Historical Detection of Atmospheric Impacts by Large Bolides Using Acoustic‐Gravity Wavesa

ABSTRACT: During the period from about 1960 to the early 1980's a number of large bolides (meteor‐fireballs) entered the atmosphere which were sufficiently large to generate blast waves during their drag interaction with the air. For example, the remnant of the blast wave from a single kiloton class event was subsequently detected by up to six ground arrays of microbarographs which were operated by the U.S. Air Force during this presatellite period. Data have also been obtained from other sources during this period as well and are also discussed in this summary of the historical data. The Air Force data have been analyzed in terms of their observable properties in order to infer the influx rate of NEOs (near‐Earth objects) in the energy range from 0.2 to 1100 kt. The determined influx is in reasonable agreement with that determined by other methods currently available such as Rabinowitz 21 , Ceplecha 4 , 5 and by Chapman and Morrison 8 despite the fact that due to sampling deficiencies only a portion of the “true” flux of large bodies has been obtained by this method, i.e., only sources at relatively low elevations have been detected. Thus the weak, fragile cometary bodies which do not penetrate the atmosphere as deeply are less likely to have been sampled by this type of detection system. Future work using the proposed CTBT (Comprehensive Test Ban Treaty) global scale infrasonic network will be likely to improve upon this early estimate of the global influx of NEOs considerably.