- Settore: Weather
- Number of terms: 60695
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The American Meteorological Society promotes the development and dissemination of information and education on the atmospheric and related oceanic and hydrologic sciences and the advancement of their professional applications. Founded in 1919, AMS has a membership of more than 14,000 professionals, ...
Sand particles picked up from the surface of the earth by the wind, reducing the horizontal visibility to less than 11 km (about 7 statute miles). This lithometeor is encoded BN as an obstruction to vision in a surface aviation weather observation and as BLSA as an obstruction to vision in a METAR or SPECI observation. In its extreme form, blowing sand constitutes a sandstorm.
Industry:Weather
Rain of reddish color caused by foreign matter (e.g., pollen, red dust) picked up by raindrops during descent. A dust-filled subcloud layer is required to yield this effect, and the dust particles must contain sufficient iron oxide to be red in color. Compare mud rain, sulfur rain.
Industry:Weather
Rapid variation of the vertical component of air motion causing an aircraft to jolt alternatively upward and downward. Bumpiness is associated generally with either convection currents in an unstable atmosphere or a flow of air across surface irregularities or both. It is more common and intense over land than over the sea. It is most marked in the lowest kilometer of the atmosphere but may extend to much higher levels, especially over mountainous terrain. Different types of aircraft may experience different types and intensities of bumpiness when flying through identical atmospheric conditions.
Industry:Weather
Radiation, especially its spectral distribution, from an ideal blackbody emitter.
Industry:Weather
Radiation over a large enough spectral region that there is a significant change in the Planck function. The two most common broadband regions pertaining to atmospheric radiation are those for solar radiation and terrestrial radiation, but many other regions are also used.
Industry:Weather
Radar echoes caused by flocks of roosting birds that take to the air as a group and fly away in different directions. Bird bursts typically occur near sunrise and have ring-shaped reflectivity signatures with weak echoes in the center and maximum reflectivity in circles that expand with time around the roosting site. In Doppler radar observations, the velocity signature resembles that of a microburst at low levels.
Industry:Weather
Pure ice in the form of large single crystals. It is blue owing to the scattering of light by the ice molecules; the purer the ice, the deeper the blue.
Industry:Weather
Profile of water surface elevation above a specified reference level along a flow path, usually upstream from an obstruction.
Industry:Weather
Process of bursting of air bubbles, rising to the ocean surface after a breaking wave, leading to breaking of a thin film cap and, for bubbles greater than a few millimeters in diameter, subsequent ejection of a Raleigh jet. These particles evaporate to leave residues that may act as cloud condensation nuclei in air of maritime origin.
Industry:Weather
Popular name for undulatus. Some forms are the result of shear instability (Kelvin–Helmholtz), and some result from gravity waves. Billow clouds are present when there is sufficient moisture present in the upward motion of the waves to make the wave structure visible by condensation of cloud droplets. Billows formed from gravity waves exhibit broad, nearly parallel, lines of cloud oriented normal to the wind direction, with cloud bases near an inversion surface. The distance between billows is on the order of 1000–2000 m.
Industry:Weather
