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Trekhmernaya model' generatsii vnutrennikh gravitatsionnykh voln pri vozdeystvii anomaliy sily tyazhesti na atmosfernoye techeniye  [Three-dimensional model of generation of atmospheric internal gravity waves induced by inhomogeneities in gravitational field]

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Alternate Title:Three-dimensional model of generation of atmospheric internal gravity waves induced by inhomogeneities in gravitational field
Authors:Ingel', L. Kh.; Makosko, A. A.
Author Affiliations:Primary:
Rossiyskaya Akademiya Nauk, Institut Fiziki Atmosfery, Moscow, Russian Federation
Volume Title:Geofizicheskiye Issledovaniya
Source:Geofizicheskiye Issledovaniya, 20(1), p.5-12. Publisher: Rossiyskaya Akademiya Nauk, Institut Fiziki Zemli, Moscow, Russian Federation. ISSN: 1818-3735
Publication Date:2019
Note:In Russian with English summary. 5 refs.
Summary:Recently the authors showed that in the highly anomalous regions gravitation force anomalies (GFAs), in principle, can lead to appreciable dynamic effects, in particular, the generation of regular currents and internal gravity waves (IGW). But this analysis has so far been limited to two-dimensional problems (that is, the effects of two-dimensional GFAs were considered). In this paper, the next step is taken: in the linear approximation, IGW generation in the atmosphere is analytically studied under the action of three-dimensional GFAs on the atmospheric flow above a flat horizontal underlying surface. The term in the expressions obtained for velocity components and pressure perturbations can be divided into two categories. One of them directly describes flow around equipotential surfaces. These terms do not contain waves propagating with vertical component and slowly decay with altitude on the same scales as the gravity anomaly. Other terms describe internal gravity waves, whose phase velocity is directed downward and the group velocity, upward. The amplitude of these waves in the velocity field exponentially increases with altitude. Taking into account the three-dimensional geometry of GFAs in the three-dimensional formulation can lead to a noticeable change in results in comparison with the two-dimensional model considered earlier. In addition to the appearance of horizontal motions perpendicular to the background flow, the wavelength and the vertical flux of wave energy can markedly vary: GFAs elongated along the stream can lead to smaller perturbations in amplitude than the "ridge" oriented perpendicular to the background flow. The analytical expression is derived; it shows that the mentioned energy flow is proportional to the background buoyancy frequency, to the squares of the GFAs amplitudes, and to the background flow velocity. According to numerical estimates, this flow can be noticeable, although it is usually much inferior to IGW sources associated with the relief.
Subjects:Atmosphere; Earth; Elastic waves; Geodynamics; Gravity anomalies; Gravity field; Heterogeneity; Three-dimensional models
Record ID:765396-1
Copyright Information:GeoRef, Copyright 2021 American Geosciences Institute. Reference includes data supplied by ICSTI, Moscow, Russian Federation
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