Applications

Contributed User Applications

User applications that are not distributed with the ROMS source code are invited here.

Changes to the code structure with the introduction of ROMS 3.0 make it straightforward to confine application-specific options to a small number of files maintained separately from the central code.

This approach has the advantages that:

• users can update their central code, adding newly developed features and fixing reported bugs, without upsetting personal options for a specific project
• users can work on more than one project at once using a single up-to-date code stem
• applications can be shared with colleagues without redistributing the entire source code, thereby fostering user community use of the most up-to-date ROMS release

Most users configuring a typical application of the forward simulation model need only edit:

• a file containing the CPP definitions, e.g. project.h. (The cppdefs.h file in previous ROMS versions has been re-structured to do this).
• an input ocean.in script
• initial, forcing and/or boundary netcdf files
• application-specific analytical options following the templates for ana_*.F files in the User/Functionals directory. (The analytical.F subroutine in previous versions has been re-structured to do this).

CBLAST

Configuration and input files for a model of the southeast New England shelf during the ONR Coupled Boundary Layers and Air-Sea Transfer (CBLAST) experiment are provided here as one example of how we recommend users configure realistic applications with ROMS 3.0.

The files required to configure and run ROMS 3.0 for CBLAST are available for download from www.myroms.org at the Datasets link on the left navigation panel (under the subheading Software), or follow this link [1].

A brief description of the files follows:

cblast.h

The CPP flags (previously in cppdefs.h) that set options for physics, numerical schemes, vertical turbulence closure, open boundary conditions, biology, sediment transport ... and output options (averages, diagnostics, stations, floats) are set in cblast.h.

ocean_cblast.in

The ocean_cblast.in file sets the values that are defined at execution. Parameters of particular relevance to CBLAST include: timestep, output frequency, open boundary nudging timescales and input netcdf file paths (amongst many others).

This example uses relative paths to indicate appropriate input files assuming the following directory hierarchy:

• cblast/
  • Data/
    • all initial, surface forcing, tides, and other open boundary data
    • the varinfo.dat file that matches model input/output variable names to corresponding netcdf data variables (here varinfo.dat is the default distributed with the code in ROMS/External/varinfo.dat
  • Forward
    • cblast.in
    • ocean_cblast.in

You can adapt this to your own requirements. Our choice of directory hierarchy anticipates other applications with the Adjoint and 4DVAR codes for model sensitivity and data assimilation studies which would require distinct cblast.h files in each subdirectory (all controlled by a master driver script).

build_cblast

This csh shell script illustrates how a specific application can be configured without editing the makefile. UNIX shell envrionmental variables are used to over-ride the system defaults. If in the makefile a flag is set with the syntax VARIABLE ?= value , then this means it can either be set by editing that line in the makefile, or if VARIABLE is set in the shell that calls the script then the job inherits that value.

In the example given here we set the variables:

• ROMS_APPLICATION = CBLAST: This forces make to look for CPP definitions in a file called cblast.h.
• MY_HEADER_DIR = : Tells make where to look for the cblast.h CPP defs file.
• MY_ANALYTICAL_DIR: Sets where ana_*.F files would be located. The CBLAST requirs no such files.
• BINDIR: Sets where te executable shold be plced following sucessful compilation.

Results from the application of this model a study of summer circulation during the 2002 CBLAST field season are described in:

Wilkin, J., 2006: The summertime heat budget and circulation of southeast New England shelf waters, Journal of Physical Oceanography, 36(11), 1997-2011.

The URL for full text article: http://ams.allenpress.com/perlserv/?request=get-document&doi=10.1175%2FJPO2968.1

A further study using this model set-up considers tidal circulation on the Nantucket Shoals:

He, R. and J. Wilkin, 2006: Barotropic tides on the southeast New England shelf: A view from a hybrid data assimilative modeling approach. Journal of Geophysical Research, 111, C08002, doi:10.1029/2005JC003254.