Wind wave

Wind wave is a type of surface wave that occurs on the free surface of oceans, seas, lakes, rivers, and canals or even on small water puddles and ponds. They result from the wind blowing across the surface of the water. Despite common perception, wind waves are not tidal waves or tsunamis.

Formation

Wind waves are generated by the frictional drag of wind over the water surface. The energy transferred from wind to water surface forms waves. The initial formation of waves by wind is known as the fetch. The distance over which the wind interacts with the water surface to creates waves is called the fetch length. The longer the fetch and the faster the wind speed, the more wind energy is imparted to the water and the larger the resulting sea state will be.

Characteristics

Wind waves have certain characteristics which can be measured and used for practical applications, such as in wave forecasting, coastal engineering, navigation, and marine biology. These characteristics include wave height, wave length, wave period, wave direction, and wave speed.

Wave Propagation

Once formed, wind waves will propagate (or travel) away from their area of origin. This propagation, or wave travel, continues even when the wind stops or changes direction. Waves generated by a distant storm are known as swell. Swell can travel thousands of kilometers across open ocean before reaching land.

Interaction with other Phenomena

Wind waves can interact with other physical phenomena in complex ways. For example, they can be refracted by the seafloor and by currents, diffracted around obstacles, and can interfere with each other. They can also break, forming whitecaps and leading to the transfer of matter and energy between the ocean and the atmosphere.

See Also

• Ocean surface wave
• Wave power
• Wave height
• Wave forecasting
• Swell (ocean)