Albedo and Earth's Energy Balance

El albedo It is the relationship between the reflected energy and the incident in the wavelength of visible light and makes the planets shine: these, having no energy of their own, reflect a part of the light they receive from the Sun. it depends on the inclination of the incident irradiation (the closer the inclination approaches the perpendicular, the more important the reflection) and the nature of the reflecting surface. For simplicity, the reflective capacity of a surface is related to its color: a light body reflects more easily than a dark one.

A snowy ground has a higher albedo than a meadow. Thus, snow has an average albedo of 0,7, while that of a green forest is 0,2. The planetary albedo is approximately 0,1, which means that about a 30% of the incoming solar energy starts again in the form of direct radiation into space. The albedo of the continents is approximately 34%, while that of the oceans is 26% and that of low and medium altitude clouds is between 50% and 70%.

Although on a planetary scale the energy balance is equal to zero, in few places on the earth's surface do we find the balance in equilibrium. Some areas receive more energy than they emit; others, on the other hand, emit more than they receive. In general, the balances are in surplus up to the parallels between 35º and 40º. In these latitudes they equalize, and beyond that they become deficient. Variations in the amount of energy received and emitted condition the heating or cooling of the air, factors that contribute to the distribution of climates and atmospheric circulation.