SWAN

Nearshore

• wind wave energy level per frequency per direction
• Hm0
• Tm02
• wave force

• Conservation of action density N(t,x,y,f,θ)
• Generation by wind
• Dissipation by depth-induced wave breaking
• Dissipation by bottom friction
• Dissipation by white capping
• Non-linear wave-wave interaction (quadruplet and triad (shallow waters))
• Refraction (by bottom and current gradient)
• Blocking (by opposing current)
• Blocking and transmission (due to obstacles and vegetation)

Default in physical and spectral space

• fully absorbing for leaving wave energy

In coastal region

• the deep water boundary is specified by the incoming wave energy

Shape of spectrum at the boundary of the computational grid could be:

• JONSWAP spectrum,
• Pierson-Moskowitz (PM) spectrum
• Gaussian-shaped frequency spectrum
• Simulated results provided by external model predictions (nested SWAN/WAM/WaveWatchIII)
• Measured spectra (at KUL, with a small matlab routine)

For model set-up:

• Bathymetry
• Wind
  • e.g. ERA-interim (at KUL)
  • measured wind (at KUL)

For B.C.

• Nesting on coarse WAM/SWAN/WW3 run
• Measured 2d spectra (at KUL)

Model generated data:

• Wave energy spectra
• Integrated wave parameters Hs, Tm02,…

less efficient on oceanic scales

Comparison

• Parametric (integrated spectral parameters, Hm0, Tm02)
• Spectral (spectral score)

Calibration tools

• Sources (wind generation coef.)
• Sinks (bottom roughness, …)
• Numerical (dt, conv. crit., …)
• Discretization (dx, dy, df, dθ, …)

Parametric Comparison (Hm0, Tm02)

• Multiple measurement stations in southern North Sea
• Shallowest at ~5 m. MSL at Trapegeer

Spectral comparison (1D or 2D)

• Directional (f-θ) and non-directional (freq. only) buoys