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Large-amplitude internal waves induce currents and turbulence in the bottom boundary layer (BBL) and are thus a key driver of sediment movement on the continental margins. Observations of internal wave–induced sediment resuspension and transport cover significant portions of the world's oceans. Research on BBL instabilities, induced by internal waves, has identified several mechanisms by which the BBL is energized and sediment may be resuspended. Due to the complexity of the induced currents, process-oriented research using theory, direct numerical simulations, and laboratory experiments has played a vital role. However, experiments and simulations have inherent limitations as analogs for oceanic conditions due to disparities in Reynolds number and grid resolution, respectively. Parameterizations are needed for modeling resuspension from observed data and in larger-scale models, with the efficacy of parameterizations based on the quadratic stress largely determining the accuracy of present field-scale efforts.
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Supplemental Video 1: Simulation of ISW of elevation in a lock release experiment shoaling onto a liner slope. Domain is 6.4x0.3 m. Upper panel shows a layer of near bottom tracer and 5 density isolines in white. Bottom panel shows wave-induced velocities saturated in the range [-0.05,0.05] m/s. Blue colors denote negative values, red colors denote positive values. Supplemental Video 2: Simulation of cross-BBL transport of an Eulerian tracer (shaded) and nepheloid layer formation by a mode-2 wave passing over isolated topography. Five isolines of density shown as black lines. Details of simulation in Deepwell and Stastna (2017). Supplemental Video 3: Experimental visualization of shoaling ISW of depression, progressing from left to right. Flow has been seeded with neutrally buoyant particles. Resuspension is evident when particles are lifted off the bed during wave breaking. Details of experiment in Boegman and Ivey (2009). Supplemental Video 4: Experimental visualization of ISW of depression propagating over a flat bottom. Pycnocline shown in green. Instability in the adverse pressure gradient region, trailing the ISW, leads to resuspension of the bed-sediment (red). Details of experiment in Aghsaee and Boegman (2015).