On the Nature of Vertical Oscillations of Constant Volume Balloons

Abstract

The neutral buoyant oscillation of a spherical balloon floating in the upper troposphere or lower stratosphere is predicted to be between 3 and 4 min for the simplest theoretical case. Variance spectra of balloonborne sensor data, as well as ground-based radar data, show the period of this motion to be roughly between 3 and 6 min. Other balloon oscillations with much longer periods are shown to be largely in response to sinusoidal motions of its equilibrium density surface rather than in response to sinusoidal variations of the vertical velocity of the atmosphere. A term which accounts for the time dependence of the balloon's equilibrium density surface is explicitly included in the equation of motion for a spherical balloon and various solutions are then presented.