Operational Forecasting Wave ModelsOperational Forecasting Wave Models

WaveWatch III (Tolman 1997, 1999a)

• Model description:– Third generation wave model developed at NOAA/NCEP.– Solves the spectral action density balance equation for wavenumber-

direction spectra.

• Physical features:– The governing equations include :

o refraction.o mean current (tides, surges etc.), when applicable.

– Parameterizations of physical processes (source terms) include:o wave growth and decay due to the actions of wind.o nonlinear resonant interactions.o dissipation (`whitecapping').o bottom friction.o Wave propagation is considered to be linear. And nonlinear effects

are included in the source terms (physics).o The model is prepared for data assimilation.

WaveWatch III

• Output options:– Mean wave parameters:

Significant wave height

Wave Direction

Frequencies

Wave period, etc.

– 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.

– The model provides binary or ASCII output, as well as output for the GrADS graphics package by means of post processing.

Domains

• 3 Domains considered:– North Atlantic Ocean (0.5ºx0.5º)– Iberian Peninsula (0.25ºx0.25º)– Portuguese Coast (0.05ºx0.05º)

• 7 days forecast – On a daily basis, updated around 7

a.m. GMT

Swan

• SWAN model is a third-generation wave model for the simulation of waves in waters of deep, intermediate and finite depth.

• It is based on the discrete spectral action balance equation.

• SWAN simulates the following physical phenomena:– Wave propagation in time and space, shoaling, refraction due to current

and depth, frequency shifting due to currents and nonstationary depth. – Wave generation by wind. – Nonlinear wave-wave interactions. – Whitecapping, bottom friction, and depth-induced breaking.

• It is also suitable for use as a wave hindcast model.

Swan

• Output options:– Mean wave parameters:

Significant wave height

Wave Direction

Frequencies

Wave period

Wave stress

Wave length

– Output of wave spectra 1D and 2D.

– Files with boundary data for nested runs.

Domains

• 4 Domains considered:– Central Portugal (1 Km resolution)– Tejo, Sado e Sines (50 meters resolution)

• 3 Day forecast on a daily basis.

Input Input (Wind)

• Wavewatch 3

• GFS wind forcing with a resolution of 0.5º

• Swan

• MM5 wind forcing with a resolution of 9 Km

InputInput

MM5 with 27 km resolution. MM5 with 9 km resolution.

InputInput

GFS Winds.

Results Results (Wavewatch3)

Results Results (Wavewatch3)

Results Results (Wavewatch3)

Results Results (Swan)

Results Results (Swan)

Results Results (Swan)

Validation Validation (Wavewatch 3 Mean Wave Parameters)

Validation Validation (Wavewatch 3 Mean Wave Parameters)