Theoretical Prediction of Acoustic-Gravity Pressure Waveforms Generated by Large Explosions in the Atmosphere

Computational Techniques for the Study of Infrasound Propagation in the Atmosphere

“…As explained in the prior report, below cutoff (that is, below WL = 0.0125 rad/sec for GR and below wL = 0.0118 rad/sec for GR 0 , in the running example) the real part kR of the horizontal wave number is the real part of W/v(1) and the imaginary part k I is the imagimary part of w/v (1) Finally, the extension by first iteration of the normal mode dispersion curves below cutoff is obtained by simply calculating w/k.…”

“…The major alterations to the computer program Infrasonic Waveforms (as described in report by Pierce and Posey, 1970) incurred consist of the computation of the imaginary part of the newly incorporated complex wavenumber, extension of the normal-mode dispersion function to lower frequencies, and a second-order correction factor to the phase velocity. mode.…”

“…Listings of G, All, A 1 2 , and X for various values of w and for the GR 1 and GR 0 modes are given in Table 1.…”

Development of an Infrasound Propagation Modeling Tool Kit

“…Pierce developed a computer code based on the normal mode theory for infrasound propagation in a relatively low frequency band of interest, motivated by interest in long range propagation of infi-asound due to large (i.e., megaton yield) events [Pierce and Kinney, 1976;Pierce et ah, 1973;Pierce and Posey, 1970]. The normal mode approach is generally usefiil for estimating received time series or waveforms.…”

“…The baseline set of acoustic propagation models contained in InfraMAP consists of: ■ Ray Tracing: a three-dimensional ray theory model, HARPA (Hamiltonian Ray-Tracing Program for Acoustic Waves in the Atmosphere) [Jones et al, 1986], ■ Normal Modes: a WKB version [Dighe et al, 1998;Hunter and Whitaker, 1997] of the normal mode model [Pierce and Kinney, 1976;Pierce et al, 1973;Pierce and Posey, 1970], and ■ PE: a continuous-wave, two-dimensional parabolic equation (PE) model [Jensen et al, 1994;West era/., 1992]. InfraMAP provides integration of these three models with the environmental characterizations described above.…”