The positive perturbation of the oxygen red line intensity (duration 1–3 hours) as a result of the existence of atmospheric shear waves

Abstract

The increased value of mid-latitude night time emission intensity of the oxygen red 630.0 nm line with duration of nearly 1- 3 hours on magnetically disturbed days is considered the result of excitation of vortical perturbations located in horizontal plane - shear waves in the inhomogeneous horizontal wind. The inhomogeneous meridional wind, generated in the polar regions during magnetically disturbed days, is considered a source of coupling between atmospheric gravity waves and shear waves. The atmospheric shear waves result in changes in the ionospheric F-region electron density distribution and correspondingly increase the red 630.0 nm line emission intensity. The shear waves, for values of meridional thermospheric winds with a shear of a = 0.001 - 0.0001 s−1 in zonal direction, are responsible in explaining the increase of the red 630.0 nm line emission intensity for 1 – 3 hours, which for the midlatitude regions, mostly appeared during magnetically disturbed days. A comparison of theoretical calculations with optical, from Abastumani (42.8°E, 41.8°N), and ionospheric, from Tbilisi (44.8°E, 41.7°N), observations is given.