The ocean waves occur at the upper layer of an ocean. They are a result of wind and geologic effects. A wave may travel more than a thousand miles before it strikes the land. The size of the wave can vary from a small ripple to a large tsunami. Although a large amount of energy and momentum is present in a wave, there is very little forward motion of the individual water particles in the wave.
The three main factors that cause waves in the ocean are:
- The speed/velocity of the wind
- The distance (of the water) over which the wind has blown
- The duration for which the wind has blown over the surface of the water
The size of the wave depends on each of the above factors, and the larger each factor is, larger will the wave be. A wave is measured by its height; that is from the trough to the crest. The wavelength of the wave is the distance from one crest to the next. The period of a wave is the time taken between two consecutive waves from a fixed point.
Types of Waves
The three different types of waves that can develop over the ocean are as follows:
- Ripples: These are also known as capillary waves and appear on smooth waters. These waves die out when the wind stops blowing, but these can move forward if ample surface tension is present.
- Seas: These are larger waves that are formed under irregular and unsustainable winds. These can last long even after the winds have died out.
- Swells: These are formed when seas move away from their point of origin, separating naturally as per direction and wavelength.
A tsunami (pronounced sue-nahm-ee) is defined as a series of huge waves that can cause major devastation and loss of life, when they hit the coast. The word 'tsunami' is a Japanese word which means 'harbor waves' (tsu - harbor, nami - waves). The possible causes of a tsunami are submarine rock slides, an underwater earthquake with the Richter scale magnitude of over 6.75, volcanic eruptions, or an asteroid/meteoroid from the space crashing into the water.
A tsunami starts when a huge volume of water is shifted by any of the phenomena mentioned above. When such a large volume of water is moved, the resulting wave is very large and can be spread over an area of a hundred miles. This wave can travel from the point of origin to the coast at great speed. A tsunami has been known to travel with speeds as high as 600 mph in the open ocean. This is the speed with which a jet travels. In addition to this, a tsunami can move from one end of the ocean to the other in a few hours.
With the advancement in technology over the years, tsunamis can now be detected before they hit the coast, thereby reducing loss of life and property. Fortunately, tsunamis are very rare with approximately six of them hitting the coast every century, most of them occurring in the Pacific Ocean.
Ocean Waves and Global Warming
Another phenomenon that has been affecting the speed of waves in the recent years is global warming. Geophysicists have predicted that as the surface of the ocean warms up, the speed with which the planetary waves travel should subsequently increase. It is believed that the speed of the waves has already increased considerably, but this has not been noticed and documented so far. The satellites that have been monitoring the speed of the waves have not been around for too long. As per the latest research report, the speed of the waves will further increase by nearly 30% by the end of the 21st century.
In a broader sense, the ocean and the waves are one of the best gifts that the nature has bestowed upon us. However at certain times, the waves of the ocean have caused a lot of devastation to life. Thus, it is important on our part that we remain alert for all warnings and stay away from the oceans when asked to. Furthermore, staying away from oceans during high tide is a good idea too, as the waves and depth of the ocean can be higher than expected.