Multilayered structures in the ionosphere F2 region and impulse-like increase of the nightglow red 630 nm line intensity as a result of influence of shear excited atmospheric vortical perturbations

G. G. Didebulidze
Levan Lomidze, Utah State University
N. B. Gudadze
M. Todua

Abstract

It is shown that the formation of multilayered structures in the midlatitude ionosphere F 2 layer can be caused by atmospheric vortical perturbation (shear wave) evolving in the meridional wind with linear zonal shear and can be accompanied by an impulse-like increase (with duration about 1–3 h) in the red 630 nm line total nightglow intensity. The shear wave can produce an enhancement of the northward wind (or decrease in the southward one), which can cause a downward motion of the F 2 layer peak height resulting in the impulse-like increase in the red line intensity. An important increase in the red line intensity occurs until the appearance of the secondary peak below the F 2 layer main peak close to the luminous layer. The observed impulse-like increase of the red line intensity followed by oscillations characteristic of short-period atmospheric gravity waves (AGWs) is considered as a possible result of transformation of shear excited three-dimensional vortical perturbation (shear wave) into AGW. The possibility of the appearance of the multilayered structure in the ionosphere F 2 region and the impulse-like increase in the red line intensity under the influence of shear excited waves with vertical wave number k z ≠ 0 is demonstrated analytically and numerically.