Spectral Characteristics of the Baroclinic Annulus Waves

Abstract

This paper reports the results of a statistical study of the temperature field of several examples of regular wave, vacillating flow and irregular flow in a rotating annulus with a gap width of 10 cm using a limited number of thermocouples. The primary results indicate that the regular waves produce several wavenumber harmonies through nonlinear interactions. The wavenumber harmonies decrease in the vacillating flow and are not detectable in the irregular flow. Further, the azimuthal coherence of the flow in the irregular regime decreases very rapidly in azimuth, and yet the vertical coherence is extremely high at all frequencies indicating a strong two-dimensional character of the irregular regime.