TIDs characteristic behavior of the oxygen red 630.0 nm line nightglow intensity caused by thermosphere wind and AGWs

Abstract:

The TIDs characteristic nighttime behavior of the mid-latitude oxygen red 630.0 nm line nightglow intensities caused by the horizontally and inclined propagated atmospheric gravity waves (AGWs) are considered. We also take into account horizontal thermospheric wind. The thermospheric wind and AGWs influence the F2 region electron density and correspondingly the oxygen red 630.0 nm line intensity emitted from this region of the ionosphere. The northward wind causes downward motion of the ionosphere F2 layer peak height hmF2 which increases the molecular ion recombination and gives relatively quick damping of the electron density. This phenomenon, at the beginning, causes the increase in the 630.0nm line intensity and after depletion of the density of molecular ions, it decreases more rapidly than during absence of northward wind. The southward wind causes the opposite phenomenon – the hmF2 moves upwards and the nighttime decrease in the red line intensity is relatively smaller than during the absence of wind. The inclined propagated AGWs, which cause MSTIDs-like behavior of the hmF2, also are influenced by horizontal thermospheric wind. The nighttime behavior in the zenithal intensity of the 630.0 nm line variations gives important information for identification of the meridional wind velocity value and direction, as well as the wavelengths of inclined propagated AGWs intensity. We made analytical estimation of the mid-latitude nighttime electron density height profile behavior under the influence of meridional wind and AGWs and correspondingly the 630.0 nm line intensity. The observed nighttime behavior of the 630.0 nm line showing the presence of AGWs and thermospheric meridional wind is demonstrated.

Acknowledgements: This study is supported by Georgian Shota Rustaveli National Science Foundation Grant no. FR17-357.