Multilayered structures in the ionosphere F 2 region and impulse‐like increase of the nightglow red 630 nm line intensity as a result of influence of shear excited atmospheric vortical perturbations

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 not = 0 is demonstrated analytically and numerically.