The Wind of Chibi in the Geography of the Three Kingdoms

Chibi is in the middle reaches of the Yangtze River in East Asia. In winter, the land cools faster than the ocean, so cold high pressure, such as Siberian high pressure, often forms in Central Asia. In this way, the northwest wind should prevail in Chibi area at that time.

However, it is not impossible to blow southeast winds in the middle reaches of the Yangtze River in the dead of winter. In summary, there are two possibilities.

1. Due to the complex and changeable atmospheric movement, it is likely that a small depression will occasionally appear in the west of Chibi area. The low pressure in the northern hemisphere is a cyclone, and the airflow flows counterclockwise. In this way, the southeast wind just blows to Chibi in the east of the low pressure.

2. It is also possible that there is a small high pressure east of Chibi. The high pressure in the northern hemisphere is an anticyclone, and the airflow flows clockwise. In this way, the southeast wind just blows in the Chibi area in the west of the high pressure.

Therefore, the truth of "borrowing" Dongfeng is actually:

A small high pressure formed in the west of Chibi and gradually moved eastward. When this anticyclone passes through Chibi area, Chibi area is affected by it, which is foggy at night and sunny during the day. When the anticyclone moved to the east of Chibi area, the southeast wind prevailed in Chibi area under its action. Dongfeng also "borrowed".

Opinion 2,

Because Chibi is located in the middle reaches of the Yangtze River, that is to say, in winter, 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.