Where are the three windy areas in China? Why is it easier to produce strong winds?

Meteorology, the threshold of strong winds is relatively high.

Generally speaking, the wind on the earth is caused by solar radiation.

The sun shines on the earth's surface, which is influenced by latitude, topography and altitude. The atmosphere is heated unevenly. The surface air in a certain place becomes lighter when heated and expands, and then rises, and the cooler air around it will flow into the filler; The rising hot air cools at high altitude and then turns into cold air and sinks to the ground. With this cold and hot cycle, the air near the surface flows and forms the wind.

In China, disasters caused by strong winds are often caused by weather system activities such as thunderstorms, squall lines, tornadoes, cyclones and cold air. Among them, thunderstorms, squall lines and tornadoes belong to strong convective weather.

Thunderstorm and gale have obvious diurnal variation, and the duration is relatively short, mostly in the afternoon when the temperature rises the highest, and the wind area is relatively small; When the squall line crosses the border, it is accompanied by strong wind, heavy rain and hail. The wind speed can reach more than ten meters per second, and it can reach forty meters per second when it is strong; The air pressure in the center of the tornado is very low, and the horizontal air pressure gradient is very large, resulting in high wind speed, which is generally estimated to reach 50- 150m/s and the maximum can reach 200m/s. Trees are often pulled up and buildings are destroyed, which is extremely destructive.

Wind force refers to the force exerted by the wind on an object. According to the wind speed at the height of standard meteorological observation station 10 meter, the wind level is divided into 18 level in turn, and the level here is called "Beaufort wind level". "Beaufort Wind Scale" is a wind scale determined by Francis Beaufort 1805 according to the influence of wind on objects on the ground (or sea).

So, what is strong wind? In winter and spring, the cold wind is howling, but in fact, the wind force may be only three or four, which is far from the meteorological standard of strong wind. In the meteorological observation business specification, when the instantaneous wind speed is ≥ 17.2m/s, that is, the wind speed reaches more than 8, it is generally called gale. Every windy day is recorded as a windy day.

In addition to the above strong convective weather, strong cold air and cyclones (such as typhoons) may also produce strong winds. It should be noted that the following statistics refer to windy days caused by all the above weather systems.

At high altitude, the windy days are the most.

The number of windy days in China has obvious regional distribution characteristics, and the number of windy days in high altitude areas is obviously higher than that in low altitude areas. There are more windy days in the canyon than around.

There are three windy areas in China.

1. The Qinghai-Tibet Plateau has more than 75 windy days a year, and one-fifth of the year is windy. It is the largest windy belt in China with the most windy days.

Second, in north-central Inner Mongolia and northwest Xinjiang, there are more than 50 windy days every year.

Third, the number of windy days in the southeast coast and its islands exceeds 50 days.

In addition, mountain passes and buttes are also areas above windy days, which are mainly caused by mountain valley winds.