Waves and Wave-Driven Currents

Abstract

Knowledge of ocean waves comes from observation and measurements in the field, laboratory experiments, mathematical theories, and numerical models. Engineering works, modern warfare, and environmental management have all stimulated and contributed to scientific research concerning ocean waves and their influence on coral reefs. Waves are one of the most important physical phenomena shaping the morphology and influencing the ecology of modern coral reefs and reef top islands. There is a large spectrum of ocean waves, ranging from wind waves, swell, tides, storm surges to tsunamis. This entry is concerned with wind waves and swell. Small amplitude wave theory is a first order linear theory for oscillatory waves of sinusoidal form. It provides relationships between the wave length, wave period, wave celerity, and wave height as waves propagate from deep water, where waves are unaffected by the bottom, through intermediate depths, where the depth has an increasing effect, into shallow water, where the depth dominates the propagation of the waves (see also Chapter Wave Shoaling and Refraction). As waves propagate across the water surface, water particles disturbed by them move in closed orbits with negligible forward transport but energy is transmitted by the waves with a velocity less than the wave celerity.