Estimation of Nuclear Explosion Energies from Microbarograph Records

FOLLOWING the US and USSR atmospheric test series in 1954–1962, numerous microbarograph records^1–8 of air waves generated by nuclear bomb tests were published. Previous theoretical interpretations^7,9 of such waveforms have required some explicit knowledge of the average atmospheric temperature and wind profiles above the path connecting source to microbarograph. Such profiles are never sufficiently well known and vary from point to point, and as seemingly small changes in the profiles cause relatively large changes in the waveforms, it would seem to be difficult to estimate the explosion energy yield to even order of magnitude accuracy from such records. Recently, however, in a further account of this work to be published elsewhere, we have succeeded in deriving an approximate theoretical relationship between certain waveform features and energy yield which is insensitive to changes in atmospheric structure. This relationship is given by where E is energy release, p_FPT is the first peak to trough pressure amplitude (see Fig. 1), r_e is radius of the Earth, r is the great circle distance from burst point to observation point, H_s is a lower atmosphere scale height, c is a representative sound speed, and T_1,2 is the time interval between first and second peaks. The purpose of the present communication is to describe the extent to which the above relation agrees with the existing available data.