Atmospheric waves caused by large explosions

Abstract

This paper considers the harmonic oscillations of several simple model atmospheres. The oscillations are of two types. In the first, the kinetic energy per unit volume tends to zero at great heights; in the second, the kinetic energy per unit volume remains finite. A large explosion at ground level excites a spectrum of both types of oscillation. The pulse ultimately separates into two parts—a train of travelling waves which can be observed at ground level at great distances, and a train of travelling waves which disappear into the upper atmosphere. The complete range of experimental observations on the pressure oscillations caused by explosions of energies varying between 10 20 and 10 24 ergs can only be interpreted with model atmospheres having one or more sound channels, i.e. having at least one minimum in the temperature-height relationship of the atmosphere. In spite of the complexity of the phenomena, the theory throws light on some of the characteristic features of the observations. The average period of the largest waves is roughly proportional to the cube root of the energy released by the explosion. The amplitudes of the waves from large explosions can be calculated. Conversely, good records enable the size of the explosion to be estimated. The energy of the Siberian meteorite of 1908 was about 10 16 cal, or 10 MT (T signifying a ton of t.n.t.).

Propagation of the Pressure Waves Produced by Auroras

“…Another difference between these types of atmospheric waves is seen in trend of wave form, i.e., most of auroral pressure wave appears with shorter wave first (Chrzanowski et at., 1961), while pressure waves detected by microbarograph after large explosion show the arrival of longer wave first and the shorter wave later later (Hunt et al, 1960).…”

“…propagation surface is hyperboloid with semi-major axis in x-direction, which is also given by (3.8) or (Lamb, 1932,) can exist in this frequency range (Hunt et at., 1960). This wave propagates only in horizontal direction (Eckart,1960, p. 105).…”

Probable asteroidal origin of the Tunguska Cosmic Body

“…The height of the explosion is closely related to the value of the energy emitted, usually estimated equal to about 10-15 Mton (Hunt 1960;Ben-Menahem 1975), although some authors considered the energy value to be higher, up to 30-50 Mton (Pasechnik 1971(Pasechnik , 1976(Pasechnik , 1986. In correspondence with the first energy range, which seems to have better grounds, the height of the explosion was found equal to 6-14 km.…”

Effects of Winds on Atmospheric Pressure Waves Produced by Hydrogen Bombs

“…The function g ( ) chosen herein is such that its real part is (1-15 ) exp (-15 ) which function corresponds to an explosion of two to three megatons of TNT (Hunt, Palmer and Penney (1960)). The effect of the size of explosion on the appearance of a microbarogram is well illustrated in that presented by Murayama (1963b) recorded at Wakkanai on 24 December 1962 when a large explosion was preceded by a smaller one.…”