Scattering of low-mode internal tides at different shaped continental shelves

Abstract

A series of numerical simulations have been performed to investigate the scattering of low-mode internal tides on different shaped continental shelves, and topographies with a linear slope, Gaussian slope and sinusoidal slope for a wide range of slope steepness are used in the model. The results indicate that 3 beams radiate from the abrupt shelf break, and 2 beams radiate from the gentle shelf beak during the scattering process. The greatest amount of energy can be reflected by the linear slope, whereas the least energy can be transmitted onto the shelf, and the results are contrary to those for the Gaussian slope. Modal decomposition are applied and the results indicate that the transmitted wave is dominated by mode 1, whereas the energy fluxes of higher modes increase with critical parameters and then decrease. For the reflected waves, the energy flux of the higher mode is obviously influenced by the topography. More energy in high modes can be reflected off-shore by topography with an abrupt junction point, and thus, the magnitude of vertical shear is enhanced in front of the slope. In addition, the region where the shear is influenced by the reflection process is within a wavelength of the incident wave.