A predictive macroscopic integral radiation efficiency model

Revelle, D. O.

doi:10.1029/jb085ib04p01803

Cited by 26 publications

(21 citation statements)

References 12 publications

(8 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A minimum expectation of one dozen bolides whose aircoupled explosive energy exceeds 1 kt (TNT equivalent) entering the atmosphere each year and about one 15 kt event occurring during the same period was determined earlier by ReVelle (1980ReVelle ( , 1997. These flux estimates apply to the moderately dense chondritic bodies, whereas the "real" influx may be factors of 2 or more higher for the weaker cometary materials that generally do not penetrate the atmosphere very deeply.…”

Section: Large Bolide Entry and Ground-based Infrasonic Detectionmentioning

confidence: 99%

“…For sources with larger blast wave relaxation radii than the proposed lower blast wave limit, the propagation occurs with negligibly small wave absorption for realistic bolide sources proposed in ReVelle (1976) and the corresponding wave frequencies are in the infrasonic branch of the acoustic-gravity wave (NG) regime. Such waves in the near-linear limit can propagate for thousands of kilometers before reaching undetectable amplitudes (ReVelle, 1980(ReVelle, , 1997. Sources with still larger blast wave radii have signals in the gravity wave branch of the A/G spectrum, for example, the case of the detection of the 1908 June 30 Tunguska (Great Siberian meteor) super-bolide event (a super-bolide is one which is >106x brighter than the minimum bolide threshold (about -5) as defined recently by Ceplecha).…”

Section: Large Bolide Entry and Ground-based Infrasonic Detectionmentioning

confidence: 99%

“…(1) Point Source, Period at Maximum Amplitude ApproachAs presented in ReVelle (1980ReVelle ( , 1997 (empirical Air Force Technical Applications Center (AFTAC) approach), the period at maximum amplitude of the signal (observed at long range) can be used to reliably infer the yield of an explosion as long as it is not at too great an altitude above the surface. As indicated below, the source energy of a small explosion (expressed in kilotons), E,T, can be empirically related to the observed period at maximum signal amplitude raised to a constant power-law exponent.…”

Section: Source Energy Estimatesmentioning

confidence: 99%

See 2 more Smart Citations

Infrasonic detection of a Leonid bolide: 1998 November 17

Revelle

Whitaker

1999

Meteorit & Planetary Scien

Self Cite

View full text Add to dashboard Cite

Abstract-During the early morning hours of the night of the peak of the annual Lconid meteor shower on 1998 November 17, a bright fireball (approximately -12 to -14 visual magnitude at 100 km in the zenith) was observed over northern New Mexico with visual sightings as far away from Los 4lamos as Albuquerque (-150 km to the south of Los Alamos), including direct persistent trail observations at the U. S. A. F. Starfire Optical Range (SOR), which is also near Albuqerque. This event did not produce any sonic boom reports, presumably because of its high altitude. It was also detected locally by an infrarc,d radiometer at Sandia National Laboratory and by an intensified charge-coupled device (CCD) camera located in Placitas, New Mexico. Subsequent investigations of the data from the six infrasound arrays used tly Los Alamos National Laboratory (LANL) and operated for the Department of Energy as a part of the Comprehensive Test Ban Treaty (CTBT) Research and Development program for the International Monitoring System (IMS) showed the presence of an infrasonic signal from the proper direction at the correct time for this bolide from two of our six arrays (both located in Los Alamos). The infrasound recordings (i.e., the wave amplitude and period data) indicated that an explosion occurred in the atmosphere at a source height of -93.5 km (with respect to sea level) or -90 km with respect to the altitude of Los Alamos, having its origins :lightly to the north and west of Los Alamos. Purely geometric solutions from the ground observers reports combined with direct measurements from the CCD camera at Placitas produced a source height of 91 ? 7 km. The signal characteristics analyzed from 0.5 to 3.0 Hz include a total duration of about 3 4 s for a source directed from Los Alamos toward 353.6 ? 0.4' measured from true north at a maximum elevation arrival angle of -72.7'. The latter was deduced on the basis of the observed signal trace velocities (for the part of the recording with the highest cross-correlation) and ranged from a constant value of about 920-1 150 d s (depending on the window length used in the analysis) for a ray trajectory along a direct refractive path between the source and the Los Alamos arrays. The dominant signal frequency at maximum amplitude at Lor Alamos was -0.71 Hz. These highly correlated signals had a peak to peak, maximum amplitude of -2.1 microbars (0.2 1 Pa). Using several methods that incorporate various observed signal characteristics, total disiance traveled, etc., our analysis indicates that the bolide probably had a source energy of -1.14 t (TNT equiqalent) or 4.77 x 109 J. This is -1 4 . 1~ smaller than the source energy estimate made using the infrasonic, empirical source energy relationship for low-altitude stationary point sources developed in the 1960s by the Air Force Technical Applications Center (AFTAC), Patrick Air Force Base, Florida. This relation was originally developed, however, for much larger source energies and at much longer ranges.

show abstract

Section: Large Bolide Entry and Ground-based Infrasonic Detectionmentioning

confidence: 99%

Section: Large Bolide Entry and Ground-based Infrasonic Detectionmentioning

confidence: 99%

Section: Source Energy Estimatesmentioning

confidence: 99%

See 1 more Smart Citation

Infrasonic detection of a Leonid bolide: 1998 November 17

Revelle

Whitaker

1999

Meteorit & Planetary Scien

Self Cite

View full text Add to dashboard Cite

show abstract

“…66 pO.66 = 1.209), with initial radius of2 m, initial velocity at entry of V oo = 15.8 krn/s, entry angle (8) of 18°, and imposing the additional constraint that only 1% of the initial kinetic energy is remaining at the end height/luminosity-cutoff (as has been found for the three photographically recorded meteorite falls; cf., ReVelle, 1980b). Additionally, we assume break-up into 10 fragments once the ram pressure exceeds the compressive strength of the body and after an initial short-time interval, these fragments are advected into the wake, heat-up and subsequently radiate light.…”

Section: Approximate Height (Km)mentioning

confidence: 99%

“…This represents the fraction of total initial kinetic energy which is converted into acoustic wave energy (cf., ReVelle, 1980b). It is the acoustic analog of the more familiar luminous efficiency.…”

Section: Infrasound Recordingsmentioning

confidence: 99%

An entry model for the Tagish Lake fireball using seismic, satellite and infrasound records

Brown

Revelle

Tagliaferri³

et al. 2002

Meteorit & Planetary Scien

Self Cite

149

118

View full text Add to dashboard Cite

Abstract-We present instrumental observations ofthe Tagish Lake fireball and interpret the observed characteristics in the context of two different models of ablation. From these models we estimate the pre-atmospheric mass of the Tagish Lake meteoroid to be -56 tonnes and its porosity to be between 37 and 58%, with the lowest part of this range most probable. These models further suggest that some 1300 kg of gram-sized or larger Tagish Lake material survived ablation to reach the Earth's surface, representing an ablation loss of97% for the fireball. Satellite recordings of the Tagish Lake fireball indicate that 1.1 x 10 12 J of optical energy were emitted by the fireball during the last 4 s of its flight. The fraction of the total kinetic energy converted to light in the satellite pass band is found to be 16%. Infrasonic observations ofthe airwave associated with the fireball establish a total energy for the event of 1.66 ± 0.70 kT TNT equivalent energy. The fraction ofthis total energy converted to acoustic signal energy is found to be between 0.10 and 0.23%. Examination ofthe seismic recordings ofthe airwave from Tagish Lake have established that the acoustic energy near the sub-terminal point is converted to seismic body waves in the upper-most portion of the Earth's crust. The acoustic energy to seismic energy coupling efficiency is found to be near 10-6 for the Tagish Lake fireball. The resulting energy estimate is near 1.7 kT, corresponding to a meteoroid 4 m in diameter. The seismic record indicates extensive, nearly continuous fragmentation ofthe body over the height intervals from 50 to 32 km. Seismic and infrasound energy estimates are in close agreement with the preatmospheric mass of 56 tonnes established from the modeling. The observed flight characteristics of the Tagish Lake fireball indicate that the bulk compressive strength of the pre-atmospheric Tagish Lake meteoroid was near 0.25 MPa, while the material compressive strength (most appropriate to the recovered meteorites) was closer to 0.7 MPa. These are much lower than values found for fireballs of ordinary chondritic composition. The behavior of the Tagish Lake fireball suggests that it represents the lowest end of the strength spectrum of carbonaceous chondrites or the high end of cometary meteoroids. The bulk density and porosity results for the Tagish Lake meteoroid suggest that the low bulk densities measured for some small primitive bodies in the solar system may reflect physical structure dominated by microporosity rather than macroporosity and rubble-pile assemblages.

show abstract