RESPONSE OF STATIONARY PLANETARY WAVES TO TROPOSPHERIC FORCING.

A steady-state, linear, quasi-geostrophic model of stationary waves on a sphere is employed to study the lower boundary forcing of airflow over topography and the internal forcing that results from the geographical distribution of diabatic heating. The lower boundary vertical motions forced by airflow over topography are shown to depend on the following: 1) whether or not consideration is made of the horizontal deflection of airflow around topographic features; 2) the level of the wind profile at which flow over topography is assumed to take place; and 3) the topographic data set that was used in the forcing formulation. It is found that the lower boundary forcing generally accounts for the phase structure of the stationary planetary waves, and the response to the internal forcing generally acts to destructively interfere with the response from the lower boundary forcing. This interference is larger for wavenumber 2 in the stratosphere than for wavenumber 1.