Four Year Study of the Schumann Resonance Regular Variations Using the Sierra Nevada Station Ground‐Based Magnetometers

Abstract

We present a study of the Schumann resonance (SR) regular variations (March 2013–February 2017) using the ground‐based magnetometers from the Sierra Nevada station, Spain (37°02′N, 3°19′W). The study is based on the fitting parameters obtained by the Lorentzian fit, calculated for each 10‐min interval record, namely, peak amplitudes, peak frequencies, width of the resonances, and the power spectrum integral for the first three SR modes. We consider three time‐scales in the study: seasonal, monthly, and daily variations. The processed data collected by the Sierra Nevada station are also made public with this work. The general characteristics of the long‐term evolution of the SR are confirmed, but discrepancies appear that require further study comparing recent measurements from different stations. Signatures of the influences of the El Niño phenomenon and the solar cycle to SR have been found.

A Novel Population of Slow Magnetosonic Waves and a Method for the Observation of the Roots of Plasma Bubbles in the Lower Ionosphere

“…The corresponding quality factor Q values are 4, 4.5, 5, 5.5 and 6 for these resonances. The SR intensities observed at a fixed location have significant diurnal and seasonal variations in amplitude, sometimes over a factor of two (Fullekrug M. , 1995) as the global rate of lightning varies as the subsolar point crosses the three main continental regions (Rodriguez-Camacho et al, 2021;Satori, 1996). From the quality of the correlation between the observed intensity of the SRs and the instantaneous lightning rate (Boldi et al, 2017) no evidence is found for contributions other than lightning to the intensity of the SRs in the EIWG.…”

“…Measurements of the magnetic field intensity of the lowest SR at ground level are typically less than 1 pT/Hz 1/2 , e.g. (Boldi et al, 2017;Fullekrug, 1995;Fullekrug & Fraser-Smith, 1996;Price, 2016;Rodriguez-Camacho et al, 2021;Salinas et al, 2016;Sentman, 1987).…”

Detection of electromagnetic anomalies over seismic regions during two strong (MW > 5) earthquakes

“…• the plasmaspheric hiss at ∼1 kHz (Malaspina et al, 2018;Tsurutani et al, 2018); • the first and second Schumann resonance, at ∼8 and ∼15 Hz respectively (Rodríguez-Camacho et al, 2022); • the signal due to the v × B field caused by the satellite motion into the geomagnetic field (Diego et al, 2021).…”

“…• ≈ 2 Hz (E y , E z ): these peaks are due to the v × B electric field present in the ELF band, caused by satellite motion into the geomagnetic field [see e.g., (Diego et al, 2021)]; • ≈ 8 and ≈15 Hz (E x , E y , E z ): first and second Schumann ionospheric resonances at CSES-01 orbit [see (Rodríguez-Camacho et al, 2022)]; • ≈ 1 kHz (E x ): signature of the plasmaspheric hiss (Malaspina et al, 2018;Tsurutani et al, 2018).…”

A Novel Population of Slow Magnetosonic Waves in the Ionosphere

“…The corresponding quality factor Q values are 4, 4.5, 5, 5.5 and 6 for these resonances. The SR intensities observed at a fixed location have significant diurnal and seasonal variations in amplitude, sometimes over a factor of two (Fullekrug M. , 1995) as the global rate of lightning varies as the subsolar point crosses the three main continental regions (Satori, 1996), (Rodriguez-Camacho et al, 2021).…”