Radiation

Radiation is the emission of energy through the movement of subatomic particles or electromagnetic waves. In atmospheric science, radiation is classified as either direct or diffuse solar radiation, or light. Direct light refers to sunlight that comes straight through the atmosphere. Diffuse light refers to light that has been scattered in the atmosphere before coming to contact with the surface, or to light of terrestrial origin.

Effects
Radiation coming into contact with a surface can be absorbed, reflected, scattered or transmitted.

Reflection
Reflection occurs when radiation bounces off of a surface. The reflectance of an object is measured by albedo (α), which is the fraction of solar radiation that is reflected by a surface. Albedo ranges from 0 (absolute absorbance) to 1 (reflection of all radiation). Albedo is calculated by the formula

$$\alpha=\bar{\alpha}(\theta_1)(1-D)+D\bar{\bar{\alpha}}$$