Why are there big waves in the sea? Why are there waves in the sea? What affects the size of the swell

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Waves of the seas vs waves of the oceans - what's the difference?

Do you know what is different sea ​​waves from oceanic? What rules of conduct should be followed when relaxing on the ocean coasts? Read the answers to these questions in the article.

Surely, many who have been to the sea have seen waves and, perhaps, even a storm. And, going to exotic resorts, which are located on the coast of the ocean, such people feel ready for the unrest of the ocean. However, not everything is as simple and safe as it might seem at first glance.

Sea and ocean wave

In fact, sea waves are different from ocean waves. And the main distinctive feature waves in the ocean is that they are always there! On any coast washed by ocean waters, there will always be waves.. And at the same time, about every two minutes, a wave runs through, which is twice as large as all the others. You will not meet such waves on the seas of the post-Soviet space.

While on vacation, for example, on the Black Sea, we can all notice that the waves are of different sizes, and have their own periodicity. And this periodicity is the same as that of waves in the ocean, but because of the magnitude, no one simply notices this. And only when you are on the ocean shore, you begin to notice such features of different waves.

This difference in the span, height and strength of the waves can be explained by the fact that sea ​​water is limited by shores and does not have time to gain the power that ocean waves have. And if the ocean coast does not have a natural barrier of corals that serve as breakwaters, then swimming on such beaches is strongly discouraged.

Rules of conduct on the coast of the ocean

There are certain rules for behavior on ocean coasts. Some of the main ones are listed below.

If you first came to the beach of the ocean, do not rush to immediately plunge into the water. See how those who are already in the water behave. The fact is that the wave that returns to the ocean has a very great strength, and can easily drag even physically strong people under water.

It is advisable to always keep the approaching wave in sight. This will help you plan your actions based on the size of the wave and its speed. And if you suddenly find yourself at the foot of a wave, do not swim away from it at all. On the contrary, you need to dive right into it. Otherwise, the wave push you down and comb to the very shore, and then back. It's hard to enjoy it. Especially if there are stones at the bottom. Then your bathing can end in tears.

To answer the question of why storms appear on planet earth, let's conduct one small experiment with you. Let's pour water into a saucer and imagine that it is the sea. And now take a full chest of air and blow into the saucer-sea, becoming a hurricane wind. Do you see how the water trembled, rippled in the saucer and small waves went over it? That's exactly how the real sea excites the real one.

Now stop blowing. See how quickly you calmed down? Now it is smooth and motionless, like a mirror.

But in fact, it never happens to be so serenely calm and motionless. Even when there is no wind at all, sea waves still roll on the shore.

Why it happens? And because even though there is no wind on the sea, the wind will still be the cause of coastal waves. After all, the sea is so huge and boundless that if a strong wind blew up somewhere many hundreds of kilometers away, raised huge waves and immediately subsided, then the sea after that cannot find peace for a very long time.

However, this very surf appears not only from distant hurricane winds, but also from the coastal light breeze, the so-called "breeze". The breezes blow as if following some kind of timetable.

During the day, the coast heats up so much that it will be too hot to run barefoot on it. From the heated earth, the air begins to heat up. Warm is much lighter than cold and it rises, and its place is quickly filled by cold, more heavy air. And this one cold air located above the sea, which does not have time to heat up during the day as much as the coast.

And late in the evening, a breath of wind appears from the sea - sea ​​breeze. This small wind and raises weak coastal waves.

But at night it's the other way around. cools down very quickly, and the sea continues to retain the heat accumulated during the day. Now the air that rises above the sea is higher, because this time it is warmer, and the cold air from the earth rushes into the sea to the vacant place.

This is called the "shore breeze", which ripples the water all morning and subsides only by noon. By itself, the breeze is quite harmless, but when powerful winds sweep from afar, then it becomes scary to look at. It becomes unfriendly and gloomy. Huge waves beat against the shore with violent force, so that the coastal rocks hum and tremble.

The terrible roar and roar of coastal waves drowns out everything around. that the wind walks along it completely freely, raising huge waves of water and there are no obstacles in its path. This is how storms begin.

Captains, having heard about the approach of a storm on the radio, try to get as far as possible from the epicenter of storms. After all, the waves can be so big that sailors look up at them. Sometimes they reach the height of a seven-story building. Such a wave will lift the ship and carry it down like a chip from its steep.

From heavy blows, the entire hull of the ship shakes and cracks, and cargo fasteners burst. Multi-ton waves, flying from above onto the deck, sweep away everything in their path. The waves can be of such monstrous force that they can even damage the ship and flood it.

Once, the American cruiser Pittsburgh came under a powerful blow from such a wave, which demolished its armored stern, like a. This is what the wind and the huge waves it raises can do.

In this article we will talk about where the waves come from and what they are. After all, the waves are unique natural phenomenon, which gives surfers a lot of emotions and sensations, forcing them to give up a lot. Surfing is waves. BUT good surf impossible without knowing how waves are born, what affects their speed, strength and shape, as well as without understanding that each wave is different from the other.

Where do ocean waves come from

It's all about the swell. If not for the swell, there would be no waves. What is a swell? Swell is the energy of the wind transferred to the waves. There are several types of swells, wind and bottom (groundswell, reel):

1. As the name suggests, a wind swell is formed due to the wind. Such a swell occurs when the wind blows right next to the coast (for example, during a storm) and creates a chop (chaotic unrest on the surface of the ocean). The wind swell is not very suitable for surfing.
2. Swell, due to which surf waves form on the ocean coast, is called bottom swell. This is exactly where the waves that interest surfers come from.

How a swell is born

Far away in the ocean, a storm is raging with strong winds. These winds start a wave on the water. How stronger wind, topics larger size waves. A certain wind speed corresponds to a very specific wave size. It works like a sail and allows the wind to disperse itself and do more.

When the waves reach their maximum possible sizes, they begin to travel to the far shores in the direction where the wind blows. After a while the waves become similar friend on the other - the larger ones absorb the small ones, and the fast ones eat the slow ones. The resulting group of waves, approximately the same size and the same power, is called a swell. Swell can travel hundreds or even thousands of kilometers before reaching the coastline.

As the swell approaches shallower depths, the lower water flows collide with the bottom, slow down and have nowhere to go but move up, pushing all the water above them. When the water can no longer bear own weight- it starts to crumble. Actually, that's where the waves come from, on which you can surf.

1. Closeouts (close-out) are closed along the entire length in whole sections. Not the best option for skiing unless you are learning to ski in foam. When the size of the waves is more than 2 meters, then such waves can be dangerous. Closeouts can be recognized by the width of the wave peak, which can reach several meters.
2. Spilling waves they slowly approach the shore and, thanks to the slight slope of the bottom, slowly begin to break, without forming a sharp wall and pipe. Such waves need to be paddled in advance, and they are more suitable for beginner surfers and longboarders.
3. Plunging waves. Fast, powerful, sharp waves that form a tube. Occurs when a swell encounters an obstacle in its path. For example, it may be a protruding reef or a stone slab. We are used to seeing such waves in surf photos and surf videos. They allow you to make passages in the pipe and airs (jumps). Dangerous for beginner surfers.

Types of surf spots

The nature of the wave is determined by the place where it rises, which place is called the surf spot. Surf spots are divided into several types.

1. Beach break: the swell comes to the beach with a sandy bottom and the wave, having collided with the alluvium of sand at the bottom, begins to break. The peculiarity of beach breaks is that the peaks rise in places where sand alluvium is formed, and their shape and position can change every day, depending on the wind, underwater currents, tide movements and other factors.
   With a change in the shape and size of the alluvium, the characteristics of the waves also change, that is, the waves can be either sharp trumpeting or gentle. The sandy bottom is not particularly dangerous, so beach breaks are great for learning to surf. In Bali, beach breaks are the entire beach along Kuta, Legian and Seminyak, as well as Brava Beach, Eco Beach and others.
2. Reef break.This type of surf spot is characterized by the presence of a reef at the bottom. As a reef can act as Coral reefs, and the stone bottom in the form of individual stones or whole slabs. The shape, power and wavelength depend on the shape of the reef at the bottom of the ocean. On a spot with a reef break, you can always predict where the wave will peak. Reef breaks are much more dangerous than beach breaks due to sharp reefs and rocks on the bottom.In Bali, most of the surf spots are reef breaks. Uluwatu, Balangan, Padang-Padang, Batu Bolong and many others.
3. Point break- is when the vell collides with some kind of barrier protruding from the shore. It can be a stone ridge, a cape, a small peninsula. After the collision, the waves go around this obstacle and begin to break one after another. In such places, the waves rise most correct form, go one by one, and can give you very, very long drives.An example of a point break in Bali is the Medewi spot.

Wind and water

In addition to location and swell, where the waves come from for surfing is also affected by the wind and the height of the water (tides).

Where do waves come from for riding or "gone with the wind"
The quality of the waves depends on the wind on the shore. The most correct wind for surfing is its absence. That is why surfers get up at 4 am or earlier to get to the spot before dawn, when the wind has not had time to wake up, and the water is still mirror-smooth (glassy).

If the wind is still blowing, then the waves will not be spoiled (and sometimes even better) if it is directed from the coast to the ocean. This wind is called offshore. Offshore keeps the waves from breaking, making them sharper.

The wind that blows from the ocean to the shore is called onshore. He breaks the waves, forcing them to close ahead of time, blowing off the peaks. The least preferred wind of all. A strong onshore can generally kill the entire gurney.

Also, the wind can blow along the coast, it is called crossshore. Here much depends on its strength and direction. Sometimes a crossshore can slightly spoil the waves, and sometimes it can act as negatively as an onshore.

Ebb and flow
About tides and how they affect waves, you can read in this article.

wave anatomy

In the structure of the wave, several elements are distinguished:
Wall (face/wall)- the section of the wave where the surfer spends most time.
Lip (lip)- falling crest of a wave.
shoulder- a place where the wave gradually disappears.
Outsole (trough)- the bottom of the wave.
Pipe (tube/barrel)- a place where water surrounds the surfer from all sides.

Now you know where the waves come from, but theory is theory, and you can truly know the waves only in the process of surfing. The more you watch the waves and ride them, the better you will read the ocean, and this will allow you to catch more and more great waves. And now the board under the armpit and run to ride! 🙂

The wind itself can be seen on weather forecast maps: these are the zones low pressure. The greater their concentration, the stronger the wind will be. Small (capillary) waves initially move in the direction the wind is blowing.

The stronger and longer the wind blows, the greater its effect on the surface of the water. Over time, the waves begin to increase in size.

The wind has a greater effect on small waves than on a calm surface of the water.

The size of a wave depends on the speed of the wind that forms it. Wind blowing at some constant speed will be able to generate a wave of comparable size. And once a wave reaches the size that the wind can put into it, it becomes "fully formed."

The generated waves have different wave speeds and periods. (More details in the article) Waves with a long period move faster and cover greater distances than their slower counterparts. As they move away from the wind source (propagation), the waves form lines of swells, which inevitably roll onto the shore. Most likely, you are familiar with the concept of a set of waves!

Waves that are no longer affected by the wind are called ground waves (ground swell)? This is exactly what surfers are looking for!

What affects the size of a swell?

There are three main factors that affect the size of waves on the high seas.
Wind speed The larger it is, the larger the wave will be.
wind duration- similar to the previous one.
Fetch(wind coverage area) - again, the larger the coverage area, the larger the wave is formed.

As soon as the influence of the wind on them stops, the waves begin to lose their energy. They'll move until the moment the ledges seabed or other obstacles in their path (a large island for example) will not absorb all the energy.

There are several factors that affect the size of a wave at a particular location. Among them:

Swell direction- will it allow the swell to get to the place we need?
ocean floor- Swell, moving from the depths of the ocean to the underwater ridge of rocks, forms large waves with barrels inside. A shallow ledge opposite will slow down the waves and cause them to lose energy.
Tidal cycle- some sports are completely dependent on it.

Find out how the best waves come about.

The main reason for the formation of waves is the wind blowing over the water. Therefore, the magnitude of the wave depends on the strength and time of its impact. Due to the wind, water particles rise up, sometimes breaking away from the surface, but after some time, under the influence of natural gravity, they inevitably fall down. From afar, it may seem that the wave is moving forward, but in fact, if this wave, of course, is not a tsunami, (tsunamis have a different nature of occurrence), it only descends and rises. For example, sea ​​bird, sitting on the surface of a rough sea, will sway on the waves, but will not budge.

Only near the shore, where it is no longer deep, the water moves forward, rolling onto the shore. By the way, according to the scallop of spray from detached drops forming a crest on a wave, experienced sailors determine the degree of sea disturbance, if the crest and foam on it have just begun to form, then the sea is 3 points.

What kind of sea wave is called a coast.

Waves on the sea can exist without wind, this is a tsunami caused by natural disasters like underwater volcanic eruptions, and a wave that sailors call a coast. It is formed at sea after a strong storm, when the wind died down, but at the expense of large mass waters set in motion by the wind and a phenomenon called wave resonance continue to sway. It should be noted that such waves are not much safer than a storm and can easily capsize a ship or boat with inexperienced sailors.