Refinement of Bolide Characteristics from Infrasound measurements

TL;DR

This study analyzes infrasound data from 78 bolide events to understand how signal characteristics relate to bolide properties, revealing that range and noise significantly influence measurements more than source height.

Contribution

It provides a detailed comparison of bolide infrasound signals with nuclear data and investigates factors affecting period measurements, highlighting the roles of range, noise, and source height.

Findings

Period-yield relations are similar to nuclear data with slight offsets.

Scatter in period measurements is mainly due to noise and attenuation.

No correlation between infrasound period and bolide height, speed, or impact angle.

Abstract

We have detected and performed signal measurements on 78 individual bolide events as recorded at 179 infrasound stations between 2006 and 2015. We compared period-yield relations with AFTAC nuclear period-yield data, finding these to be similar with a slight offset. Scatter in period measurements for individual bolide is found to be caused in part by station noise levels and by attenuation effects with range. No correlation was found between the infrasound signal period and any of bolide height at peak brightness, entry speed or impact angle. We examined in detail three well constrained bolides having energy deposition curves, known trajectories and infrasound detections finding some evidence at shorter ranges that a component of station period scatter is due to varying source heights sampled by different stations. However, for longer-range stations in these three case studies, we were not able to assign unique source heights using raytracing due to large uncertainties in atmospheric conditions. Our results suggest that while source height contributes to the observed variance in infrasound signal periods from a given bolide, range and station noise play a larger role.