Generation of Long Internal Gravity Waves in Waveguides by Rising Buoyant Air Masses and Other Sources

Abstract

The displacement fields generated in an internal gravity wave waveguide between plane rigid walls are compared for two types of source: an explosive point source and a rising buoyant sphere moving at constant speed. It is concluded that for large enough spheres and comparable energy expenditures, the buoyant sphere is a far more efficient source of long internal gravity waves. In particular it appears possible to conclude that, in the case of large events such as nuclear or volcanic explosions in the atmosphere, the rising heated air mass can generate long wavelength (λ > 500 km) internal gravity waves at ionospheric heights.