The atmospheric absorption can cause an excitation or falling into the energy state of a particle, while the scattering is related to absorption and re-emission of radiation at all directions without changes in its frequency. Particularly, the main contributors of the incoming solar radiation absorptions are various molecules like the nitrogen (N2), oxygen (O2), ozone (O3), water vapor (H2O). Additionally, other constituents of the atmosphere such as CO2 and CH4, and other trace gases, aerosols, and cloud droplets can also absorb significant portion of the incoming solar radiation. Generally, the absorption of solar radiation is related to the wavelength of the solar spectrum. For example, gases and specific type of aerosols (black carbon, BC) or elementary carbon (EC) absorb in the ultraviolet (UV) and visible (VIS) part of solar spectrum. On the contrary, cloud droplets which are suspended in the atmosphere mainly scatter in UV and VIS and absorb in the infrared. The absorption of the incoming solar radiation from the atmospheric constituents reduces the harmful UV radiation and it is considered as the driving of atmospheric photochemistry. Moreover, scattering in the atmosphere can be divided into two mainly categories, firstly, the Rayleigh scattering which is the scattering of radiation by gases (mainly N2 and O2) and, secondly, the Mie scattering which is the scattering by aerosol particles and cloud droplets. The main difference between Rayleigh and Mie scattering is the direction of the re-emission of the incident solar radiation. For example, in the Rayleigh scattering the light have symmetrical direction either forward or backward whereas in Mie scattering the light is mainly scattered in the forward direction, depending on the size of the particle.