Why does the tide of the Qiantang River rise on August 18 and August 18?

Tides are tidal phenomena that cause periodic fluctuations in the surface of the ocean due to the gravitational force of the moon and the sun. From the 16th to the 18th day of the eighth month of the lunar calendar, the sun, the moon, and the earth are almost in a straight line, so the tidal gravitational force on the sea water on this day (the difference between the gravitational force of the moon, the sun or other celestial bodies on the earth's unit mass object and the gravitational force of the earth's centroid on the earth's centroid (sun), or the resultant force of the inertial centrifugal force generated by the earth's movement around the center of mass of the earth and the moon (sun). Maximum.

So the tides are also at their highest at this time.

Due to well-known reasons, Hangzhou Bay is a big bell mouth, when a large amount of tide water pours in from the mouth of the Qiantang River, due to the rapid shrinkage of the river, so that the tide does not have time to rise evenly, so it has to push the back waves and the front waves, layer upon layer. A spectacular Qianjiang tide has been formed.

The formation of tides is mainly due to the gravitational pull of the sun and moon.

Many times, we think that the tide seems to be the wave, so we think that the tide is caused by the wind, but in fact, people who live by the sea must be familiar with the fact that no matter how big or small the wind is, the sea water rises and falls regularly, which shows that the tide has other influences.

And this influence is the celestial body. I believe that when we study physics, we all understand the formula for calculating gravity, but it is difficult for us to feel the difference in gravitational force brought to us by celestial bodies, for example, between day and night, we do not feel the obvious change in gravitational force.

But when this scale is magnified to an astronomical scale, then the gravitational effect is obvious. The two major planets, the Sun and the Moon, have created a huge gravitational pull on our Earth, and this gravitational pull acts on the ground, which is the tidal phenomenon of the oceans.

Because so science wants to know ask yourself.

Hello dear, this is mainly due to the geographical advantage. The cause of the tide of the Qiantang River is due to the favorable time, location and wind: the time of the day

From the 16th to the 18th day of the eighth month of the lunar calendar every year, the sun, the moon and the earth are almost in a straight line, so the sea water is subject to the greatest gravitational force on this day. Geographical advantage: Qiantang River Zheshan to the outer 12 kilometers section is like a big belly mouth small bottle, the tide is easy to advance and difficult to retreat, the outer mouth of Hangzhou Bay is as wide as 100 kilometers, to the outer 12 sections are only a few kilometers wide, the riverbed in the eastern section of the estuary rises suddenly, the beach is high and the water is shallow.

When a large amount of tide water pours in from the mouth of the Qiantang River, due to the rapid shrinkage of the river surface, the tide does not have time to rise evenly, so it has to push the back wave to push the front wave, layer upon layer, the Qiantang River is related to the sedimentation of more sediment under the water, these sedimentation plays a role in blocking and friction against the tide, making the front slope of the tide steepen, and the speed slows down, so as to form the back wave to catch up with the front wave, and the wave is stacked and surging. Winds: Southeasterly winds often blow along the coast, and the direction of the wind is roughly the same as the direction of the tide, which contributes to the tide.