Acoustic analysis of shock production by very high-altitude meteors—I: infrasonic observations, dynamics and luminosity

Brown, Peter; Edwards, Wayne N.; Revelle, D. O.; Spurný, Pavel

doi:10.1016/j.jastp.2006.10.011

Cited by 30 publications

(28 citation statements)

References 22 publications

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“…For the IS27 composite plot, the elevation angle and back azimuth suggests that ~35km is the source height though these are not strongly constrained solutions. This height is also consistent with the ballistic angle closest to 90, consistent within uncertainty to a true ballistic arrival assuming some non-linear shock behaviour near the source (Brown et al, 2007). This is the most internally consistent height for a true cylindrical shock for this station.…”

Section: Antarctica Fireball -September 3 2004supporting

confidence: 77%

“…However, bolides produce cylindrical line source shock along their entire trail (ReVelle, 1976), thus the period measured at each station can be different simply because returns correspond to the size of the cylindrical blast cavity at that particular segment of the trail having an acoustical path to each station. The actual length of segment of the trail that contributes to the signal is unclear since the length depends on non-linear bending near trail (Brown et al, 2007). So one possibility for this large variation is that signals are coming from different part of the bolide trail.…”

Section: Period-yield Relationmentioning

confidence: 99%

“…This is the most internally consistent height for a true cylindrical shock for this station. According to Brown et al, (2007) the angular deviation of ballistic angle can be up to 24 degrees. For this event, we see up to about 30 degrees deviation, which would not be unreasonable for such an energetic event where the shock is strongly non-linear for considerable distance from the trail and bending of the wave front may also be pronounced.…”

Section: Antarctica Fireball -September 3 2004mentioning

confidence: 99%

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Refinement of bolide characteristics from infrasound measurements

Brown

2017

Planetary and Space Science

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We have detected and performed signal measurements on 78 individual bolide events as recorded at 179 infrasound stations between 2006 and 2015. We compared period-yield relations with AFTAC nuclear period-yield data, finding these to be similar with a slight offset. Scatter in period measurements for individual bolide is found to be caused in part by station noise levels and by attenuation effects with range. No correlation was found between the infrasound signal period and any of bolide height at peak brightness, entry speed or impact angle. We examined in detail three well constrained bolides having energy deposition curves, known trajectories and infrasound detections finding some evidence at shorter ranges that a component of station period scatter is due to varying source heights sampled by different stations. However, for longer-range stations in these three case studies, we were not able to assign unique source heights using raytracing due to large uncertainties in atmospheric conditions. Our results suggest that while source height contributes to the observed variance in infrasound signal periods from a given bolide, range and station noise play a larger role.

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Section: Antarctica Fireball -September 3 2004supporting

confidence: 77%

Section: Period-yield Relationmentioning

confidence: 99%

Section: Antarctica Fireball -September 3 2004mentioning

confidence: 99%

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Refinement of bolide characteristics from infrasound measurements

Brown

2017

Planetary and Space Science

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“…Moreover, the seasonal winds in the upper stratosphere (at ~ 50 km altitude) can create a favorable propagation duct when the energy is moving in the directions of those winds (e.g., Tolstoy, 1973;Georges et al, 1977;Drob et al, 2003;Kulichkov, 2010). Because meteoroids can produce shock waves at any altitude up to ~ 100 km and in rare cases even higher (depending on the parameters described in preceding sections, such as Kn) (Zinn et al, 2004;Brown et al, 2007;Silber and Brown, 2014), the resulting infrasound signals may take multiple paths through the atmosphere, and even reach altitudes of 120 km before being refracted back to the surface. Thus, the full atmospheric state from the ground to those altitudes is needed for source characterization, although this in itself is a challenging task (e.g., see de Groot-Hedlin et al, 2010).…”

Section: Infrasoundmentioning

confidence: 99%

Physics of meteor generated shock waves in the Earth’s atmosphere – A review

Silber

Boslough

Hocking

et al. 2018

Advances in Space Research

105

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Shock waves and the associated phenomena generated by strongly ablating meteoroids with sizes greater than a few millimeters in the lower transitional flow regime of the Earth's atmosphere are the least explored aspect of meteor science. In this paper, we present a comprehensive review of literature covering meteor generated shock wave phenomena, from the aspect of both meteor science and hypersonic gas dynamics. The primary emphasis of this review is placed on the mechanisms and dynamics of the meteor shock waves. We discuss key aspects of both shock generation and propagation, including the great importance of the hydrodynamic shielding that develops around the meteoroid. In addition to this in-depth review, the discussion is extended to an overview of meteoroid fragmentation, followed by airburst type events associated with large, deep penetrating meteoroids. This class of objects has a significant potential to cause extensive material damage and even human casualties on the ground, and as such is of great interest to the planetary defense community. To date, no comprehensive model exists that accurately describes the flow field and shock wave formation of a strongly ablating meteoroid in the non-continuum flow regime. Thus, we briefly present the current state of numerical models that describe the comparatively slower flow of air over non-ablating bodies in the rarefied regime. In respect to the elusive nature of meteor generated shock wave detection, we also discuss relevant aspects and applications of meteor radar and infrasound studies as tools that can be utilized to study meteor shock waves and related phenomena. In particular, infrasound data can provide energy release estimates of meteoroids entering the Earth's atmosphere. We conclude with a summary of unresolved questions in the domain of meteor generated shock waves; topics which should be a focus of future investigations in the field.

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“…A further indicator explaining detections and nondetections at numerous stations is the local time of day and the associated ambient noise conditions at the stations during this time [Bowman et al, 2005;Matoza et al, 2013]. At most stations, clear detections of the Chelyabinsk meteorite event predominantly took place during nighttime.…”

Section: Introductionmentioning

confidence: 99%

CTBT infrasound network performance to detect the 2013 Russian fireball event

Pilger

Ceranna

Ross

et al. 2015

Geophysical Research Letters

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The explosive fragmentation of the 2013 Chelyabinsk meteorite generated a large airburst with an equivalent yield of 500 kT TNT. It is the most energetic event recorded by the infrasound component of the Comprehensive Nuclear‐Test‐Ban Treaty‐International Monitoring System (CTBT‐IMS), globally detected by 20 out of 42 operational stations. This study performs a station‐by‐station estimation of the IMS detection capability to explain infrasound detections and nondetections from short to long distances, using the Chelyabinsk meteorite as global reference event. Investigated parameters influencing the detection capability are the directivity of the line source signal, the ducting of acoustic energy, and the individual noise conditions at each station. Findings include a clear detection preference for stations perpendicular to the meteorite trajectory, even over large distances. Only a weak influence of stratospheric ducting is observed for this low‐frequency case. Furthermore, a strong dependence on the diurnal variability of background noise levels at each station is observed, favoring nocturnal detections.

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Acoustic analysis of shock production by very high-altitude meteors—I: infrasonic observations, dynamics and luminosity

Cited by 30 publications

References 22 publications

Refinement of bolide characteristics from infrasound measurements

Refinement of bolide characteristics from infrasound measurements

Physics of meteor generated shock waves in the Earth’s atmosphere – A review

CTBT infrasound network performance to detect the 2013 Russian fireball event

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