Framework
ROMS is a 4D modeling system. It is a 3-dimensional model (a 2D horizontal grid and a vertical grid) that can be run over a given amount of time, time being the 4th dimension. It is gridded into vertical levels that make up the water column and horizontal cells that make up the coordinates of the 2D cartesian plane of the model region.Kernel
Central to the ROMS framework are four models that form what is called the dynamical/numerical core or kernel: # Non-Linear Model kernel (NLM): NLROMS # Perturbation Tangent Linear Model kernel (TLM): TLROMS # Finite-amplitude tangent linear Representer Model kernel (RPM): RPROMS # Adjoint Model kernel (ADM): ADROMSVertical grid
The vertical grid is a hybrid stretched grid. It is hybrid in that its stretching intervals fall somewhere between the two extremes of 1) the evenly-spaced sigma grid used by the Princeton Ocean Model and 2) a true z-grid with a static depth interval . The vertical grid can be squeezed or stretched to increase or decrease the resolution for an area of interest, such as aHorizontal grid
The horizontal grid is a structured grid, meaning that it has a rectangular 4-sided grid cell structure. The horizontal grid is also an orthogonal curvilinear grid, meaning that it maximizes ocean grid cells of interest and minimizes extra land grid cells. The horizontal grid is also a staggered grid or Arakawa-C grid, where the velocities in the north-south and east-west directions are calculated at the edges of each grid cell, while the values for scalar variables such as density are calculated at the center of each grid cell, known as "rho-points."Physics
In both the vertical and horizontal directions, the default equations use centered, second-orderSource code
ROMS uses an open-access source code that can be downloaded by filling out an online request form. It runs on C-processing and was developed for shared computing uses. To download the source code a user must create an account and file a request with the developers on thInput and output
Input
Boundaries such as coastlines can be specified for a given region using land- and sea-masking. The top vertical boundary, the air-sea interface, uses an interaction scheme developed by Fairall et al. (1996). The bottom vertical boundary, the sediment-water interface, uses a bottom stress or bottom-boundary-layer scheme developed by Styles and Glenn (2000). Inputs that are needed for an implementer to run ROMS for a specific ocean region include: * Bathymetry and coastline * Freshwater input * Wind * Tides * Open boundary forcings (idealized, such as a reanalysis product, or specific data) * Heat flux * Physical mixing (see above) The programming framework of ROMS is split into three parts: Initialize, Run, and Finalize, which is standard for the Earth System Modeling Framework (ESMF). "Run" is the largest of these three parts, where the user chooses which options they want to use and assimilates data if desired. The model run must be initialized or compiled before it is run.Output
The output format of model run files isUser options
The general approach of ROMS gives model implementers a high level of freedom and responsibility. One approach cannot meet the needs of all the diverse applications the model is currently used for. Therefore, it is up to each model implementer (either an individual or a research group) to choose how they want to use each of the available options. Options include choices such as: * Mixing formulations in the horizontal and vertical directions * Vertical grid stretching * Processing mode (serial, parallel with MPI, or parallel with OpenMP) * Debugging turned on or off When using ROMS, if an implementer runs into a problem or bug, they can report it to thApplications
Coupled model applications
Biogeochemical, bio-optical, sea ice, sediment, and other models can be embedded within the ROMS framework to study specific processes. These are usually developed for specific regions of the world's oceans but can be applied elsewhere. For example, the sea ice application of ROMS was originally developed for the Barents Sea Region. ROMS modeling efforts are increasingly being coupled with observational platforms, such as buoys, satellites, and ship-mounted underway sampling systems, to provide more accurate forecasting of ocean conditions.Regional applications
There is an ever-growing number of applications of ROMS to particular regions of the world's oceans. These integrated ocean modeling systems use ROMS for the circulation component, and add other variables and processes of interest. A few examples are: * Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) * Experimental System for Predicting Shelf and Slope Optics (ESPRESSO) * New York Harbor Observing and Prediction System (NYHOPS) * Chesapeake Bay Estuarine Carbon & Biogeochemistry (ChesROMS ECB) * Climatic indices in the Gulf of AlaskaSee also
* General circulation model (GCM) * Ocean general circulation model (OGCM) * List of ocean circulation models *References
External links