On using computational aeroacoustics for long-range propagation of infrasounds in realistic atmospheres

Abstract

In this study, a perturbative formulation of non linear euler equations is used to compute the infrasound propagation in real atmospheres. Based on a Dispersion-Relation-Preserving numerical scheme, the discretization provides very good properties for both sound generation and long range infrasound propagation over a variety of spatial atmospheric scales. The background flow is obtained by matching the comprehensive empirical global model of horizontal winds HWM-93 with radio and rocket soundings of the lower atmosphere. Comparison of calculations and experimental data from the explosive "Misty Picture" test (on May 14, 1987) shows that asymptotic techniques based on high frequency approximations cannot explain some important features of the measurements. The small scales of high resolution meteorological data provide changes in the detection predictions and the emergence of large-scale coherent shuctures of atmospheric turbulence. Copyright 2007 by the American Geophysical Union.