What is OceanModelersOutput about?
Status: Planning
Brought to you by:
tomgrossccmp
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This project will provide a suite of Fortran and Fortran 90 subroutines which
can be incorporated into a wide variety of oceanographic hydrodynamic modelling
systems. The subroutines will produce a standardized NetCDF output file which
will be independent, in format, of the particular model which produced it. The
file writing subroutines and a few testing mainline fortran programs will be
this projects product. They will depend upon the existence of the NetCDF
libraries and include files.
There are dozens of oceanographic hydrodynamic modeling systems, POM, ROMS,
Quoddy, ELCIRC, ADCIRC, CH3D, EFDC etc.. Each is different in various ways
and all have unique output file formats. A common output format will not be
the optimal solution for every model, or any model. It will be a compromise of
some attributes in order to achieve a useful universal standard. We propose
that a core set of variables can be listed which will be valuable output and
usable for the widest set of graphical displays. The time and location of
velocity, sea level and optionally salinity and temperature are the core
variables. The Modelers NetCDF file format will specify these universal
variables while maintaining as much fidelity of the original model as
possible. The main approximation is in the specification of a location and
time for all variables. Most models use staggered grids and sometimes
staggered time steps. It will be necessary to perform some degree of averaging
to place all variables on a single location and time step grid.
NetCDF is only one of dozens of "universally accepted" file formats. It is
probably the most popular in the oceanographic community and is also widely
used by the atmospheric modeling community. In theory it is "self describing".
This means that programs written with the NetCDF library may read these files,
find the names and descriptions of the included variables and pull out enough
information to make meaningful graphs quickly. They are also flexible. For
instance a standard NetCDF file may have extra variables and attributes added
to the file, at anytime, and still be perfectly usable by graphics programs
which expected the older files. Of course if the self description specifies
the contents to be Speed and Direction rather than U, eastward and V, northward
the universal graphics plotter may not be able to make sense of it. So we will
specify some common sense names and units for the expected variables of a
Modelers NetCDF file.
These are not technical issues of great complexity. But a community effort is
necessary to get community buy in to the idea of universal output files. The
SourceForge method will allow us to finally come to concensus on many
unresolved issues such as what type of meta-data to include and whether to
allow time zones other than UTC.
I hope to help promote your site, to get
some other folks around New England on to it.
We have a individual coming to Woods Hole on June
1st to give a talk on this topic of standardizing model output. His web site is at:
http://www.gri.msstate.edu/research/damap/
I just downloaded the HYDROnetcdf tar and will
check it out next week.
-JiM.