AIR-FLOW OVER A 2-DIMENSIONAL ESCARPMENT .3. NONHYDROSTATIC FLOW

Forced flow over the asymmetric topography of the Darling Scarp. Weste rn Australia is modelled, using a nonhydrostatic model, and compared w ith observations. Drag histories and sensitivity tests indicate that i t is possible for the flow to be dominated by hydrostatic downslope wi ndstorms even if the hydrostatic index indicates nonhydrostatic domina nce. Experiments on a wide range of one- or two-layered flows suggest that nonhydrostatic effects on windstorm events are very small. Howeve r. the development and location of trapped lee waves can be significan tly affected if there is sufficient hydrostatic forcing in the flow. F or hydrostatic forcing to dominate over trapped lee waves it is necess ary for reflection, from a region of wave breaking or a critical layer , to occur at the right height.