Air

Unequal energy distribution

The amount of solar energy that reaches the Earth’s surface depends on different factors, the most important of which is the magnitude of the angle formed between the direction of the Sun’s rays and the surface itself: the greater the angle, the greater the amount of thermal energy that reaches the ground per unit of surface area. Theoretically, the angle of incidence of the Sun’s rays should be greatest at the Equator, but due to the inclination of the Earth’s axis, it varies during the year and is maximum in the belt that runs between the Tropics. The angle of incidence decreases at higher latitudes: for this reason, at low altitudes, the average temperature is greater than at higher altitudes. The inclination of the Earth’s orbital plane and the fact that it is elliptical, together with the inclination of the Earth’s rotational axis, are therefore the cause of the differences between the various climatic zones of the Earth, of the alternation of the seasons and of the meteorological variations connected to them.