chapter  6
45 Pages

Climate effects

ByBernardo Caicedo

Sun is the main source of energy for the ground’s surface and is therefore the main variable affecting a road’s temperature, especially near the surface. Total sun irradiance arrives at the earth with relatively high power of around 1361 W/m2. However, as shown in Figure 6.1a, the atmosphere reflects and absorbs portions of the radiation in the form of specific or latent heat before solar energy reaches the ground. The solar energy spectrum is approximately the same as that which would be by a black-body at 5523 K, but as a result of absorption, the energy of certain wavelengths in the spectrum of solar radiation is diminished, see Figure 6.1b.