Tidal rise and fall time of Feiyun River or Oujiang River in Wenzhou

Oujiang tide:

High tide is a natural phenomenon. There are high tides and low tides in seawater. At high tide, the sea rises, the waves roll and the scenery is spectacular. At low tide, the sea receded quietly, revealing a beach. High tide and low tide are usually twice a day.

The fluctuation of sea water is called tide during the day and sunseeker at night, so it is also called tide. China's ancient book says: "The sea is the tide in the morning and the sunseeker at night". There is a period between high tide and low tide when the water level does not rise or fall, which is called flat tide.

Extended data:

The law of universal gravitation shows that gravity is directly proportional to the product of the mass of two objects and inversely proportional to the square of the distance between them. The attraction of the sun to the earth is much stronger than that of the moon, but the tidal force of the sun is less than that of the moon 1/2.

Although the original tidal force (or tidal force) that caused the fluctuation of seawater was caused by the gravity of the sun and the moon, it was not the absolute gravity of the sun and the moon, but the difference between the gravity of the attracted objects and the gravity.

Tidal force is directly proportional to the mass of tidal celestial bodies and inversely proportional to the cube of the distance from celestial bodies to the earth. Because the mass of the sun is 27,023,369 times that of the moon, and the average distance between the sun and the earth is 389 times that of the moon, the tidal force of the moon is 2. 17 times that of the sun, which proves that tides are really mainly caused by the moon.

For example, if the highest tide in a certain place is 10 meters high, almost 7 meters is caused by the moon, and the contribution of the sun is only 3 meters, and other planets are less than 0.6 mm.