Modeling Schumann resonances with schupy

Bozóki, Tamás; Prácser, Ernő; Sátori, Gabriella; Dálya, G.; Kapas, Kornel; Takátsy, János

doi:10.1016/j.jastp.2019.105144

Cited by 13 publications

(7 citation statements)

References 34 publications

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“…However, to reveal the best possible CMC‐based spatial distribution of global lightning corresponding to the months with increased SR intensity, a geophysical inversion algorithm ingesting multi‐ELF‐station spectral information is required (Nelson, 1967; Nickolaenko & Hayakawa, 2014). Our group is working on the implementation of such an algorithm (Bozóki et al., 2019; Prácser et al., 2019) which will hopefully contribute to the better understanding of variations in lightning activity on the ENSO timescale. Time series data from a large number of ELF receivers worldwide have been assembled for the period of the second super El Niño and inversion calculations are planned as a future effort.…”

Section: Discussionmentioning

confidence: 99%

Evolution of Global Lightning in the Transition From Cold to Warm Phase Preceding Two Super El Niño Events

et al. 2021

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Multistation observations of Schumann resonance (SR) intensity document common behavior in the evolution of continental‐scale lightning activity in two super El Niño events, occurring in 1997/98 and 2015/16. The vertical electric field component of SR at Nagycenk, Hungary and the two horizontal magnetic field components in Rhode Island, USA in 1997, and in 2014–2015, the two horizontal magnetic field components at Hornsund, Svalbard and Eskdalemuir, United Kingdom as well as in Boulder Creek, California and Alberta, Canada exhibit considerable increases in SR intensity from some tens of percent up to a few hundred percents in the transition months preceding the two super El Niño events. The UT time distribution of anomalies in SR intensity indicates that in 1997 the lightning activity increases mainly in Southeast Asia, the Maritime Continent and India, i.e. the Asian chimney region. On the other hand, a global response in lightning is indicated by the anomalies in SR intensity in 2014 and 2015. SR‐based results are strengthened by comparison to independent lightning observations from the Optical Transient Detector and the World Wide Lightning Location Network, which also exhibit increased lightning activity in the transition months. The increased lightning is attributable to increased instability due to thermodynamic disequilibrium between the surface and the midtroposphere during the transition. The main conclusion is that variations in SR intensity may act as a precursor for the occurrence and magnitude of these extreme climate events, and in keeping with earlier findings, as a precursor to maxima in global surface air temperature.

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Section: Discussionmentioning

confidence: 99%

Evolution of Global Lightning in the Transition From Cold to Warm Phase Preceding Two Super El Niño Events

et al. 2021

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“…And because they are also remote from thunderstorm activity they are not subjected to the interference caused by nearby lightning. These two properties make high latitude stations highly valuable for SR-connected research aims, such as the reconstruction of global lightning activity (see e.g., Bozóki et al, 2019;Prácser et al, 2019) by inversion methods. However, because of the extraterrestrial effects on the SR cavity at higher latitude as documented in this work, it is of vital importance to realize all possible masking effects when analyzing these data-sets in connection with lightning-related climate research.…”

Section: Discussionmentioning

confidence: 99%

Solar Cycle-Modulated Deformation of the Earth–Ionosphere Cavity

et al. 2021

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The Earth–ionosphere cavity resonator is occupied primarily by the electromagnetic radiation of lightning below 100 Hz. The phenomenon is known as Schumann resonances (SR). SR intensity is an excellent indicator of lightning activity and its distribution on global scales. However, long-term measurements from high latitude SR stations revealed a pronounced in-phase solar cycle modulation of SR intensity seemingly contradicting optical observations of lightning from satellite, which do not show any significant solar cycle variation in the intensity and spatial distribution of lightning activity on the global scale. The solar cycle-modulated local deformation of the Earth–ionosphere cavity by the ionization of energetic electron precipitation (EEP) has been suggested as a possible phenomenon that may account for the observed long-term modulation of SR intensity. Precipitating electrons in the energy range of 1–300 keV can affect the Earth–ionosphere cavity resonator in the altitude range of about 70–110 km and modify the SR intensities. However, until now there was no direct evidence documented in the literature supporting this suggestion. In this paper we present long-term SR intensity records from eight stations, each equipped with a pair of induction coil magnetometers: five high latitude (|lat| > 60°), two mid-high latitude (50° < |lat| < 60°) and one low latitude (|lat| < 30°). These long-term, ground-based SR intensity records are compared on the annual and interannual timescales with the fluxes of precipitating 30–300 keV medium energy electrons provided by the POES NOAA-15 satellite and on the daily timescale with electron precipitation events identified using a SuperDARN radar in Antarctica. The long-term variation of the Earth–ionosphere waveguide’s effective height, as inferred from its cutoff frequency, is independently analyzed based on spectra recorded by the DEMETER satellite. It is shown that to account for all our observations one needs to consider both the effect of solar X-rays and EEP which modify the quality factor of the cavity and deform it dominantly over low- and high latitudes, respectively. Our results suggest that SR measurements should be considered as an alternative tool for collecting information about and thus monitoring changes in the ionization state of the lower ionosphere associated with EEP.

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“…Few other numerical approaches were used for the estimation of the parameters of the Earth-ionosphere resonator, like the two-dimensional telegraph equation (TDTE) in a twodimensional spherical transmission line model of the Earthionosphere cavity (Kulak et al, 2003;Bozóki et al, 2019) and the transmission line matrix (TLM) numerical method in Cartesian and spherical coordinate systems (Morente et al, 2003;Toledo-Redondo et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Finite-difference time-domain analysis of ELF radio wave propagation in the spherical Earth–ionosphere waveguide and its validation based on analytical solutions

2022

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Abstract. The finite-difference time-domain (FDTD) model of electromagnetic wave propagation in the Earth–ionosphere cavity was developed under assumption of an axisymmetric system, solving the reduced Maxwell equations in a 2D spherical coordinate system. The model was validated on different conductivity profiles for the electric and magnetic field components for various locations on Earth along the meridian. The characteristic electric and magnetic altitudes, phase velocity, and attenuation rate were calculated. We compared the results of numerical and analytical calculations and found good agreement between them. The undertaken FDTD modeling enables us to analyze the Schumann resonances and the propagation of individual lightning discharges occurring at various distances from the receiver. The developed model is particularly useful when analyzing ELF measurements.

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Modeling Schumann resonances with schupy

Cited by 13 publications

References 34 publications

Evolution of Global Lightning in the Transition From Cold to Warm Phase Preceding Two Super El Niño Events

Evolution of Global Lightning in the Transition From Cold to Warm Phase Preceding Two Super El Niño Events

Solar Cycle-Modulated Deformation of the Earth–Ionosphere Cavity

Finite-difference time-domain analysis of ELF radio wave propagation in the spherical Earth–ionosphere waveguide and its validation based on analytical solutions

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