Knowledge about the wind

Wind is a natural phenomenon on the earth, which is caused by solar radiation heat. Sunlight shines on the earth's surface, causing the surface temperature to rise, and the surface air to expand and become lighter and lighter. After the hot air rises, the cold air with low temperature flows in horizontally, and the rising air falls down because it gradually cools and becomes heavier. Because the surface temperature is high, it will heat up the air, and this airflow will produce wind.

Classification of wind:

1. Gust: When the airflow speed is high or low, the wind will be large and small, and people will feel a burst when blowing it. This is a recognized gust of life.

Meteorology, wind speed usually refers to the average situation within 2 minutes, with high or low wind speed, and gust usually refers to the maximum instantaneous wind speed during this period. If the weather forecast, today's wind is 4-5, and the gust is 6, which means that today's average wind is 4-5, and the maximum instantaneous wind can reach 6.

2. Cyclone: When the air flies in the air with dust to form a vortex, this is a whirlwind.

3. Foehn: When the air crosses the ridge, it is easy to produce warm (or hot) dry wind on the leeward slope due to the sinking of the air, which is called Foehn.

4. Typhoon: It is an atmospheric vortex that occurs in the tropical ocean, so it is also called a tropical cyclone. When the maximum wind force in the vortex center reaches more than 8, it is called typhoon; The maximum wind force in the center is 6-7, which is called weak typhoon; When the maximum wind force in the center reaches 8 to 12, it is called a strong typhoon.

5. Tornado: A small destructive air vortex extending from the cumulonimbus cloud to the ground. What happens on land is called tornado, and what happens on the ocean is called tornado, also called waterspout. Tornado is a violent storm with strong rotating force, and the maximum wind speed can reach more than 100 meters per second.

6. Mountain and valley wind: In mountainous areas, the wind blows up along the slopes and valleys during the day and down along the slopes and valleys at night. This wind, which changes direction between hills and valleys alternately day and night, is called valley wind.

7. Sea-land wind: In coastal areas, the wind blows from the sea to the mainland during the day and from the land to the sea at night. This kind of wind that changes direction regularly day and night is called land-sea wind.

8. Glacier wind: shallow wind blowing down the mountain along the glacier during the day and night.

9. Monsoon: With the alternation of seasons, the prevailing wind direction changes regularly. In winter, air flows from high-pressure land to low-pressure sea, which is called winter wind; In summer, the wind blows from the sea to the land, which is called summer monsoon. China is a country with remarkable monsoon, with northerly winds in winter and southerly winds in summer. This brings the monsoon climate characteristics of dry winter and wet summer to most parts of China.

10. Trade winds: persistent winds blowing from subtropical high to equatorial regions in the lower atmosphere. In the northern hemisphere, trade winds prevail in the northeast; In the southern hemisphere, it is in the southeast. Trade winds are characterized by a high degree of regularity, blowing in one direction with almost constant intensity all year round.

1 1. Anti-trade wind: The hot air rising at the equator flows in two layers in the upper atmosphere, which is called anti-trade wind. Because of the earth's rotation, the anti-trade winds are to the right in the northern hemisphere and to the left in the southern hemisphere. Anti-trade winds constantly bring the atmosphere to the latitude between 30 and 35, forming a state of air accumulation and forming a subtropical high pressure area. So there are more deserts in this area.

Extended data:

First, the division method of wind

Wind speed refers to the horizontal distance of air flow per unit time. According to the phenomenon caused by the wind to the ground objects, the wind is divided into 13 grades, which are called wind grades.

The "East Wind Level 3" that people usually hear in the weather forecast refers to the "Beaufort Wind Level". "Beaufort Wind Scale" is a wind scale determined by Francis Beaufort in England in 1805 according to the influence degree of wind on objects on the ground (or at sea), and * * * is divided into 0~ 17.

Second, the agricultural role of wind power

Wind is one of the environmental factors of agricultural production. Moderate wind speed plays an important role in improving farmland environmental conditions. The increase of wind speed accelerates or strengthens the surface heat exchange, evapotranspiration of farmland and the transportation of carbon dioxide and oxygen in the air.

Wind can spread plant pollen and seeds and help plants pollinate and reproduce. Wind energy is widely distributed and inexhaustible. Monsoon prevails in China, which is beneficial to the growth of crops. The Inner Mongolia Plateau, the Northeast Plateau, the southeast coast and the inland mountainous areas are rich in wind energy resources, which can be used as energy development and utilization.

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