Abstract
The effect of non-uniformity of vertical potential temperature gradient on downslope windstorms in a uniform environmental flow is analytically investigated by employing a steady 2-dimensional hydrostatic model. Both the potential temperature and a vorticity-like quantity become functions of the stream function. Their functional forms are chosen so that the environmental flow has a uniform horizonal velocity and non-uniform potential temperature gradient. Only the case of small parabolic deviation from uniform potential temperature gradient with the average value fixed is examined. The calculation shows the following. For a prescribed atmospheric height, the concentration of the potential temperature gradient in the upper (lower) layer increases (decreases) both the downslope wind speed and required mountain height. This result, compared with the case of a uniform increase of potential temperature gradient, implies that the upper layer stability is more effective for downslope windstorms.
