Geoelectric sections of some areas of Palestine and Tanzania were determined based on fund materials of vertical electrical soundings (VES). They are required to verify the predictive maps of the parameters of the geoelectric sections of the Earth's continents. Geoelectric sections obtained on the sea sandy beaches of Palestine washed by the waters of the Mediterranean Sea and on the rock complexes of Tanzania are presented. Using the VES parameters, the frequency dependences of the surface impedance of various types of rocks were calculated in the range from 10 kHz to 30 MHz. Layered geoelectric structures with strongly inductive surface impedance have been established.
The features of the frequency dependence of normalized surface impedance for the “ice-sea” structure at frequency of 300 kHz are determined. Five models of ice structure were considered, which take into account the change in ice thickness based on the spatial Fourier series. In the calculations, the ice thickness varied from 0.2 to 3.8 m. The results of modeling are necessary to assess the conditions for LW-MW radio waves propagation along the paths of the Northern Sea Path.
Fund materials of vertical electrical soundings (VES) was used to determine the surface impedance of the layered medium "dry sand - watered sea sand" in the VLF-VHF radio wave. The results of calculations of the frequency dependence of the surface impedance of a three-layers medium "dielectric on watered sea sand" in the frequency range from 10 kHz to 30 MHz indicate that the dielectric layer "dry sand" with thickness up to 2-3 m shifts the phase of impedance to the highly inductive area (from 10 kHz to 10 MHz). The impedance modulus in this frequency range is satisfy boundary conditions of impedance. The phase of impedance reaches –82º. "Dry sand - watered sea sand" medium is an analogue of the "ice-sea" medium with a strong inductive impedance in the VLF-HF ranges. There are wide distribution of sand beaches on all oceans and seas of the Earth. "Dry sand - watered sea sand" structures are typical for large areas of the Earth and calculations of coastal refraction of the "land-sea" in radio systems it should take into account. The modeling results are required to check the forecast maps of geoelectric sections (GES) of the Earth's continents and for calculations of radio waves propagation.
A model for the propagation of LF-MF radio waves over ice paths with a spatial change in impedance is proposed and substantiated by numerical calculations. Its features are determined for a two-layer “ice-sea” radio path with a spatial change in ice thickness. The surface impedance, the attenuation function W and the field level |Ez| over a two-layer ice path are considered with a spatial change in ice thickness at a frequency of 300 kHz according to: a) harmonic law and b) sawtooth change in ice thickness. The simulation results are necessary to estimate the conditions for the propagation of LF-MF-HF radio waves along the paths of the Northern Sea Route.
For calculations of the electromagnetic field over the two-layer structure “thick ice-sea”, the areas of applicability of the impedance boundary conditions for a vertically polarized wave in the range of 0.01 ˗ 120 MHz are determined. Seven models of ice cover are considered. The ice thickness varied from 2 to 9 m. Results are needed to calculate the attenuation function W and the field level in the LF-MF-HF range of radio waves.
The results of modeling the conditions of propagation of LF-MF radio waves over the impedance structure "thick ice - sea" in the Arctic Ocean are presented. To calculate the electromagnetic field of the two-layer structure “thick ice-sea”, the applicability regions of impedance boundary conditions for a vertically polarized wave depending on the thickness of the ice are determined. Methods of calculating the ground wave field tension on high-latitude impedance paths with an ice thickness of 2-9 meters are considered. The results are necessary for calculating the attenuation function W and the field level E of radio waves.
Electrometric studies of the aquatic environment of Lake Baikal, the Selenga river, and other rivers, lakes, and wells located in different areas of the natural Baikal territory were performed. The electrical resistivity of salt lakes in the region and the seas were compared. Samples of drinking tap water from Irkutsk, Yakutsk, and Ulan-Ude and wells of the villages of Baikal region were measured. Significant variability of resistivity at various points of water sampling due to its different salinity were established.
The purpose of the research is to identify areas with high resistance of the earth's crust. Impedance measurements in the ELF and VLF ranges were carried out in sounding and profiling modifications within a large granitoid massif. For probing in the VLF range, the areas of the basement, folded with granites, studied by the aerial survey of the radioimpedance method (RIS) in the VLF range were selected. When interpreting, to improve the reliability and stability of the solution, data from the impedance VLF measurements at frequencies of 17-50 kHz were also used.
For calculations of the electromagnetic field of the two-layer "thin ice-sea" structure, the areas of applicability of the impedance boundary conditions are determined depending on the thickness of the ice and the angle of incidence of the vertically polarized wave. Results are needed to calculate the attenuation function W and the radio wave field level. It is shown that for the "thin ice-sea" structure, taking into account the dependence of surface impedance on the angle of incidence is important for over-the-horizon radar systems in the HF range of radio waves. In the VHF range for ice 80 cm thick, frequency bands are identified in which impedance boundary conditions are applicable.
The results of ELF measurements in the east of Russia using the electromagnetic field of the "Zeus" installation at frequencies of 33, 44, 82 and 188 Hz are considered. A highly sensitive apparatus for amplitude-phase measurements of the surface impedance of the earth's crust is considered. The analysis of field variations in the far zone of the source is carried out. To explain the field variations, calculations of the propagation of ELF radio waves for the model of an inhomogeneous waveguide are performed. A comparison of the calculated and measured values of Нτ shows their good agreement.
Propagation conditions of radio waves over the “ice-sea” structure with a highly inductive impedance are often more favorable than over a clear sea due to the appearance of a surface electromagnetic wave. Numerical calculation algorithms for various radio wave propagation path models have been developed. The method of making prognostic maps of the surface impedance of the “ice-sea” structure according to the ice situation maps for the Arctic Ocean (AO) in different seasons of the year is considered. A formula is proposed for converting the spatial dependence of the ice thickness into the spatial dependence of the surface impedance at a fixed frequency in VLF-LF-MF ranges. Calculations of surface impedance for various types of sea ice are presented.
The technique of compiling predictive maps of the surface impedance of the ice-sea structure by maps of ice conditions for the Arctic Ocean in different seasons of the year is considered. A formula is proposed for transforming the spatial dependence of the ice thickness into the spatial dependence of the surface impedance at a fixed frequency of the VLFLF-MF ranges. Surface impedance calculations for various types of sea ice are presented. The novelty and practical significance of the work is that a prediction map of the surface impedance of the seas of the Arctic Ocean is created, which is necessary for the calculation of the spatial and energy characteristics and the selection of operating frequencies for high-latitude radio links and navigation on various radio propagation paths, including a surface electromagnetic wave (SEW).
On the shoreline of the lake Baikal (near vil. Goryachinsk) established a relationship between the wave hydrodynamic and electrical processes. The physics of the phenomenon belongs to the class of electrokinetic effects. The filtrational natural electric field is associated with the movement of an incoming Baikal wave in porous sand. When fresh water moves in a porous medium (sand), an electric field is formed. The equipment and measurement procedure are considered. The results of measurements under various conditions of the wave process (storm, ordinary wave, calm weather) are presented. The novelty and practical significance of the work is that for the first time an electrokinetic effect was found on the shoreline of lake Baikal, which can be used to develop equipment for estimating the parameters of wave hydrodynamic processes in large freshwater reservoirs.
The results of measurements of the horizontal electric field Eh components of the natural electromagnetic field of the Earth (Schumann resonances, SR) in the extreme low frequency (ELF) radio wave bands on Novaya Zemlya Island and settlement Tiksi are considered. In the electromagnetic clean arctic region on August 2016 (the Bay of Blagopoluchiya (75°41′59″ N; 63° 42′ 36″ E)) the global electromagnetic resonances (SR) of the Earth-ionosphere cavity up to the 7th and 8th resonant peaks in spectra are identified. Calculated and experimental values of the peak frequencies fn and Qnfactors of the cavity "Earth-ionosphere" are presented. On the spectra of records received on July, 2015 also in high latitudes near settlement Tiksi (71°35′3″ N; 128°46′4″ E) we work with the same measuring equipment and observed the 4th and 5th SR resonances. Diurnal variations of basic parameters of Schumann resonances are investigated.
The paper is devoted to estimation of the LF-MF high latitude communication radio lines range on surface electromagnetic waves (SEW). A surface impedance of sea areas of water in summer and winter time is considered. An example of calculations of the ground wave field over inhomogeneous impedance paths including stratified inhomogeneous structure “ice-sea” is given. It is shown that due to the emergence of SEW the Arctic radio lines range increases significantly.
Seismo electromagnetic effects in the upper ionosphere were examined during Kultuk earthquake 27.08.08 using data received by the DEMETER satellite. High intensity of the spectrum line on the daytime sonograms of NWC station (19.8 kHz) before the earthquake 27.08.08 (23.08.08 and 26.08.08) were detected. Decrease of the spectrum line intensity after the earthquakes on August 27th and 30th was registered. The computer program was written for quantitative analysis of sonograms, allowing to build spectra determining distance to a given sub-satellite point or time of flight of the satellite.
Results of geoelectric mapping of the some countries of Asia with high seismic activity are presented. The methodology
of the geoelectric mapping is considered. Maps of geoelectric sections of Turkey, Iran, Afghanistan, Pakistan, Korea, and
Japan on a scale of 1:5 000 000 are constructed. The scale of ρj and hj has three gradations per decade.
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