Abstract
An incompressible, homogeneous (autobarotropic) atmosphere is assumed under steady-state and friction-less conditions. The equations for an airstream of infinite lateral extent are used for the airflow over a north–south mountain range. A quasi-stationary wave is assumed to the west of this mountain range. A series of steady-state conditions with different initial values of the north–south velocity and vorticity at the western edge of the mountain is obtained by progressively displacing the quasi-stationary wave eastward. The resulting pressure profile is computed for each case. The results show a deepening and an abrupt eastward displacement of the pressure trough as the wave is moved across the mountain. The deepest trough occurs when the computed mountain trough occurs at the position where the undisturbed trough would have occurred. Beyond this point, the computed trough is displaced slowly eastward and gradually fills.
The average pressure profile, which is obtained by taking at each point the mean of the pressure values computed for each of the successive phases as the wave is displaced eastward, is found to be identical with that obtained in the case of an initial westerly current to the west of the mountain.
