Why does the wind blow?

According to the definition, the wind is horizontaldirected movement of air masses (streams) at a small distance from the earth's surface. Everything is clear. A more complex question: what drives these air masses, that is, why does the wind blow?

Factors forming the wind

In a global, that is, planetary scale, the wind is formed by three factors, which have a close interconnection:

1. The difference in pressure in different points of the atmosphere.
2. Temperature difference between different parts of the land and the atmosphere.
3. The Coriolis force. It is generated by the rotation of our planet around its own axis.

The first factor is a direct consequence of the secondfactor a. That is, different pressure occurs at different points of the atmosphere, because these points have different temperatures. Warm air has a low pressure due to the fact that its molecules are trying to maximally push apart from each other. On the contrary, the molecules of cold air tend to have a minimum distance between them. Therefore, cold air masses exert more pressure on the atmosphere.

Thus there is a wind - air currentsfrom the high-pressure region are moved to the low-pressure region. There is a pressure equalization and filling of atmospheric voids. This can be represented by the example of 2 ponds. At 1-st level of water is higher than that of the 2nd. If the gateway is opened, then the water from the 1st pond will flow into the 2nd pond until their level becomes the same.

This can explain why the wind blows from the sea todry in summer, and in winter on the contrary. The thing is that in summer the air over the sea is cooler than over the heated land. In winter, sea water cools more slowly than the earth's surface. Therefore, air masses over the seas and oceans have a higher temperature at this time of year.

On a planetary scale, rather than a local one,say that cold air masses move to the equator from the poles. These flows are not uniform, but turbulent, that is, they are separate air jets. Because each local heat source has different effects on the weather. The direction of the wind in each region of the Earth depends on the location of land, mountains and water surface. In addition, in some areas of our planet there are areas with constant high atmospheric pressure. Such areas determine the direction of winds in these areas and are called "anticyclones".

Types of winds

• Monsoon is a seasonal steady wind thatis caused by the difference in temperature of air masses over certain areas of the planet and changing its direction depending on the time of year. Summer monsoons blow from the oceans to the land, and winter from the land to the oceans.
• Trade winds - constant air flow overoceans in the tropics, arising under the action of the Earth's rotation force around its axis (the Coriolis force). Where does the wind blow from this force? The Northern Hemisphere is characterized by the northeastern direction of the wind, and for the South - the southeast. In the oceanic expanses the trade winds caused the emergence of sea trade-wind currents, on the land surface they contributed to the formation of a zone of tropical deserts.
• The typhoon is one of the species of the tropical cyclone, which is typical for the southeast coast of the Pacific Ocean.

The wind plays a huge role in the development ofof our planet. The wind carries most of the seeds. He participates in the formation of the relief of the planet, making from one lands blossoming oases, and from other barren deserts. Thanks to the wind, man learned to overcome huge water areas, which contributed to the development of science and trade.