Explain the story of Zhuge Liang's "clever borrowing from the east wind" during the Three Kingdoms period.

During the Three Kingdoms period, there was a story about Zhuge Liang borrowing from the east wind, which is still circulating among the people in China.

This story happened in ll month in the 13th year of Jian 'an (AD 208). At that time, Cao Cao led an army of 500 thousand, claiming to be 800 thousand, to attack Sun Quan. Sun Quanbing was weak. He joined forces with Liu Bei, Cao Cao's enemy, with a strength of only 30,000 to 50,000. He had to rely on the natural barrier of the Yangtze River to refuse to defend the south bank of the Yangtze River.

This year 10, the allied forces of Sun Quan and Liu Bei met Cao Cao's vanguard troops in Chibi (now Puyi County, Hubei Province). Cao Jun spent most of his time as a soldier in the north. He didn't learn water warfare. Many people will get sick. The rust is very low. As soon as the two armies came into contact, Cao Cao suffered a small defeat. Cao Cao was forced to return to the north bank of the Yangtze River and stationed in Wulin (now Honghu County, Hubei Province) to confront the allies across the river. In order to reduce the turbulence of the ship, Cao Cao ordered craftsmen to connect the warships and lay boards on them. In this way, the hull is much more stable and people can walk and ride horses on it. This is the so-called "serial warship", and Cao Cao thinks it is a good way to cross the river.

However, the "serial battleship" has a big goal and is inconvenient to move. Therefore, Cao Cao was reminded to beware of Wu Jun's fire attack. Cao Cao, on the other hand, thought: "Whoever attacks with fire will use the east wind to make it in the middle of winter, but there is a northwest wind, so there is a southeast wind." I live in the northwest, and all my soldiers are on the south bank. If he uses fire, he will burn his own soldiers. what can I do? If it is in the spring of October, I am ready. Zhou Yu also saw this problem, but due to unfavorable weather conditions, he was so anxious that he was "vomiting blood and unconscious." "Zhuge Liang, Liu Bei's strategist, revealed the cause of Zhou Yu with a phrase" unexpected events happen in the sky "and secretly wrote the words 16:" If you want to break Cao Gong, attack him with fire; Everything is ready, only the east wind. " It can be seen that Cao, Zhou and Master Ge all have the same understanding of the conditions of fire attack.

However, Zhuge Liang, who lives in Nanyang (now near Xiangyang, Hubei) not far from Chibi, has a deeper and more specific understanding of the weather and climate around Chibi than Cao Hezhou. The northwest wind is only a climatic phenomenon, and the east wind can appear under the climatic background, which is a weather phenomenon. In military meteorology, in addition to climate laws, we must also consider weather laws as a supplement. At that time, according to the analysis of weather and climate change and my own experience, I accurately predicted the time of the east wind. However, in order to fool Zhou Yu, he set up an altar to worship God.

1 1 One night, the southeast wind really blew, and the wind was very strong. Zhou Yu sent Huang Gai to lead a fire attack fleet and sailed straight to Cao Jun Shuizhai, pretending to surrender. The ship was loaded with reeds and dry wood soaked in oil, disguised with a curtain, and a flag was inserted in the bow. At the forefront are ten attack ships. Ten ships headed for the center of the river. Huang Gai ordered all the ships to set sail, so the fleet moved faster and gradually saw the water town of Cao Jun. At this time, Huang Gai ordered the soldiers to shout in unison: "Huang Gai is coming!" " "Cao Ying officers and soldiers heard that Huang Gai came and craned their necks to watch. Cao Bing didn't know the truth and was unprepared. Huang Gai's fleet is only two miles away from Cao Cao Shuizhai. Then Huang Gai ordered "arson!" Commanded, all the warships fired together, just like a fire dragon, heading straight for the water town of Cao Jun. The southeast wind blew harder and harder, and the fire started with the wind. The wind fueled the fire, and all the water towns in Cao Jun caught fire. The "serial battleship" could not be dismantled for a while, and the fire could not be put out. It burned bigger and bigger until it reached the river bank. I saw flames flying and candlelight flickering, and Cao Jun's camp by the river was in flames.

Sun and Liu Hebing killed Cao's troops and burned warships ... In the fireworks, Cao Cao led the defeated troops to retreat to Huarong (now northwest of Jianli County, Hubei Province). Unexpectedly, there was another storm on the way, and the road was muddy. Cao Cao had to order all the old and frail soldiers to find branches and weeds and spread them on the muddy road to let the cavalry pass. But those old, weak and sick soldiers were crushed and trampled, and many people died. Later, he had to leave some troops to defend Jiangling and Xiangyang and lead the remnants back to the north.

Battle of Red Cliffs, the east wind has played a great role. Du Mu, a poet in the Tang Dynasty, wrote two famous poems: "The east wind is not convenient for Zhou Lang, and the copper finches lock the second bridge." Thank God Dongfeng lent it to Zhou Yu so that he could do things conveniently. Otherwise, Sun Ce's wife Da Qiao and Zhou Yu's wife Xiao Qiao will be taken to Tongquetai by Cao Cao. In the Peking Opera "Heroes", Cao Cao has a lyric: "I only said that the east wind is rare in November." Obviously, I regret my misjudgment of the weather and suffered a big loss.

However, the legend of Zhuge Liang borrowing from the east wind is considered to be fiction after textual research. However, from the middle of Battle of Red Cliffs, a strong southeast wind blew on the Yangtze River, and then Cao Jun lost Huarong Road and was caught in a rainstorm, which looked like a frontal cyclone at that time.

Frontal cyclones are most common in China in spring and less in autumn. It is a deeply developed low-pressure system, in which the heart is low and the surrounding air pressure is high. Air flows from the periphery to the center and rotates counterclockwise. Therefore, in the front of the cyclone (that is, in the east), the southeast wind blows; Behind the cyclone (west), the northwest wind blows. Convergent updraft generally exists in cyclones, which may lead to large-scale rainfall. Therefore, when the southeast wind continues to blow, it often indicates that the weather will get worse. The weather proverb says: "the southeast wind and rain of ancestors, the northwest wind is empty" and "the east wind and rain, the west wind and clear" have certain practical significance.

In addition, some people analyze the east wind borrowed by Zhuge Liang: from the modern weather map, we can see that when a place is affected by a moving closed high-pressure center, the wind direction changes clockwise. In other words, when the cold high pressure begins to move to the sea, the southeast wind prevailing behind the high pressure will temporarily control the middle and lower reaches of the Yangtze River. Due to the rapid southward movement of cold high pressure in winter, the cold air following the southward invasion soon arrived again; Therefore, the southeast wind lasts for a short time, and people often ignore it. Zhuge Liang, who knows astronomy and geography, lives in Nanyang, not far from Chibi. He grasped the signs before the southeast wind appeared, so he made the medium-term weather forecast accurately.

In this way, Zhuge Liang predicted that there would be strong winds in the southeast of 1 1 early winter according to the weather changes in the middle and lower reaches of the Yangtze River at that time, and further inferred that the weather would deteriorate, which was in line with the law of weather evolution.