Infrasound propagation modeling: near-real-time environmental
characterization and variability studies.
Robert Gibson and David Norris
Developments in the propagation modeling capabilities of the InfraMAP
analysis tool kit are reported in two areas. First, the output products of
numerical weather prediction models are being used to supplement the
baseline climatological characterizations of the propagation
environment. These near-real-time wind and temperature updates capture
atmospheric features at finer temporal and spatial scales than do
climatological models. Second, the propagation variability induced by the
environment is predicted and used to evaluate the performance of infrasonic
networks. A gravity wave spectral model is used to generate realizations
of horizontal wind perturbation as a function of height. A Monte Carlo
simulation is then executed to calculate probability distributions of
travel time and azimuthal deviation for a path of interest. Modeled
variances, along with the uncertainty introduced by measurement error, are
used to calculate the confidence bounds of multi-station
localizations. Applications and case studies are discussed.
Work supported by the Defense Threat Reduction Agency, USA