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WAVEWATCH III™ © 2009 National Weather Service (NWS), National Oceanic and Atmospheric Administration, all rights reserved. WAVEWATCH III™ is a trademark of the NWS. No unauthorized use without permission.

Model Description

WAVEWATCH III™ (Tolman 1997, 1999a, 2009) is a third generation wave model developed at NOAA/NCEP in the spirit of the WAM model (WAMDIG 1988, Komen et al. 1994). It is a further development of the model WAVEWATCH, as developed at Delft University of Technology (Tolman 1989, 1991a) and WAVEWATCH II, developed at NASA, Goddard Space Flight Center (e.g., Tolman 1992). WAVEWATCH III™, however, differs from its predecessors in many important points such as the governing equations, the model structure, the numerical methods and the physical parameterizations. Furthermore, with model version 3.14, WAVEWATCH III™ is evolving from a wave model into a wave modeling framework, which allows for easy development of additional physical and numerical approaches to wave modeling.

WAVEWATCH III™ solves the random phase spectral action density balance equation for wavenumber-direction spectra. The implicit assumption of this equation is that properties of medium (water depth and current) as well as the wave field itself vary on time and space scales that are much larger than the variation scales of a single wave. With version 3.14 some source term options for extremely shallow water (surf zone) have been included, as well as wetting and drying of grid points. Whereas the surf-zone physics implemented so far are still fairly rudimentary, it does imply that the wave model can now be applied to arbitrary shallow water.

Model Features

Physical features:

• The governing equations of WAVEWATCH III™ include refraction and straining of the wave field due to temporal and spatial variations of the mean water depth and of the mean current (tides, surges etc.), when applicable.
• Parameterizations of physical processes (source terms) include wave growth and decay due to the actions of wind, nonlinear resonant interactions, dissipation (`whitecapping'), bottom friction, surf-breaking (i.e., depth-induced breaking) and scattering due to wave-bottom interactions. The model is prepared for triad interactions and is prepared for other, as of yet undefined source terms, but the latter have not been implemented yet. WAM cycle 4, bottom scattering, surf zone physics and wetting/drying new in model version 3.14.
• Wave propagation is considered to be linear. Relevant nonlinear effects such as resonant interactions are, therefore, included in the source terms (physics).
• The model includes several alleviation methods for the Garden Sprinkler Effect (Booij and Holthuijsen, 1987, Tolman, 2002c).
• The model includes sub-grid representation of unresolved islands (Tolman 2002e). A software package based on Matlab^® has been developed to automate generation of grids including obstructions due to unresolved islands (Chawla and Tolman, 2007, 2008). Grid generation package first distributed with model version 3.14 through model distribution web page (see below).
• The model includes options for choosing various term packages, some intended for operations, others for research. The source term packages are selected at the compile level.
• The model includes dynamically updated ice coverage.
• The model is prepared for data assimilation, but no data assimilation package is provided with the present distribution of the source code.
• Spectral partitioning is now available for post-processing of point output, or for the entire wave model grid using the Vincent and Soille (1991) algorithm (Hanson and Jenssen, 2004; Hanson et al , 2006, 2009). New in model version 3.14

Numerical features:

• The model is written in ANSI standard FORTRAN 90, fully modular and fully allocatable.
• The model uses a regularly spaced longitude-latitude grid (longitude and latitude increment do not need to be equal) and, optionally, a Cartesian grid.
• The model is set up for traditional one-way nesting, where model grids are run as separate models consecutively, starting with the models with the lowest spatial resolution..
• With model version 3.14, a `mosaic' approach is available, where an arbitrary number of grids can be considered with full two-way interactions between all grids, effectively making the mosaic of grids operate as a single model with variable spatial resolution (Tolman, 2006, 2008). New in model version 3.14.
• The mosaic approach introduced in version 3.14 only considers static grids. Relocatable grids within the mosaic are being developed. Already available in model version 3.14 is an approach where (a mosaic of grids) moves along a user-defined path. This allows for moving grid modeling of hurricanes away from the coast (Tolman and Alves, 2005). New in model version 3.14
• Wave energy spectra are discretized using a constant directional increment (covering all directions), and a spatially varying wavenumber grid. The latter grid corresponds to an invariant logarithmic intrinsic frequency grid (Tolman and Booij 1998).
• Both a first order accurate and third order accurate numerical scheme are available to describe wave propagation (Tolman 1995). The propagation scheme is selected at the compile level.
• The source terms are integrated in time using a dynamically adjusted time stepping algorithm, which concentrates computational efforts in conditions with rapid spectral changes (Tolman 1992, 1997, 1999a, 2009).
• The model can optionally be compiled to include shared memory parallelisms using OpenMP compiler directives.
• The model can optionally be compiled for a distributed memory environment using the Message Passing Interface (MPI, see Tolman 2002a).

Output options:

• Gridded fields of 31 input and mean wave parameters such as the significant wave height, directions, frequencies etc. Up from 18 in model version 2.22
• Output of wave spectra at selected locations.
• Output of wave spectra along arbitrary tracks.
• Up to 9 restart files per model run.
• Files with boundary data for up to 9 separate nested runs in a one-way nested model approach where models are run independently. In the mosaic approach, input boundary data for each grid in the mosaic can be dumped for later use.
• Partitioned wave field information is available for the full model grid or sub-sets and sub-sampled grids. New in model version 3.14.
• The model provides binary or ASCII output, as well as output for the GrADS graphics package by means of post processing. Postprocessors for GRIB data are available, but will require GRIB packing libraries.

Documentation and Source Code

The documentation of WAVEWATCH III™ is available on line in pdf files. For each released model version an errata page is maintained, which is the sole source of distributing errors and fixes of the model. To receive information on model changes etc, subscribe to the MMAB mailing list.

Model version 1.15:

• Tolman , H. L, 1997: User manual and system documentation of WAVEWATCH-III version 1.15. NOAA / NWS / NCEP / OMB Technical Note 151, 97 pp. (0.74MB PDF file). The source code of this model has never been distributed.

Model version 1.18:

• Tolman , H. L, 1999a: User manual and system documentation of WAVEWATCH-III version 1.18. NOAA / NWS / NCEP / OMB Technical Note 166 , 110 pp. (0.76MB PDF file).
• Tolman , H. L, 1999b: WAVEWATCH-III version 1.18: Generating GRIB files. NOAA / NWS / NCEP / OMB Technical Note 167, 7 pp. (0.15MB PDF file)
• Tolman , H. L, 1999c: WAVEWATCH-III version 1.18: Post-processing using NCAR graphics. NOAA / NWS / NCEP / OMB Technical Note 168, 9 pp. (0.15MB PDF file)
• Version 1.18, errata, problems and fixes. With the release of model version 2.22, the older code is no longer maintained, and this web site is no longer updated.

Model version 2.22 :

• Tolman, 2002g: User manual and system documentation of WAVEWATCH-III version 2.22. NOAA / NWS / NCEP / MMAB Technical Note 222, 133 pp. (0.89MB PDF file).
• Version 2.22, errata, problems and fixes. With the release of model version 3.14, the older code is no longer maintained, and this web site is no longer updated.

Model version 3.14 :

• Chawla and Tolman, 2007: Automated grid generation for WAVEWATCH III. NOAA / NWS / NCEP / MMAB Technical Note 254, 71 pp. (23.3MB pdf file).
• Tolman, 2009: User manual and system documentation of WAVEWATCH III™ version 3.14. NOAA / NWS / NCEP / MMAB Technical Note 276, 194 pp + Appendices. (0.83MB pdf file).
• Tolman, 2010: WAVEWATCH III (R) development best practices Ver. 0.1. NOAA / NWS / NCEP / MMAB Technical Note 286, 19 pp. (0.13MB pdf file).
• Version 3.14, errata, problems and fixes.
• Version 3.14-11, changes and diff file..
• Version 3.14-12, changes and diff file..
• Version 3.14-13, changes and diff file..
• Version 3.14-14, changes and diff file..
• diff file for patching v3.14-14 directly onto v3.14-10 (last public release).

Model distribution

Model versions 1.18 and 2.22 have been distributed as public domain software, and can be found at the previous WAVEWATCH source code ftp site Model versions 3.14 through 5.16 WAVEWATCH III™ was distributed under an open source style license through a password protected distribution site.

Starting with version 6.07, WAVEWATCH III&trade is distributed using GitHub. This means that users and developers are no longer required to submit requests for usernames and passwords to access the software package.

The WAVEWATCH III^® project page is here.

The latest release (currently at 6.07) is available as a compressed tarball or zipfile from the project page.

To help users and developers navigate the new repositories, we have created two sets of guidelines in GitHub to help you navigate our community modeling framework, one for users and the other for developers:

• If you are a user and would like to access the code for applications and do not plan to engage in development work, see the User Guide.


• If you are a developer and would like to add a new feature to the code, see the Developer Guide.

The WW3 GitHub wiki hosts a description of the model, its main features, output options, user and developer guides, technical documentation and latest news.

Let's Go Modeling!

Model development

The model is subject to continuous development. The following new features are presently being incorporated in WAVEWATCH III™ at NCEP and by our partners, or are considered for incorporation in the future.

• Unifying Cartesian and spherical grid approaches, and expanding to curvilinear grids (NRL Stennis).
• Unstructured grid options (developed at SHOM, method of Aron Roland).
• Relocatable grids in mosaic approach (NCEP).
• Alternative propagation schemes (second order scheme from MetOffice).
• Expanded list of output parameters, particularly for model coupling.
• ESMF wrapper to facilitate model coupling (NRL Stennis),
• Alternative source term parameterizations (many from NOPP projects and others).
• New GSE alleviation (NCEP).
• Quasi-steady model integration compatable with SWAN approach (NCEP).

New releases will generally become available after implementation of a new model version at NCEP. Research model versions may be made available to those interested in and committed to basic model development. Contact NCEP.EMC.wavewatch@NOAA.gov for requests to get access to the research versions of the model.

References

Booij, N. and L. H. Holthuijsen, 1987: Propagation of ocean waves in discrete spectral wave models. J. Comp. Phys., 68, 307-326.

Chawla, A., and H. L. Tolman, 2007: Automated grid generation for WAVEWATCH III. NOAA / NWS / NCEP / MMAB Technical Note 254, 71 pp.

Chawla, A., and H. L. Tolman, 2008: Obstruction grids for spectral wave models, Ocean Modelling, 22, 12-25.

Komen, G. J., L. Cavaleri, M. Donelan, K. Hasselmann, S. Hasselmann and P. A. E. M. Janssen, 1994: Dynamics and Modelling of Ocean Waves. Cambridge University Press, 532 pp.

Chawla, A., and H. L. Tolman, 2007: Automated grid generation for WAVEWATCH III. NOAA / NWS / NCEP / OMB Technical Note 254, 71 pp..

Chawla, A. and H. L. Tolman, 2008: Obstruction grids for wave models. Ocean Modelling, 22, 12-25.

Hanson, J. L. and R. E. Jensen, 2004: Wave system diagnostics for numerical wave models. In 8^th International Workshop on Wave Hindcasting and Forecasting, JCOMM Tech. Rep. 29, WMO/TD-No.1319.

Hanson, J.L., B. A. Tracy, H. L. Tolman and D. Scott, 2006: Pacific hindcast performance evaluation of three numerical wave models. in 9^th International Workshop on Wave Hindcasting and Forecasting, JCOMM Tech.Rep.34. Paper A2.

Hanson, J. L., B. A. Tracy, H. L. Tolman and R. D. Scott, 2009: Pacific hindcast performance of three numerical wave models, J. Atmos. Oceanic Techn., In Press.

Tolman, H. L., 1989: The numerical model WAVEWATCH: a third generation model for the hindcasting of wind waves on tides in shelf seas. Communications on Hydraulic and Geotechnical Engineering, Delft Univ. of Techn., ISSN 0169-6548, Rep. no. 89-2, 72 pp.

Tolman, H. L., 1991a: A third-generation model for wind waves on slowly varying, unsteady and inhomogeneous depths and currents. J. Phys. Oceanogr. , 21, 782-797

Tolman, H. L., 1991b: Effects of tides and storm surges on North Sea wind waves. J. Phys. Oceanogr. , 21, 766-781

Tolman, H. L., 1992: Effects of numerics on the physics in a third-generation wind-wave model. J. Phys. Oceanogr., 22, 1095-1111.

Tolman, H. L., 1995: On the selection of propagation schemes for a spectral wind wave model. NWS/NCEP Office Note 411, 30 pp. + figures.

Tolman, H. L., 1997: User manual and system documentation of WAVEWATCH-III version 1.15. NOAA / NWS / NCEP / OMB Technical Note 151, 97 pp. (0.74MB PDF file).

Tolman, H. L., 1999a: User manual and system documentation of WAVEWATCH-III version 1.18. NOAA / NWS / NCEP / OMB Technical Note 166, 110 pp. (0.76Mb pdf file).

Tolman, H. L., 1999b: WAVEWATCH-III version 1.18: Generating GRIB files. NOAA / NWS / NCEP / OMB Technical Note 167, 7 pp. (0.15MB pdf file)

Tolman, H. L., 1999c: WAVEWATCH-III version 1.18: Post-processing using NCAR graphics. NOAA / NWS / NCEP / OMB Technical Note 168, 9 pp. (0.15Mb pdf file).

Tolman, H. L., 2001: Improving propagation in ocean wave models. Ocean Wave Measurement and Analysis, San Francisco, CA, B. L. Edge and J. M. Hemsley, Eds., ASCE, 507-516.

Tolman, H. L., 2002a: Distributed memory concepts in the wave model WAVEWATCH III. Parallel Computing, 28, 35-52.

Tolman, H. L., 2002b: Validation of WAVEWATCH III version 1.15 for a global domain. NOAA / NWS / NCEP / OMB Technical Note Nr. 213, 33 pp. (2.7Mb pdf file).

Tolman, H. L., 2002c: Alleviating the Garden Sprinkler Effect in wind wave models. Ocean Modelling, 4, 269-289.

Tolman, H.L. 2002d: Limiters in third-generation wind wave models. Global Atmosphere and Ocean. System, 8, 67-83.

Tolman, H. L., 2002f: Testing of WAVEWATCH III version 2.22 in NCEP's NWW3 ocean wave model suite. NOAA / NWS / NCEP / OMB Technical Note Nr. 214, 99 pp. (13 Mb pdf file in color or gresyscales).

Tolman, H. L., 2002g: User manual and system documentation of WAVEWATCH-III version 2.22. NOAA / NWS / NCEP / MMAB Technical Note 222, 133 pp. (0.89Mb pdf file).

Tolman, H. L., 2003: Treatment of unresolved islands and ice in wind wave models. Ocean Modelling, 5, 219-231.

Tolman, H. L., 2006: Development of a multi-grid version of WAVEWATCH III. NOAA / NWS / NCEP / MMAB Technical Note 256, 88 pp.+ Appendices.

Tolman, H. L., 2008: A mosaic approach to wind wave modeling. Ocean Modelling, 25, 35-47.

Tolman, H. L., 2009: User manual and system documentation of WAVEWATCH III version 3.14. NOAA / NWS / NCEP / MMAB Technical Note 276, 194 pp.+ Appendices (0.83Mb pdf file).

Tolman, H. L., and J. H, G, M. Alves, 2005: Numerical modeling of wind waves generated by tropical cyclones using moving grids. Ocean Modelling, 9, 305-323.

Tolman, H. L., B. Balasubramaniyan, L. D. Burroughs, D. V. Chalikov, Y. Y. Chao, H. S. Chen, and V. M. Gerald, 2002: Development and implementation of wind generated ocean surface wave models at NCEP. Weather and Forecasting, 17, 311-333.

Tolman, H. L., and N. Booij, 1998: Modeling wind waves using wavenumber-direction spectra and a variable wavenumber grid. The Global Atmosphere and Ocean System, 6, 295-309.

Tolman, H. L. and D. Chalikov, 1996: Source terms in a third-generation wind-wave model. J. Phys. Oceanogr, 26, 2497-2518.

Vincent, L. and P. Soille, 1991: Watersheds in digital spaces: An efficient algorithm based on immersion simulations. IEEE Transactions of Pattern Analysis and Machine Intelligence, 13, 583-598.

WAMDIG 1988: The WAM model - A third generation ocean wave prediction model. Journal of Physical Oceanography, 18, 1775-1810.