Operational 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

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

Input GFS Winds.

Results Results (Wavewatch3)

Results Results (Swan)

Validation Validation (Wavewatch 3 Mean Wave Parameters)