WAVEWATCH III Model Data Access (Text)

Model data from the latest WAVEWATCH III runs is available in GRIB (GRIdded Binary) format on the Marine Modeling and Analyses Branch FTP server, the NCEP NOMADS GDS/DODS data server, and the NCEP Central Operations Production FTP server, at the following URLs:

• Current Data (WAVEWATCH III multigrid latest version)
  1. FTPPRD (NCO Production FTP Server, today and three days prior.)
  2. MMAB FTP (Marine Branch FTP server, last six runs)
  3. NOMADS via (OpenDAP) (last seven runs)
  
  
• Current Data (WAVEWATCH III version 2.22 grids)
  1. MMAB FTP (Marine Branch FTP server, last seven runs)
  
  
• Current Data (WAVEWATCH III ensemble)
  1. MMAB FTP (Marine Branch FTP server, today and three days prior)
  
  
• Archived Data (WAVEWATCH III version 2.22 Hindcast reanalysis)
  1. MMAB FTP (Marine Branch FTP server, Aug 1999 to present)

Notes and Information on Using WAVEWATCH III Model Data

GRIB

The operational data file format is GRiB (GRIdded Binary). Additional information on the use of GRiB at NCEP is available here.

To work with WAVEWATCH III GRiB, any standard tools which read GRiB will work. One such tool is the freely available wgrib utility. The wgrib home page and software is here.

Another free GRiB file reader is the read_grib utility that can decode GRiB data directly into MATLAB (MATLAB is a registered trademark of The Mathworks, Inc.).

• The home page for read_grib is here.
• An updated version of read_grib can be downloaded here.
  The updates to read_grib include the latest changes to the MMAB optional table 128 and the NCO table 129 of GRiB parameter variable definitions. Included with the read_grib files is the getgrib.m utility for simplified extraction of the data from the WAVEWATCH III grib files.

Note: A new version of getgrib.m is now available from the MMAB FTP server. This new version decodes the NWW3 latitude and longitude vectors from the GRiB header. You can get it here.

NetCDF

We realize that many users of WAVEWATCH III output may be more familiar with NetCDF (network Common Data Form). This is not a format available from NCEP operational systems.

To convert GRiB to netCDF, you will need a utility such at gribtonc, described here. Source code for gribtonc is available here as part of the UNIDATA decoders package.

The netCDF files are approximately 6 times the size of the GRiB files.

NOMADS/DODS

The NOMADS (NOAA Operational Model Archive Distribution System) data server offers WAVEWATCH III data access. The server can be accessed at nomad5.ncep.noaa.gov/ncep_data/index.html, and offers interactive graphics, direct data downloads, and DODS/OpenDAP access.

More information on NOMADS is available here, and DODS/OpenDAP client software can be found here.