Multi-Arrival Infrasound from Meteoroids: Fragmentation Signatures versus Propagation Effects in a Fine-Scale Layered Atmosphere

TL;DR

This study uses modeling and regional infrasound data to distinguish meteoroid fragmentation signatures from atmospheric effects, improving the accuracy of source characterization in infrasound monitoring.

Contribution

It introduces a novel approach combining PPE simulations with regional data to identify true fragmentation signals versus atmospheric artifacts.

Findings

Fine-scale atmospheric layering can distort signals but does not cause pulse splitting below 140 km.

The double arrival at 100 km for event 20060305 indicates separate fragmentation episodes.

New diagnostic criteria are established for interpreting infrasound signals from meteoroids.

Abstract

Infrasonic signatures of meteoroid fragmentation are frequently ambiguous: do multiple arrivals signify a complex breakup or merely the distorting effects of a layered atmosphere? Resolving this ambiguity is critical for accurate energy estimates and source reconstruction. In this study, we address this challenge by analyzing a unique regional dataset of well-constrained meteoroid events observed by the Southern Ontario Meteor Network and the co-located Elginfield Infrasound Array. We employ pseudo-differential parabolic equation (PPE) simulations to quantify how fine-scale gravity-wave structures in the stratosphere and lower thermosphere modify acoustic waveforms at ranges <300 km. Our modeling reveals that while fine-scale layering can stretch signals and generate diffuse oscillatory tails, it does not produce discrete, high-amplitude pulse splitting at ranges below ~140 km. By applying these results to the rare multi-arrival event 20060305, we demonstrate that its distinct double arrival at 100 km range is inconsistent with atmospheric multipathing and provides definitive evidence of separate fragmentation episodes. These findings establish new diagnostic criteria for separating source physics from propagation artifacts, improving the reliability of infrasound as a monitoring tool for natural bolides, space debris re-entries, and catastrophic launch failures.