What causes waves?

Waves occur in many different mediums throughout nature, including light and sound.

In the context of the surface of the sea, we know them well because we watch them break on shore, we swim or surf in them, and they determine the comfort of our travel across the ocean.

However, they are somewhat of a misleading abstract notion, for it is merely the circular up and down motion of the particles in the water that create the illusion of a ‘moving wave’. Waves in the sea surface work much like flicking a hose or rope and creating a moving loop along its length; each part of the line only has the net effect of moving up and down, and the actual ‘wave’ is the just that motion.

There are three main groups of what we call ‘waves’ when looking at the ocean;

- surface waves

- tsunamis

- tides.

Surface waves are the ones we are most familiar with.

They are caused primarily by wind.

How these waves look and behave usually depends on how far away they were created.

Shorter, choppy waves are created by nearby wind.

The long waves of ‘ocean swell’ are created by winds far away, so when on the surface of large oceans, such as the Pacific, the potential for large swell is strong because of the large distances.

Persistent and strong wind creates longer, faster and higher waves.

The more persistent the wind, the longer the wave; and the longer the wave, the faster they travel.

The stronger the wind, the higher the wave.

(future image of swell)

For more images and information about the Open Ocean, refer to the book:

Ecosystem Guides - "Ocean Surfaces of Australasia"