Introduction

This user's manual for the Regional Ocean Modeling System and the Terrain-following Ocean Modeling System (ROMS/TOMS) describes the model equations and algorithms, as well as additional user configurations necessary for specific applications. Some idealized tests of ROMS/TOMS are described in Haidvogel and Beckmann (1999) some of which are documented here. This manual also describes the sea-ice model that we are using, derived from that of Hibler (1979). It was rewritten and coupled to ROMS/TOMS by Paul Budgell.

The principle attributes of the model are as follows:

General

• Primitive equations with potential temperature, salinity, and an equation of state.
• Hydrostatic and Boussinesq approximations.
• Optional third-order upwind advection scheme.
• Option for point sources and sinks.

Horizontal

• Orthogonal-curvilinear coordinates.
• Arakawa C grid.
• Closed basin, periodic, prescribed, radiation, and gradient open boundary conditions.
• Masking of land areas.

Vertical

• s (terrain-following) coordinate.
• Free surface.
• Tridiagonal solve with implicit treatment of vertical viscosity and diffusivity.

Ice

• Hibler viscous-plastic dynamics.
• Mellor-Kantha thermodynamics.
• Orthogonal-curvilinear coordinates.
• Arakawa C grid.
• Smolarkiewicz or third-order upwind advection of tracers.
• Optional ridging scheme.

Mixing options

• Horizontal Laplacian and biharmonic viscosity and diffusion along constant s, z or density surfaces.
• Horizontal free-slip or no-slip boundaries.
• Vertical harmonic viscosity and diffusion with a spatially variable coefficient, with options to compute the coefficients with Large et al. (1994), Mellor and Yamada (1974), or Pacanowski and Philander (1981) mixing schemes.

Implementation

• Dimensional in meter, kilogram, second (MKS) units.
• Fortran 90 and common extensions.
• Runs under UNIX, requires the C preprocessor.
• All input and output is done in NetCDF (Network Common Data Format) requires the NetCDF library.
• Optimized for vector computers.
• Pre- and post-processing graphics package available which uses the NCAR (National Center for Atmospheric Research) graphics libraries.