A series of laboratory experiments in a rotating differentially heated annulus have been conducted to determine the effect of azimuthal thermal forcing at the lower boundary, of the kind representative of continent/ocean thermal contrasts, on the forcing of standing waves and the modulation of free baroclinic waves. An azimuthal wave number 2 thermal forcing at the lower boundary induces a wave number 2 in the flow field, which interacts with transient baroclinic waves. The induced wave number 2 in the flow field is a climatologically standing wave, with its phase dependent on the intensity of forcing. An analysis of the velocity data reveals that the trough of the time-averaged stream field is located at the ''continent/ocean'' boundary, on the downstream side of the ''continent,'' and that the variance of the transient waves peaks approximately in the middle of the ''continent.'' ¿ American Geophysical Union 1991