Realistic terrain boundary conditions for the three-dimensional finite-difference parabolic equation method applied to infrasonic propagation

Abstract

Infrasound propagation in the atmosphere can be significantly influenced by environmental parameters such as meteorology and topography. An accurate modelling of these parameters and their effects can improve signal processing of infrasound arrivals and development of more accurate prediction tools. Over the last few decades, much attention has been given to the integration of complex atmospheric features, namely, absorption, turbulence, density, and refraction, into the numerical methods, while topographic effects have usually been neglected. In this respect, the Parabolic Equation (PE) method has been continuously improved to deal with complex configurations encountered in various applications, such as atmospheric waveguides, ocean acoustics and electromagnetics. We have further extended the Beilis-Tappert (BTPE) generalized coordinate transform to three-dimensional propagation in order to account for out-of-plane scattering by irregular three-dimensional topography, in the presence of air density varia...