Direction of Wave Propagation

The direction of wave propagation is the compass heading along which a wave train’s energy travels, taken normal to the wave crests. For a sea state it is reported as a mean wave direction or, in spectral form, as the directional spectrum that gives energy by frequency and direction. Convention usually states the direction waves come FROM, matching wind reporting, though some models report the direction waves go TO, so the 180-degree convention must be checked. Propagation direction is reset by refraction over varying depth, which turns crests toward the contours, and it controls the alongshore component of wave energy that drives littoral sediment transport.