Details of the Abstract
| Title of paper | Study on the temporal variation and regional differences of Schumann Resonance based on observations from an extremely low frequency electromagnetic network in China |
| List of authors | Han, B., Tang, J., Zhao, G. Z., Dong, Z. Y. |
| Affiliation(s) | The State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration |
| Summary | Based on 10 years of quasi-continuous data from extremely low-frequency (ELF) electromagnetic stations, the temporal and spatial variations of Schumann resonances (SR) were analyzed. Three major parameters were obtained: peak intensity, peak frequencies, and the Q factor, determined through Lorentz fitting of the electromagnetic (EM) auto-spectrum. The focus was on their seasonal and inter-annual variations, as well as regional differences in the first three modes at the stations. Fengning station, seasonal variations of SR parameters were exemplified, with intensity peaking in the northern hemisphere's summer and reaching a minimum in winter, while frequency exhibited an inverse phase. The range of these parameters from summer to winter also varied. The Q factor, however, did not show significant seasonal variation. Inter-annual variations across 10 stations revealed a more consistent pattern in the magnetic field than in the electric field. Seasonal variations of SR parameters were primarily influenced by the periodic intensity changes and migration of lightning activities, corroborated by global observations. Additionally, strong links between SR parameters and the 11-year solar cycle were confirmed through comparisons with the El Niño index and solar X-radiation flux, with enhanced intensity during the 2015/2016 super El Niño event.SR exhibited significant spatial distribution differences across different stations. The amplitude differences, especially in the horizontal electric field components, ranged from ten to a hundred times. Despite this, the amplitude variation range (difference between the highest and lowest values) was relatively uniform, about half an order of magnitude. Magnetic field component amplitude tended to increase with latitude. The mean and median frequencies across different stations were quite similar, but the variation range differed, with Ex and Hy showing larger variations and Ey and Hx showing smaller variations. The overall Q factor distribution was fairly uniform, with minor differences between different modes and components. |
| Session Keyword | 5.0 Monitoring: of GICs, environmental, tectonic and geomorphological hazards |
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