Gravity waves in a realistic atmosphere

Abstract

The atmospheric winds at ionospheric altitudes exhibit irregular short-period wavelike components that have been observed through their distortion of meteor ionization trails and rocket vapor trails. An explanation for these components was proposed by Hines in his theory for internal atmospheric gravity waves in an isothermal medium. The isothermal theory is refined here to unify the treatment of acoustic, gravity, and evanescent waves in a gravitational atmosphere and to explain the physical processes behind these atmospheric motions. A technique is developed for the solution of the complete hydrodynamic equations that avoids the fatal difficulties normally caused by ‘Viscous waves’ and their thermal counterpart. This technique is used to solve the general problem of gravity wave propagation in a realistic atmosphere for a wide range of wave parameters. The height of maximum wind amplitude and the fraction of reflected energy have been plotted from the results of these calculations. These maxima are also compared with simpler analytic approximations and experimental observations.