Operational Forecasting Wave Models Wave Watch III Tolman

Operational Forecasting Wave Models

Wave. Watch III (Tolman 1997, 1999 a) • 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.

Wave. Watch III • Output options: – Mean wave parameters: v. Significant wave height v. Wave Direction v. Frequencies v. 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 Gr. ADS graphics package by means of post processing.

Domains • 3 Domains considered: – North Atlantic Ocean (0. 5ºx 0. 5º) – Iberian Peninsula (0. 25ºx 0. 25º) – Portuguese Coast (0. 05ºx 0. 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: v Significant wave height v Wave Direction v Frequencies v Wave period v Wave stress v Wave length – Output of wave spectra 1 D and 2 D. – Files with boundary data for nested runs.

Domains • 4 Domains considered: – – • 3 Day forecast on a daily Central Portugal (1 Km resolution) basis. Tejo, Sado e Sines (50 meters resolution)

Input (Wind) • Wavewatch 3 • GFS wind forcing with a resolution of 0. 5º • Swan • MM 5 wind forcing with a resolution of 9 Km

Input MM 5 with 27 km resolution. MM 5 with 9 km resolution.

Input GFS Winds.

Results (Wavewatch 3)

Results (Wavewatch 3)

Results (Wavewatch 3)

Results (Swan)

Results (Swan)

Results (Swan)

Validation (Wavewatch 3 Mean Wave Parameters)

Validation (Wavewatch 3 Mean Wave Parameters)