We all love to go to the beach and enjoy the good weather, sunbathe, and take a nice swim. However, on windy days, the waves prevent us from taking that refreshing dip. You've probably wondered how those endless waves that never end are formed, but you don't know why or what waves really are.
Do you want to know what ocean waves are and how they form?
What is a wave?
A wave is simply a ripple of water on the surface of the sea. Waves can travel many kilometers across the ocean and, depending on the wind, do so at varying speeds. When waves reach the beach, they break and their cycle ends. You can also learn more about how wave height is measured in this article on wave measurement and how that can influence the prevention of dangerous waves.
Origin
Although waves are often thought to be caused by the wind, the reality is much more complex. The true source of a wave is not the wind, but the sun. The sun heats the Earth's atmosphere, but not uniformly. Some parts of the Earth heat up more than others due to the sun's influence. When this happens, atmospheric pressure changes. In areas where the air is warmer, atmospheric pressure is higher, creating zones of stability and fair weather, where anticyclones predominate. Conversely, in areas less heated by the sun, atmospheric pressure is lower. This causes winds to form in the direction of higher pressure to lower pressure.
Atmospheric wind dynamics function similarly to those of water. The fluid, in this case the wind, tends to move from areas of higher pressure to areas of lower pressure. The greater the pressure difference between one area and another, the stronger the wind will be, leading to the formation of storms. It is also interesting to observe how ocean currents affect wave formation.
When the wind begins to blow and affects the surface of the sea, air particles rub against water particles, creating tiny ripples. These are called capillary waves, and they are simply small waves only a few millimeters long. If the wind blows several kilometers away, these capillary waves grow, eventually becoming larger waves. It is also important to consider how global warming affects sea level.
Factors involved in its formation
Several factors can influence wave formation and size. Stronger winds obviously generate higher waves, but the speed and intensity of the wind, as well as the duration of that speed, must also be considered. Other factors influencing the formation of different types of waves are the affected area and the depth. As waves approach the shore, they slow down due to the shallower water, while the crest increases in height. This process continues until the upwelling moves faster than the underwater portion, at which point the movement becomes unstable and the wave breaks.
There is another type of wave that is lower and more rounded, formed by differences in pressure, temperature, and salinity in adjacent areas. These differences cause the water to move, creating currents that form small waves. This is called swell. It is also interesting to explore the concept of wave action to better understand how these formations interact, as you can see in this article on wave action.
The most common waves we see on the beach are usually between 0,5 and 2 meters high and between 10 and 40 meters long, although some waves can reach 10 to 15 meters in height. It's also important to keep in mind that wave size can vary in different parts of the world.
Another way to produce
There is another natural process that also leads to the formation of waves, and it's not wind. It's earthquakes. Earthquakes are geological processes that, if they occur in a maritime zone, can generate gigantic waves called tsunamis.
When an earthquake occurs on the ocean floor, the sudden change on the surface generates waves hundreds of kilometers long around the affected area. These waves travel across the ocean at incredibly fast speeds, reaching up to 700 km/h . This speed is comparable to that of a jet aircraft.
When the tidal waves are far from shore, the waves move a few meters high. It is when it approaches the coast when they rise between 10 and 20 meters in height and are authentic mountains of water that impact on the beaches and cause serious damage to the surrounding buildings and all the infrastructures in the area.
Tsunamis have caused numerous disasters throughout history. For this reason, many scientists study the types of waves that form at sea to make coastlines safer and, furthermore, to harness the vast amount of energy released by them to generate electricity as a renewable resource. In addition, the study of earthquakes provides valuable information about changes in the elastic properties of the Earth's crust, which are also related to climate change.
Types of waves
There are several types of waves depending on the strength and height they have:
- Free or oscillating waves. These are waves that occur on the surface and are caused by variations in sea level. In these waves, the water doesn't move forward; it simply rotates as it rises and falls, almost at the same point where the wave originated.
- Translation waves. These waves occur close to shore. When they advance they touch the seabed and end up crashing with the coastline forming a lot of foam. When the water returns again the hangover forms.
- Forced waves. These are produced by the violent action of the wind and can be very high.
As a consequence of global warming, sea levels are rising, and waves will increasingly damage coastlines. Therefore, it is essential to understand as much as possible about wave dynamics to make our coasts safer. Furthermore, it is important to consider the types of weather events that can influence this phenomenon and how they may be related to climate change.
