Hybrid vertical coordinates for modeling internal solitary waves

We develop a hybrid vertical coordinate system for modeling near-bed processes under large amplitude internal solitary waves (ISWs) initialized with a Dubreil-Jacotin-Long (DJL) solver. Isopycnals are used to capture the ISW with minimal numerical diffusion of the pycnocline. Terrain-following layers in the weakly stratified bottom of the domain give additional vertical resolution and allow for simulations of unstable bottom boundary layers that would not be possible with isopycnal coordinates alone. Momentum and scalar advection schemes are implemented using QUICK and SHARP to further minimize numerical diffusion. Simulations of the bottom boundary layer under a propagating ISW are performed to demonstrate the capabilities of the model for analyzing near-bed processes under ISWs. Results are compared to simulations performed with traditional vertical coordinate systems.