Multi-instrument observations of the Pajala fireball: Origin, characteristics, and atmospheric implications

Abstract

Meteor observations provide information about Solar System constituents and their influx onto Earth, their interaction processes in the atmosphere, as well as the neutral dynamics of the upper atmosphere. This study presents optical, radar, and infrasound measurements of a daytime fireball that occurred on 4 December 2020 at 13:30 UTC over Northeast Sweden. The fireball was recorded with two video cameras, allowing a trajectory determination to be made. The orbital parameters are compatible with the Northern Taurid meteor shower. The dynamic mass estimate based on the optical trajectory was found to be 0.6–1.7 kg, but this estimate can greatly vary from the true entry mass significantly due to the assumptions made. The meteor trail plasma was observed with an ionosonde as a sporadic E-like ionogram trace that lasted for 30 min. Infrasound emissions were detected at two sites, having propagation times consistent with a source location at an altitude of 80–90 km. Two VHF specular meteor radars observed a 6 minute long non-specular range spread trail echo as well as a faint head echo. Combined interferometric range-Doppler analysis of the meteor trail echoes at the two radars, allowed estimation of the mesospheric horizontal wind altitude profile, as well as tracking of the gradual deformation of the trail over time due to a prevailing neutral wind shear. This combined analysis indicates that the radar measurements of long-lived non-specular range-spread meteor trails produced by larger meteoroids can be used to measure the meteor radiant by observing the line traveled by the meteor. Furthermore, a multistatic meteor radar observation of these types of events can be used to estimate mesospheric neutral wind altitude profiles.

Spatially Resolved Observations of Meteor Radio Afterglows With the OVRO‐LWA

“…The multi‐instrument observations of the Pajala fireball conducted by Vierinen et al. (2022) shares some interesting properties with the MRAs presented in this paper. Radar observations of a fireball induced non‐specular meteor trail shows similar temporal behavior of MRAs in this work.…”

“…The radar echoes reported in Vierinen et al. (2022) also display varied onset times at different altitudes. The authors suggest this is due to variability in plasma turbulence formation.…”

“…A similar effect has been observed for the resolved radio structures of the long duration events, MRA1 and MRA2 (predominantly). The radar echoes reported in Vierinen et al (2022) also display varied onset times at different altitudes. The authors suggest this is due to variability in plasma turbulence formation.…”

Variation in the Reflection Height of VLF/LF Transmitter Signals in the D‐Region Ionosphere and the Possible Source: A 2018 Meteoroid in Hokkaido, Japan

“…Plasma turbulence and neutral winds of the trails of meteoroids in the ionosphere have been reported based on observations of very high frequency meteor radars, ionosondes, optical cameras, and infrasound sensors (Vierinen et al., 2022). During the Chelyabinsk meteoroid event on 15 February 2013 (the largest since 1908), three types of TID were observed using Global Positioning System total electron density (TEC) (Yang et al., 2014).…”

Radar, radio and optical observations of long duration meteors over northern Germany

“…Radar and optical long duration meteor trails, lasting more than a few seconds to minutes, although studied for many years, their physical understanding is still enigmatic. In part due to their differing composition, mass, and trajectory characteristics, but also to the different atmospheric conditions upon entering the Earth's atmosphere [1]. Moreover, recently it has been discovered that some long-duration meteor events can even be observed in radio, called Meteor Radio Afterglows (MRAs) [2].…”