Wave Spectrum
D2. Hydrography, tides, waves, bathymetry and marine geologyDefinition
Distribution of wave energy with frequency and direction.
A wave spectrum gives the distribution of sea-surface variance (wave energy) across frequency and direction, the complete statistical description of a sea state from which significant wave height, peak and mean periods, and direction are derived. Empirical forms include the Pierson-Moskowitz spectrum for a fully developed sea and the JONSWAP spectrum for a fetch-limited growing sea. Spectral wave models (WAM, WAVEWATCH III) forecast the evolving spectrum globally.