Studies of ELF propagation in the spherical shell cavity using a field decomposition method based on asymmetry of Schumann resonance curves

Kułak, Andrzej; Młynarczyk, Janusz; Zięba, S.; Micek, S.; Nieckarz, Zenon

doi:10.1029/2005ja011429

Cited by 31 publications

(42 citation statements)

References 24 publications

(30 reference statements)

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“…In this approach the measured field fluctuations have to be decomposed into the resonance field and the traveling wavefield. In the frequency range 1 to 48 Hz we analyzed the observed ELF spectrum, and we fit to the observational data the function with asymmetric resonance maxima [ Kułak et al , ]:

W (f, θ) = s + \frac{z}{f^{m}} + \sum_{k = 1}^{N} \frac{p_{k} (θ) [1 + e_{k} (θ) (f - f_{k})]}{{(f - f_{k})}^{2} + {(\frac{g_{k}}{2})}^{2}},

where W ( f , θ ) is the wave power spectrum (T 2 /Hz), s represents the white noise term (T 2 /Hz), z / f m is the color noise term (T 2 /Hz), which describes all internal and external (man‐made) noises and parameter z has physical units of Hz m − 1 T 2 , p k ( θ ) is the power parameter of k th peak from the observed N = 7 resonance peaks and its physical units are T 2 Hz, e k is the introduced asymmetry parameter (Hz −1 ), f k is the resonant frequency (Hz), and g k is the peak width (Hz). The example of the decomposition function fit to the observational ELF data is shown in Figure (left).…”

Section: Application Of the Sr Decomposition To The Calculation Of Somentioning

confidence: 98%

Application of the Schumann resonance spectral decomposition in characterizing the main African thunderstorm center

et al. 2014

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In this paper we present a new method for quantifying the main tropical thunderstorm regions based on extremely low frequency (ELF) electromagnetic wave measurements from a single station-the Hylaty ELF station in Central Europe. Our approach is based on Schumann resonance (SR) measurements, which we apply as an example to thunderstorms in Africa. By solving the inverse problem, using the SR power spectrum templates derived analytically, we calculate distances to the most powerful thunderstorm centers and present simplified 1-D thunderstorm lightning activity "maps" in absolute units C 2 m 2 /s. We briefly describe our method of SR power spectrum analysis and present how this method is used with real observational data. We obtained the monthly lightning activity maps of the African storm centers with a spatial resolution of 1 • and temporal resolution of 10 min for January and August 2011. This allowed us to study the varying location and intensities of the African storm centers in different seasons of the year. A cross check of the obtained lightning activity maps with Tropical Rainfall Measuring Mission satellite data recorded by the Lightning Imaging Sensor and the derived correlation coefficients between SR and optical data were used to validate the proposed method. We note that modeling a maximum possible number of resonance modes in the SR power spectra (in our case, seven resonances) is essential in application of the proposed approach.

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W (f, θ) = s + \frac{z}{f^{m}} + \sum_{k = 1}^{N} \frac{p_{k} (θ) [1 + e_{k} (θ) (f - f_{k})]}{{(f - f_{k})}^{2} + {(\frac{g_{k}}{2})}^{2}},

Section: Application Of the Sr Decomposition To The Calculation Of Somentioning

confidence: 98%

Application of the Schumann resonance spectral decomposition in characterizing the main African thunderstorm center

et al. 2014

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“…Such problem also appears in helioseismic resonance activity as described by Gabriel et al []. Having in mind this, we decompose the observational SR power spectra into the symmetric part (a fundamental resonance frequency of the cavity, which does not depend on the distance from thunderstorm centers) and the asymmetric part (due to traveling waves, a component varying in time with changing source distances), as discussed in detail by Kułak et al []. The measured SR spectrum is approximated by the function:

W (f) = s + \frac{z}{f^{m}} + \sum_{k = 1}^{7} \frac{p_{k} [1 + e_{k} (f - f_{k})]}{{(f - f_{k})}^{2} + {(g_{k} / 2)}^{2}}

where W ( f ) is the signal power spectrum, s is the white noise component, z / f m is the color noise term, p k is the power parameter of the k th resonance peak, e k is the peak asymmetry parameter, f k is the resonant frequency, and g k is the resonant mode half‐width parameter.…”

Section: Schumann Resonance Measurement During the Sidmentioning

confidence: 99%

Novel analysis of a sudden ionospheric disturbance using Schumann resonance measurements

et al. 2015

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A spherical cavity between Earth and the lower ionosphere forms a global resonator for Extremely Low Frequency electromagnetic waves. Constant thunderstorm activity leads to the formation of a resonance field in the cavity, known as the Schumann resonance. Solar flare generated Sudden Ionospheric Disturbances (SID) modify the ionosphere affecting the ground-based radio communication systems. They are also expected to modify radiowave propagation in the cavity. In this paper, the Schumann Resonance spectral decomposition method is used for the first time to study the cavity resonance frequencies during the SID accompanying a strong X2.1 solar flare. We analyzed rapid changes in the frequencies and Q factors of the first five resonance modes using a 5 min timescale. The observed frequency shifts were compared to the ionizing solar flare fluxes in the UV, X-ray, and high-energy rays.

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“…A 10 minute interval was used in the first successful experiment [7,8]. While SR observations have been ongoing for many years in Hungary [59], USA [26], Japan [60], and Israel [54], recently new observatories have been opened in Poland [61], India [62], China [63,64], Greece [65] and Spain [66].…”

Section: Sr Background Observations Of Global Lightning Activitymentioning

confidence: 99%

ELF Electromagnetic Waves from Lightning: The Schumann Resonances

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2016

Atmosphere

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Lightning produces electromagnetic fields and waves in all frequency ranges. In the extremely low frequency (ELF) range below 100 Hz, the global Schumann Resonances (SR) are excited at frequencies of 8 Hz, 14 Hz, 20 Hz, etc. This review is aimed at the reader generally unfamiliar with the Schumann Resonances. First some historical context to SR research is given, followed by some theoretical background and examples of the extensive use of Schumann resonances in a variety of lightning-related studies in recent years, ranging from estimates of the spatial and temporal variations in global lighting activity, connections to global climate change, transient luminous events and extraterrestrial lightning. Both theoretical and experimental results of the global resonance phenomenon are presented. It is our hope that this review will increase the interest in SR among researchers previously unfamiliar with this phenomenon.

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Studies of ELF propagation in the spherical shell cavity using a field decomposition method based on asymmetry of Schumann resonance curves

Cited by 31 publications

References 24 publications

Application of the Schumann resonance spectral decomposition in characterizing the main African thunderstorm center

Application of the Schumann resonance spectral decomposition in characterizing the main African thunderstorm center

Novel analysis of a sudden ionospheric disturbance using Schumann resonance measurements

ELF Electromagnetic Waves from Lightning: The Schumann Resonances

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