provide a general overview of sound propagation under various atmospheric conditions a two-dimensional ray-tracing model according to a modified version of Snell’s law is used. The state of the crossed atmosphere can be estimated from measurements of acoustic travel time between sources and receivers at different points. Derivation of area-averaged values of the sound speed and furthermore of air temperature results from the inversion of travel time values for all acoustic paths. Thereby, the applied straight ray two-dimensional tomographic model using SIRT (simultaneous iterative reconstruction technique) is characterised as a method with small computational requirements, satisfactory convergence and stability properties as well as simple handling, especially, during online evaluation.     

考虑雷暴活动的全球近地稳态大气电场的精确数学解

全球大气电模式是指大气和地表构成的闭合回路,其中考虑雷暴为主要充电电源,并将雷暴作为一个垂直电偶极子来考虑.本文从电流连续方程出发,采用球谐函数展开法,边界条件采用下边界为地表大气电势,上边界为电离层底部电势,非齐次电流源函数项采用垂直偶极子假设.通过所做的非线性函数变换,得出了考虑雷暴活动的全球电模式的近地稳态解析解,并证明其能展开为有限多项式级数之和.所得结论与过去的理论分析结果和实验观测是一致的.该文的工作是对以前相关工作仅能得到近似解的一种改进,同时本文所得公式可用于今后对大气电参量进行相关的数值计算及模拟之中.     

Solar modulation of galactic cosmic rays during the last five solar cycles

We study the cosmic ray modulation during different solar cycles and polarity states of the heliosphere. We determine (a) time lag between the cosmic ray intensity and the solar variability, (b) area of the cosmic ray intensity versus solar activity modulation loops and (c) dependence of the cosmic ray intensity on the solar variability, during different solar activity cycles and polarity states of the heliosphere. We find differences during odd and even solar cycles. Differences during positive and negative polarity periods are also found. Consequences and implications of the observed differences during (i) odd and even cycles, and (ii) opposite polarity states (A<0 and A>0) are discussed in the light of the modulation models, including drift effects.     

Time fluctuations of small ion number density in the atmospheric surface layer

The standard deviations and time-spectra of small ion number density have been measured at ground level under different atmospheric stability conditions. The auto-correlation correlograms and the time-spectra imply a scale of fluctuations corresponding to 1 to 4 min. No clear relationships between standard deviations of small ion number density and micro-meteorological parameters are observed. Thus the results are not a support for Monin-Obukhov similarity theory. For the highest frequencies the slopes of the spectra seem to follow the –5/3-law fairly well and the frequencies of the peak values of individual spectra lnfS(f) increase when the atmosphere stability increases, which is valid for ordinary micrometeorological parameters.     

The wind profile from surface through 30 km in atmospheric ballistics problems

Summary The individual wind profile may differ considerably from the mean monthly profile. In cognizance, the correlation method was developed. This method yields some improvement, but requires elaborate mathematical treatment. The computational effort is probably not in accord with the results obtained due to the limitations of the linear correlation concept.The author has developed a new method, called characteristics method. The individual wind profile is represented by mathematically describing the profile with a few characteristic coefficients. This method seems superior to the correlation method.

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Zusammenfassung Das individuelle Windprofil kann im Einzelfalle erheblich vom Monatsmittelprofil abweichen. Um dieser Tatsache Rechnung zu tragen, wurden bis jetzt die Korrelationskoeffizienten mit herangezogen. Die dadurch erzielten Verbesserungen sind jedoch mit einem Rechenaufwand verbunden, der in keinem Verhältnis zu dem Gewinn steht, da der Verwendung des linearen Korrelations Koeffizienten natürliche Grenzen gesetzt sind.Es wird daher eine neue Methode diskutiert, die vom Autor entwickelte Charakteristik Methode. Dabei wird das individuelle Windprofil mathematisch durch wenige charakteristiche Terme beschrieben. Aus Vergleichsbeispielen geht hervor, dass die neue Methode der (linearen) Korrelationsmethode überlegen ist. Auch der Rechenaufwand ist gering, wenn einmal die Grundkoeffizienten gewonnen sind.

     

Effect of synthetic fertilizers and atmospheric precipitation on nitrogen enrichment in surface waters

The increase of the nitrate concentration in surface waters used as water supply resources has been investigated with a view to the effects of agricultural activities and atmospheric precipitation. The nitrate concentration increased beyond the acceptable limit for infants after 1975, when due to the permanent augmentation of the synthetic fertilizer rates the organic humus quantities decreased to a minimum. The variability of nitrate concentrations in atmospheric precipitation is dependent on the magnitude of precipitation and the intensity of industry in the given region. At an average value of atmospheric precipitation the nitrogen value in agricultural regions varies within 6 to 12 kg · ha^?1 · a^?1, in regions with extended industries up to 24 kg · ha^?1 · a^?1.