Water And Oceanography

# Properties of Ocean Waves

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Anyone who goes to the beach observes waves. Some are big, and others are ripples working their way to shore.

Waves come in all shapes and sizes. No two waves are alike, and yet they all share the same characteristics. The following breaks down the way a wave begins and ends.

Wave Energy Example

Think of laying a rope down on the ground. Think about lifting one end of the rope and snapping it. A person will notice the ripple effect that goes all the way to the other end of the rope. This rippling effect is how waves work. It starts at one end and energy releases at the other end. It travels in one direction and ripples until the end of the rope.

To propel the energy, someone snapped the rope. This is the role wind plays in waves. Wind propels the waves to travel in the ocean and eventually releases the energy on the shore.

Determining the Size of Waves

There is a formula used to determine wave size.

>>> Fetch is the distance the wind blows over open water.

>>> How long the wind blows

>>> How fast the wind is blowing

The mix of these three factors determines wave height. An easy way to determine the approximate height of waves is to check the wind speed at the beach and divide it in half. For example, the wind is blowing 2 to 5 miles per hour. Divide the speed of two in half and the wave is approximately one foot high. At 5 mph the wave will be approximately 2 to 3 feet high.

Wave Anatomy Vocabulary

Crest is the highest part of the wave.

Trough is the lowest part of the wave. Think of a C, the top of the is Crest, the bottom is the trough C_. The distance between the crest and trough is the wave height. _↓

The distance between crests is the wave length. _ _.

Still-water Line is the place the water would be if there were no wave.  <.

Amplitude is the area that is one-half the wave height or the distance between the crest to the still-water line, or the trough to the still-water line.

The waves, as they tumble are “breakers”. The two main types of breakers are the “spilling” and “plunging”.

The favorite of surfers are the spilling breakers. They form when the water is turbulent. As the wave crests, foam cascades in front of the crest. They roll immense distances before breaking. These waves build slowly and steadily before breaking.

Another, more challenging wave for surfers is the plunging wave. The bottom rises quickly from the shore. This causes the wave to have an air pocket. Surfers ride the wave inside the pocket until it splashes up on the shore.

Waves Origination

An easy way to tell where a wave begins is to look at its size and shape. A steep, choppy wave is formed by a nearby storm out at sea. It did not travel very far and considered a “young” wave. It breaks quickly.

A long distance traveling wave is slow and steady wave that crests near the shore and plunges into foam comes from afar (think of the rope example). This type of wave may have come from a different hemisphere.

Waves remind us of the power of nature. This vast, mystical sea continues to roll in and out for all eternity.

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