Atmospheric disturbances caused by the passage of a tsunami wave

     Detection and forecasting of tsunami waves is an urgent task of modern geophysics. Tsunami waves, the formation of which is usually associated with tectonic movements under the water column, are the source of atmospheric waves in a wide frequency range that propagate to thermospheric heights. A tsunami wave generates acoustic (AWs) and internal gravity waves (IGWs) in the atmosphere.

     The atmosphere is the medium in which disturbance from surface ocean waves propagate efficiently. The main role in such a process belongs to infrasound. Qualitative modeling of such waves requires the use of a numerical model that correctly resolves AWs and IGWs over a wide range of altitudes. Due to the significant amplitudes of atmospheric waves at high altitudes, a mathematical proof of the non-negativity of density and temperature in numerical models is required to correctly calculate their propagation. The coefficients of the solved equations change very strongly with altitude and the numerical method of the model should minimize the accumulation of computational errors. The numerical regional model of the neutral atmosphere AtmoSym, based on the solution of the system of nonlinear hydrodynamic equations, which satisfies these requirements, is used in the study.

     The paper considers the features of numerical experiment for modeling of atmospheric disturbances caused by tsunamis. Calculations were performed for the tsunami recorded on June 17, 2017 on the west coast of Greenland. This tsunami was caused by a subaerial landslide that occurred in a fjord. Calculations were also performed for a more significant event, the tsunami observed due to the strong earthquake in Japan on March 11, 2011 (Tohoku). The dependence of the upper atmosphere response on the tsunami wave intensity in the troposphere was analyzed. In the case of modeling the tsunami wave in Japan, a numerical calculation was made taking into account the preceding earthquake.

     The study was funded by the Russian Science Foundation grant No. 23-77-10004, https://rscf.ru/project/23-77-10004/.