Fair-weather Electric Field Research Articles

First measurements of wind-turbine perturbations of fair-weather electric fields

Wind turbines have been shown to develop corona at blade tips due to the presence of the fair-weather electric field, but up to now there have been no published investigations of how the presence of a wind turbine perturbs the fair-weather field as measured on the ground near the turbine. Such data may be useful to evaluate the integrity of turbine lightning protection systems. We present the first such published measurements in this paper. Our model predicts measurable periodic variations, and our experimental measurements show a peak-to-peak perturbation up to about 7 V m−1 in a nominal 100 V m−1 fair-weather field as measured on the ground under the moving turbine's blades. Smaller perturbations are detectable at greater distances.

Влияние рельефа на атмосферное электрическое поле

Measurements of the fair-weather electric field in mountainous areas are affected by the terrain, and therefore need additional calibration to be included in the global field picture. To do this, it is proposed to solve the three-dimensional electric current continuity problem of the atmosphere in the region between the Earth's surface and the ionosphere. As an example, the neighborhood of Klyuchevskaya Sopka is considered. With an increase in the height of the plateaus, the fair-weather electric current density above them increases, and the electric field strength decreases. A one-dimensional model of atmosphere conductivity is not applicable for terrain with steep slopes. A comparison of the daily-seasonal diagrams constructed according to the data of the Carnegie Cruise VII and according to the Tomsk Observatory showed the similarity of variations of the fair-weather electric field strength in such different places on the Earth. The field over the sea is about half as small as over low-lying land at the same time.

Influence of relief on the atmospheric electric field

Measurements of the fair-weather electric field in mountainous areas are affected by the terrain, and therefore need additional calibration to be included in the global field picture. To do this, it is proposed to solve the three-dimensional electric current continuity problem of the atmosphere in the region between the Earth's surface and the ionosphere. As an example, the neighborhood of Klyuchevskaya Sopka is considered. With an increase in the height of the plateaus, the fair-weather electric current density above them increases, and the electric field strength decreases. A one-dimensional model of atmosphere conductivity is not applicable for terrain with steep slopes. A comparison of the daily-seasonal diagrams constructed according to the data of the Carnegie Cruise VII and according to the Tomsk Observatory showed the similarity of variations of the fair-weather electric field strength in such different places on the Earth. The field over the sea is about half as small as over low-lying land at the same time.

A Categorization of the Global Fair-weather Electric Field According to Position and Weather Conditions

Atmospheric electricity is an important branch of physics, which mainly studies various electrical phenomena occurring in the atmosphere and the action process of various parameters in the atmosphere. This paper categorizes and integrates research literature based on different spaces and weather conditions. It focuses on analyzing specific regions and meteorological activities and obtains important conclusions. There is a certain correlation between atmospheric electric field and geological conditions, aerosol concentration, and atmospheric particle concentration, among other influencing factors. The significance of studying atmospheric electricity is to improve people’s understanding of the charge distribution in the atmosphere and related electrical phenomena, help people better protect the environment, improve the quality of life, and lay the foundation for future scientific and technological development. This paper helps people understand the impact of changes in atmospheric electric fields on the atmospheric environmental system and monitor air quality through the characteristics of atmospheric electric fields, thereby improving technology in related fields.

Exploring the global thunderstorm influence on the fair weather electric field in Buenos Aires

The Global atmospheric Electric Circuit (GEC) sustains the fair weather (FW) electric field, or potential gradient (PG). In this article, we analyze PG measurements recorded between 2017 and 2021 at the Instituto de Investigaciones Científicas y Técnicas para la Defensa (CITEDEF) in Buenos Aires, Argentina, to calculate the daily PG (FW) curve and examine whether local PG measurements capture the GEC signal. With the aim of supporting future common methodologies that do not rely on meteorological data for FW identification - and hence aid inter-comparisons, we rely on previously developed statistical methodologies to propose a FW selection based on the absolute deviation from the median of the data series. Using this methodology we filtered FW days and showed that the local PG (FW) curve had a significant correlation of 0.83 with the Carnegie curve. In order to test the extent to which the local daily PG (FW) curve captures the global thunderstorm signal, the area of thunderstorms was calculated at both global and regional scales using data from the Thunder Hour Database (http://thunderhours.earthnetworks.com). The PG (FW) curve was shown to have a good correlation with the daily median variation of the global thunderstorm area on both annual and quarterly scales. Additionally, the analysis of coincident aerosol optical thickness (AOD) measurements by the AERONET network and temperature observations helped to conclude that local effects such as pollution from a near highway are not dominating the PG (FW) curve behaviour. Both analyses allowed us to conclude that the GEC signal can be detected in Buenos Aires.

Seasonal dependence of the equatorial electrojets generated by thunderstorms

A model for the distribution of the ionospheric potential which drives the ionospheric currents closing the electric currents from/to the atmosphere is constructed. It is a part of the global electric circuit (GEC). Only the internal electric fields and currents generated by thunderstorms are studied, and without any magnetospheric or ionospheric generators. The atmospheric conductivity profiles with altitude are empirically determined, and the topography of the Earth’s surface is taken into account. A two-dimensional approximation of the ionospheric conductor is based on high conductivity along the geomagnetic field. The model of the global distribution of thunderstorms obtained from the ground-based World Wide Lightning Location Network is used as a proxy for the electric currents to the ionosphere from the atmosphere above thunderstorm regions. The global distributions of the electric potential in the ionosphere are calculated for twelve months during a year with low solar activity. The designed models contain the equatorial electrojets. There are day-time electrojets, the strengths of which are up to 200 A, and night-time ones (which are up to only half this value), while the total current of the GEC is taken equal between 1.5 and 2.5 kA in our model to satisfy the Carnegie data for the simulated dates and UT. The results are presented as diagrams of the currents in the electrojets depending on the geomagnetic longitude and month for 04 and 18 UT. These times are chosen to be the times of minimum and maximum fair weather electric field in accordance with the Carnegie results. The diagrams could help us to choose optimal conditions for measurements of the magnetic perturbations observed on the ground or by satellites to find the electrojets of the GEC which are obtained in our simulations.

On the Radon-Related Mechanism of the Seismo- and Volcanogenic Geomagnetic Anomalies: Experiments in Tlamacas Mountain (Volcano Popocatepetl Area) and Electrode Effect Model

The noise-like behavior of the geomagnetic anomalies observed in Tlamacas station (volcano Popocatepetl, Mexico), linked to the ionization produced by intensive radon release, are presented in the experimental part of this study. The magnetic field perturbations produced by charge spreading currents within the fair-weather electric field are considered in the theoretical model based on the electrode. The electric charges are generated by the air ionization due to radon emanation. The simulations demonstrated that the ionization of the air leads to magnetic field perturbations of about 0.001–0.1 nT in the ULF (ultra low frequency) range 10−3–10−1 Hz. Magnetic field perturbations can be higher when the radon emanation occurs in a region with terrain irregularities.

Mathematical model of the global ionospheric electric field generated by thunderstorms

A model is created for the thunderstorm-related ionospheric part of the global electric circuit in January. This current system consists of both mid-latitude currents and equatorial electrojets, day-time and night-time, westward and eastward, up to 120 A. Data on the atmospheric fair weather electric field obtained during Carnegie cruise VII are plotted as a two dimensional map in Universal Time and month coordinates to show both time and seasonal variations.

Study of the Ground Level Enhancements effect on atmospheric electric properties and mineral dust particle charging

The effect of Ground Level Enhancements (GLEs) on the atmospheric and dust particles electrical properties is studied. It has been found that in the case of fair weather conditions, GLE events enhance the atmospheric electrical conductivity, reduce the columnar resistance, and modify the fair weather electric field, air–earth conduction current, and possibly the Ionospheric Potential (IP) in a way that depends on the geomagnetic cut-off rigidity of the location and the altitude. If a dust particle layer is present, GLE events tend to cancel its electrical effects in the ambient atmosphere. This means that the enhancement of the electric field and the reduction of atmospheric electrical conductivity, caused by the ion attachment to dust particles, not only tend to return to their ambient fair weather values, but they can be further modified as if the dust layer was not present. Finally, in terms of dust particles’ electrical properties, GLE events tend to modify the ion attachment mechanism, and in principle, the particle net charge, and the electric field “sensed” by them, increase. Nevertheless, since the electrical force magnitude is up to six orders of magnitude less than gravity, the increase of the particles’ electrical properties is not sufficient to modify the particle settling dynamics and settling velocities.

Local Impacts Dominate the Diurnal Variation of the Fair-Weather Atmospheric Electric Field in Yunnan, China

Local Impacts Dominate the Diurnal Variation of the Fair-Weather Atmospheric Electric Field in Yunnan, China

Observations from the one year electric field Study-North Slope of Alaska (OYES-NSA) field campaign, and their implications for observing the distribution of global electrified cloud activity

For over a century, the electric Potential Gradient (PG) of the atmosphere has been measured and studied. The local vertical electric field (Ez) is strongly influenced by the presence of lightning, electrified clouds, rainfall, aerosols, and many others. The One Year Electric Field Study-North Slope of Alaska (OYES-NSA) field campaign was established in the summer of 2017 to measure the vertical electric field at the ARM site in Barrow, Alaska alongside a wide array of supplementary instrumentation, including a Micro-Pulse Lidar and upward facing Ka-band radar. Two years of observations (072017-062019) have shown the possibility to quantify the local effects from aerosols and clouds observed by the Lidar and Radar on the measured EZ. Throughout the manuscript, the physics convention of negative downward fair-weather electric fields is used. Three cases (convective clouds, high concentration of near surface aerosols, and blowing snow) are used to demonstrate the localized effects on the measured EZ. Utilizing the relationships between EZ and backscatter/reflectivity, we have developed a methodology to distinguish samples with local influences. A fair-weather (FW) condition is determined to be associated with a low Lidar backscattering (less than 15 km−1sr−1), in the presence of no significant cloud activity (radar reflectivity less than −10dBZ). The samples satisfying these criteria are found with a 5-min averaged standard deviation of less than 15 V/m, and EZ between −250 V/m to −50 V/m. Using only properties of the EZ measurements allows for the simultaneous comparisons of FW at multiple sites, without the need for supplementary information of local weather conditions. Simultaneous EZ measurements from 8 FW cases are shown between Barrow, AK and Corpus Christi, TX on the timescale of minutes to hours. Similar variation patterns in the FW EZ are shown at both sites, providing evidence of the global nature of the atmospheric electric system. Furthermore, the seasonal-diurnal variability of FW at multiple sites shows similar distributions of the PG.

An Array of Low-Cost, High-Speed, Autonomous Electric Field Mills for Thunderstorm Research.

The atmospheric electric field is an important research parameter in understanding storm electrification and energy exchange between lightning and the atmosphere across the globe. The near‐surface electric field can range from a few V/m (order of 10–100 V/m), mainly produced by the currents in the global electric circuit and local charge perturbations, to tens of kV/m in the presence of electrified clouds. The electric field mill (EFM), a variable capacitance electrometer, has been the instrument of choice in the atmospheric electricity community studying phenomena associated with the atmospheric electric field. The EFM is particularly useful in following storm movement and evolution, monitoring the fair‐weather electric field at distant locations, and measuring the vertical electric field inside clouds with EFM deployments on balloons. In this paper, we describe a new electric field mill ground‐based design, which focuses on lowering the manufacturing and operational costs of doing research with an array of EFM instruments while maintaining the scientific capabilities offered by past designs and commercially available devices. The theory of operation, data processing, and calibration of the instrument are also described. Example data from the first generation of these new field mills, deployed in the RELAMPAGO campaign in Argentina, are presented here. The RELAMPAGO deployment and data set illustrate important strengths of this design, for example, cost, autonomy, longevity, and measurement quality.

Fair weather electric field meter for atmospheric science platforms

A miniature field meter is described for measuring fair weather electric fields (of magnitude ~100 Vm-1). It is a brushless field mill constructed from machine-cut parts, driven by a computer fan motor. It resolves fair weather fields at ~1 mV per (Vm−1), with a time response of 0.65 s. It implements self-calibration through combining a mechanical shutter with a programmable bipolar calibration electrode. It has a mass of 86 g, dimensions 4 cm × 4 cm x 8 cm and consumes <100 mA at 6 V. This design will facilitate new climate-related measurements using balloons and remotely piloted aircraft.

Extensive layer clouds in the global electric circuit: their effects on vertical charge distribution and storage.

A fair-weather electric field has been observed near the Earth's surface for over two centuries. The field is sustained by charge generation in distant disturbed weather regions, through current flow in the global electric circuit. Conventionally, the fair-weather part of the global circuit has disregarded clouds, but extensive layer clouds, important to climate, are widespread globally. Such clouds are not electrically inert, becoming charged at their upper and lower horizontal boundaries from vertical current flow, in a new electrical regime—neither fair nor disturbed weather; hence it is described here as semi-fair weather. Calculations and measurements show the upper cloud boundary charge is usually positive, the cloud interior positive and the lower cloud boundary negative, with the upper charge density larger, but of the same magnitude (∼nC m−2) as cloud base. Globally, the total positive charge stored by layer clouds is approximately 105 C, which, combined with the positive charge in the atmospheric column above the cloud up to the ionosphere, balances the total negative surface charge of the fair-weather regions. Extensive layer clouds are, therefore, an intrinsic aspect of the global circuit, and the resulting natural charging of their cloud droplets is a fundamental atmospheric feature.

Experimental Study of Diurnal and Seasonal Variations in the Atmospheric Electric Field

In order to separate global and local effects of atmospheric electricity, measurements of the fair-weather electric field were performed in Nizhny Novgorod in 2013-2018. As a result of processing 139 diurnal records from four observation points spaced 6–8 km apart, diurnal variations in the fair-weather atmospheric electric field for different seasons and weekdays (working days and weekends) were studied. The curve of the local diurnal variation is shown to always have two maxima. The evening maximum of the diurnal variation (19:00–20:00 UT) coincides in time with the maximum of the Carnegie curve, which is a characteristic of the global electrical circuit. The highest values of the field amplitude are reached in the winter period. The field-intensity maximum in the first half of the day (09:00–11:00 LT) is characteristic of the urban environment and shows that local effects associated with the presence of aerosol particles in the air significantly contribute to the formation of diurnal variation, especially in summer. According to the 2013–2018 measurements, the seasonal variation in the monthly-average values of the atmospheric electric field is revealed and analyzed compared with the results of measurements of seasonal variation in other regions of the globe. The obtained results allow one to reveal the role of local effects in the formation of diurnal variation in the mid-latitude areas with temperate continental climate and provide a basis for developing a theory which can explain the physical mechanisms of local effects and suggest appropriate parametrization for finding the surface electric field in the weather and climate models.

Turbulent electric current in the marine convective atmospheric boundary layer

The atmospheric boundary layer considered a part of the planetary global electric circuit is known to exhibit a most dramatically changing in space and time atmospheric electrical variables. Extremely low specific electrical conductivity in the lower atmosphere is accompanied by the work of the electric generator associated with turbulent dynamo realizing itself through the space charge transport by boundary layer flows. The electromotive force of this generator acting in fair weather atmospheric regions provides a contribution to the global potential drop between the lower ionosphere and the earth's surface. In this study, the vertical electric current density produced by the turbulent transfer of space charge is investigated in the cases of the buoyancy-dominated and shear-dominated convective boundary layer (CBL) over the oceans based on second-order dissipation-conditioned Lagrangian stochastic model (LSM) applied near air-sea interface and conjugated with first-order LSM in the rest of the CBL. The total electric charge flux is treated in terms of mechanical transfer of atmospheric ions and charged aerosol particles by Lagrangian turbulence together with the drift of small ions in the self-consistent electric field. This approach based on a transported probability density function method offers persuasive advantages for quantitative estimates of local perturbations in the fair-weather electric field created by the atmospheric space charge carried by turbulent flows. It is found that the space charge density vertical profile only slightly depends on turbulence everywhere except for the wavy boundary layer about 10 m thick, a new parameterization of space charge vertical profile is proposed. Based on the simulation results, it can be predicted that in the buoyancy-dominated CBLs the electric field must be greater than in the sheared CBLs with other things being equal. Turbulent electromotive force and changes in total downward atmospheric electric current density are quantified. Simulated vertical profiles of electrical conductivity, space charge, electric field, and turbulent current density reasonably well reproduce previously reported observation results.

A global atmospheric electricity monitoring network for climate and geophysical research

The Global atmospheric Electric Circuit (GEC) is a fundamental coupling network of the climate system connecting electrically disturbed weather regions with fair weather regions across the planet. The GEC sustains the fair weather electric field (or potential gradient, PG) which is present globally and can be measured routinely at the surface using durable instrumentation such as modern electric field mills, which are now widely deployed internationally. In contrast to lightning or magnetic fields, fair weather PG cannot be measured remotely. Despite the existence of many PG datasets (both contemporary and historical), few attempts have been made to coordinate and integrate these fragmented surface measurements within a global framework. Such a synthesis is important in order to fully study major influences on the GEC such as climate variations and space weather effects, as well as more local atmospheric electrical processes such as cloud electrification, lightning initiation, and dust and aerosol charging.The GloCAEM (Global Coordination of Atmospheric Electricity Measurements) project has brought together experts in atmospheric electricity to make the first steps towards an effective global network for atmospheric electricity monitoring, which will provide data in near real time. Data from all sites are available in identically-formatted files, at both 1 s and 1 min temporal resolution, along with meteorological data (wherever available) for ease of interpretation of electrical measurements. This work describes the details of the GloCAEM database and presents what is likely to be the largest single analysis of PG data performed from multiple datasets at geographically distinct locations. Analysis of the diurnal variation in PG from all 17 GloCAEM sites demonstrates that the majority of sites show two daily maxima, characteristic of local influences on the PG, such as the sunrise effect. Data analysis methods to minimise such effects are presented and recommendations provided on the most suitable GloCAEM sites for the study of various scientific phenomena. The use of the dataset for further understanding of the GEC is also demonstrated, in particular for more detailed characterization of day-to-day global circuit variability. Such coordinated effort enables deeper insight into PG phenomenology which goes beyond single-location PG measurements, providing a simple measurement of global thunderstorm variability on a day-to-day timescale. The creation of the GloCAEM database is likely to enable much more effective study of atmospheric electricity variables than has ever been possible before, which will improve our understanding of the role of atmospheric electricity in the complex processes underlying weather and climate.

Relationship between the global electric circuit and electrified cloud parameters at diurnal, seasonal, and interannual timescales

AbstractIn the early 1900s, J. W. Whipple began to validate C. T. R. Wilson's global electric circuit (GEC) hypothesis by correlating the diurnal variation of global thunder days with the diurnal variation of the fair weather electric field measured by the Carnegie Cruise. This study applies 16+ years of precipitation feature (PF) data from the Tropical Rainfall Measuring Mission, including lightning data from the Lightning Imaging Sensor, alongside 12 years of electric field measurements from Vostok, Antarctica, to further examine this relationship. Joint diurnal‐seasonal variations of the electric field are introduced and compared with a variety of PF parameters that are potentially related to the GEC. All tested PF parameters showed significant correlations to the electric field on the joint seasonal‐diurnal timescale, with the flash rate and volume of 30 dBZ between the −5°C and −35°C isotherms showing the best linear correlations with R2 values of 0.67 and 0.62, respectively. Furthermore, these relationships are analyzed during the two different phases of the El Niño–Southern Oscillation. Results show different seasonal‐diurnal variations of the electric field during El Niño and La Niña periods, with enhancements in the electric field between the months of January through April at 16–24 UTC in La Niña years. A similar trend is shown in global PF parameters, indicating relationships between the variations seen in the fair weather electric field and the variations of global PFs at diurnal, seasonal, and interannual timescales. This provides further evidence that PFs around the globe have a direct connection to the GEC.

Electrical conductivity channels in the atmosphere produced by relativistic-electron microbursts from the magnetosphere

The properties of a cylindrical-shaped magnetic-field-aligned channel of electrical conductivity produced by the precipitation of relativistic-electrons into the atmosphere during a spatially localized magnetospheric microburst are estimated. The conducting channel connects the middle atmosphere (~50km) to the ionosphere. A channel diameter of ~ 8km with an electric conductivity of 1.2×10−9Ω−1m−1 near the bottom and 1.8×10−7Ω−1m−1 higher up is found. In the fair-weather electric field, the higher-conductivity portions of the channel can carry substantial electrical currents.

Local and global impacts on the fair-weather electric field in Israel

Ground-based measurements of the vertical electric field (Ez or potential gradient) during fair weather days in the Negev desert, southern Israel are presented for the period June 2013–July 2015. We show results of the diurnal variation of Ez on seasonal and annual time scales, and make comparisons with the well-known Carnegie curve. We show a positive correlation between the diurnal Ez values and the number of global thunderstorm clusters on the same days. However, the diurnal Ez curves observed in the Negev desert show a local morning peak (8–10 UT) that is missing from the Carnegie Curve, but observed in other land-based Ez data from around the world. The morning peak is assumed to be a local effect and shown to correlate with a peak in the local aerosol loading in the lower atmosphere due to the increase in turbulence and mixing caused by solar heating in the morning hours.