1. Absorption by the Atmosphere:
* Ozone layer: This layer in the stratosphere absorbs most of the harmful ultraviolet (UV) radiation from the sun.
* Other atmospheric gases: Gases like carbon dioxide, methane, and water vapor absorb infrared radiation, which contributes to the greenhouse effect.
* Clouds: Clouds reflect a significant portion of incoming solar radiation back into space.
2. Reflection by the Atmosphere and Surface:
* Clouds: As mentioned above, clouds reflect sunlight back into space.
* Surface: The reflectivity of the Earth's surface (albedo) varies depending on the material. Snow and ice reflect a large amount of sunlight, while forests and oceans absorb more.
3. Scattering by the Atmosphere:
* Rayleigh scattering: This scattering occurs when sunlight interacts with molecules in the atmosphere, causing it to be scattered in different directions. This is why the sky appears blue.
* Mie scattering: This scattering is caused by larger particles in the atmosphere, such as dust and aerosols. It can cause the sky to appear hazy.
4. Curvature of the Earth:
* The Earth's curvature causes some radiation to miss the surface altogether. This is particularly true for radiation coming in at a low angle.
5. Absorption by Clouds and Aerosols:
* Clouds and aerosols can absorb some of the incoming radiation, preventing it from reaching the surface.
6. Nighttime:
* Obviously, during nighttime, the Earth does not receive any direct solar radiation.
In summary:
The Earth's atmosphere acts as a shield, filtering and absorbing radiation from the sun. The surface of the Earth itself also reflects and absorbs radiation. These factors determine the amount of radiation that actually reaches the Earth's surface.
