Correctness of the problem of propagation of nonlinear acoustic-gravity waves in the atmosphere from pressure variations on the lower boundary

2017 ◽  
Keyword(s):  
Gravity Waves ◽  
Lower Boundary ◽  
Acoustic Gravity Waves ◽  
Nonlinear Acoustic

scholarly journals Propagation to the upper atmosphere of acoustic-gravity waves from atmospheric fronts in the Moscow region

2019 ◽  
Vol 37 (3) ◽  
pp. 447-454 ◽  
Author(s):  
Yuliya Kurdyaeva ◽  
Sergey Kulichkov ◽  
Sergey Kshevetskii ◽  
Olga Borchevkina ◽  
Elena Golikova
Keyword(s):  
Experimental Data ◽  
Gravity Waves ◽  
Pressure Fluctuations ◽  
Lower Boundary ◽  
Lower Troposphere ◽  
Upper Atmosphere ◽  
Moscow Region ◽  
Atmospheric Front ◽  
Lower Boundary Condition ◽  
Acoustic Gravity Waves

Abstract. The paper uses experimental data of pressure variations on the Earth's surface during the passage of an atmospheric front recorded by a network of four microbarographs in the Moscow region. Applying these experimental data, empirical approximations of atmospheric pressure field oscillations are suggested. The obtained approximating surface pressure functions are used as the lower boundary condition for simulating the vertical propagation of acoustic-gravity waves from a source in the lower troposphere. Estimates of the amplitude of temperature disturbances in the upper atmosphere caused by acoustic-gravity waves from a propagating atmospheric front are obtained. For the amplitude of wave temperature disturbances, values of about 200 K are obtained. The amplitude of temperature disturbances in the upper atmosphere caused by background pressure fluctuations on the Earth's surface is estimated at 4–5 K.

scholarly journals Vertical propagation acoustic-gravity waves from atmospheric fronts into the upper atmosphere

2019 ◽  
Vol 55 (4) ◽  
pp. 3-12
Author(s):  
Y. A. Kurdyaeva ◽  
S. N. Kulichkov ◽  
S. P. Kshevetskii ◽  
O. P. Borchevkina ◽  
E. V. Golikova
Keyword(s):  
Gravity Waves ◽  
Atmospheric Pressure ◽  
Lower Boundary ◽  
Lower Troposphere ◽  
Upper Atmosphere ◽  
Atmospheric Front ◽  
Lower Boundary Condition ◽  
Acoustic Gravity Waves ◽  
Temperature Disturbance ◽  
Atmospheric Fronts

Using experimental observations of atmospheric pressure variations on the Earth’s surface recorded with a network of 4 microbarographs located in the Moscow region during the passage of an atmospheric front, empirical approximations of oscillations of atmospheric pressure field were constructed. The obtained approximating functions were used as the lower boundary condition for the numerical simulation of acoustic-gravity wave propagation to the upper atmosphere from the source in the lower troposphere. Estimates of the amplitude of temperature disturbances in the upper atmosphere caused by iacoustic gravity waves from the atmospheric front are given. The obtained estimates for the temperature disturbance amplitude take values around 170 K. The amplitude of temperature disturbances in the upper atmosphere, caused by background variations of pressure on the Earth's surface, is estimated at 4-5 K.

scholarly journals Verifications of the high-resolution numerical model and polarization relations of atmospheric acoustic-gravity waves

2015 ◽  
Vol 8 (6) ◽  
pp. 1831-1838 ◽  
Author(s):  
N. M. Gavrilov ◽  
S. P. Kshevetskii ◽  
A. V. Koval
Keyword(s):  
High Resolution ◽  
Numerical Model ◽  
Numerical Simulations ◽  
Gravity Waves ◽  
Numerical Models ◽  
Lower Boundary ◽  
Simulation Models ◽  
Free Atmosphere ◽  
Wave Source ◽  
Acoustic Gravity Waves

Abstract. Comparisons of amplitudes of wave variations of atmospheric characteristics obtained using direct numerical simulation models with polarization relations given by conventional theories of linear acoustic-gravity waves (AGWs) could be helpful for testing these numerical models. In this study, we performed high-resolution numerical simulations of nonlinear AGW propagation at altitudes 0–500 km from a plane wave forcing at the Earth's surface and compared them with analytical polarization relations of linear AGW theory. After some transition time te (increasing with altitude) subsequent to triggering the wave source, the initial wave pulse disappears and the main spectral components of the wave source dominate. The numbers of numerically simulated and analytical pairs of AGW parameters, which are equal with confidence of 95 %, are largest at altitudes 30–60 km at t > te. At low and high altitudes and at t < te, numbers of equal pairs are smaller, because of the influence of the lower boundary conditions, strong dissipation and AGW transience making substantial inclinations from conditions, assumed in conventional theories of linear nondissipative stationary AGWs in the free atmosphere. Reasonable agreements between simulated and analytical wave parameters satisfying the scope of the limitations of the AGW theory prove the adequacy of the used wave numerical model. Significant differences between numerical and analytical AGW parameters reveal circumstances when analytical theories give substantial errors and numerical simulations of wave fields are required. In addition, direct numerical AGW simulations may be useful tools for testing simplified parameterizations of wave effects in the atmosphere.

scholarly journals Spectra of Acoustic-Gravity Waves in the Atmosphere with a Quasi-Isothermal Upper Layer

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 818
Author(s):  
Sergey P. Kshevetskii ◽  
Yuliya A. Kurdyaeva ◽  
Nikolai M. Gavrilov
Keyword(s):  
Gravity Waves ◽  
Evolution Operator ◽  
Mathematical Problem ◽  
Cutoff Frequency ◽  
Lower Boundary ◽  
Low Frequency ◽  
Acoustic Gravity Waves ◽  
Wide Range ◽  
Different Altitudes ◽  
Wave Modes

In this paper, we study, in theoretical terms, the structure of the spectrum of acoustic-gravity waves (AGWs) in the nonisothermal atmosphere having asymptotically constant temperature at high altitudes. A mathematical problem of wave propagation from arbitrary initial perturbations in the half-infinite nonisothermal atmosphere is formulated and analyzed for a system of linearized hydrodynamic equations for small-amplitude waves. Besides initial and lower boundary conditions at the ground, wave energy conservation requirements are applied. In this paper, we show that this mathematical problem belongs to the class of wave problems having self-adjoint evolution operators, which ensures the correctness and existence of solutions for a wide range of atmospheric temperature stratifications. A general solution of the problem can be built in the form of basic eigenfunction expansions of the evolution operator. The paper shows that wave frequencies considered as eigenvalues of the self-adjoint evolution operator are real and form two global branches corresponding to high- and low-frequency AGW modes. These two branches are separated since the Brunt–Vaisala frequency is smaller than the acoustic cutoff frequency at the upper boundary of the model. Wave modes belonging to the low-frequency global spectral branch have properties of internal gravity waves (IGWs) at all altitudes. Wave modes of the high-frequency spectral branch at different altitudes may have properties of IGWs or acoustic waves depending on local stratification. The results of simulations using a high-resolution nonlinear numerical model confirm possible changes of AGW properties at different altitudes in the nonisothermal atmosphere.

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