WAVEWATCH III® Production Hindcast, Multigrid: Feb 2005 to May 2019

Summary

The multigrid production hindcast uses the current operational multi-grid spectral wave model WAVEWATCH III® with operational NCEP winds and ice fields as input forcing fields. No wave data assimilation is performed. The model is run after the end of the month, with all available data. Output is available from February 2005 to May 2019.

UPDATE: 21 Dec 2020
EMC's WAVEWATCH III global wave model Multi-1 will be decommissioned in NCEP operations in February 2021. It is being replaced by a new configuration of global wave model coupled to GFS v16. Details of GFS v16 are available here. There is a plan in place to run the GEFS v12 wave model reanalysis/reforecasts for a period of 20 years starting in 1999. Details on these will be made available later.

Data Set Access and Validation

Multigrid Data Access*
Multigrid Data Validation

* Important Note: The Production Hindcast data set was recently moved from our FTP server to our web server. Please update your bookmarks and links as needed with the new location.

Some browsers (Firefox, Chrome) may try to display the contents of a GRiB file in the browser window instead of downloading it. If that happens, right-click on the GRiB file link and select "Save Link As..." to download the file.

Multigrid Timeline

• Feb 2005 through Jul 2015: The model was run with the Tolman and Chalikov (1996) source term package (ST2), friction velocity from Tolman and Chalikov input (FLX2), stability correction for ST2 enabled (STAB2).
• Aug 2015 to Present: The model was run with the Ardhuin et al (2010) source term package (ST4) which includes the flux computation in the sources (FLX0, STAB0). Additionally, the model uses a third order propagation scheme (UQ), with no damping or scattering by sea ice (IC0, IS0), and no reflection (REF0).

Multigrid Model Setup

• Propagation scheme: Higher-order schemes with Tolman (2002a) averaging technique (PR3).
• Linear input: Cavaleri and Malanotte-Rizzoli with filter (LN1)
• Nonlinear interactions: Discrete interaction approximation (NL1)
• Bottom friction: JONSWAP bottom friction formulation (BT1)
• Depth induced breaking: Battjes-Janssen (DB1)
• Use Miche-style shallow water limiter in equation for maximum wave energy (MLIM)

Model Grid Descriptions

The wave model suite consists of 9 rectilinear global and regional nested grids. These grids were developed using ETOPO-1 bathymetry (Amante and Eakins, 2009), together with v1.10 of the Global Self-Consistent Hierarchical High Resolution Shoreline (GSHHS) Database. The higher-resolution grids have been masked to improve model efficiency, and only provide data near shore. See Chawla and Tolman (2007,2008) for details on the software used for developing these grids.

Name (click for map)	ID	Nx	Ny	dx	dy	Lon0	Lat0
Global 30 min	glo_30m	720	336	1/2	1/2	0	-77.5
Arctic Ocean 30 min	ao_30m	720	51	1/2	1/2	0	65.0
NW Atlantic 10 min	at_10m	301	331	1/6	1/6	260	0.0
US West Coast 10 min	wc_10m	241	151	1/6	1/6	210	25
East Pacific 10 min	ep_10m	511	301	1/6	1/6	130	-20
Alaskan 10 min	ak_10m	401	187	1.5/6	1/6	140	44
Gulf of Mexico and NW Atlantic 4 min	at_4m	586	481	1/15	1/15	261	15
US West Coast 4 min	wc_4m	736	526	1/15	1/15	195	15
Alaskan 4 min	ak_4m	548	391	2/15	1/15	165	48

Model Input

• Wind input are from the operational Global Forecast System or GFS. The wind fields used are 10 meter winds at 1/2 degree resolution and 3 hour intervals.
• Ice concentrations are obtained from passive microwave sea ice concentration from the SMMR and SSMI, using the NCEP high resolution algorithm based on NASA Team2. The ice fields used are daily with 1/12 degree resolution.

Model output

• Field output in grib2 format, available every 3 hours
  .wind. = U-component of input wind, V-component of input wind (m/s). The vector described by these components shows the direction in which the wind blows (oceanographic convention)
  .hs. = significant height of combined wind waves and swell (m)
  .tp. = primary wave mean period (s)
  .dp. = primary wave direction (degrees true, i.e. 0 deg => coming from North; 90 deg => coming from East)
  In addition, starting in February of 2017:
  .pdir.= direction of swell waves (degrees true)
  .phs. = significant height of swell waves (m)
  .ptp. = mean period of swell waves (s)
• Partition output
  These provide bulk spectral estimates for each wave system.
  Available hourly for each individual grid.
ASCII (Feb 2005 through Dec 2016)
NetCDF (Jan 2017 onwards)

• Point output
  Hourly spectra, bulk parameters, and partition data is saved at over 2000 points (buoy locations and virtual locations).

Here is information about what each buoy file type contains.

Help and hints

Here is an example of how to read GRiB files with Python: how_to_plot_grib2.txt

Here is an example Python script to read the NetCDF partition files.

Here is an example Matlab script to read the NetCDF partition files.

Here is an example Matlab script to subset the NetCDF partition files.