Comparison of global lightning activity variations inferred from Q-bursts, Schumann resonances, and WWLLN-detected lightning strokes

Author(s):  
Karolina Szabóné André ◽  
József Bór ◽  
Gabriella Sátori ◽  
Tamás Bozóki ◽  
Péter Steinbach

<p>Measured time series of the extremely low frequency (ELF, 3 Hz-3 kHz) band electromagnetic field can be considered as a superposition of background and transient signals. Transient signals produced by exceptionally powerful lightning strokes far from the recording station are named Q-bursts. The direction of the source lightning stroke at the recording station can be calculated using the horizontal components of the Poynting vector. The source lightning stroke can be identified in the lightning database of the World Wide Lightning Location Network (WWLLN, wwlln.net) by the matching detection time and direction calculated from ELF measurements.</p><p>Schumann resonance (SR) peaks appear at ~8Hz, ~14Hz, ~20 Hz, etc., in the spectra computed from the background ELF timeseries. SRs are natural electromagnetic resonances with wavelengths comparable to the circumference of the Earth-ionosphere waveguide. Peak amplitudes and frequencies in the resonance spectrum detected in the ELF band at any given location on the Earth depend on the distribution and intensity of the global lightning activity which excites SR.</p><p>ELF measurements are routinely performed in the Széchenyi István Geophysical Observatory (NCK, 47°38' N, 16°43' E) near Nagycenk, Hungary. Vertical electric and the horizontal magnetic components of the atmospheric electromagnetic field are monitored by the Schumann resonance recording system. In this work, we study the variation of the number of lightning strokes with high charge moment change (CMC; indicated by the number of large amplitude Q-bursts recorded at NCK) and the variation of the number of lightning strokes with large peak current (indicated by the number of WWLLN-detected energetic lightning strokes). In addition to considering the total number of WWLLN-detected lightning strokes and Q-bursts, we analyze lightning strokes occurring  only in west, south, east, and north directions from NCK, corresponding predominantly to the three main lightning producing regions of the tropical lands in America, Africa, and Indonesia as well as to the Pacific Ocean. Time variations of the number of high CMC and large peak current lightning strokes during November, 2014 are compared with time variation of the cumulative SR intensity detected at NCK station in the vertical electric field component in the same month. Similarities and differences in the time variations of the considered quantities are discussed in order to show how these indicators mirror the changing distributions of the global lightning activity.</p>

2013 ◽  
Author(s):  
Κωνσταντίνος Ράλλης

The aim of this doctoral thesis is to study electromagnetic compatibility problems dealing with field couplings to underground transmission lines, communication systems or electronic devices. As an overview: (i) we develop expressions for the accurate computation of mutual impedances between two underground conductors of finite length, (ii) we use a modern technique to solve the well-known Pollaczek and Carson formulas for the evaluation of the earth-return impedance for underground and overground conductors, (iii) we present a method for calculating the electromagnetic field generated by a lightning stroke for studying the problem of induced over-voltage on lines and electronic devices both in power and telecommunication systems, (iv) we deal with the computation of the current distribution along a vertical grounding rod. In all cases, our approach is purely electromagnetic with the use of the elementary electric dipoles technique. More specifically: In the first chapter we provide the expressions for the field generated by a vertical or horizontal elementary electric dipole placed in air or in ground. We form the boundary problem of the system dipole and air-ground interface for the calculation of the Hertz vector components generated by the dipole and the calculation of the electromagnetic field. We also provide tables with the cylindrical components of the produced field. In the second chapter we study the problem of the mutual impedance between two underground conductors of finite length and arbitrary position. With the use of the elementary dipoles technique we derive expressions for the accurate calculation of the mutual impedance that have the form of double infinite improper integrals and we evaluate them by using advanced integration algorithms. We then follow an alternative approach which involves the computation of the equivalent Sommerfeld type integrals by using the Discrete Complex Image Method (DCIM). This method allows the transformation of the Sommerfeld integrals to semi-infinite integrals with known analytical solutions. This is possible by approximating the integrand by a sum of complex exponentials. We finally give results of the mutual impedance and carry out comparisons in order to validate our expressions. In the third chapter we deal with the computation of the current distribution along a vertical grounding rod. We derive the mathematical model by applying the elementary dipoles technique and then we use the Method of Moments for solving the electric field integral equation. For the validation of the developed model, we solve the problem with the FEM method by using the software package COMSOL. In the fourth chapter we evaluate the well-known Pollaczek and Carson formulas for the earth-return impedance for underground and overground conductors. The integrals are solved by using again the DCIM method. For the approximation of the integrand with a sum of exponentials we use the Generalized Pencil of Function (GPOF) method (one and two level). The results of the impedance are compared with results derived with numerical integration of the Pollaczek integral and the analytical solution of Carson’s integral. In chapter five we evaluate the electromagnetic field generated by the lightning stroke in an observation point above and underground. The knowledge of the field is very important when we study couplings with power lines or telecommunication conductors. The expressions for the lightning field have the form of semi-infinite improper integrals in frequency domain, and their numerical computation poses a computational challenge. The problem is more demanding in the case of time domain response, were a large number of computations for a frequency range is required, in order to carry out the required inverse Fourier transform. We propose an efficient method for calculating the lightning integrals, based on their numerical calculation along a deformed path of integration. The method is combined with an interpolation technique in order to reduce the number of frequencies required in the Fourier synthesis of the time domain electric field. The result is a very fast and straightforward tool for the calculation of the underground and overground lightning field, without the use of specially developed numerical algorithms or analytical approximations.


Author(s):  
G. Tatsis ◽  
A. Sakkas ◽  
V. Christofilakis ◽  
G. Baldoumas ◽  
S.K. Chronopoulos ◽  
...  

Radio Science ◽  
2007 ◽  
Vol 42 (2) ◽  
pp. n/a-n/a ◽  
Author(s):  
Gabriella Sátori ◽  
Mariusz Neska ◽  
Earle Williams ◽  
Judit Szendrői

2019 ◽  
Vol 27 (3) ◽  
pp. 466-477 ◽  
Author(s):  
E. D. Kuzmenko ◽  
S. M. Bahrii ◽  
U. O. Dzioba

On the basis of the analysis of the literature sources, we determined the possible range of using the method of the Earth`s natural pulse electromagnetic field. As a result of detailed analysis of domestic and foreign research, we demonstrated the relevance of conducting research focused on development of the Earth'snatural pulse electromagneticfield (or ENPEMF). Using the results of theoretical studies, the advantages and disadvantages of the ENPEMF method were determined. A complex of physical processes which preceded the development of the pulse electromagnetic field of the Earth was characterized, and the impact of mechanical deformations of rocks on the change in the condition of the electromagnetic field was experimentally proven. The main fundamentals on the determination of depth range of the ENPEMF method were examined and a new approach to interpretation of the data was suggested. We conducted an analysis of methods developed earlier of calculating geometric parameters of the sources which generate electromagnetic impulses. Their practicability at a certain stage of solving the data of geological tasks was experimentally tested. We determined the factors which affect the depth range of the ENPEMF method. A mathematical solution of the effectiveness of the ENPEMF method was suggested and determined the relations between the depth parameter of the study and the frequency of measuring and effective value of specific electric resistance. On the example of different objects, the effectiveness and correctness of the suggested method of determining the depth range parameter was proven. In particular, the theoretical results of the study were tested and confirmed on objects of different geological-morphological and engineering-technical aspects, i.e. Novo-Holyn mine in the Kalush-Holynske potash deposit and the multi-storey educational building of the University in Ivano-Frankivsk. The practicability of using the ENPEMF method in combination with other methods of electrometry for solving practical geological tasks was experimentally proven.


2021 ◽  
Author(s):  
Colin Price ◽  
Tair Plotnik ◽  
Anirban Guha ◽  
Joydeb Saha`

<p>Tropical cyclones have been observed in recent years to be increasing in intensity due to global warming, and projections for the future are for further shifts to stronger tropical cyclones, while the changes in the number of storms is less certain in the future.  These storms have been shown to exhibit strong lightning activity in the eyewall and rainbands, and some studies (Price et al., 2009) showed that the lightning activity peaks before the maximum intensity of the tropical cyclones.  Now we have investigated the impact of these tropical storms on the upper tropospheric water vapor (UTWV) content.  Using the ERA5 reanalysis product from the ECMWF center, together with lightning data from the ENTLN network, we show that the lightning activity in tropical cyclones is closely linked to the increase in UTWV above these storms.  We find the maximum enhancement in UTWV occurs between the 100-300 mb pressure levels, with a lag of 0-2 days after the peak of the storm intensity (measured by the maximum sustained winds in the eyewall).  The lightning activity peaks before the storm reaches its maximum intensity, as found in previous studies.  The interest in UTWV concentrations is due to the strong positive feedback that exists between the amounts of UTWV and surface global warming.  Water Vapor is a strong greenhouse gas which is most efficient in trapping in longwave radiation emitted from the Earth in the upper troposphere.  Small changes in UTWV over time can result in strong surface warming.  If tropical cyclones increase in intensity in the future, this will likely result in increases in UTWV, reducing the natural cooling ability of the Earth.  Lightning may be a useful tool to monitor these changes.</p>


2019 ◽  
Vol 127 ◽  
pp. 03006
Author(s):  
Yiyang Luo ◽  
Nguyen Xuan An ◽  
Vladislav Lutsenko ◽  
Vladimir Uvarov

To study the electromagnetic radiation of the lithosphere associated with seismic waves, we used the recordings of the natural electromagnetic radiation obtained under conditions of weak industrial noise and a high level of microseismicity in the ELF-VLF wave bands. It is shown that these data contain information about the surface waves of the Earth’s crust and are accompanied by a frequency close to the first harmonic of the Schumann resonance. The distribution of spikes over thresholds is obtained, which can be indicators of the activity in the processes of the Earth’s crust. The averaged form of the spikes for different components of the electromagnetic field is obtained. Attention is drawn to the differences in the various components of the electromagnetic field and their diurnal differences are analyzed. The possibility of using the approach to predict the short-term movement of the Earth’s crust is considered.


2016 ◽  
Vol 16 (2) ◽  
pp. 607-616 ◽  
Author(s):  
Dieter Roel Poelman ◽  
Wolfgang Schulz ◽  
Gerhard Diendorfer ◽  
Marina Bernardi

Abstract. Cloud-to-ground (CG) lightning data from the European Cooperation for Lightning Detection (EUCLID) network over the period 2006–2014 are explored. Mean CG flash densities vary over the European continent, with the highest density of about 6 km−2 yr−1 found at the intersection of the borders between Austria, Italy and Slovenia. The majority of lightning activity takes place between May and September, accounting for 85 % of the total observed CG activity. Furthermore, the thunderstorm season reaches its highest activity in July, while the diurnal cycle peaks around 15:00 UTC. A difference between CG flashes over land and sea becomes apparent when looking at the peak current estimates. It is found that flashes with higher peak currents occur in greater proportion over sea than over land.


2021 ◽  
Vol 249 ◽  
pp. 105357
Author(s):  
Andrea Pizzuti ◽  
Jonathan M. Wilkinson ◽  
Serge Soula ◽  
Janusz Mlynarczyk ◽  
Ivana Kolmašová ◽  
...  

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