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Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere. [1]: 26‑1 As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and scattering. [2]
R is the radius of the Earth, h is the height of the ground station, H is the height of the air station d is the line of sight distance In the case, when there are two stations involve, e.g. a transmit station on ground with a station height h and a receive station in the air with a station height H , the line of sight distance can be ...
Air is tenuous enough that in the Earth's atmosphere radio waves travel at very nearly the speed of light. The wavelength λ {\displaystyle \lambda } is the distance from one peak (crest) of the wave's electric field to the next, and is inversely proportional to the frequency f {\displaystyle f} of the wave.
Ultraviolet, of wavelengths from 10 nm to 200 nm, ionizes air molecules, causing it to be strongly absorbed by air and by ozone (O 3) in particular. Ionizing UV therefore does not penetrate Earth's atmosphere to a significant degree, and is sometimes referred to as vacuum ultraviolet. Although present in space, this part of the UV spectrum is ...
Ground waves propagate parallel to and adjacent to the surface of the Earth, and are capable of covering long distances by diffracting around the Earth's curvature. This radiation is also known as the Norton surface wave , or more properly the Norton ground wave , because ground waves in radio propagation are not confined to the surface.
Ionizing radiation creates high-speed electrons in a material and breaks chemical bonds, but after these electrons collide many times with other atoms eventually most of the energy becomes thermal energy all in a tiny fraction of a second. This process makes ionizing radiation far more dangerous per unit of energy than non-ionizing radiation.
Outgoing longwave radiation (OLR) is the longwave radiation emitted to space from the top of Earth's atmosphere. [ 1 ] : 2241 It may also be referred to as emitted terrestrial radiation . Outgoing longwave radiation plays an important role in planetary cooling.
Radiative transfer (also called radiation transport) is the physical phenomenon of energy transfer in the form of electromagnetic radiation. The propagation of radiation through a medium is affected by absorption , emission , and scattering processes.