Resonant infrasonic disturbances in Total-Electron-Content during a
severe thunderstorm on October 23, 2021
Abstract
Deep convective clouds and lightning activity during thunderstorms
imprint Infrasonic (>3 mili Hertz) oscillations in the
ionospheric density or Traveling Ionospheric Disturbances (TIDs).
The wave characteristics of these oscillations and the coupling
mechanisms remain a subject of investigation, noting that the coupling
energetics may alter the spectral and propagation characteristics.
Moreover, the availability of numerous convective dynamics time scales
makes the oscillation detection time uncertain.
To study these aspects, the present work examines the spatial-temporal
lightning flash rate during a severe thunderstorm (cloud top temperature
< -80 ºC) from the GOES16 infrared channel and the
total electron content of the ionosphere from the GNSS network over the
tropical Southern hemisphere.
The study finds TIDs amplification above the deep convective clouds.
The strongest amplification occurs at the earliest, at 9 minutes, from
the most intense lightning flash rate and propagates at the most
probable speed of 1000 m/s.
In contrast to the spectral peak of the active storm, which is 1.2 mHz,
the spectral peak of TIDs is 4.8 mHz.
The results highlight the magnitude of coupling energetics to determine
the wave propagation characteristics of infrasonic TIDs.