Infrasound direction of arrival determination using a balloon-borne aeroseismometer

Article Acoustics

Ray tracing in a stratified moving atmosphere: Azimuthal deviation in sound propagation

Vladimir E. Ostashev et al.

Summary: This study proposes a ray tracing method based on a closed-form expression for the sound propagation path in a stratified moving medium. It involves a one-dimensional integration over the vertical coordinate and can complement existing ray tracing codes. The method provides a benchmark solution and a closed-form expression for the azimuthal deviation, enabling estimation of the deviation given crosswind or remote sensing of the crosswind. The study focuses on sound propagation in the atmospheric surface layer characterized by friction velocity and surface heat flux.

JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA (2022)

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Article Geochemistry & Geophysics

Estimates on the Frequency of Volcanic Eruptions on Venus

Paul K. Byrne et al.

Summary: This study estimates that up to 120 discrete volcanic eruptions may occur on Venus per Earth year based on analysis of volcanic eruption records on Earth. The study also proposes several techniques to search for volcanic activity on Venus and calls for validation of these estimates.

JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS (2022)

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Article Astronomy & Astrophysics

Topographically Scattered Infrasound Waves Obeserved on Microbarometer Arrays in the Lower Stratosphere

E. J. Bird et al.

Summary: When an acoustic wave encounters a topographic feature, it scatters and loses some of its energy. In this study, we observed the scattered acoustic waves that travel upward before refracting back to the ground. These waves were intercepted by balloon-borne infrasound microbarometers in the lower stratosphere over northern Sweden. The presence of the scattered waves generated a coda, which can be linked to the topography beneath the balloons and low-altitude acoustic ducts. The inclination of the coda signals changed over time, indicating waves arriving from scatterers closer to the receivers. These observations provide insights into the mechanism of amplitude loss due to scattering, which was previously difficult to measure. They contribute to a better understanding of the interaction between atmospheric infrasound propagation and the solid earth.

EARTH AND SPACE SCIENCE (2022)

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Article Geochemistry & Geophysics

An active source seismo-acoustic experiment using tethered balloons to validate instrument concepts and modelling tools for atmospheric seismology

R. F. Garcia et al.

Summary: The study demonstrates the effectiveness of using infrasonic sensors and accelerometers mounted on a tethered helium balloon for controlled seismo-acoustic experiments. It validates ground to air coupling theory and numerical modelling tools, while also highlighting the impact of accelerometer location on records and identifying the optimal sensor placement at the bottom of the balloon envelope.

GEOPHYSICAL JOURNAL INTERNATIONAL (2021)

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Article Geosciences, Multidisciplinary

The First Detection of an Earthquake From a Balloon Using Its Acoustic Signature

Quentin Brissaud et al.

Summary: By detecting an earthquake for the first time from a balloon-borne microbarometer, this study demonstrates that seismic activity can be detected from a high-altitude platform on Earth. It also shows that Rayleigh wave-induced infrasound can be used to constrain subsurface velocities, laying the groundwork for the detection and characterization of such signals on Venus.

GEOPHYSICAL RESEARCH LETTERS (2021)

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Article Acoustics

Directional infrasound sensing using acoustic metamaterials

Jerry W. Rouse et al.

Summary: This study introduces a compact infrasound direction of arrival sensor based on acoustic metamaterials, which can determine the direction of arrival in a small footprint. The sensor design greatly expands the locations where it can be deployed, providing further avenues for research.

JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA (2021)

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Article Acoustics