On the possibility of in situ shear excitation of vortical perturbations and their coupling with short-period gravity waves by airglow and ionosphere observations

Different long-term trends of the oxygen red 630.0 nm line nightglow intensity as the result of lowering the ionosphere F2 layer

“…Important changes in the thermosphere wind occurred on magnetically disturbed days as well. The variations in the mid-latitude red line nightglow intensity on magnetically disturbed days is possible to be a result of the increase in the upper atmosphere temperature, the value of the ratio [O]/[N 2 ] and the increase in the southward wind (Fishkova, 1983;Didebulidze et al, 2002). An increase in the southward wind velocity on magnetically disturbed days affects the upward drift of the ionosphere F2 region plasma and increase in the hmF2 (Mikhailov, 2006).…”

“…The long-term trend of the annual mean value of the atomic oxygen red 630.0 nm line total nightglow intensity was observed at Abastumani in 1957-1993(Givishvili et al, 1996Gudadze et al, 2007) and that of the ionosphere F2 layer peak height at the Tbilisi ionospheric station in 1963-1986(Bremer, 1998. Unlike Givishvili et al (1996), Gudadze et al (2007) (Fishkova, 1983;Semeter et al, 1996;Didebulidze et al, 2002). This process along with collision deactivation of oxygen atoms O * ( 1 D) by the neutral particles (O, O 2 , N 2 ) occurring in this region makes the 630 nm line intensity sensitive to different helio-geophysical conditions (Megrelishvili, 1981;Fishkova, 1983) including environmental changes in the lower atmosphere.…”

“…To interpret these processes, we employ the analytic expressions for the red 630.0 nm line nightglow volume emission rate (VER) (Semeter et al, 1996;Didebulidze et al, 2002) …”

“…1, 2 as well) is mainly determined by the behaviour of the ionosphere F2 region electron density N e (h, t) (Didebulidze at al., 2002). The average densities of the neutrals N 2 , O 2 and O at these regions of the thermosphere increase by a factor of up to 7 from solar minimum to solar maximum (Hedin, 1991), but their daily variations are smaller than those of the electron density N e (h, t).…”

Coupling processes between atmospheric vortical perturbations and acoustic–gravity waves in the mesosphere–thermosphere regions

“…In this paper a linear theory of atmospheric wave ampliÿcation and damping in the horizontal wind with horizontal shear (horizontal shear ow) recently proposed by Didebulidze (1997Didebulidze ( , 1999 and Didebulidze et al (2002) is developed further. The necessity for such investigation is connected with many atmospheric phenomena detected by ground-based, rocket and satellite measurements of parameters of the mesosphere-thermosphere around the globe (e.g.…”