Travelling Ionosphere Disturbance Signatures on Ground-Based
Observations of the O(1D) Nightglow Inferred from 1D Modeling
Abstract
This paper reports our simulations of the volume emission rate (VER) of
the O($^1D$) redline nightglow perturbed by waves traveling across
the thermosphere at around 250 km altitude. Waves perturb the electronic
and neutral background densities and temperatures in the region and
modify the O($^1D$) layer intensity as it is captured by
ground-based nightglow instruments. The changes in the integrated volume
emission rate are calculated for various vertical wavelengths of the
perturbations. We demonstrate that, as the solar activity intensifies,
the vertical scales of most likely observable TID waves become larger.
For high solar activity, we demonstrate that only waves presenting
vertical wavelengths larger than 360 km are likely to be observed. The
variation of the range of likely observable vertical wavelengths with
the solar cycle offers a plausible explanation for the low occurrence
rate of TID in measurements of the redline nightglow during high solar
activity periods. We have compared our results with those of
\citeA{Negale:2018} and
\citeA{Paulino:2018} to verify that observed vertical
wavelengths distribute around 140-210 km, in good correspondence with
our predicted threshold wavelength
$\lambda_{z}^t\sim$160 km for very
low solar cycle period.