Topographically Scattered Infrasound Waves Observed on Microbarometer Arrays in the Lower Stratosphere ...
When an acoustic wave strikes a topographic feature, some of its energy is scattered. Sensors on the ground cannot capture these scattered signals when they propagate at high angles. We report observations of upwardly-scattered acoustic waves prior to refraction back to the ground, intercepting them...
| Main Authors: | , , , |
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| Format: | Text |
| Language: | English |
| Published: |
John Wiley and Sons Inc
2022
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| Subjects: | |
| Online Access: | https://dx.doi.org/10.17615/81gg-ym19 https://cdr.lib.unc.edu/concern/articles/44558p89j |
| Summary: | When an acoustic wave strikes a topographic feature, some of its energy is scattered. Sensors on the ground cannot capture these scattered signals when they propagate at high angles. We report observations of upwardly-scattered acoustic waves prior to refraction back to the ground, intercepting them with a set of balloon-borne infrasound microbarometers in the lower stratosphere over northern Sweden. We show that these scattered waves generate a coda whose presence can be related to topography beneath balloons and low-altitude acoustic ducts. The inclination of the coda signals changes systematically with time, as expected from waves arriving from scatterers successively closer to receivers. The codas are present when a temperature inversion channels infrasound from a set of ground chemical explosions along the ground, but are absent following the inversion's dissipation. Since scattering partitions energy away from the main arrival, these observations imply a mechanism of amplitude loss that had previously ... |
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