Atmospheric electric filed (AEF) measured at the earth's surface varies in time and space in an irregular manner, which makes interpreting the results of such measurements a challenging task. Simultaneous measurements of the AEF using several sensors make it possible to study the spatiotemporal structure of AEF variations associated with local sources. In one dimension there is an optimal placement of sensors along a straight line with distances between them that are proportional to the divisions in the Golomb ruler such that, with a fixed number of sensors, there is a maximum possible number of different pairwise distances. An array of 7 electric field mills in a line and one more at a distance greater than the total length of the Golomb ruler was used to obtain simultaneous observational data set and estimate temporal and spatial autocorrelation functions of AEF variations in the range of distances 2.5-400 m and frequency range 10-3 - 1 Hz. In addition, to quantitatively describe and interpret the obtained dependences, the autocorrelation functions of the electric field created over a conducting plane by extended one-dimensional random Gaussian charge distribution with exponential autocorrelation function are analyzed. It is found that autocorrelation functions of observed and modeled electric field can be approximated by incomplete gamma functions with parameters depending on the height of charges and the correlation radius in charge distribution. The integral scales of AEF variations of local nature are examined depending on the same parameters, and the time integral scale is found to be inversely depends on the density of zeros of standardized time series of the AEF. The autocorrelation function of electric field created by charges, which are located at a distance from the earth's surface, much less than correlation radius in charge distribution, is the same as for the charges, and the rate of its decline decreases with increasing height of the system of charges.

This paper examines the response in geomagnetic-field variations caused by the 2020–2023 earthquakes with magnitudes Mw ≥ 7.0 in the Aegean Sea and eastern Turkey. A detailed comparison of high-precision observations of the geomagnetic field and seismograms recorded at complex geophysical observatories within a radius of 3000 km from the epicenters was carried out. The joint analysis involves averaged 1-s data on the rate of change of the magnetic field and records from broadband seismic stations. Their characteristics are assessed in both in time and frequency domains. The spectral characteristics of body and surface waves are separately compared with those of the geomagnetic signal. It is shown that the beginning of disturbance in the magnetic field at each observatory strictly coincides with the arrival of the P-wave and intensifies with the arrival of S-waves. The maximum geomagnetic disturbance is caused by surface waves. The amplitude of electromagnetic excitations is proportional to the amplitude of the parent seismic phases. Thus, the coseismic nature of the observed electromagnetic signal has been confirmed, suggesting its excitation in the Earth’s crust as seismic waves propagate.

It follows from the observational data that variations of the atmospheric electric field occur during geomagnetic storms. In this paper, we present the simulation results of ionospheric electric fields during the main phase of the geomagnetic storm on March 17, 2015, within the framework of a quasi-stationary model of a conductor consisting of the atmosphere and the ionosphere. For this purpose, the satellite data on the global distribution of currents between the magnetosphere and the ionosphere are used to describe the magnetospheric source of the electric field. A variation of the electric potential in the ionosphere leads to a variation of the electric field in the entire atmosphere, including its surface layer. It is important that during a geomagnetic storm, the observatory in which the atmospheric electric field is measured significantly changes its position relative to the direction of the Sun. This leads to significant changes in the ionospheric conductivity above the observatory, which affects both the ionospheric electric field and the atmospheric part of the global electrical circuit (GEC). Therefore, when assessing the effect of a geomagnetic storm on the atmospheric electric field in a particular observatory, it is necessary to take into account the local time when comparing the measurement data with the geomagnetic activity indices. For the storm on March 17–18, 2015, we found that taking into account the variations of the ionospheric electric field when calculating the atmospheric electric field allowed us to reproduce the disturbances of the fair weather electric field observed at the Borok Geophysical Observatory. Based on the simulation results, it is shown that during extremely strong magnetic storms, additional atmospheric electric field variations in some places on the Earth have the same scale as the fair-weather field itself.

The ecological and toxicological assessment of the of the soil and vegetation cover at the Streletskaya Steppe site of the V.V. Alekhin Central Chernozem Reserve is presented. The contents of a number of heavy metals (HM) and radionuclides in the typical chernozem are determined. The values of concentration clarks of HM (Cc), geoaccumulation indices (Igeo) for As, Cd, Co, Cs, Cu, K, Pb, Sr, Zn, 232Th, 238U and pollution indices (PI) for individual HM in chernozem were calculated. It is shown that increased values of the pedogeochemical background in comparison with clark values in the lithosphere are observed only with respect to Cd and As. At the same time, for the studied HM (As, Cd, Cu, Pb, Zn), it can be argued that they do not pollute the soil. The content of radionuclides (40K, 137Cs, 232Th, 238U), HM and potassium in various types of natural steppe vegetation was determined. Based on the plant accumulation coefficients of HM and radionuclides, the degree of biophilicity of radionuclides and HM was estimated. The values of the aggregated transfer factors (Cag) 137Cs and 40K from soil to plants were also determined and a comparative analysis of the bioavailability of cesium and potassium during root uptake was carried out. The vertical distribution of 137Cs and 40K radionuclides in the root-inhabited soil layer of 0–20 cm was studied. It was established that 40K is evenly distributed in the root layer of the soil The features of the vertical distribution of 137Cs in the soil profile are noted, consisting in the displacement of the maximum from a depth of 0–5 to 5–10 cm. Based on the data obtained, the value of the migration coefficient 137Cs is calculated, taking into account the convective and diffusion components of the radionuclide translocation process in a typical chernozem.

The ecological and toxicological assessment of the soil and plant cover of a key site in the Streletskaya Steppe in the V.V. Alekhin Central Chernozem Reserve is presented. The content of heavy metals (HMs) and radionuclides in typical chernozem is determined. The clarkes of concentration of HMs (Cc); geoaccumulation lithogeochemical indices (Igeo) for As, Cd, Co, Cs, Cu, K, Pb, Sr, Zn, 232Th, and 238U; and pollution indices (PI) for individual HMs in chernozem have been calculated. It is shown that the pedogeochemical background is higher in comparison with the lithosphere clarkes only for Cd and As. In may be concluded that soils are not polluted with the studied HMs, namely, As, Cd, Cu, Pb, and Zn. The content of radionuclides (40K, 137Cs, 232Th, and 238U), HMs, and potassium in various types of natural steppe vegetation has been determined. Based on the plant accumulation coefficients of HMs and radionuclides, the biophilicity of radionuclides and HMs was estimated. The transfer factors (TFs) of 137Cs and 40K from soil to plants have been calculated, and a comparative analysis of the bioavailability of cesium and potassium during root uptake is performed. The vertical distribution of 137Cs and 40K radionuclides in the root-inhabited soil layer from 0- to 20-cm-thick is studied. It is shown that 40K is evenly distributed in the root-inhabited layer. The vertical distribution of 137Cs in the soil profile is characterized by the shift of the maximum from a depth of 0–5 to that of 5–10-cm. Based on the data obtained, the migration coefficient of 137Cs is calculated, taking into account the convective and diffusion components of the radionuclide translocation in typical chernozem.

The atmospheric boundary layer is the lowermost part of the atmosphere, the turbulent dynamics and electrodynamics of which are determined by the complex organization of processes in a dissipative environment with energy input from many sources. Regions of the atmosphere undisturbed by thunderstorms and precipitation are characterized by low-energy electrical processes, the study of which requires a developed instrument base and knowledge of the methods of synchronous spaced high-precision measurements of several physical quantities. This paper presents the results of recent studies of electricity of the atmospheric boundary layer of midlatitudes carried out using the measuring complex of Borok Geophysical Observatory of the Institute of Physics of the Earth, Russian Academy of Sciences (IPE RAS), and numerical modeling. Quantitative estimates of the average values and variability of small ion concentration, the corresponding components of electrical conductivity, and atmospheric electric field intensity are performed. Two types of electric structures formed by the electric current flow through a turbulent medium with inhomogeneous conductivity are defined.

This article discusses the processes of transition to the aqueous phase and uptake from it by plants of stable (Cd) and radioactive ( 109 Cd) isotopes. Regularities of the distribution of Cd/ 109 Cd between different forms of their chemical compounds in the soil were revealed by means of sequential extraction procedure (SEP) according to the Tessier–Förstner sceme. It was shown that the content of labile and conditionally labile forms of compounds (fraction F1-F3) of stable Cd was 1.2–1.8 times lower than that of radioactive 109 Cd and, conversely, fixed conservative forms of metal compounds (fraction F4–F6) by 2.4–5.3 times more. The Cd concentration, 109 Cd activity concentration, distribution and concentration coefficients of natural Cd and 109 Cd radionuclide, and accumulation and removal of metal by plants were evaluated. The values of enrichment factors of natural (stable) Cd contained in sequentially extracted chemical fractions by 109 Cd radioisotope were determined, and the value of pool of labile cadmium compounds in studied soil was calculated. Based on the results of solid-state 13 C NMR spectrometry, the qualitative composition of high-molecular organic compounds of the soil solution was determined and their ability to specifically sorb heavy-metal cations was assessed.

We study analytically and numerically the relationships for a passive horizontal ring antenna, which is used as a collector for long-term observatory measurements of the atmospheric electric current density. The spatial distributions of the potential and the electric field as functions of the geometric characteristics of the antenna, which is located in a uniform atmospheric electric field, are determined in the electrostatic approximation and the parameters of the atmosphericion motion in the neighborhood of the antenna are calculated. The effective collecting area of the antenna is determined by two different methods. The time of deposition of the atmospheric ions with a given mobility on the collector as a function of the impact parameter and the initial height, which is determined by this parameter, is established. The results of direct measurements of the atmospheric electric current density by a collector are compared with the results of synchronous observations of the atmospheric electric field and the electrical conductivity in the surface layer.

We investigate the contribution of gamma radiation of natural radionuclides constituting the Earth crust, radioactive emanations, and their decay product in the ground to the rate of production of ion pairs in the atmosphere against the background of ionization of the atmosphere by radioactive gases exhaled to the atmosphere from the ground and propagating together with their short-lived daughter products. The radon flux density to the atmosphere is estimated by three methods: the reservoir method, the integration of altitude profiles of volume activity of radon, based on gamma spectroscopic observations and the diffusion model. The distribution of the gamma radiation dose from the earth radionuclides in the soil and the atmosphere is calculated using Gleant4 software. The propagation of the radon isotopes and their decay products in the atmosphere is calculated simulated using large eddy simulation supplemented with kinematic simulation of subgrid flux of a passive scalar. It is shown that depending on the specific activity of radionuclides in the ground, the soil parameters, and the turbulent regime of the atmosphere, the total contribution of gamma radiation to the ion pair production rate in the atmospheric boundary layer is approximately from 1 to 20% and increases upon a decrease in the penetrability of the upper ground layer for radioactive emanations.

The transfer of zinc (natural stable Zn and radioactive tracer 65Zn) to aqueous phase and its uptake by barley have been studied using a specially designed vegetation testbench comprising a lysimeter unit filled with coarse-textured soil and drainage and the vegetation vessels with aqueous barley culture. Although the zinc migration to soil aqueous phase and its uptake by plants are spatially separated, they are sequentially coupled. The patterns of Zn(65Zn) distribution among different compounds (chemical fractions) in soil were determined using parallel and sequential fractionation procedures. The relative content of native (stable) Zn in labile and conventionally labile forms is 2.1–6.5-fold lower as compared with the relative content of radionuclide 65Zn and, vice versa, 2.8–3.0-fold higher for conservative (fixed) fractions of the metal in soil. The dynamics of the following parameters were assessed: Zn concentration, 65Zn specific activity, distribution and concentration factors of natural Zn and 65Zn, and uptake and removal of the metal by plants. The enrichment factors of stable Zn, contained in sequentially extracted chemical fractions, with radioisotope 65Zn, were determined, and the pool of the labile zinc compounds in the studied soil was evaluated.

This work presents the results of ground-based and tethered balloon observations of altitude profiles of the components of the atmospheric vertical electric current density. The magnitude of the conduction current density was observed in the range 0.2 - 2 pAm−2. The ratio of the negative to positive component of the conduction current density averaged 1.6 outside the layer, where their dependence on the height was noticeable. In the framework of developed numerical model with reasonable values of the parameters it is found that the ratio of the convection current density to the density of the total vertical atmospheric electric current in the atmospheric boundary layer mainly falls in the range 0.2 - 0.6 and tends to increase under strong convection and low electrical conductivity. An exponential parameterization of the dependence of the electromotive force on the ground-level electrical conductivity is proposed.

The variability of radon-220 (thoron) distribution in the surface atmosphere is investigated by mathematical modeling of thoron turbulent transport, based on the data of continuous field natural observations at Borok Geophysical Observatory (Central Russia). The thoron flux from the surface was set according to the observations. Variations of turbulent diffusion coefficient altitude profiles were calculated by the observations of wind velocity pulsations at two altitudes made synchronously on the same location. The altitude profiles of thoron volumetric activity typical for the atmospheric surface layer are estimated. It is shown that the thoron volumetric activities at any altitudes vary concurrently, but the largest thoron volumetric activity, as well as its gradient, occurs below 0.5 m at nighttime.

The paper presents the results of the analytical and hardware development of a bipolar sensor for the concentration of small atmospheric ions, designed for long-term geophysical field observations. Theoretical estimates of the response function of the sensor are obtained. The dependence of the concentration of small atmospheric ions on the magnitude of the measured current of the aspiration capacitor and ion mobility spectrum is given. Numerical computations of the trajectories of small ions in an aspiration condenser of specified dimensions and geometry are performed. The probability of recording ions depending on their mobility is found. The circuit solutions and algorithms for the functioning of the hardware of the devices are described. Based on the development materials, prototypes of sensors are made. The technical characteristics and recommendations for the use of devices are given. Unlike analogues, the device is resistant to environmental influences. The sensors are tested in laboratory conditions and during the field observations of the electricity of the atmospheric boundary layer. In addition to being used as a part of a ground-based complex for geophysical observations, the developed sensor was used in an instrumental platform for balloon observations aloft. As a result of testing the devices, it was found that the functioning of the sensors is stable and the data are representative.

The development of an atmospheric electricity-monitoring network stimulates research into the relationship between the global electrical circuit and environmental conditions. Small air ions in the lower atmosphere are the main carriers of the conduction current and, at the same time, are themselves carried by atmospheric turbulence. However, it is not clear to what extent the statistics of fluctuations in the concentration of small ions in the electrode layer adjacent to the earth's surface bears the features of scalar turbulence. Based on field experiment data, the probability density functions of fluctuations of both the concentration of small ions and temperature are found to be non-Gaussian and approximated by a stable distribution model with the index of stability alpha in the range from 1.1 to 1.96. Observations have demonstrated that statistics of temperature fluctuations is more intermittent, compared to height-dependent statistics of fluctuations of the concentration of small ions. It is found that the autocorrelation function and second-order structure function have different behavior for the concentration of small ions and temperature in the time range 1-50 s.

The response of strong magnetic storms in variations of the electric field of the near-ground atmosphere of the midlatitudes are studied according to data from long-term observations of aeroelectric (Ez) and geomagnetic fields at the midlatitude Borok Geophysical Observatory. For the period 1998–2015, 19 strong and very strong magnetic storms with a minimal Dst index of < –100 nT and a maximal index value of Kp > 7, which correspond to undisturbed meteorological conditions of the lower atmosphere (i.e., good weather conditions), are identified at Borok Observatory. The effect of a magnetic storm on changes in the electric field of the near-surface atmosphere is shown to be more efficiently manifested in the daytime around noon. A statistically significant variation in the strength of the aeroelectric field was found. It was characterized by an increase in the Ez value over a time interval of ±4 h relative to the time of the minimum of the Dst variation of the magnetic storm.

In this work, we study the space-time statistical features of variations in the atmospheric electric field (Ez) and space charge in the atmospheric boundary layer using a three-dimensional model and analysis of observational data. The model is a combination of large-eddy simulation supplemented with a subgrid kinematic model for scalar and the three-dimensional Poisson equation for the electric potential. Based on the calculated evolution of three-dimensional distributions of the space charge and electric potential, the variability of the spectral slopes of variations in the space charge, vertical potential difference, and the vertical component of the electric field Ez is investigated. The vertical profiles of Ez and the frequency power spectra of Ez variations at different heights computed are in reasonable agreement with the observed ones. It is shown that the cross-correlation of Ez at spatially separated points located on one straight line near the earth's surface decreases with increasing distance with a characteristic scale of a few tens meters and has a dependence on the angle between this line and the direction of the wind. Mean large-scale horizontal electric field defined through the position and amplitude of the potential extrema at the same height depends on height non-monotonically having a maximum value of about 5 V/m. Scaling exponents of structure functions for Ez variations are found to be significantly larger than those for space charge variations.

This paper reports the first investigations of the mid-latitude convective boundary layer (CBL) electricity above the homogeneous land surface using a large-eddy simulation (LES). Our approach uses LES together with a subgrid kinematic model for relative dispersion of scalar to calculate Lagrangian trajectories of notional particles carrying radioactive nuclei, small atmospheric ions, and charged aerosol particles. This technique opens up new possibilities for quantifying the influence of various environmental conditions on the formation of the electrical state of the undisturbed lower atmosphere. We examine the altitude distribution of principal atmospheric electrical quantities in the CBL and lower free weakly stable atmosphere without clouds depending on surface turbulent heat flux, geostrophic wind speed, mixed-layer height, ionospheric potential, and various ion production rates due to cosmic rays and radioactive gases.