Variations of global thunderstorm activity derived from the long-term Schumann resonance monitoring in the Antarctic and in the Arctic

Koloskov, A. V.; Nickolaenko, A. P.; Yampolsky, Yu.; Hall, Chris M.; Budanov, O. V.

doi:10.1016/j.jastp.2020.105231

Cited by 15 publications

(40 citation statements)

References 25 publications

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“…Higher magnitudes can be identified in the years near the solar maxima and smaller ones near the solar minimum (see Figures 3C-J). This observation had been noted earlier for the total horizontal magnetic field by Koloskov et al (2020). To take a closer look at this phenomenon we have removed the yearly averages from the VRN records for each (H NS , H EW ) field component and plotted the residuals (ΔI) in Figure 4.…”

Section: Long-term Variationssupporting

confidence: 69%

“…Here we note only that data segments with distorted SR spectra were removed from the VRN and SOU databases before averaging. From the VRN station an extended dataset of the spectral intensity at 11 Hz (between the first and second resonance peaks) is also presented (Koloskov et al, 2020). Later in this study we show that a substantial portion of long-term SR intensity variations are related to changes in the quality factor (Q-factor) of the Earth-ionosphere cavity, which characterizes the rate of energy dissipation at a given resonance mode (Madden and Thompson, 1965;Kulak et al, 2003a).…”

Section: Sr Datamentioning

confidence: 74%

“…The For more information about the stations and data processing we refer to the paper of Koloskov et al (2020). Here we note only that data segments with distorted SR spectra were removed from the VRN and SOU databases before averaging.…”

Section: Sr Datamentioning

confidence: 99%

“…SR measurements have also revealed the long-term solar cycle modulation of SR frequencies (e.g., Kulak et al, 2003a;Kulak et al, 2003b;Sátori et al, 2005;Ondrášková et al, 2011;Nickolaenko et al, 2015;Musur and Beggan, 2019;Koloskov et al, 2020) which has been attributed to the more than two orders of magnitude difference in solar X-ray flux between the minimum and maximum of solar activity (Sátori et al, 2005;Williams and Sátori, 2007). This effect is inherently non-uniform as only the sunlit portion of the lower ionosphere is affected by X-rays (and EUV radiation).…”

Section: Introductionmentioning

confidence: 99%

“…In 2015 long-term SR intensity records from the Ukrainian Antarctic station "Akademik Vernadsky" were published which clearly showed a pronounced solar cycle modulation (up to 60%) of SR intensity (Nickolaenko et al, 2015), just as in an earlier paper by Füllekrug et al (2002) using data from the Antarctic station Arrival Heights. Recently, Koloskov et al (2020) reported that SR intensity records at the Vernadsky station are still in phase with the solar cycle and that a new SR station began operation at Svalbard in the Arctic in 2013 that also shows the solar cycle modulation of SR intensity. The origin of this effect is a challenging question as satellite observations do not show a solar cycle variation in the intensity and distribution of lightning activity (which is recognized as the primary origin of SR intensity variations) (Christian et al, 2003;Williams et al, 2014;Williams, 2016).…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Long-term Variationssupporting

confidence: 69%