Observed features of acoustic gravity waves in the heterosphere

Fedorenko, A.K.; Kryuchkov, E. I.

doi:10.1134/s0016793214010022

Cited by 13 publications

(7 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Likewise, some previous papers addressed fluctuations of thermospheric quantities at F region altitudes using in situ neutral component observations but showed no decisive evidence of accompanying fluctuations in F region plasma density [e.g., Johnson et al , ; Forbes et al , ; Liu et al , ; Fedorenko , ; Fedorenko and Kryuchkov , ; Park et al , ; Fedorenko et al , ]. A comparison between F region ionospheric fluctuations and E region atmospheric gravity waves (AGWs) at high latitudes has been conducted by Nygrén et al [].…”

Section: Introductionmentioning

confidence: 99%

Plasma density undulations correlated with thermospheric neutral mass density in the daytime low‐latitude to midlatitude topside ionosphere

et al. 2015

View full text Add to dashboard Cite

Plasma density undulations in the dayside low‐latitude/midlatitude ionospheric F region were often attributed to thermospheric gravity waves (TGWs). However, the relationship between the former and the latter has been at best indirectly evidenced. In this study we investigate daytime fluctuations in neutral mass density (ρ) and plasma density (ne) measured onboard CHAMP from 2001 to 2010. A significant amount of daytime fluctuations in ne is strongly correlated with in situ fluctuations of ρ, which we term “TGW‐related ne fluctuations.” The TGW‐related ne fluctuations are (1) stronger in the winter hemisphere than in the summer hemisphere and (2) strongest in the South American sector during June solstice months. These climatological features are in general agreement with those of TGWs reported previously, especially at midlatitudes. On the other hand, the relative amplitude of TGW‐related ne fluctuations does not depend strongly on solar activity.

show abstract

Section: Introductionmentioning

confidence: 99%

Plasma density undulations correlated with thermospheric neutral mass density in the daytime low‐latitude to midlatitude topside ionosphere

et al. 2015

View full text Add to dashboard Cite

show abstract

“…We have to also take into account that the temperature in the upper mesosphere decreases with average vertical gradient of ∼3 • K/km. The latter can be accounted for by using the additional term which is similar to the non-isothermal frequency of Brunt-Väisälä (Fedorenko, Kryuchkov, 2014). Under such assumptions, Eq.…”

Section: Agw Fluctuations Of Atmospheric Parametersmentioning

confidence: 99%

“…But the region of adiabatic gas expansion moves upwards and the density inside the volume remains higher than the background density. Such regions are observed as concentration maxima (∆N n /N n ) max (Dudis, Reber, 1976;Fedorenko, Kryuchkov, 2014).…”

Section: Agw Fluctuations Of Atmospheric Parametersmentioning

confidence: 99%

Recover of acoustic-gravity wave properties revealed from measurements of VLF radio wave amplitudes

Fedorenko,

Kryuchkov,

Cheremnykh

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

A simple method has been proposed to determine acoustic-gravity wave (AGW) properties at mesosphere heights from measurements of VLF radio signals. For relatively short paths (less than ∼ 2000 km long), simple relations are obtained for estimation of AGW neutral density fluctuation from measurements of amplitudes of radio signals. In the wave-hop approximation, we relate the fluctuations in radio signal reflection height with AGW-induced vertical displacement of an elementary volume of atmospheric gas. Using these relations, we can recover some properties of AGWs at mesosphere heights.

show abstract

“…However, when interpreting the results of observations, it is necessary to take into account a number of features that go beyond the framework of this approximation. Thus, at the heights of the Earth's thermosphere, the propagation of AGWs should be considered taking into account the multicomponent gas composition [5,12]. Above 200 km, it is also necessary to take into account the effects of viscosity and thermal conductivity leading to attenuation of waves.…”

Section: Introductionmentioning

confidence: 99%

Attenuation of Evanescent Acoustic-Gravitational Modes in the Earth’s Thermosphere

Cheremnykh

Fedorenko

Kryuchkov

et al. 2021

Kinemat. Phys. Celest. Bodies

Self Cite

View full text Add to dashboard Cite

The attenuation of the acoustic-gravitational nondivergent f-mode and inelastic γ-mode in the Earth's upper atmosphere due to viscosity and thermal conductivity is studied. To analyze the attenuation, a system of hydrodynamic equations is used, including the modified Navier-Stokes and heat transfer equations. These modified equations take into account the contribution of the background density gradient to the transfer of energy and momentum by waves. Dispersion equations are obtained for f-and γ-modes in an isothermal dissipative atmosphere. It is shown that viscosity and thermal conductivity have little effect on the frequency of these modes under typical conditions in the thermosphere. Expressions are obtained for the damping decrements of the f-and γ-modes. It was established that the decrement of the γ-mode attenuation is almost an order of magnitude higher in the Earth's thermosphere than the corresponding decrement of the f-mode. It is also found that the attenuation of the f-mode does not depend on the thermal conductivity but is due only to the dynamic viscosity and increases with an increase in the relative contribution of the bulk viscosity. The dissipation of the γ-mode is caused by dynamic viscosity and thermal conductivity and does not depend on the bulk viscosity. The time variation of the perturbation amplitudes for the f-and γ-modes at different heights of the thermosphere is considered. The characteristic attenuation times of the f-and γ-modes at different heights depending on the wavelength, as well as at different levels of solar activity, are calculated. The boundary heights in the thermosphere above which the f-and γ-modes cannot exist due to dissipation are determined.

show abstract

Observed features of acoustic gravity waves in the heterosphere

Cited by 13 publications

References 5 publications

Plasma density undulations correlated with thermospheric neutral mass density in the daytime low‐latitude to midlatitude topside ionosphere

Plasma density undulations correlated with thermospheric neutral mass density in the daytime low‐latitude to midlatitude topside ionosphere

Recover of acoustic-gravity wave properties revealed from measurements of VLF radio wave amplitudes

Attenuation of Evanescent Acoustic-Gravitational Modes in the Earth’s Thermosphere

Contact Info

Product

Resources

About