Two-frequency acoustic-gravitational waves, simulation of satellite measurements

Heading: 
Dynamics and Physics of Solar System Bodies
Kryuchkov, EI, 1Zhuk, IT, 1Cheremnykh, OK
1Space Research Institute under NAS and National Space Agency of Ukraine, Kyiv, Ukraine
Kinemat. fiz. nebesnyh tel (Online) 2020, 36(6):22-36
https://doi.org/10.15407/kfnt2020.06.022
Start Page: Dynamics and Physics of Bodies of the Solar System
Language: Ukrainian
Abstract: 

The theory of acoustic gravity waves (AGW) considers free disturbances of the atmosphere within the framework of a single-frequency approach. In this case, the theory implies the existence of two separate types of waves with different natural frequencies - acoustic and gravitational. In the single-frequency approach, wave fluctuations of density, temperature, and velocity are related to each other through the spectral characteristics of the wave, and these relationships are unchanged. However, satellite observations of AGW parameters cannot always be explained within the framework of a single-frequency approach. This paper presents a two-frequency approach to the study of AGWs using the model of two coupled oscillators. It is shown that the perturbed movements of the elementary volume of the medium occur simultaneously at two natural frequencies. In this case, the connections between the wave fluctuations of the parameters are determined by the initial conditions, which can be arbitrary. Solutions in real functions for an isothermal atmosphere are obtained. The conditions under which single-frequency AGWs are obtained from the general two-frequency solution are investigated. The AGW waveforms measured from the satellite for velocities and displacements in single-frequency and dual-frequency modes are numerically simulated. The results of simulating two-frequency AGWs agree with the data of satellite measurements. Two-frequency AGWs are not always implemented at two different frequencies. It is shown that when the frequencies approach each other, the beat effect occurs and two closely related modes become indistinguishable. At the same wavelength, they have one center frequency and one phase velocity. The main feature of the two-frequency approach to the study of AGW is the expansion of the relationships between the wave parameters of the medium. This makes it possible to achieve satisfactory agreement of the model waveforms with the data of satellite measurements. Thus, the use of a two-frequency AGW treatment opens up new possibilities in the interpretation of experimental data.
Keywords: acoustic-gravity wave, coupled oscillators, natural frequencies

Full text (PDF)

References: 

1. Crawford F. S. (1968) Waves. Berkley Physics Course. Vol. 3. 600.

 2. Magnus K. (1965) Vibrations. Blackie & Son. 299.

 3. Fedorenko A. K., Kryuchkov E. I. (2011) Distribution of medium-scale acoustic gravity waves in Polar Regions according to satellite measurement data. Geomagn. and Aeron. 51(4). 520—533.

 4. Fedorenko A. K., Kryuchkov E. I. (2013) Wind control of the propagation of acoustic gravity waves in the polar atmosphere. Geomagn. and Aeron. 53(3). 377—388.

 5. 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.

 6. Cheremnykh O. K. (2011) Resonant mode in the Earth’s termosphere. Space Sci. and Tehnol. 17(6). 74—76.

 7. Beer T. (1974) Atmospheric Waves. John Wiley, New York. 300.

 8. 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.

 9. Cheremnykh O. K., Kryuchkov E. I., Fedorenko A. K., Klymenko Yu. O. (2019) Two- frequency approach to the theory of atmospheric acoustic-gravity waves. arXiv preprint arXiv:1908.07789.

10. Fedorenko A. K., Bespalova A. V., Cheremnykh O. K., Kryuchkov E. I. (2015) A dominant acoustic-gravity mode in the polar thermosphere. Ann. Geophys. 33. 101—108.
https://doi.org/10.5194/angeo-33-101-2015

11. Hines C. O. (1960) Internal gravity waves at ionospheric heights. Can. J. Phys. 38. 1441—1481.
https://doi.org/10.1139/p60-150

12. Innis J. L., Conde M. (2002) Characterization of acoustic-gravity waves in the upper thermosphere using Dynamics Explorer 2 Wind and Temperature Spectrometer (WATS) and Neutral Atmosphere Composition Spectrometer (NACS) data. J. Geo­phys. Res. 107(A12).
https://doi.org/10.1029/2002JA009370

13. Johnson F. S., Hanson W. B., Hodges R. R., Coley W. R., Carignan G. R., Spencer N. W. (1995) Gravity waves near 300 km over the polar caps. J. Geophys. Res. 100. 23993—24002.
https://doi.org/10.1029/95JA02858

14. Kaladze T. D., Pokhotelov O. A., Shah H. A., Khan M. I., Stenflo L. (2008) Acoustic- gravity waves in the Earth’s ionosphere. J. Atmos. Sol.-Terr. Phys. 70. 1607—1616.
https://doi.org/10.1016/j.jastp.2008.06.009

15. Sutherland B. R. (2010) Internal Gravity Waves. Cambridge University Press. 395.
https://doi.org/10.1017/CBO9780511780318

16. Tolstoy I. (1963) The theory of waves in stratified fluids including the effects of gravity and rotation. Rev. of Modern Phys. 35. № 1. P. 207—230.
https://doi.org/10.1103/RevModPhys.35.207

17. Waltercheid R. L., Hecht J. H. (2003) A reexamination of evanescent acoustic-gravity waves: Special properties and aeronomical significance. J. Geophys. Res. 108(D11). 4340.
https://doi.org/10.1029/2002JD002421

18. Yeh K. S., Liu C. H. (1974) Acoustic-gravity waves in the upper atmosphere. Rev. Geo­phys. Space. Phys. 12. 193—216.
https://doi.org/10.1029/RG012i002p00193