Dissipation of acoustic–gravity waves in the Earth’s thermosphere

Fedorenko, A.K.; Kryuchkov, E. I.; Cheremnykh, O. K.; Selivanov, Yu.A.

doi:10.1016/j.jastp.2020.105488

Cited by 3 publications

(7 citation statements)

References 26 publications

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“…Since the atmosphere is assumed to be homogeneous in the horizontal plane, it is sufficient to consider the two-dimensional case. For an isothermal compressible dissipative atmosphere, the linearized system of hydrodynamic equations for the perturbed values of velocity , , density , and temperature has the following form [13]:…”

Section: Initial Equationsmentioning

confidence: 99%

“…The modification of these equations consists in taking into account the terms proportional to (see details in [6,13]).…”

Section: Initial Equationsmentioning

confidence: 99%

“…Note that equations ( 3)-( 5), in contrast to the usual Navier-Stokes and heat transfer equations (see, for example, [17,19]), contain terms that take into account the contribution of the background density gradient to the transfer of energy and momentum by waves. A system of equations of this type was first used in [6,13].…”

Section: Initial Equationsmentioning

confidence: 99%

“…For internal gravitational waves, the dependences of dissipation on height and spectral properties were considered in [2,13,19,20]. Since the coefficients of viscosity and thermal conductivity in the atmosphere are functions of height, taking them into account leads to a system of hydrodynamic equations with variable coefficients.…”

Section: Introductionmentioning

confidence: 99%

“…However, these expressions gave an increase in AGW amplitudes at long wavelengths, which is impossible in a dissipative atmosphere. In [13], the original hydrodynamic equations were modified by adding terms that take into account the transfer of momentum and energy due to the background density gradient. This modification made it possible to exclude the paradoxical effect of amplification of amplitudes at large wavelengths.…”

Section: Introductionmentioning

confidence: 99%

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

Cheremnykh

Fedorenko

Kryuchkov

et al. 2021

Kinemat. Phys. Celest. Bodies

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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.

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Section: Initial Equationsmentioning

confidence: 99%

“…The modification of these equations consists in taking into account the terms proportional to (see details in [6,13]).…”

Section: Initial Equationsmentioning

confidence: 99%

Section: Initial Equationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

Cheremnykh

Fedorenko

Kryuchkov

et al. 2021

Kinemat. Phys. Celest. Bodies

View full text Add to dashboard Cite

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Attenuation of evanescent acoustic-gravity modes in the Earth thermosphere

Cheremnykh¹,

Fedorenko²,

Kryuchkov³

et al. 2021

Kinemat. fiz. nebesnyh tel (Online)

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Âèâ÷åíî çàòóõàííÿ àêóñòèêî-ãðàâ³òàö³éíèõ áåçäèâåðãåíòíî¿ f-ìîäè ³ íåïðóaeíî¿ g-ìîäè ó âåðõí³é àòìîñôåð³ Çåìë³ âíàñë³äîê â'ÿçêîñò³ ³ òåï ëîïðîâ³äíîñò³. Äëÿ àíàë³çó çàãàñàííÿ âèêîðèñòàíî ñèñòåìó ã³äðî -äèíàì³÷íèõ ð³âíÿíü, ùî âêëþ÷àº ìîäèô³êîâàí³ ð³âíÿííÿ Íàâ'º -Ñòîê ñà ³ òåïëîïåðåíîñó. Ö³ ìîäèô³êîâàí³ ð³âíÿííÿ âðàõîâóþòü âíåñîê ãðàä³ºíòà ôîíîâî¿ ù³ëüíîñò³ â ïåðåíåñåííÿ õâèëÿìè åíåðã³¿ ³ ³ìïóëüñó. Îòðèìàíî äèñïåðñ³éí³ ð³âíÿííÿ äëÿ f-³ g-ìîä â ³çîòåðì³÷í³é äè ñèïàòèâí³é àòìîñôåð³. Ïîêàçàíî, ùî â'ÿçê³ñòü ³ òåïëîïðîâ³äí³ñòü ìàëî âïëèâàþòü íà ÷àñòîòó öèõ ìîä ïðè õàðàêòåðíèõ óìîâàõ ó òåðìîñôåð³. Îòðèìàíî âèðàçè äëÿ äåêðåìåíò³â çàòóõàííÿ f-³ g-ìîä. Âñòàíîâëåíî, ùî â çåìí³é òåðìîñôåð³ äåêðåìåíò çàòóõàííÿ g-ìîäè ìàéaeå íà ïîðÿäîê ïåðåâèùóº â³äïîâ³äíèé äåêðåìåíò f-ìîäè. Ïðè öüîìó çàòóõàííÿ f-ìîäè íå çàëåaeèòü â³ä òåïëîïðîâ³äíîñò³, à çóìîâëåíå ò³ëüêè äèíàì³÷íîþ â'ÿçê³ñòþ ³ çðîñòàº ç³ çá³ëüøåííÿì â³äíîñíîãî âêëà äó îá'ºìíî¿ â'ÿçêîñò³. Äèñèïàö³ÿ g-ìîäè âèêëèêàºòüñÿ äèíàì³÷íîþ â'ÿçê³ñòþ ³ òåïëîïðîâ³äí³ñòþ, à â³ä îá'ºìíî¿ â'ÿçêîñò³ íå çàëåaeèòü. Ðîçãëÿíóòî çì³íó ç ÷àñîì àìïë³òóä çáóðåíü äëÿ f-³ g-ìîäè íà ð³çíèõ âèñîòàõ òåðìîñôåðè. Ðîçðàõîâàí³ õàðàêòåðí³ ÷àñè çàòóõàííÿ f-³ g-ìîä íà ð³çíèõ âèñîòàõ â çàëåaeíîñò³ â³ä äîâaeèíè õâèë³, à òàêîae ïðè ð³çíèõ ð³âíÿõ ñîíÿ÷íî¿ àêòèâíîñò³. Âèçíà÷åíî ãðàíè÷í³ âèñîòè â òåðìîñôåð³, âèùå ÿêèõ f-³ g-ìîäè íå ìîaeóòü ðåàë³çóâàòèñÿ ÷åðåç äèñèïàö³þ.

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