What are the long and low tides in the sea?

Judging from the causes of tides, the gravitational effect of the moon and the sun on seawater is the main reason, which is embodied in:

First: the moon and the sun have gravitational effects on seawater. In terms of distance, the moon and the sun are closest to the earth, so they have a great continuous gravitational effect on seawater.

Both the moon and the sun are revolving around the earth, so the distance between them is changing, but gravity remains unchanged, and the seawater on the earth's surface will still be affected by gravity, which is the main cause of tides. Therefore, in order to understand the tidal phenomenon, we should pay attention to the influence of the moon and the sun on seawater. ?

Second: the attraction of the moon and the sun to the sea water causes the sea water to fluctuate. It is precisely because the moon and the sun have a certain gravitational effect on seawater that seawater fluctuates frequently and regularly. ?

Third, the periodic changes in the positions of the moon and the sun make the tides rise and fall. Tides have ups and downs, called tides during the day and sunseekers at night.

The regular fluctuation of sea water changes with the periodic change of the distance between the moon and the sun and the earth, with high tide at peak and low tide at low tide, thus forming a regular tidal phenomenon. It is the key to study tidal phenomena to master the periodic changes of positions between the moon, the sun and the earth. ?

What's the effect of tides?

When tides occur, the sea water will change, and the production and life of coastal residents will be affected by tidal fluctuations. ?

First of all, tides have affected fishermen's offshore operations. When the sea rises, that is, when the tide rises, it is very unsafe for fishermen to go out to sea, so the time for going out to sea is shortened, and fishermen can only choose to go out to sea after the high tide, which also has a certain impact on fishery production. It is of great practical significance to master the law of tidal fluctuation for fishermen's offshore operations and fishery production. ?

Second: Tides have affected coastal tourism. The seaside is a place where tourists often choose to travel during holidays, especially in summer, but you must pay attention to the changes of tides when you go to the seaside.

When the tide is high, the safety of tourists is the first priority, so the beaches for coastal tourism are required to be closed.

In the news of previous years, tourists were often seen walking to the center to take photos along the drainage pipe facing the sea. Suddenly, the tide began to rise and the waves became bigger and bigger. They are trapped on a "reef" and so on. Therefore, we should pay enough attention to the tides. When we go to the seaside, we must know the changes of tides in advance to avoid getting into danger. ?

Third, the tide affects the shipping time and travel route. There are certain rules for the fluctuation of tides, and the shipping time and driving route should also be formulated according to this law, otherwise accidents such as ship anchoring or ship collision will occur. In order to ensure the safety and efficiency of shipping, it is very necessary to know the characteristics of tides. ?

Extended data:

Application of tides

Among all marine phenomena, tides are the first phenomenon that attracts people's attention. It has a very close relationship with human production and life, and is gradually applied to human production and life. There is huge energy in the periodic fluctuation of seawater, and how to develop and utilize this energy has become the main task of mankind. ?

(1) tidal power generation?

Tidal power generation has both advantages and disadvantages that need to be avoided. ?

Advantages are mainly reflected in:

First, conventional hydropower generation will be affected by weather and climate, while tidal power generation energy is stable. Tidal energy is a kind of energy produced by tidal changes in seawater due to the attraction of the moon and the sun to the earth. Tidal energy is very reliable and can be used all the time;

Secondly, we can use computers to predict the periodicity and regularity of tides.

Third, there is no need for long-distance power transmission, because it is close to the power consumption center. ?

Disadvantages mainly include:

First, because of the periodicity of tides, tidal power generation also has the characteristics of periodicity and intermittence;

Secondly, compared with river power stations, the investment cost of tidal power stations is higher. ?

Tidal power generation in China began in the late 1950s, and by 20 15, eight tidal power stations have been built. At present, the technology related to tidal power generation is becoming more and more mature, the equipment is gradually improving, and the cost of building tidal power stations is gradually decreasing. Therefore, the prospect of tidal power generation is very broad. ?

(2) Military application of tides?

In landing and anti-landing operations, the influence of tidal changes on military operations can not be ignored. ?

When Zheng Chenggong, our national hero, recovered Taiwan Province Province, the soldiers set out from Kinmen Island, arrived at Penghu Islands and attacked chibi city. At that time, there were many soldiers in Dagang waterway and it was difficult to attack. Luermen Waterway is weak, but there are many shallow reefs.

In order to take it by surprise, Zheng Chenggong chose to land in Heliao Port at the high tide of the Luermen waterway, which was a great success. If you choose Dagang Waterway, the possibility of waiting for them is landing failure. ?

During the Korean War, the Korean people entered Busan, and the United States assembled United Nations multinational troops to land in Incheon and directly invaded Korea. The sea surface of Incheon Port is the largest tidal range in Asia, with a high tide on September 15. On September 15, the commander of the US invasion of the DPRK successfully landed in Incheon Port. At that time, the Korean people neglected to defend Incheon Port because of victory, and the invading army quickly captured Seoul. ?

In a word, the change of tide has an impact on many combat operations such as landing and anti-landing, and it is an important factor to be considered in military operations. ?

(3) Tourism application of tides?

"The frolicking Xiang Tao stands upright and the red flag is not wet" is a portrayal of frolicking. In China, the Qiantang River Tide is very famous, and it is also one of the three tidal bore.

Due to the change of tides and the topography of special bays, we can see many spectacular scenes. There are also some special tidal power stations that many tourists will choose to watch. Tidal phenomena not only enrich China's tourism resources, but also broaden our horizons. From this point of view, tides are also widely used in tourism.

China Net-Mysterious Moon and Tide Phenomena: How Tides Are Formed (Figure)