A Spectral Model for Process Studies of Rotating, Density-Stratified Flows

A numerical model designed for three-dimensional process studies of rotating, stratified flows is described. The model is freely available, parallel, and portable across a range of computer architectures. The underlying numerics are high quality, based on spectral expansions, and third-order time stepping. Optional submodels include accurate calculation of Lagrangian trajectories. Special consideration has been taken to ensure ease of use by geophysical, as distinguished from computational, scientists. The mathematical and computational methods underlying the model are presented here as are several illustrative applications highlighting the model capabilities and the types of flows amenable to simulation using the model. Sample applications include forced inertial gravity waves, parametric subharmonic instability, shear-driven mixing layers, instability of a low Froude number vortex street, and geostrophic adjustment of intermittent, isolated mixing patches.