Worldwide Observations of Infrasonic Waves

Campus, P.; Christie, D. R.

doi:10.1007/978-1-4020-9508-5_6

Cited by 83 publications

(57 citation statements)

References 97 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the last decade, detection bulletins determined from near‐real‐time analysis were produced and correlated with observations of natural or man‐made atmospheric sources, such as exploding meteoroids, volcanic eruptions, hurricanes, earthquakes, and ocean swelling [ Campus and Christie , ; Le Pichon et al ., ; Matoza et al ., ]. More recently, well‐determined repetitive infrasound sources are used to probe the upper atmosphere [ Le Pichon et al ., ; Lalande et al ., ; Assink et al ., ].…”

Section: Observationsmentioning

confidence: 99%

Ten year observations of gravity waves from thunderstorms in western Africa

et al. 2014

View full text Add to dashboard Cite

A new study of gravity waves produced by thunderstorms was performed using continuous recordings at the IS17 (Ivory Coast) infrasound station of the International Monitoring System developed for the verification of the Comprehensive Nuclear Test-Ban Treaty. A typical case study is presented for a large thunderstorm on 10-11 April 2006 lasting near 14 h. Comparison with cloud temperature measured by the Meteosat 6 satellite shows that wave activity is large when the cloud temperature is low inside convection cells located over the station. Statistics based on 10 year data show that the wave activity is intense throughout the year with peak periods in May and October and less intense activity in January, in good agreement with the local keraunic level. The seasonal variations of the wave azimuth highlight clear trends from northward direction from February to August to southward direction from August to December. Lightning flashes, observed from space, show a similar motion confirming that thunderstorms are the main sources of the gravity wave activity. The gravity wave azimuth follows the seasonal motion of the tropical rain belt partly related to the Intertropical Convergence Zone of the winds. The contribution of other possible sources, such as wind over relief, is weak because surface winds are weak in this region and only oceans are present south of the station. We conclude that the large observed wave activity is mainly produced by convection associated to thunderstorms.

show abstract

Section: Observationsmentioning

confidence: 99%

Ten year observations of gravity waves from thunderstorms in western Africa

et al. 2014

View full text Add to dashboard Cite

show abstract

“…This International Monitoring System (IMS) infrasound network is designed to detect and locate explosions with a yield of one kiloton of TNT anywhere in the world with at least two stations [e.g., Christie et al , 2001; Christie and Campus , 2010]. Even though the IMS infrasound network is not yet fully established, its data have been exploited in numerous source, propagation and detection studies [e.g., Campus and Christie , 2010; Brachet et al , 2010].…”

Section: Introductionmentioning

confidence: 99%

Incorporating numerical modeling into estimates of the detection capability of the IMS infrasound network

2012

View full text Add to dashboard Cite

[1] To monitor compliance with the Comprehensive Nuclear-Test ban Treaty (CTBT), a dedicated International Monitoring System (IMS) is being deployed. Recent global scale observations recorded by this network confirm that its detection capability is highly variable in space and time. Previous studies estimated the radiated source energy from remote observations using empirical yield-scaling relations which account for the along-path stratospheric winds. Although the empirical wind correction reduces the variance in the explosive energy versus pressure relationship, strong variability remains in the yield estimate. Today, numerical modeling techniques provide a basis to better understand the role of different factors describing the source and the atmosphere that influence propagation predictions. In this study, the effects of the source frequency and the stratospheric wind speed are simulated. In order to characterize fine-scale atmospheric structures which are excluded from the current atmospheric specifications, model predictions are further enhanced by the addition of perturbation terms. A theoretical attenuation relation is thus developed from massive numerical simulations using the Parabolic Equation method. Compared with previous studies, our approach provides a more realistic physical description of long-range infrasound propagation. We obtain a new relation combining a near-field and a far-field term, which account for the effects of both geometrical spreading and absorption. In the context of the future verification of the CTBT, the derived attenuation relation quantifies the spatial and temporal variability of the IMS infrasound network performance in higher resolution, and will be helpful for the design and prioritizing maintenance of any arbitrary infrasound monitoring network.Citation: Le Pichon, A., L. Ceranna, and J. Vergoz (2012), Incorporating numerical modeling into estimates of the detection capability of the IMS infrasound network,

show abstract

“…Infrasound signals result from low‐frequency acoustic waves with a frequency content below 20 Hz. These waves, because of their relatively low attenuation, can be observed at distances up to 10,000 km or more [ Campus and Christie , ]. They are generated by a variety of natural (meteors, auroras, lightning, tornadoes, ocean waves, earthquakes, avalanches, tsunamis, and volcanoes) and man‐made (nuclear explosions, mining activities, rockets, industrial and cultural sources, and other chemical explosions) sources [ Campus , ; Campus and Christie , ].…”

Section: Introductionmentioning

confidence: 99%

“…These waves, because of their relatively low attenuation, can be observed at distances up to 10,000 km or more [ Campus and Christie , ]. They are generated by a variety of natural (meteors, auroras, lightning, tornadoes, ocean waves, earthquakes, avalanches, tsunamis, and volcanoes) and man‐made (nuclear explosions, mining activities, rockets, industrial and cultural sources, and other chemical explosions) sources [ Campus , ; Campus and Christie , ]. The propagation is strongly dependent on the temperature and wind structure of the atmosphere, with infrasound refraction resulting from the atmosphere's vertical temperature and wind profile [ Georges and Beasley , ].…”

Section: Introductionmentioning

confidence: 99%