Wind - How does it work?

Wind could be described as the physical interaction of sun, earth and the surrounding atmosphere. 

 

Since 4.6 billion years the sun delivers light and energy i.e. heat to the earth (and will continue to do so for the next 4 - 5 billion years). Our Atmosphere can be look at as a closed layer covering the earth storing the solar energy. Every second 47 billion kWh of solar energy are entering the earth in terms of light and heat.

 

The heat distribution faces a very uneven spread due to:

 

    • Spherical shape of the earth. Irradiance is highest at the equator
    • Different heat capacities of the surface
    • Topography, because temperature decreases with height
    • Rotation of the earth - at night the surface of the earth is not warmed up
    • Weather - shading of clouds
    • Humidity

 

 

Due to these factors global and local air circulation starts.

The sun heats up the air. Hot air expands and rises due to lower density. The free space is taken by cooler air of higher density.

Differences in air temperatures and resulting differences in air pressure lead to flow of air molecules balancing the system ? wind.