Wind can be defined as moving air! The earth’s atmosphere is subject to uneven heating by the sun. This is one of the factors that enhance wind to blow. There is a global circulation of air which is constituted by all the winds of the world.
Usually the sun indulges in warming the earth’s surface. In the process atmosphere also gets warmed up. There is uneven heating in different parts of the earth. Some parts which receive the rays of the sun throughout the year are always hot and keep warm. Equatorial regions fall in this category. On the other hand, there are some places which are subject to indirect rays; the climate is much cooler and in fact cold in such regions.
Since the warm air is lighter than the cool air, it tends to rise creating a region of low pressure. In turn, the cool air sinks and creates a region of high pressure. The cold wind moves and becomes a replacement of the warm air which is rising. These differences in temperatures usually lead to a difference of air pressure in different regions hence making the wind blow.
Fact: Global Wind Pattern
The wind system balances the pressure and temperature across the world. The differential and uneven heating causes the difference in pressure and temperature. Interestingly if one knows the pressure and temperature in different regions, the wind direction would be very easy to predict.
The above method results in the formation of the global wind pattern. There is a movement of air between different parts of the world as well as different heights of the atmosphere. What happens is that the colder air from the Polar Regions usually end up sinking meeting the warm air which is coming from the equator since it is close to the Earth surface. However winds do not blow from North to South i.e. in straight lines. They are directed by the Earth’s spin!