Acoustic-gravity waves with height-independent amplitude in the isothermal atmosphere
Heading:
| 1Cheremnykh, OK, 1Fedorenko, AK, Cheremnykh, OS, 2Kronberg, EA 1Space Research Institute under NAS and National Space Agency of Ukraine, Kyiv, Ukraine 2Max Planck Institute, Göttingen, Germany |
| Kinemat. fiz. nebesnyh tel (Online) 2023, 39(5):54-64 |
| https://doi.org/10.15407/kfnt2023.05.054 |
| Language: Ukrainian |
Abstract: Acoustic-gravity wave modes in the Earth’s thermosphere, the amplitude of which does not depend on height, are theoretically investigated in this paper. The stimulus for these studies is satellite observations, according to which the amplitudes of acoustic-gravity waves in the polar thermosphere do not show dependence on height in the altitude interval of 250...450 km. It is shown that the propagation of acoustic-gravitational wave modes with the height-independent amplitude should be considered as an oscillatory process that occurs simultaneously at two natural frequencies. The dispersion equation for these waves was obtained. On the frequency-wave vector diagnostic diagram, the dispersion dependence of waves with constant amplitude is in the area prohibited for free propagation. It separates horizontally propagating waves in which the amplitude in the vertical direction increases from waves in which the amplitude decreases in the vertical direction. Solutions were found for the perturbed quantities in the two-frequency mode of oscillations. It is noted that the superposition of several such modes can lead to the emergence of complex resulting motions close to turbulent ones. It is shown that there is a selected quasi-harmonic mode with constant amplitude, which is characterized by a fixed frequency and wavelength. It was concluded that this kind of wave mode with height-independent amplitude of the perturbed values prevails in the observations in the Earth’s polar thermosphere. |
| Keywords: acoustic-gravity wave, Earth’s thermosphere, two-frequency oscillation mode |
References:
1. Kryuchkov E. I., Zhuk I. T., Cheremnykh O. K. (2020). Two-frequency acoustic-gravitational waves and simulation of satellite measurements. Kinematics and Phys. Celestial Bodies. 36. 265-273. https://doi.org/10.3103/S0884591320060045
2. Cheremnykh O. K., Kryuchkov E. I., Fedorenko A. K., Cheremnykh S. O. (2020). Two-frequency propagation mode of acoustic-gravity waves in the Earth's atmosphere. Kinematics and Phys. Celestial Bodies. 36(2). 64-78. https://doi.org/10.3103/S0884591320020026
3. Yavorsky B. M., Detlaff A. A. (1981). Handbook of Physics. Nauka, Moscow.
4. Carignan G. R., Block B. P., Maurer J. C, Hedin A. E., Reber C. A., Spencer N. W. (1981). The neutral mass Spectrometer on Dynamics Explorer. Space Sci. Instrum.
5. 429-441. 5. Cheremnykh O. K., Fedorenko A. K., Kryuchkov E. I., Selivanov Y. A. (2019). Evanescent acoustic-gravity modes in the isothermal atmosphere: systematization, applications to the Earth's and Solar atmospheres. Ann. Geophys. 37(3). 405-415. https://doi.org/10.5194/angeo-37-405-2019
6. Cheremnykh O., Fedorenko A., Selivanov Y., Cheremnykh S. (2021). Continuous spectrum of evanescent acoustic-gravity waves in an isothermal atmosphere. Mon. Notic. Roy. Astron. Soc. 503(4). 5545-5553. https://doi.org/10.1093/mnras/stab845
7. Fedorenko A. K., Kryuchkov E. I., Cheremnykh O. K., Klymenko Yu. O., Yampolski Yu. M. (2018). Peculiarities of acoustic-gravity waves in inhomogeneous flows of the polar thermosphere. J. Atmos. and Solar-Terr. Phys. 178. 17-23. https://doi.org/10.1016/j.jastp.2018.05.009
8. Ghosh P., Antia H. M., Chitre S. M. (1995). Seismology of the solar f-mode. I. Basic signatures of shearing velocity fields. Astrophys. J. 451. 851-858. https://doi.org/10.1086/176271
9. Hines C. O. (1960). Internal atmospheric gravity waves at ionospheric heights. Can. J. Phys. 38. 1441-1481. https://doi.org/10.1139/p60-150
10. Huang K. M., Zhang S. D., Yi F., Huang C. M., Gan Q., Gong Y., Zhang Y. H. (2014). Nonlinear interaction of gravity waves in a nonisothermal and dissipative atmosphere. Ann. Geophys. 32. 263-275, https://doi.org/10.5194/angeo-32-263-2014
11. Lamb H. (1911). On atmospheric oscillations. Proc. Roy. Soc. Lond. A, 84. 551-572. https://doi.org/10.1098/rspa
12. Miles Alan J., Roberts B. (1992). Magnetoacoustic-gravity surface waves. I. Constant Alfven Speed. Solar Phys. 141. 205-234. https://doi.org/10.1007/BF00155176
13. Rosental C. S., Gough D. O. (1994). The Solar f-mode as interfacial mode at the chromosphere-corona transition. Astrophys. J. 423. 488-495. https://doi.org/10.1086/173826
14. Stenflo L., Shukla P. K. (2009). Nonlinear acoustic gravity waves. J. Plasma Phys. 75. 841-847. https://doi.org/10.1017/S0022377809007892
15. Tolstoy I. (1963). The theory of waves in stratified fluids including the effects of gravity and rotation. Rev. Modern Phys. 35(1). 207-229. https://doi.org/10.1103/RevModPhys.35.207
16. Waltercheid R. L., Hecht J. H. (2005). A reexamination of evanescent acoustic-gravity waves: Special properties and aeronomical significance. J. Geophys. Res. 108 (D11, 4340). https://doi.org/10.1029/2002JD002421