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| Author: | Lars Ceranna |
| Institution: | BGR, Hannover, Germany |
| Email: | ceranna@sdac.hannover.bgr.de |
| Authors: | Lars Ceranna |
Abstract Title:
"Simulating the propagation of infrasound in the atmosphere" |
Abstract:
A method is presented which allows the calculation of the acoustic wave-field in the
atmosphere using a Chebyshev pseudospectral approach. The acoustic equation of motion in a
moving media is solved in spherical coordinates with a rotationally symmetric approximation.
This approximation reduces drastically the computational time, without losing the three-dimensional geometrical spreading which is conserved for a point-like source near the lateral singularity.
Since the complete wave-field is simulated in the two-dimensional model this solution reveals
the pressure propagation from the source to the receiver. The resulting synthetic barograms
obtained by this method are compared with barograms based on the reflectivity method. The main disadvantage of the latter method is its limitation to a one-dimensional effective and static velocity model.Taking the results calculated by the Chebyshev pseudospectral method
as reference, the comparison of both synthetic waveforms enables to review the non-conformances caused by simplifying assumptions concerning the velocity model.
Furthermore, some examples between simulated and recorded infrasonic signals from IS26 are presented (e.g. the Bavarian bolide) demonstrating the strong dependency of the waveforms on the wind conditions. |
| Keywords: | numerical modeling, synthetic barograms, acoustic propagation |
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