Internal tide dynamics in a topographically complex region: Browse Basin, Australian North West Shelf

Field observations and numerical circulation modeling revealed the spatial variability of the tidally driven dynamics in the topographically complex, continuously stratified, macrotidal environment of the Browse Basin on the Australian North West Shelf. Internal wave generation occurred at a number of discrete topographic features, and the resultant interaction of multiple waves led to a spatially variable internal wave climate. The generation of baroclinic energy was most intense in regions where the barotropic tide was aligned with steep topography. Generation of low-mode internal waves occurred at the inner-shelf break, where the ratio of tidal excursion distance to topographic length scale was large. In contrast, generation of high-mode beam-like internal waves occurred at the outer-shelf break, where the ratio of tidal excursion distance to topographic length scale was very small. The most efficient conversion from barotropic to baroclinic energy occurred at the outer-shelf break. The internal waves generated at the inner-and outer-shelf breaks interacted to produce a partly standing internal wave, resulting in a large along-shelf energy flux, and discrete locations with small ratios of horizontal kinetic energy to available potential energy. This phenomenon is likely to occur in other regions with semienclosed topography and multiple generation sites.