Infrasound in the ionosphere from earthquakes and typhoons

Chum, Jaroslav; Liu, J.-Y.; Podolská, Kateřina; Šindelářová, Tereza

doi:10.1016/j.jastp.2017.07.022

Cited by 38 publications

(32 citation statements)

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“…Previous studies showed that extreme meteorological events such as deep convection systems (Azeem et al, 2015;Lane et al, 2003), tropical cyclones (TCs) including typhoons, hurricanes, tropical storm (Chum et al, 2018;Georges, 1973;Hung & Kuo, 1978;Xiao et al, 2007;Yue et al, 2014), thunderstorms (Curry & Murty, 1974;Taylor & Hapgood, 1988), and tornadoes (Nishioka et al, 2013) can generate acoustic waves and gravity waves, which can propagate upward and have the potential to change the upper atmosphere via momentum flux and heat deposition. Bauer (1958) first showed the influence of hurricanes on critical frequency of the F2 layer of the ionosphere.…”

Section: Introductionmentioning

confidence: 99%

Tropical Cyclone‐Induced Gravity Wave Perturbations in the Upper Atmosphere: GITM‐R Simulations

et al. 2020

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The tropical cyclone (TC)‐induced concentric gravity waves (CGWs) are capable of propagating upward from convective sources in the troposphere to the upper atmosphere and creating concentric traveling ionospheric disturbances (CTIDs). To examine the CGWs propagation, we implement tropical cyclone‐induced CGWs into the lower boundary of global ionosphere‐thermosphere model with local‐grid refinement (GITM‐R) and simulate the influence of CGWs on the ionosphere and thermosphere. GITM‐R is a three‐dimensional non‐hydrostatic general circulation model for the upper atmosphere with the local‐grid refinement module to enhance the resolution at the location of interest. In this study, CGWs induced by the typhoon Meranti in 2016 have been simulated. Information of the TC shape and moving trails is obtained from the TC best‐track dataset, and the gravity wave patterns are specified at the lower boundary of GITM‐R (100 km altitude). The horizontal wavelength and phase velocity of wave perturbation at the lower boundary are specified to be consistent with the TEC observations. The simulation reveals a clear evolution of CTIDs, which shows reasonable agreement with the GPS‐TEC observations. This is the first time the typhoon‐driven TEC perturbation has been simulated in a general circulation model. To further examine the dependence of the CTIDs on the wavelength and frequency of the gravity wave perturbation at the lower boundary, different waveforms have been tested as well. The magnitude of CTIDs has a negative correlation with the period but a positive correlation with the wavelength when the horizontal phase velocities are sufficiently fast against the critical‐level absorption.

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Section: Introductionmentioning

confidence: 99%

Tropical Cyclone‐Induced Gravity Wave Perturbations in the Upper Atmosphere: GITM‐R Simulations

et al. 2020

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“…Earthquakes can induce strong far‐field signatures in ionograms but not significant GPS‐derived TEC perturbations in the near field (Berngardt et al, ). Ionospheric signatures observed by Doppler sounders (Artru et al, ; Chum et al, ; Liu et al, ) in far field can have comparable magnitudes with the ionospheric signatures in near field (Chum et al, ). Analysis of both the ground motion data and the Doppler sounding data revealed that no more than one tenth of the acoustic wave energy excited at the ground can reach the upper atmosphere between 210 and 220 km altitudes (Chum et al, ).…”

Section: Summary Of Major Observational Resultsmentioning

confidence: 96%

“…These observations have provided insights on the coupling mechanisms between surface disturbances and the upper atmosphere. Consequently, researchers have gained a good understanding of the acoustic‐gravity waves generated from different types of impulsive surface disturbances and the corresponding upper atmospheric responses (e.g., Artru, Ducic, et al, ; Astafyeva et al, ; Chum et al, ; Heki, ; Hickey, ; Huang et al, ; Jin et al, ; Lognonné et al, ; Liu et al, ; Makela et al, ; Nakashima et al, ; Occhipinti et al, ; Rolland et al, )…”

Section: Introductionmentioning

confidence: 99%

Upper Atmospheric Responses to Surface Disturbances: An Observational Perspective

et al. 2019

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We review observations on the coupling between Earth's surface disturbances and the upper atmosphere. In particular, we focus on the upper atmospheric responses to atmospheric acousticgravity waves generated during impulsive surface disturbance events including earthquakes, tsunamis, volcanic eruptions, and explosions. We review the theoretical background for the generation and propagation of atmospheric acoustic-gravity waves from surface disturbance events as well as of the ionospheric plasma response to such acoustic-gravity waves. We review a variety of observational techniques that have been successfully utilized to detect upper atmospheric perturbations induced by surface disturbances and summarize the state-of-the-art knowledge on the coupling processes learnt from these observations. Finally, we touch on some most recent advances in the field and propose directions for future research.Plain Language Summary Earthquakes, tsunamis, volcanic eruptions, and chemical and nuclear explosions on or under the ground create sudden and violent motions of the ground or ocean surface. While ground shakings during some massive earthquakes can be felt by people who live thousands of kilometers away from the epicenters, the shakings can also be detected from the atmosphere hundreds of kilometers above the ground (upper atmosphere). Similarly, tsunamis, volcanic eruptions, and explosions can have footprints in the upper atmosphere as well. These footprints have been successfully detected by a variety of observational techniques. This paper reviews the observational results and the current understanding of the physical mechanisms behind the coupling between the ground/ocean and the upper atmosphere. In addition, future research directions are proposed in order to address the open questions.

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“…The time resolution of 6 s is used in this study. The primary data processing is described in more detail by Chum et al (2018).…”

Section: Continuous Doppler Soundingmentioning

confidence: 99%

Continuous Doppler sounding of the ionosphere during solar flares

Chum

Urbář

Laštovička

et al. 2018

Earth Planets Space

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Solar flares cause a rapid increase in ionization in the ionosphere owing to significant enhancement of ionizing solar radiation in the X-ray and extreme ultraviolet (EUV) spectral ranges. The change of electron densities in the ionosphere influences the propagation of radio waves. The ionospheric response to solar flares is investigated for three selected examples recorded during the maximum and decreasing phase of the solar cycle 24 with time resolution of several seconds by continuous Doppler sounding systems installed in the Czech Republic (50N, 14E), Taiwan (24N, 121E) and Northern Argentina (27S, 65W). The reflection heights of sounding signals are derived from nearby ionospheric sounders. The measured Doppler shifts are compared with EUV and X-ray data from the GOES-15 satellite. It is shown that the largest Doppler shifts are observed at times when the time derivatives of EUV fluxes are maximal, while the Doppler shifts are around zero at times when the EUV fluxes reach maxima. This means that loss processes balance the ionization when the EUV fluxes maximize. The attenuation of Doppler signal caused by enhanced electron density in the D and E layer was well correlated with the cosmic noise absorption measured by riometer. For large ionizing fluxes, the attenuation leads to very low signal-to-noise ratio, loss of the received signal, and inability to process both Doppler shift spectrograms and ionograms.

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Infrasound in the ionosphere from earthquakes and typhoons

Cited by 38 publications

References 32 publications

Tropical Cyclone‐Induced Gravity Wave Perturbations in the Upper Atmosphere: GITM‐R Simulations

Tropical Cyclone‐Induced Gravity Wave Perturbations in the Upper Atmosphere: GITM‐R Simulations

Upper Atmospheric Responses to Surface Disturbances: An Observational Perspective

Continuous Doppler sounding of the ionosphere during solar flares

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