Internal atmospheric gravity waves near the coast of Antarctica

Abstract

Two gravity wave events as observed at Georg von Neumayer Station in Antarctica are described and analyzed. Wind and temperature are recorded at a meteorological tower. Surface pressure time series are available from four sites so that rather exact evaluations of phase speed and wavelength are possible. Radiosonde ascents provide information on the structure of the atmosphere above the boundary layer.

The pressure traces of both events are dominated by sinusoidal oscillations with a well defined frequency. Related variations of wind and temperature are small during the first event (16 July 1986) as are those of temperature on 29 September 1986. However, wind oscillations are quite large during this second event. An attempt is made to interpret the data in the light of linear gravity theory. It is found that linear gravity waves of frequency and phase speed as observed were able to propagate throughout the troposphere on 16 July. We conjecture on the basis of linear theory that the wave of 29 September was propagating on the surface inversion.