Laboratory observations of rotating, stratified flow in the vicinity of a submarine canyon

• Published in: Dynamics of atmospheres and oceans 2000, Vol.31 (1), p.47-72
• Main Authors: Boyer, Don L., Zhang, Xiuzhang, Pérenne, Nicholas
• Format: Article
• Language: English
• Subjects: Continental slope model; Earth, ocean, space; Exact sciences and technology; External geophysics; Marine; Other topics; Physics of the oceans; Stratified flow; Submarine canyon
• ISSN: 0377-0265; 1872-6879
• DOI: 10.1016/S0377-0265(99)00028-7

Laboratory experiments are conducted concerning an oscillatory, along-isobath flow of a linearly stratified fluid along a continuous continental shelf, shelf-break, and continental slope model topography interrupted only by a single isolated canyon. The model topography is located along the periphery of a circular tank, which is placed at the center of a turntable. Modulating the turntable rotation rate drives the oscillatory background current. The experiments employ particle-tracking techniques using DigImage software to determine the time dependent and mean velocity, vorticity and horizontal divergence fields at various vertical levels. Both subinertial and superinertial forced oscillation cases are presented which demonstrate the asymmetry of the flow for the oscillation phases with the coast on the left and right, respectively. The mean motion fields are shown to exhibit the properties of (i) a mean flow of fluid downstream, where downstream is defined as the observation direction with the coast on the right and (ii) a mean flow from the deep water up the canyon at all observation levels (mean upwelling is thus associated with this phenomena). The mean flows generated are shown to be significantly stronger for the subinertial case. An analysis is presented which shows the conditions under which the motion field generated by modulating the rotation rate of a turntable is similar to that which would occur in a system rotating with constant Coriolis parameter.