Abstract
The baroclinic instability theories which are relevant to the differentially heated, rotating annulus are reviewed and recalculated in a way which brings out the importance of the vertical stratification of the fluid. Experimental measurements of the wave-regime neutral surface are presented which qualitatively agree with most of the predictions of the theories; in particular, good agreement with the predicted effect of the vertical stratification is obtained. Some details concerning an observed transition from high amplitude waves to low amplitude waves are given. Also some experimental evidence on the existence of a one-wave mode and a mixed one-wave and two-wave mode is presented.