Internal hydraulic adjustment on a discontinuous escarpment slope

The Darling Scarp, located in Western Australia, is an escarpment that runs roughly north to south approximately 25 kilometers inland of the coast. Field studies carried out near the escarpment in Wagerup, Western Australia, between July and October 2006, aimed to determine atmospheric mixing and dispersion mechanisms in the area. Of principal interest were the effects of wintertime stability as well as topographically influenced flow. Coherent Doppler lidar was utilized along with other equipment to monitor the area throughout the measurement campaign. Gravity flows occurred on the escarpment slope producing conditions resembling an internal hydraulic adjustment. The adjustment occurred near a discontinuity in the escarpment slope in which the slope angle, with respect to the horizontal, decreased. Internal hydraulic jumps induced by slope discontinuities are predicted by theory and have been displayed in laboratory experiments. These internal hydraulic jumps are important in the scope of this study as they cause a great deal of turbulent mixing. Comparison between theory and field observations will be presented along with an assessment of the conditions necessary to produce the observed flow patterns.