Global energy balance
There are many reasons why we have a redistribution of energy.
There is a surplus of energy at the tropics and a deficit in polar areas.
Atmospheric and oceanic circulation redistributes this energy, so energy is moved from areas of surplus (between 38藲 North and South) to areas of deficit (above 38藲 North and below 38藲 South).
This process maintains the global energy balance.
Atmospheric circulation
Scientists have studied atmospheric circulation and have agreed on a simplified model to explain the redistribution of energy from areas of surplus to areas of deficit. This is called the three cell model and can be seen in the diagram below.