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| Titel |
Localization of infrasonic sources generated by the swell |
| VerfasserIn |
Matthieu Landès, Lars Ceranna, Alexis Le Pichon, Robin Matoza |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250048512
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| Zusammenfassung |
| Although currently not fully established, the infrasound network of the International
Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty organization
enables studies at a global scale, such as detection capability of infrasound networks,
continuous observations of the atmosphere, or atmosphere/ocean interface modeling. The
background noise conditions play a dominant role in the selection of signals of interest
at infrasonic stations especially around 0.2 Hz where the noise is increased due
to microbarom signals. The study of microbarom sources will therefore help to
understand the detectability of nuclear explosions and volcanic eruptions, and will allow
microbarom detections to be used as continuous sources for monitoring atmospheric
variations.
Continuous infrasound monitoring over four consecutive years from 2006 to 2010 show
that microbaroms are globally observed at several middle-, high-latitude, and equatorial
infrasound IMS-stations, showing clear seasonal trends in back-azimuth driven by
stratospheric winds. To provide global and quantitative observations of these seasonal
variations, we perform, via a simple cross-bearing method of back-azimuths, monthly
localizations of microbarom sources with a multi-year averaging approach. Maps of acoustic
source pressure calculated from NOAA wave-watch model III and our microbarom source
location estimates provide a first attempt of a comparison between global continuous
microbarom measurements and ocean swell. Such an approach can help to evaluate global
infrasound detection capabilities, providing new insights on quantitative relationships
between infrasonic observables, atmospheric specifications, and interactions between
atmosphere and ocean. |
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