Simulation of Propagation of Acoustic-Gravity Waves Generated by Tropospheric Front Instabilities into the Upper Atmosph
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Pure and Applied Geophysics
Simulation of Propagation of Acoustic-Gravity Waves Generated by Tropospheric Front Instabilities into the Upper Atmosphere S. KSHEVETSKII,1
YU. KURDYAEVA,2
S. KULICHKOV,3 E. GOLIKOVA,3 O. BORCHEVKINA,1,2
Abstract—A numerical model of the propagation of acousticgravity waves excited by pressure fluctuations on the Earth’s surface is developed. Propagation of acoustic-gravity waves generated by instabilities of tropospheric fronts into the upper atmosphere is simulated. The experimental data on atmospheric pressure variations during 2016 year registered on a net of four microbarographs located in the Moscow region are processed. A case of very significant pressure fluctuations (up to 30 times larger than the average level) is selected, which were caused by an atmospheric front arrival. Observed surface pressure field variations for this field were approximated and used as the lower boundary condition for simulating the vertical wave propagation. The numerical simulations showed that just after the boundary source activation, the infrasonic waves in the upper atmosphere may have amplitudes of perturbations of temperature up to 100 K, and horizontal velocity up to 60 m/s. Internal gravity waves come into the upper atmosphere later and far horizontally away from the wave source. The influence of the limited dimensions of the computational domain on the simulation results is investigated. The conditions at the horizontal boundaries of the computational domain, which allow the runaway of waves beyond the domain are proposed. The frequency spectrum of waves in the non-isothermal atmosphere is analyzed. Keywords: Numerical simulation, atmosphere, acousticgravity waves, upper atmosphere, atmospheric front.
1
Immanuel Kant Baltic Federal University, st. A.Nevskogo, 14, Kaliningrad, Russia. E-mail: [email protected]; [email protected] 2 Kalinigrad Branch of N.M.Pushkov Institute of Terrestrial Magnetism, Ionosphere, and Radiowave Propagation, Russian Academy of Sciences, Pionerskaya, 61, Kaliningrad, Russia. E-mail: [email protected] 3 A. M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, Pyzhevskii per., 3, Moscow, Russia. E-mail: [email protected]; [email protected] 4 Saint Petersburg State University, Botanicheskaya St., 70, bldg. 2, Peterhof, Russia. E-mail: [email protected]
and N. GAVRILOV4
1. Introduction Experimental observations show that perturbations of parameters of the upper atmosphere and ionosphere are often associated with meteorological phenomena (hurricanes, thunderstorms, atmospheric fronts, squalls, tornadoes, mesoscale turbulence, and others), which may generate acoustic-gravity waves (AGWs) (Blanc et al. 2014; Pierce and Coroniti 1966; Fritts and Alexander 2003; Fritts et al. 2006; Plougonven and Snyder 2007; Plougonven and Zhang 2014; Medvedev and Gavrilov 1995). Propagating upward AGWs from meteorological phenomena may reach heights of the upper atmosphere and ionosphere, where they dissipate and change the neutral atmosphere and io
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