Zhuge Liang borrowed the east wind

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 the 13th year of Jian 'an (AD 208) in ll month. At that time, Cao Cao led an army of 500,000, claiming to be 800,000, 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 and refused to defend the south bank of the Yangtze River.

In October this year, the allied forces of Sun Quan and Liu Bei met Cao Cao's vanguard troops in Chibi (now Puyi County, Hubei Province). Cao Jun was mainly a soldier in the north, and he didn't learn water warfare. Many people will get sick. The corrosion rate 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 battleship? Cao Cao thinks this is a good way to cross the river.

But? Serial battleship? The target is large and it is not convenient to move. So remind Cao Cao to beware of Wu Jun's fire attack. Cao Cao thinks:? Anyone who attacks it with fire will use the east wind to make it in the middle of winter, but there is a northwest wind and 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 was October and spring, I would have been ready. ? Zhou Yu also saw this problem, but he was in a hurry because of unfavorable weather conditions. Vomiting blood, unconscious? . Liu Bei's strategist Zhuge Liang used it? Something unexpected happened in the sky? In a word, he broke Zhou Yu's karma and secretly wrote 16 words:? If you want to break tso, you will attack him with fire; Everything is ready except the east wind. ? It can be seen that Cao, Zhou and Zhuge have the same understanding of fire attack conditions.

Zhuge Liang, who lives in Nanyang (now near Xiangyang, Hubei Province) not far from Chibi, has a deeper and more specific understanding of the weather and climate laws around Chibi than Cao and Zhou. The northwest wind is only a climate phenomenon, and the east wind can appear under the climate background, which is a weather phenomenon. In military meteorology, in addition to climate laws, weather laws must also be considered as a supplement. At that time, Yan accurately predicted the time of easterly wind based on the analysis of weather and climate change and her own experience. But in order to fool Zhou Yu, he set up an altar to worship the gods? Borrow the east wind? .

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 water town, pretending to surrender. The ship was loaded with reeds and dry wood soaked in oil, covered with a curtain, and with a flag in the bow. At the forefront are ten attack ships. Ten ships sailed to the middle of the river. Huang Gai ordered all the ships to 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:? The yellow cover is down! ? When the officers and men in Cao Ying heard that Huang Gai was coming, they all craned their necks to watch. Cao Bing couldn't tell the truth from the false, and he was unprepared. Huang Gai's fleet is only two miles away from Caocao Water Village. At this time, Huang Gai ordered? Set fire! ? 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 borrowed from the wind, which fueled the fire, and all the water towns in Cao Jun caught fire. ? Serial battleship? At that time, the fire could not be put out, and it grew bigger and bigger, reaching the river bank. I saw flames dancing and candlelight flickering, and Cao Jun's camp on the river and the bank was in flames.

Sun and Liu Lianhe got up, wiped out Cao Cao's great troops and burned all the 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 and difficult to walk. Cao Cao had to order all the old and weak 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, trampled and died a lot. 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: If the east wind is not convenient for Zhou Yu, I'm afraid the outcome will be Cao Cao's victory and Er Qiao's detention in Tongquetai. ? Thank God for lending Dongfeng to Zhou Yu, so that he can do things smoothly. Otherwise, Sun Ce's wife Da Qiao and Zhou Yu's wife Xiao Qiao will be taken to Tongquetai by Cao Cao. In the Beijing opera Hero, Cao Cao has a lyric:? I only said that the east wind was sparse in November. ? Obviously, I regret my misjudgment of the weather and suffered a big loss.

However, the legend of Zhuge Liang's borrowing from the east wind is considered fictional 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 fell into a downpour, 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 with low heart and high ambient air pressure. Air flows from the periphery to the center and rotates counterclockwise. So in the front of the cyclone (that is, in the east), the southeast wind is blowing; Behind the cyclone (west), the northwest wind blows (as shown in the left picture). Convergent updraft is dominant in cyclones, which may lead to large-scale rainfall. Therefore, when the southeast wind blows continuously, it often indicates that the weather will get worse. The weather proverb says: the southeast wind and rain ancestors, the northwest wind is empty? And then what? East wind rain, west wind sunny? It has certain practical significance.

In addition, some people analyze Zhuge Liang like this? Borrow? 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 invading from the south soon came 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.

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In this way, Zhuge Liang predicted that there would be a southeast wind in the early winter of 1 1 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 get worse, which was in line with the law of weather evolution.