Planetary wave-like oscillations in the ionosphere retrieved with a longitudinal chain of ionosondes at high northern latitudes

TL;DR

This study identifies planetary wave-like oscillations in the high-latitude ionosphere using a chain of ionosondes, revealing wave activity not directly driven by magnetic indices but possibly coupled via mesospheric atomic oxygen diffusion.

Contribution

It demonstrates the presence of planetary wave-like structures in the ionosphere and links their motion to mesospheric planetary waves, highlighting an indirect coupling mechanism.

Findings

Wave structures in the ionosphere are not correlated with magnetic activity indices.

Observed wave activity matches mesospheric planetary waves in motion.

Indicates a coupling mechanism via mesospheric atomic oxygen diffusion.

Abstract

This paper examines the influence of neutral dynamics on the high latitude ionosphere. Using a longitudinal chain of ionosondes at high northern latitudes ($52\,^{\circ}{\rm}$-$65\,^{\circ}{\rm}$N), planetary wave-like structures were observed in the spatial structure of the peak electron density in the ionosphere. Longitudinal wavenumbers S$_{0}$, S$_{1}$ and S$_{2}$ have been extracted from these variations of the F layer. The observed wave activity in wavenumber one and two does not show any significant correlation with indices of magnetic activity, suggesting that this is not the primary driver. In addition, the motion of the S$_{1}$ ionospheric wave structures parallels that of the S$_{1}$ planetary waves observed in the winds of the mesosphere-lower-thermosphere derived from a longitudinal array of SuperDARN meteor-radar wind measurements. The time delay between the motions of the wave structures would indicate a indirect coupling, commensurate with the diffusion to the ionosphere of mesospheric atomic oxygen perturbations.