Schedule of high tide and low tide of seawater

The schedule of high and low tide of seawater is as follows:

Because the high tide and low tide of seawater are geographical phenomena influenced by the gravity of the moon, they can follow regularly, with a period of 15 days. Therefore, the next day's high tide is 0.8 hours (48 minutes) later than the previous day, and the daily high tide time can be calculated according to the lunar calendar date. The specific calculation method is as follows: according to the lunar calendar, if the number of days is less than 15, if the number of days is greater than 15.

You must subtract the number of days from 15 and multiply it by 0.8 to get the highest climax time of the day. At the same time, the interval between high tide and low tide is generally 6 hours, that is to say, the high tide can last for more than an hour before the low tide begins, and the lowest tide is in the middle of the two high tides.

tidal effect

1. Tides and the slow rotation of the earth. Due to the viscous force of the relative movement of seawater and the friction between seawater and land and seabed, tides have a braking effect on the earth's rotation, which gradually slows down the earth's rotation.

The moon always faces us with the same face. People find that the moon always faces us with the same face, but the other side of it is invisible to us on the earth. This is because the period of the moon's rotation is exactly equal to the period of the moon's rotation around the earth, and the same two periods are the result of the long-term action of tides.

3. With the increase of the distance between the moon and the earth, tides slow down the earth's rotation, which leads to the decrease of the angular momentum of the earth's rotation. Because the total angular momentum of the Earth-January system should remain unchanged, and the direction of the moon's rotation around the Earth is basically the same as that of the Earth's rotation, the decrease of the angular momentum of the Earth's rotation will inevitably increase the angular momentum of the center of mass of the Moon-January system, thus maintaining the conservation of the total angular momentum of the Earth-January system. The actual effect of this effect is to slowly increase the distance between the moon and the earth.

Refer to the above content: Baidu Encyclopedia-Tidal Effect