Abstract

The origin of onshore propagating large-amplitude internal solitary waves is intimately linked with the interaction of the barotropic tide, ambient stratification and topography. An complication is that the radiated internal tide at the shelf break is often dominated by a vertically propagating beam, while the solitary waves that eventually emerge have single vertical mode structure and propagate horizontally. This talk considers idealized stratification, topography, and forcing to focus on the underlying dynamics and uncover the general conditions that promote or inhibit the disintegration of the incident beam into modal internal tides and internal solitary waves on the shelf. Numerical simulations are based on non-hydrostatic form of the incompressible Boussinesq equations. The structure of the stratification and the ratio of the vertical scale of the beam to the depth of the thermocline are crucial on the beam evolution onto the shelf.