Wave that is collapsing or breaking as a result of the wave approaching the shore and reaching shallower water. The decreasing water depth causes the wavelength and speed to decrease and the wave height to increase. Consequently wave steepness increases and the wave becomes unstable: it breaks when the wave height is about 0.8 times the water depth. Several types of breaker have been described, e.g. spilling breakers (in which the wave breaks forward, with broken water spilling down the front of the wave), and plunging breakers (in which the wave crest curls over a large air pocket and falls vertically into the trough).
Subjects: Ecology and Conservation — Earth Sciences and Geography.