SEMINAR: Topographic Interactions Over a Small Bank on the Continental Shelf

Interactions of a stratified fluid with topography take many forms. Inevitably, these interactions extract energy / momentum from the flow. While such effects are parameterized in atmospheric circulation models, present numerical models of the coastal ocean do not account for them. Towards quantifying the effects of topographic interactions on the coastal circulation we have developed new seafloor pressure sensors to measure the effects and executed a series of experiments over the continental shelf. While the ultimate goal is to assess the form drag of topographic features on the circulation, it is first necessary to properly interpret the seafloor pressure measurements.

Using combined shipboard profiling and seafloor velocity and pressure measurements, two examples are discussed that are similar in gross structure but differ in their dynamics and on their effects on the circulation. The first is the equivalent of a severe downslope flow in the atmosphere and interpreted here in terms of a Bernoulli function. The second is an internal bore stalled at the bank (shown in the image). The former extracts energy from the mean flow, the latter presumably from the tide.