Estimating tropospheric and stratospheric winds using infrasound from explosions

Area of Science:

• Atmospheric physics
• Geophysics
• Acoustics

Background:

• Atmospheric infrasound propagation is affected by winds, causing directional biases.
• Infrasound signals from explosions in northern Finland were measured over 30 years.
• The measurement array is located in a shadow zone, yet strong signals were detected, likely due to stratospheric reflections.

Purpose of the Study:

• To investigate the impact of atmospheric cross-winds on infrasound backazimuth measurements.
• To demonstrate the feasibility of estimating atmospheric cross-winds using infrasound data.
• To validate infrasound-derived wind estimates against reanalysis data.

Main Methods:

• Utilized infrasound data from 598 surface explosions over 30 years in northern Finland.
• Employed a high-resolution infrasound array situated 178 km north of the sources.
• Applied wave-propagation modeling and compared backazimuth deviations with European Centre for Medium-Range Weather Forecasts Reanalysis (ERA)-Interim cross-wind data.

Main Results:

• Observed significant backazimuth deviation in infrasound signals, attributed to tropospheric and stratospheric cross-winds.
• Wave-propagation modeling showed good correspondence between observed backazimuth deviations and ERA-Interim cross-wind data.
• Infrasound data successfully estimated atmospheric cross-winds.

Conclusions:

• Atmospheric cross-winds can be accurately estimated directly from infrasound propagation time and backazimuth deviation.
• Infrasound-derived cross-wind estimates show good agreement with ERA-Interim reanalysis data.
• This method offers a novel approach for monitoring atmospheric winds using geophysical acoustic data.