Identification of Acoustic-Gravity Waves According to the Satellite Measurement Data

Abstract

A method of identification of acoustic-gravity waves (AGWs) in the atmosphere according to the satellite measurement data has been proposed. It has been shown that the polarization relations between fluctuations of the wave parameters (velocity, density, temperature, and pressure) for freely propagating waves and evanescent wave modes are considerably different, which makes it possible to identify different types of atmospheric waves in the experimental data. A diagnostic chart was plotted that can be used for determining a wave type and its direction of the vertical motion based on the phase shifts of the observed parameters. Using phase shifts between the velocity fluctuations and thermodynamic parameters of the atmosphere, not only the wave type but also its spectral characteristics can be determined. Verification of the proposed method was performed for identifying polar wave perturbations based on the measurements from the Dynamics Explorer 2 low-orbit satellite. Verification showed that the polarization relations of AGWs in the thermosphere preferably correspond to the gravitational branch of acoustic-gravity waves, which freely propagate in the direction of bottom up. This conclusion agrees with other results of the observations of AGWs in the atmosphere and the ionosphere using the ground and satellite methods. The evanescent waves were not observed at the considered orbits of the satellite.