Statistical Analysis of Very Low Frequency Atmospheric Noise Caused by the Global Lightning Using Ground‐Based Observations in China

Gu, Xudong; Li, Guangjian; Pang, Hong; Wang, Shiwei; Ni, Binbin; Luo, Fan; Peng, Rui; Chen, Long

doi:10.1029/2020ja029101

Cited by 10 publications

(8 citation statements)

References 37 publications

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“…The amplitude and phase are obtained by considering that transmitter signals are modulated using the Minimum Shifting Key (MSK) method (Gross et al., 2018; Paschal, 1988; Pasupathy, 1979). The VLF data collected using this system have been widely used in studies of lightning discharge (Gu, Li, et al., 2021; Yi et al., 2020), sunrise effects (Wang et al., 2020), and solar eclipses (Gu, Peng, et al., 2021). Phase instability has been an issue for VLF studies (Gross et al., 2018; S. Kumar et al., 2022).…”

Section: Vlf Instrument and Flare Measurementsmentioning

confidence: 99%

Measurements and Modeling of the Responses of VLF Transmitter Signals to X‐Class Solar Flares at the Great Wall Station in Antarctica

et al. 2023

Space Weather

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Section: Vlf Instrument and Flare Measurementsmentioning

confidence: 99%

Measurements and Modeling of the Responses of VLF Transmitter Signals to X‐Class Solar Flares at the Great Wall Station in Antarctica

et al. 2023

Space Weather

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“…The digital receiver mainly comprised an analog to digital converter, a USB interface, and a GPS synchronization module, providing a timing accuracy of ~100 ns for the detection system [36,37]. With a dynamic range of ~110 dB, this system is highly sensitive to VLF waves emitted by lightning discharges and navy transmitters [38,39] and represents one of the most sensitive VLF receivers that are currently operational for subionospheric studies [40][41][42]. In this study, we report measurements of the VLF signals from the NWC transmitter, which is located at the North West Cape, Australia (21.82 • S, 114.17 • E) and operates at 19.8 kHz with an emitting power of 1 MegaWatt.…”

Section: Vlf Instrument and Eclipse Measurementmentioning

confidence: 99%

A Comparative Study of VLF Transmitter Signal Measurements and Simulations during Two Solar Eclipse Events

Cheng

et al. 2023

Remote Sensing

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To monitor the Very-Low-Frequency (VLF) environment, a VLF detection system has been installed in Suizhou, China, a location with the longitude almost identical to that of the NWC transmitter in Australia. In the years 2019 and 2020, two solar eclipses crossed the NWC–Suizhou path at different locations. Each solar eclipse event represents a naturally occurring controlled experiment, but these two events are unique in that similar levels of electron density variation occurred at different locations along the VLF propagation path. Therefore, we conducted a comparative study using the VLF measurements during these two eclipses. Previous studies mostly estimated a pair of the reflection height (h′) and sharpness parameter (β) using the Long Wavelength Propagation Capability code, whereas, in this study, we use the VLF amplitude and phase as constraints in order to find the electron density change that best explains the VLF measurements. The eclipse measurements could be best explained if the path-averaged β value was 0.56 and 0.62 km−1 for the 2019 and 2020 eclipse, respectively. The VLF reflection height increased from 71.5 to 73.3 km for the 2019 eclipse and from 71.1 to 72.8 km for the 2020 eclipse. The best-fit β values were consistent with the Faraday International Reference Ionosphere model and statistical studies, and the h′ change was also consistent with previous studies and theoretical calculations. Moreover, present results suggested that VLF signals collected by a single receiver were not sensitive to where the electron density change occurs along the propagation path but reflected the average path condition. Therefore, a network of VLF receivers is required in order to monitor in real time the spatial extent of the space weather events that disturb the lower ionosphere.

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“…The detection system has a high dynamic range of ∼110 dB, and thus the signal with a wide range of intensity variation can be sampled as completely as possible. With a dynamic range sensitivity of ∼110 dB and time accuracy of ∼100 ns, the WHU ELF/VLF receiving system enables the reception of artificial and natural VLF signals with resolutions that suffice most ionospheric and magnetospheric studies (Chen et al., 2017; Gu, Chen, et al., 2022; Gu, Li, et al., 2021; Gu, Luo, et al., 2021; Gu, Peng, et al., 2022; Wang et al., 2020; Yi et al., 2019, 2020; Zhou et al., 2020).…”

Section: Instrumentmentioning

confidence: 99%

First Results of the Wave Measurements by the WHU VLF Wave Detection System at the Chinese Great Wall Station in Antarctica

Wang

et al. 2022

JGR Space Physics

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The Extremely Low Frequency (ELF) and VLF waves, with frequencies typically ranging from 300 Hz to 30 kHz, can be categorized as the naturally occurring waves and artificial emissions (e.g., Cohen et al., 2010;Ni et al., 2022). Lightning discharges and man-made VLF transmitters are the two dominant sources of ELF/ VLF waves that repetitively reflect and propagate within the Earth-ionosphere Waveguide (EIWG) (e.g., Barr et al., 2000;Silber & Price, 2016). With wavelengths of 10-1000 km, these waves are well bounded by the terrestrial surface and the lower ionosphere, and can thus propagate thousands of kilometers with relatively low attenuation (∼2 dB/Mm) (e.g., Davies, 1990;Sasmal, 2018). As such, the propagation of ELF/VLF waves is primarily influenced by the variation of the lower and upper boundaries of EIWG, especially a region that Abstract A Very Low Frequency (VLF) wave detection system has been designed at Wuhan University (WHU) and recently deployed by the Polar Research Institute of China at the Chinese Great Wall station (GWS, 62.22°S, 58.96°W) in Antarctica. With a dynamic range of ∼110 dB and timing accuracy of ∼100 ns, this detection system can provide observational data with a resolution that can facilitate space physics and space weather studies. This paper presents the first results of the wave measurements by the WHU VLF wave detection system at GWS to verify the performance of the system. With the routine operation for 3 months, the system can acquire the dynamic changes of the wave amplitudes and phases of various ground-based VLF transmitter signals emitted in both North America and Europe. A preliminary analysis indicates that the properties of the VLF transmitter signals observed at GWS during the X-class solar flare events are consistent with previous studies. As the HWU-GWS path crosses the South Atlantic Anomaly region, the observations also imply a good connection in space and time between the VLF wave disturbances and the lower ionosphere variation potentially caused by magnetospheric electron precipitation during the geomagnetic storm period. It is therefore well expected that the acquisition of VLF wave data at GWS, in combination with datasets from other instruments, can be beneficial for space weather studies related to the radiation belt dynamics, terrestrial lightning discharge, whistler wave propagation, and the lower ionosphere disturbance, etc., in the polar region. Plain Language Summary Considering the good coverage and quiet electromagnetic environment,Antarctica is an ideal place for plasma wave measurements. Various stations have been established in Antarctica, of which Palmer station is particularly noteworthy and has historically provided valuable VLF data for atmospheric, ionospheric, and magnetospheric studies. An Extremely Low Frequency/Very Low Frequency (VLF) wave detection system has been designed by Wuhan University and recently set up at Great Wall station (GWS) in Antarctica. This device can effectively record VLF signals with frequencies of 1-50 kHz, including...

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Statistical Analysis of Very Low Frequency Atmospheric Noise Caused by the Global Lightning Using Ground‐Based Observations in China

Abstract: The very low frequency (VLF) atmospheric noise with a frequency range of 3-30 kHz, among which lightning discharge is the primary source (

Cited by 10 publications

References 37 publications

Measurements and Modeling of the Responses of VLF Transmitter Signals to X‐Class Solar Flares at the Great Wall Station in Antarctica

Measurements and Modeling of the Responses of VLF Transmitter Signals to X‐Class Solar Flares at the Great Wall Station in Antarctica

A Comparative Study of VLF Transmitter Signal Measurements and Simulations during Two Solar Eclipse Events

First Results of the Wave Measurements by the WHU VLF Wave Detection System at the Chinese Great Wall Station in Antarctica

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