A climatology of microbarom detections at the Kerguelen Islands

Unravelling the ambient noise wavefield

Journal Article (2022)
Author(s)

Olivier F.C. Den Ouden (Royal Netherlands Meteorological Institute (KNMI), TU Delft - Applied Geophysics and Petrophysics)

Jelle Assink (Royal Netherlands Meteorological Institute (KNMI))

PSM Smets (TU Delft - Applied Geophysics and Petrophysics)

L. Evers (Royal Netherlands Meteorological Institute (KNMI), TU Delft - Applied Geophysics and Petrophysics)

Research Group
Applied Geophysics and Petrophysics
Copyright
© 2022 O.F.C. den Ouden, Jelle D. Assink, P.S.M. Smets, L.G. Evers
DOI related publication
https://doi.org/10.1093/gji/ggab535
More Info
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Publication Year
2022
Language
English
Copyright
© 2022 O.F.C. den Ouden, Jelle D. Assink, P.S.M. Smets, L.G. Evers
Research Group
Applied Geophysics and Petrophysics
Issue number
3
Volume number
229
Pages (from-to)
1646-1664
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Abstract

The ambient infrasonic noise field is complex due to the interference of spatially distributed infrasound sources. Microbaroms are one of the most dominant omnipresent infrasonic sources within this wavefield. These microbaroms are generated by nonlinear ocean surface wave interactions, and have a characteristic and continuous signature within the infrasound spectrum. Under noisy conditions, microbaroms can mask infrasonic signals of interest, such as infrasound from volcanoes or explosions, which limits detection and identification of such sources. This study performs an infrasonic climatology for infrasound array I23FR, using five years of data between 2015-2020. The array is located on the Kerguelen Islands, within the Southern Ocean, and is part of the International Monitoring System for the verification of the Comprehensive Nuclear-Test-Ban Treaty. The climatology analysis addresses the expected ambient noise levels, propagation paths and potential sources within the vicinity of an infrasound sensor. Time- and frequency-domain beamforming methods have been applied to analyse the infrasonic wavefield from the I23FR observations. A recently introduced method is applied to compute so-called soundscapes, to be compared with beamform results. Although the comparison indicates a disagreement in amplitude, there is a good agreement in directionality and frequency between both.