Why does the Qiantang River form such a spectacular tide? 40

The cause of the Qianjiang tide.

Time of day: On the eighteenth day of the eighth month of the lunar calendar, the sun, the moon, and the earth are almost in a straight line, so the gravitational pull of the sea is the greatest on this day.

Geographical advantage: It is related to the trumpet-shaped shape of the Qiantang River estuary. Nearly 500,000 acres of reclamation land in the east of Zheshan on the south bank of the Qiantang River like a peninsula block the estuary, so that the Qiantang River Zheshan to the outer 12 sections resemble a bottle with a big mouth and a small mouth, the tide is easy to advance and difficult to retreat, the outer mouth of Hangzhou Bay is as wide as 100 kilometers, and 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 Qiantang estuary, because the river surface shrinks rapidly, the tide does not have time to rise evenly, so that the back wave pushes the front wave, the front wave does not run fast, the back wave catches up, layer upon layer.

Secondly, it is also related to the sedimentation of the Qiantang River, which blocks and rubs the tide, making the front slope of the tide steeper and the speed slowing down, thus forming the back wave to catch up with the front wave, a wave on top of each other, a wave high and a wave surge.

Winds: Southeasterly winds often blow along the coast of Zhejiang in summer and autumn, and the wind direction is roughly the same as the direction of the tide, which promotes the tide.

Hangzhou Bay outside the Qiantang River, wide on the outside and narrow on the inside, deep on the outside and shallow on the inside, is a very typical trumpet-shaped bay. The river at the mouth of the sea is 100 kilometers wide, and to the west to Pengpu, the river shrinks to 20 kilometers. When you reach the area of Yanguan Town in Haining, the river is only 3 kilometers wide.

At the beginning of the tide, the wide and deep mouth of the bay swallows a large amount of seawater at once, and because the river surface shrinks rapidly, it narrows and becomes shallow, and the tide that rises on the road does not have time to rise evenly, so the back wave pushes the front wave, and the wave is higher than the other. In the vicinity of Dajia Mountain, we encounter a huge barrage sand bar under water, and the tide rushes up, setting off a towering and amazing huge wave, forming a steep water wall, and causing the initial tide peak.

1. The "trumpet" terrain makes the tide very high, a bit like a "tsunami" effect;

2. The latitude is close to the "white channel", and the gravitational pull of the moon is relatively large.

Say a thousand, say ten thousand, are the two reasons.

In addition to the gravitational influence of the moon and the sun, the cause of the majestic Qianjiang tide is also related to the trumpet-shaped shape of the Qiantang River estuary. Nearly 500,000 acres of reclamation land in the east of Zheshan on the south bank of the Qiantang River like a peninsula block the estuary, so that the Qiantang River Zheshan to the outer 12 sections resemble a bottle with a big mouth and a small mouth, the tide is easy to advance and difficult to retreat, the outer mouth of Hangzhou Bay is as wide as 100 kilometers, and 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 Qiantang estuary, because the river surface shrinks rapidly, the tide does not have time to rise evenly, so that the back wave pushes the front wave, the front wave does not run fast, the back wave catches up, layer upon layer. Secondly, it is also related to the sediment under the Qiantang River, which blocks and rubs the tide, making the front slope of the tide steeper and the speed slowing down, thus forming the back wave to catch up with the front wave, one wave on top of the other, one wave higher and one wave surge.

It seems to be related to the topography of the bell mouth of the Qiantang River, and of course, the formation of tides is also related to the gravitational attraction of the earth and the moon.

Celestial time: 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 on the earth's centroid (sun), or the resultant force of the inertial centrifugal force generated by the earth's movement around the earth-moon (sun) center of mass and the moon (sun) gravity. Maximum.

Geographical advantage: It is related to the trumpet-shaped shape of the Qiantang River estuary. Nearly 500,000 acres of reclamation land to the east of Zheshan on the south bank of the Qiantang River block the estuary like a peninsula, so that the Qiantang River Zheshan to the outer 12th section resembles a bottle with a big mouth and a small mouth, the tide is easy to enter and difficult to retreat, the outer mouth of Hangzhou Bay is as wide as 100 kilometers, only a few kilometers wide to the outer 12th section, 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 Qiantang estuary, because the river surface shrinks rapidly, the tide does not have time to rise evenly, so it has to push the back wave to the front wave, layer upon layer.

Secondly, it is also related to the sediment under the Qiantang River, which blocks and rubs the tide, making the front slope of the tide steeper and the speed slowing down, thus forming the back wave catching up with the front wave, and the wave on top of each other. 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.

Because that's the closest atmosphere to the moon.

The topography of the Qiantang River is trumpet-shaped, so the tide is so spectacular.

It seems to be because of the moon ...

1. The tide of the Qiantang River.

Of course, the reason for the formation is also inseparable from the movement of celestial bodies, from the 16th to the 18th of the eighth month of the lunar calendar, the sun and the moon.

The earth is almost in a straight line, so the gravitational pull of the sea water and the gravitational force caused by the centrifugal movement of the moon are the largest, and the deflection angle and rotation motion of the earth itself cause the sea water to rise and tide.

The phenomenon is even more pronounced.

2. Nearly 500,000 acres of reclamation land east of the south bank of the Qiantang River block the estuary like a peninsula, making the Qiantang River resemble a bottle with a big belly and a small mouth.

Push the front waves, layer upon layer, forming a tidal surge.

3. Qiantang River is located in Hangzhou Bay.

Hangzhou Bay is located in the place where the Pacific Ocean envy the tide waves rush straight to the east, and it is also the direction with the largest tidal range on the west coast of the East China Sea, which is uniquely endowed. Therefore, various reasons came together to contribute to the tide of the Qiantang River.

Classification of the tide of the Qiantang River.

1. Cross tide (also known as cross tide).

In Dingqiao Town, Haining City, 55 kilometers away from Hangzhou Bay, there is a place called the big gap, which is an excellent place for the cross tide. Due to the long-term sediment accumulation, a sandbar is formed in the middle of the river, and the tide wave from Hangzhou Bay is divided into two streams, namely the east tide and the south tide.

At the moment when the two tides collide, a column of water is stirred, several feet high, and the waves splash and are thrilling. When the water column fell back to the river, the two tide heads were already in the shape of a cross on the river, and they quickly rushed westward. At the same time, the intersection quickly shifted northward like an avalanche, crashing into the straight pond, causing a huge splash and falling on the top of the pond.

2. A line of tide.

After seeing the cross-tide of the big gap, it is recommended that you drive to Yanguan as soon as possible.

Wait for the first line of tide. Before seeing the shadow of the tide, I heard the sound of the tide first. There was a loud rumbling sound in my ears, and the river was still calm. The sound became louder and louder, like beating the drums of war on all sides.

Deafening. In the distance, a white line appeared on the foggy surface of the river.

Moving westward rapidly, it is like "practicing across the river, and raising white rainbows in the flat sand".

Closer, the white line becomes a wall of water, gradually rising, "the tide is a little higher, and the mountains are crossed in the waves". With the rapid advancement of a white wall, the surging tide came in front of him, with the momentum of thousands of horses galloping, the power of thunder, unstoppable.

The first-line tide is not only for salt officials. Where the river road is straight, there is no place in Shazhou, the tide is in a line, but it is not as good as Yanguan. The reason is that not far after the salt official position and the width of the river trough shrink sharply upstream, the east and south tides meet just into a straight line, the tide energy is concentrated, and the tide head is particularly high, usually 1-2 meters, sometimes up to more than 3 meters.

The momentum is magnificent, and the tide scene is spectacular.

The reason why the tide of the Qiantang River is spectacular is because:

1. Topographic conditions: The width gap between the mouth of the Qiantang River estuary and the mouth is very large. The estuary of the Qiantang River is much wider than the estuary of the Yangtze River, and it is more than 100 kilometers wide.

However, the width of the estuary (such as Yanguan) immediately shrank to about 3 kilometers. A huge trumpet-shaped mouth was formed, and the river water quickly poured into the mouth of the river from wide to narrow, and the water surface and flow rate rose rapidly to form a large tide.

2. Lunar gravity: If you have studied geography, you know that ocean tides are closely related to lunar gravity. The Qianjiang tide also has this reason, so the tide is generally the largest around the Mid-Autumn Festival every year when the moon is the fullest.

Coupled with the special topographical reasons of the first one, a spectacular Qianjiang tide has been formed.

Reason 1: The centrifugal effect of the gravitational force of the celestial tomb and the rotation of the earth. Reason 2:

The mouth of the Qiantang River resembles a trumpet-like terrain. Reason 3: Wind direction.

Southeasterly winds often blow along the coast, and the direction of the wind is generally the same as that of the tide, which contributes to the tide of Congzhao. Reason for seepage and rent 4: There is a lot of sediment under the Qiantang River, which blocks and rubs the tide.

Qiantang River, located in Zhejiang Province of China, eventually flows into the East China Sea, the tide at its mouth is the Qiantang tide, famous all over the world, and there are many tourists who come to ** every year.

Every year on the 15th day of the eighth month of the lunar calendar, the tide of the Qiantang River is the largest, and the tide head can reach several meters. On August 18 of the lunar calendar, the water army can be inspected on the Qiantang River, and then it will be followed by the Xi Cheng Festival.

In ancient times, the tide was watched in Hangzhou, with the Phoenix Mountain and Jianggan as the best points. Due to the change of geographical location, from the Ming Dynasty, Haining Yanguan was the first resort to watch the tide, so it was called"Haining tide watching"。