Atmosphärenstreuung

Atmosphärenstreuung refers to the scattering of electromagnetic radiation by particles in the Earth's atmosphere. This phenomenon is responsible for many visible atmospheric effects, including the blue color of the sky and the red appearance of sunsets.

The primary mechanism behind atmospheric scattering is Rayleigh scattering, which occurs when the wavelength of light is much larger than the size of the scattering particles. In the atmosphere, these particles are mainly nitrogen and oxygen molecules. Rayleigh scattering is inversely proportional to the fourth power of the wavelength, meaning shorter wavelengths (like blue and violet) are scattered much more effectively than longer wavelengths (like red and orange). When sunlight enters the atmosphere, the blue light is scattered in all directions, making the sky appear blue.

Mie scattering, on the other hand, occurs when the size of the scattering particles is comparable to or larger than the wavelength of light. This type of scattering is less dependent on wavelength and is responsible for the white appearance of clouds and haze. Larger particles like dust, water droplets, and ice crystals in clouds scatter all wavelengths of visible light more or less equally.

The effect of atmospheric scattering is also evident during sunrise and sunset. When the sun is low on the horizon, sunlight has to travel through a greater thickness of the atmosphere. This longer path results in more scattering of the shorter blue wavelengths, allowing the longer red and orange wavelengths to reach our eyes directly, creating the vibrant colors often seen at these times.

The intensity and characteristics of atmospheric scattering can vary significantly depending on factors such as the composition and density of the atmosphere, the presence of aerosols, and the angle of the incident radiation.