NCPAprop—A software package for infrasound propagation modeling

Abstract

Developed by the infrasound group at the National Center of Physical Acoustics, University of Mississippi, and a few collaborators, NCPAprop is an open source software package aiming at providing a comprehensive set of tested and validated numerical models for simulating the long range propagation of infrasonic signals through the earth's atmosphere. The algorithms implemented in NCPAprop are designed for frequencies large enough that the effects of buoyancy can be neglected and small enough that propagation to ranges of hundreds to thousands of kilometers is possible without significant signal attenuation. Nominally, NCPAprop can, without modification, be used to efficiently model narrowband propagation from 0.1 to 10 Hz and broadband propagation from 0.05 Hz to 2 or 3 Hz. NCPAprop provides both geometrical acoustic and full wave models which will be presented. The geometrical acoustics part consists of 2-d and 3-d ray tracing programs as well as a non-linear ray theory model. The full wave models consist of a suite of normal mode models of increasing complexity and a Parabolic Equation (PE) model.